Medicinal plants: An invaluable, dwindling resource in sub-Saharan Africa

Role of plant phytochemicals/extracts for the control of Dermanyssus gallinae in poultry and its zoonotic importance

Dermanyssus gallinae (poultry red mite) has negative impact on poultry production, causing major economic losses by damaging the health of chickens and other bird species, globally. D. gallinae also acts as vector and reservoir of different viral and bacterial pathogens such as, E. coli, S. enteriditis, P. multocida, S. gallinarum, Newcastle disease, Avian influenza, Erysipelothrix rhusiopathiae, Eastern, Western and Venezuelan equine encephalomyelitis viruses. Some of them are important from zoonotic point of view like, S. enteritidis, Borrelia burgdorferi and avian influenza A virus. It also causes gamasoidosis in humans. For its control various acaricides have been used, but because of D. gallinae resistance against these chemicals, and environmental issues related to these acaricides have encouraged research into different alternatives. One of them are plant extracts and phytochemicals that play a major role by offering a promising option for permanent pest control because of their bioactive abilities. Important phytochemicals that are most effective against these mites are phenol, flavonoid, terpenoid, tannin, and phenylpropanoids. That give their effects by creating neurotoxicity, digestive and metabolic disruption, cuticle disruption, oxidative stress, cell membrane damage, respiratory inhibition, and hormonal disruption in these mites. This review explains the significance of various plant extracts, their phytochemicals and their methods of application against D. gallinae infestations in poultry. Different types of plant's active metabolites have acaricidal, repellent and growth inhibitory effects such as tannins, phenols, terpenoids, and flavonoids. The mode of action, effectiveness and toxicity of these extracts are also discussed. This review also discusses zoonotic importance of D. gallinae.

Anti-inflammatory activity of essential oil from medicinal plants: An insight into molecular mechanism, in-silico studies and signaling pathways

BACKGROUND

Medicinal plants have historically been the cornerstone of treatment for a myriad of ailments. With modern pharmacology, many contemporary drugs have been derived from traditional medicine practices. Essential oils from these plants, known for their anti-inflammatory capabilities, have played a significant role in treating conditions such as cardiovascular and inflammatory skin diseases, as well as joint inflammation. This study revisits these ancient remedies to further explore their efficacy and mechanisms in the modern context.

FOCUS AREA

This review focuses on identifying and analysing the primary phytochemical in medicinal plants that exhibit anti-inflammatory properties. The chemical classes of interest include alkaloids, polyphenols, terpenoids, flavonoids, saponins, and tannins, which are prevalent in the essential oils derived from therapeutic plants. By understanding their role in modulating molecular pathways, this study aims to highlight their potential in the treatment of inflammatory diseases.

METHODS

The study employs in silico techniques such as molecular modelling and docking to examine the pharmacokinetics and toxicity profiles of selected phytochemical. This approach facilitates a deeper understanding of how these natural compounds interact at the molecular level, either as activators or inhibitors, which can influence various biochemical pathways related to inflammation.

RESULTS

Preliminary findings suggest that specific phytochemical significantly modulate inflammatory pathways, offering potential therapeutic targets. The analysis reveals that these natural substances can effectively reduce inflammation without the adverse side effects commonly associated with synthetic drugs. The study provides a detailed characterization of the active components within essential oils and their respective anti-inflammatory actions.

CONCLUSION

The review underscores the immense potential for medicinal plants as a source for developing new and safer pharmaceuticals aimed at treating inflammatory conditions. By harnessing the power of natural phytochemical, there is a promising avenue for creating innovative drug therapies. This study encourages further research into the utilization of natural plant products, promoting a broader application in medicinal treatments and a return to nature-centric solutions in healthcare.

Plants used for the management of venereal diseases in sub-Saharan Africa: a systematic review and critical assessment of their research status

BACKGROUND

Sub-Saharan Africa faces one of the highest burdens of venereal diseases (VDs) globally. This review aims to critically evaluate the existing literature on the diverse Indigenous knowledge and medicinal plants utilised for treating VDs in sub-Saharan Africa.

METHODS

We used the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) protocol to guide the execution of the review. Relevant papers from scientific databases and search engines were assessed. The inclusion criteria included literature published from 2008 and May 16, 2024, and assessment of specific predetermined VDs. Medicinal plants based on certain ethnobotanical indices and data were recorded from each literature.

RESULTS

Among the 131 studies included in this review, a total of 20 relevant ethnobotanical reports were identified, with Nigeria and South Africa having the highest contributions (25% each). A high diversity and richness of 445 ethnobotanically valued anti-venereal plants (99 families) from over 872 Indigenous knowledge holders were inventoried. Plants with the highest diversity of use in traditional treatment of VDs are Cassia abbreviata, Ziziphus mucronata, Ximenia caffra, Catharanthus roseus, and Terminalia prunioides. The most represented families are Fabaceae (15.8%), Cucurbitaceae (5.9%), Solanaceae (5.9%), Euphorbiaceae (5%), and Combretaceae (5%). Roots and leaves were highly utilised with frequencies of 41.5% and 26.3%, respectively. The most used method of preparation are decoctions (36.7%) and infusions (12.2%), whereas oral route (72.9%) dominated the mode of administration of the medicinal plants.

CONCLUSIONS

This review consolidated data from sub-Saharan Africa-notwithstanding a limited number of studies in quantitative synthesis-and identified a diverse array of ethnobotanically valued anti-venereal plants, enabling meaningful conclusions to be drawn for future ethnopharmacological assessments. Effective plant conservation and advancement of ethnobotanical research in the region require stringent regulations and cross-country collaborations.

Ethnobotany in Angola: The contribution of late 19th century christian missionaries to the knowledge of medicinal wild plants

ETHNOPHARMACOLOGICAL RELEVANCE

Angola has an extraordinary plant diversity and a great ethnobotanical potential. However, there is a general lack of information about the first botanical explorations in the country and their contribution to the knowledge of the medicinal flora.

AIM OF THE STUDY

The main aim of this study was to unveil the ethnobotanical legacy of José Maria Antunes and Eugène Dekindt, priests of the first Catholic mission in Huíla (Angola) and shed light on their contribution to the knowledge of medicinal wild plants of the country, including information on the uses, plant parts used, and preparation methods documented in the late 19th century. The findings are discussed considering recent ethnobotanical studies to offer a more comprehensive understanding of the historical and traditional uses of plants in Angola over the last two centuries.

MATERIALS AND METHODS

Based on the information available in manuscripts and on the study of botanical collections preserved in herbaria of Portugal and Angola, we extracted relevant information about the species used in traditional medicine by the rural population of Huíla, the health conditions treated, and the mode of preparation and application.

RESULTS

Our results revealed that Antunes and Dekindt conducted the first ethnobotanical study in Huíla, and documented a large number of medicinal wild plants. From these, we report 191 medicinal species, including 25 endemic and four introduced species, belonging to 56 plant families and 146 genera. Fabaceae family presents the highest richness of medicinal plants (39 taxa), followed by Rubiaceae (13), Asteraceae (10), and Apocynaceae (9). The illnesses reported were classified into 15 different categories, with the highest number of species (49) corresponding to unspecific conditions, such as general pains, chills, and fever. Thirty-seven species were reported for respiratory diseases, 31 for musculoskeletal problems, and 30 for digestive issues. Leaves were the most used plant part for medicinal purposes (84 species). Infusion was the most frequently described preparation method (40 species), followed by maceration (24 species), and powdering (36 species).

CONCLUSIONS

The legacy of Antunes and Dekindt's work improves our understanding of Angola's botanical richness and traditional uses of plant resources. Our findings highlight the presence of unique medicinal resources in Angola, especially among endemic species, which hold the potential to improve the quality of life of rural communities. Moreover, our research underscores the lack of knowledge of medicinal species, emphasizing the risk of losing valuable historical information.

Spatial distribution and priority conservation areas identification in Three-River-Source National Park considering the multifaceted values of plants

Spatially differentiated conservation effort for natural resources is critical to achieving a balance between protection and development in national parks. However, the extent of priority conservation areas for plants that integrate multispecies and multifaceted values is unclear. Here, we selected fine-resolution environmental variables with stronger impacts on wild plant survival to spatialize the distribution of all modeling-eligible species using species distribution models in Three-River-Source National Park, China. These were then combined with in situ conservation results for insufficient data species to identify priority conservation areas (PCAs) in terms of diversity, ecological and economic values, respectively. We analyzed the spatial characteristics of the priority conservation areas and searched for conservation gaps not covered by national nature reserves. The results showed that this study obtained more precise results on the spatial distribution of species by improving environmental variables and upgrading the spatial resolution. In Three-River-Source National Park, the species richness of wild plants showed a decreasing trend from southeast to northwest. There were significant differences in the spatial distribution of the priority conservation areas identified based on the three values, which was the basis for the spatially differentiated conservation and development of wild plant resources. In addition, the priority conservation areas obtained based on ecological value found Top17% priority conservation areas in the Hoh Xil Natural Reserve, which could not be revealed based on diversity or economic value. These results highlight the urgency of implementing multispecies and multifaceted values studies in national parks. In the future, studying conflicts between wildlife priority conservation areas and human activities, and expanding to national parks on a global scale, will be the focus that this study will continue to explore.

Anthelmintic activity of three selected ethnobotanical plant extracts against Strongyloides venezuelensis

The agropastoral farmers have employed Turraea vogelii(TVL),Senna podocarpa(SPL), and Jaundea pinnata (JPL) leaves for treating various diseases, including intestinal parasites in livestock and the human population in Nigeria. Gastrointestinal nematodes are highly significant to livestock production and people's health, and natural products are interesting as sources of new drugs. In this study, we evaluated the effectiveness of extracts derived from these plants in treating parasitic infections using third-stage infective larvae (L3) of Strongyloides venezuelensis. We obtained crude extracts using n-gexane (Hex), ethyl acetate (Ea), and methanol (Met). The extracts were analyzed for their phytochemical composition, and their ability to prevent hemolysis were tested. The mean concentrations of total phenols in SPL Hex, SPL Ea, and SPL Met were 92.3 ± 0.3, 103.0 ± 0.4, and 128.2 ± 0.5 mg/100 g, respectively. Total tannin concentrations for JPL Ea, SPL Ea, SPL Hex, and TVL Hex were 60.3 ± 0.1, 89.2 ± 0.2, 80.0 ± 0.1, and 66.6 ± 0.3 mg/100 g, respectively. The mean lethal concentration (LC50) at 72 h for JPL Ea 39 (26-61) μg/mL. SPL Ea was 39 (34-45) μg/mL, and TVL Hex 31 (26-36) μg/mL. The antiparasitic activities of the extracts against L3 were dose- and time-dependent. All the extracts were slightly hemolytic to the erythrocytes. In this study, the plant extract tested demonstrated significant anti-S. venezuelensis activity. These phytobotanical extracts could be used to create formulations for the potential treatment of helminthiasis in animals and humans.

Anticancer diterpenes of African natural products: Mechanistic pathways and preclinical developments

BACKGROUND

The African continent is home to five biodiversity hotspots, boasting an immense wealth of medicinal flora, fungi and marine life. Diterpenes extracted from such natural products have compelling cytotoxic activities that warrant further exploration for the drug market, particularly in cancer therapy, where mortality rates remain elevated worldwide.

PURPOSE

To demonstrate the potential of African natural products on the global stage for cancer therapy development and provide an in-depth analysis of the current literature on the activity of cancer cytotoxic diterpenes from African natural sources (to our knowledge, the first of its kind); not only to reveal the most promising candidates for clinical development, but to demonstrate the importance of preserving the threatened ecosystems of Africa.

METHODS

A comprehensive search by means of the PRISMA strategy was conducted using electronic databases, namely Web of Science, PubMed, Google Scholar and ScienceDirect. The search terms employed were 'diterpene & mechanism & cancer' and 'diterpene & clinical & cancer'. The selection process involved assessing titles in English, Portuguese and Spanish, adhering to predefined eligibility criteria. The timeframe for inclusion spanned from 2010 to 2023, resulting in 218 relevant papers. Chemical structures were visualized using ChemDraw 21.0, PubChem was utilized to search for CID numbers.

RESULTS

Despite being one of the richest biodiverse zones in the world, African natural products are proportionally underreported compared to Asian countries or otherwise. The diterpenes andrographolide (Andrographis paniculata), forskolin (Coleus forskohlii), ent-kauranes from Isodon spp., euphosorophane A (Euphorbia sororia), cafestol & kahweol (Coffea spp.), macrocylic jolkinol D derivatives (Euphorbia piscatoria) and cyathane erinacine A (Hericium erinaceus) illustrated the most encouraging data for further cancer therapy exploration and development.

CONCLUSIONS

Diterpenes from African natural products have the potential to be economically significant active pharmaceutical and medicinal ingredients, specifically focussed on anticancer therapeutics.

Medical ethnobotany

This collection on medical ethnobotany focuses on contributions that explore the invaluable potential associated with the ethnobotanical uses of medicinal plants, their phytochemical profiling, safety, and efficacy studies as well as their cultural and ecological context. This call for papers is expected to expand the knowledge base on how medicinal plants contribute toward the achievement of the United Nations Sustainable Development Goals (UN SDGs), in this case, goal 15 (life on land).

Bio-functional properties and phytochemical composition of selected Apis mellifera honey from Africa

Globally, the demand for natural remedies such as honey to manage ailments has increased. Yet, the health benefits and chemical composition of African honeys are not well understood. Therefore, this study aimed to characterise the bio-functional properties and the phytochemical composition of 18 Apis mellifera honeys from Kenya, Uganda, and Cameroon in comparison to the popular and commercially available Manuka 5+ honey from New Zealand. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH-RSA) was used to determine the antioxidant property, whilst the agar well diffusion and broth dilution (Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) assays were used to determine antimicrobial property. Further, colorimetric methods were used for phytochemical analysis. Our results showed that honeys collected from Rift Valley region of Kenya (e.g. Poi, Salabani and Mbechot) and Western region of Cameron (e.g. Bangoulap) had the highest antioxidant (DPPH RSA of 41.52-43.81%) and antimicrobial (MIC (3.125-6.25% w/v) and MBC (6.25-12.5% w/v)) activities. Additionally, the total flavonoid (770-970 mg QE/100 g), phenol (944.79-1047.53 mg GAE/100 g), terpenoid (239.78-320.89 mg LE/100 g) and alkaloid (119.40-266.57 mg CE/100 g) contents reached the highest levels in these bioactive African honeys, which significantly and positively correlated with their bio-functional properties. The functional and phytochemical composition of these bioactive African honeys were similar to or higher than those of the Manuka 5+ honey. Furthermore, gas chromatography-mass spectrometry analysis of African honeys revealed 10 most prominent volatile organic compounds that contribute to their geographical distinction: triacontane, heptacosane, (Z)-9-tricosene, tetracosane, 6-propyl-2,3-dihydropyran-2,4-dione, octacosane, 1,2,4-trimethylcyclohexane, 1,3-bis(1,1-dimethylethyl) benzene, 2-methylheptane and phytol. Overall, our findings suggest that some of the tested African honeys are natural sources of antimicrobial and antioxidant therapies that can be exploited upon further research and commercialized as high value honey.

Corchorus tridens L.: A Review of Its Botany, Phytochemistry, Nutritional Content and Pharmacological Properties

Phytotherapy is a cost-effective alternative that continues to evolve. This has sparked significant research interest in naturally occurring compounds found in edible plants that possess antibacterial, antioxidant, and anticancer properties. Corchorus tridens L. is a wild edible plant widely recognised for its edible leaves, which are used for vegetable and animal feed. The plant is widely distributed across the African continent and is utilised in numerous countries for treating fever, pain, inflammation, and sexually transmitted diseases. Extracts from various parts of this plant exhibit antimicrobial, antioxidant, and pesticidal properties. This plant is a rich source of amino acids, vitamins, essential fatty acids, proteins, and minerals, as well as secondary metabolites such as alkaloids, flavonoids, quinines, steroids, terpenoids, phenols, and tannins. Additional studies are still needed to determine other biological activities, such as anti-inflammatory activity, involvement in the treatment of measles, prevention of anaemia, and pain-relieving properties. The current review aims to provide information on the characteristics, distribution, nutritional content, bioactive compounds, traditional uses, and biological activities of the edible plant species C. tridens L. to stimulate further research interest to address the existing literature gaps concerning this plant.

A Review on Medicinal and Ethnomedicinal Uses, Biological Features, and Phytochemical Constituents of Sesbania sesban L. Merr., A Nitrogen-Fixing Plant Native to the Republic of Chad

This study reports on a literature review of the leguminous tree Sesbania sesban (L.) Merr which is found in the N'djamena region, the Republic of Chad. The study focused on S. sesban's medicinal and ethnomedicinal uses, biological features, and phytochemical constituents to assist in future evaluations. A literature review was conducted using academic websites, such as Science Direct and Springer, online international plant databases, and data from national herbaria. S. sesban is a perennial shrub or tree that measures 3-4 m in height. This species is becoming rare in N'djamena but can be found in the rainy season, while in winter, it occurs mainly in ponds (called the Chadian dialect "Bouta") and on the shores of the Chari and Logone rivers. The local inhabitants in Chad use the species as medicine, livestock feed, and fuelwood and for improving soil fertility and repelling desert encroachment. Traditional healers use its leaves to treat breast cancer and edema. S. sesban is an essential species native to the Republic of Chad that needs conservation and valorization. Viewing its importance and rarity in N'djamena , a strategy for replanting the species in gardens, homes, and fields around N'djamena and other regions of Chad is recommended.

Analysis of Three Species of Cassipourea Traditionally Used for Hypermelanosis in Selected Provinces in South Africa

There is a growing demand and use of herbal cosmetics for skin purposes due to their perceived safety when applied to the skin. Three Cassipourea species commonly known as "ummemezi" are used interchangeably by women in rural areas of Eastern Cape and KwaZulu-Natal provinces to treat hypermelanosis as well as sun protection. We conducted a phytochemical comparison of three Cassipourea species; Cassipourea flanaganii (Schinz) Alston, Cassipourea gummiflua Tul. verticillata (N.E.Br.) J. Lewis and Cassipourea malosana (Baker) Alston by Liquid Chromatography-Mass Spectrometry (LC-MS/MS) analysis in negative mode. The results obtained from the LC-MS/MS yielded a total number of twenty-four compounds of different chemical classes, including fatty acids, steroids, di- and tri-terpenoids, flavonoids, phenolic acids, and eighteen among them were tentatively identified. The LC-MS /MS analysis showed that the three studied Cassipourea extracts contain compounds that have anti-tyrosinase activity and consequently. The presence of these compounds, either in synergy or individually, can be attributed to the anti-tyrosinase effect. Although the traditional names of the species are used interchangeably, they are different, however, they possess similar skin-lightening properties. Despite the recent popularity of modern cosmetic products, plants continue to play an important role in the local cosmetics industry in South Africa's Eastern Cape and KwaZulu-Natal community provinces.

Ghana's herbal medicine industry: prospects, challenges and ways forward from a developing country perspective

The herbal medicine industry is one of the fastest growing industries in the world. However, no detailed assessments have been undertaken on how to achieve the benefits of this industry for developing countries. This study examined the herbal medicine industry in Ghana, with a particular focus on its prospects, challenges and ways forward. The prospects of the medicinal plant trade are huge, and include reducing the national health budget, being a source of foreign and domestic income, as well as creation of employment and poverty reduction. However, the industry is currently inundated with several challenges, such as registration of herbal medicine products and practitioners, a lack of clinical trials for herbal products, standards and quality control issues, shortage of raw plant materials for production, and insufficient scientific research to support traditional claims on the pharmacological effects of medicinal plants. I propose a number of interventions to address these challenges: increased government support, capacity building initiatives, improved regulation of herbal medicines, application of modern technology in the manufacturing of herbal products, large-scale cultivation of medicinal plants, and improved packaging and branding for herbal medicines. Both the national government and the private sector have crucial roles to deliver in the development of the herbal medicine industry in a country like Ghana.

Quality, Safety and Biological Studies on Campylanthus glaber Aerial Parts

In Cabo Verde, several endemic species are used in traditional medicine. However, no scientific studies have been conducted on the quality, efficacy, and safety of most of these plants. This study focused on establishing the botanical and chemical identification parameters required for a quality monograph of Campylanthus glaber Benth. aerial parts, a medicinal plant of Cabo Verde traditionally used to treat fever and muscular pain. In addition, in vitro antioxidant and antihyperglycemic activity, cytotoxicity, and genotoxicity were assessed for this medicinal plant. Optical microscopy, LC/UV-DAD-ESI/MS, and colorimetric assays were used for botanical, chemical, and biological studies, respectively. Cytotoxicity was assessed by the MTT assay with HepG2 cells, and genotoxicity by the Ames test. Microscopically, the xeromorphic leaf of C. glaber presents a thick cuticle (13.6-25.5 µm), thick-walled epidermal cells, anomocytic-type stomata, glandular trichomes (stalk length = 49.4-120.8 µm), and idioblasts containing calcium oxalate microcrystals. The chemical screening of aqueous and hydroethanolic extracts of this medicinal plant revealed the presence of organic acids, iridoids, phenylethanoids, and flavonoids as the main classes of marker compounds, with malic acid, citric acid, and verbascoside being the main marker compounds identified. Both extracts showed similar LC/UV-DAD/ESI-MS qualitative profiles and DPPH radical scavenger activity (IC50 = 130.9 ± 1.4; 134.3 ± 3.1 µg/mL). The hydroethanolic extract inhibited both α-amylase and α-glucosidase enzymes in a dose-dependent manner. Both extracts showed no cytotoxicity (up to 1000 µg/mL) by the MTT assay and no genotoxic potential with or without metabolic activation up to 5 mg /plate. The results obtained are an important contribution to the monographic quality assessment of C. glaber aerial parts and suggest that this medicinal plant may be safe and potentially used as an herbal drug raw material for pharmaceutical purposes.

Ethnomedicinal Uses, Phytochemistry, and Anticancer Potentials of African Medicinal Fruits: A Comprehensive Review

Africa is home to diverse medicinal plants that have been used for generations for the treatment of several different cancers and, presently, they are gaining interest from researchers as promising approaches to cancer treatment. This review aims to provide a comprehensive review of dietary and medicinal African fruits including their traditional uses, botanical description, ethnobotanical uses, bioactive phytochemical compositions, and anticancer properties investigated to date in vitro, in vivo, and in clinical studies. Data on recent updates concerning the traditional uses and anticancer properties of these fruits were collected from a myriad of available publications in electronic databases, such as Web of Science, PubMed, ScienceDirect, Scopus, SpringerLink, and Google Scholar. The results suggest that approximately 12 native or commercially grown African fruits belonging to different plant species, including Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum, have been reported for their potential as treatment options for the management of cancer. We further found that approximately eight different fruits from native plant species from Africa, namely, Sclerocarya birrea, Dovyalis caffra, Parinari curatellifolia, Mimusops caffra, Carpobrotus edulis, Vangueria infausta, Harpephyllum caffrum, and Carissa macrocarpa, have been widely used for the traditional treatment of different ailments but somehow failed to gain the interest of researchers for their use in anticancer research. In this review, we show the potential use of various fruits as anticancer agents, such as Tribulus terrestris, Xanthium strumarium, Withania somnifera, Xylopia aethiopica, Abelmoschus esculentus, Carissa macrocarpa, Carpobrotus edulis, Syzygium cumini, Kigelia Africana, Annona muricata, Persea americana, and Punica granatum; unfortunately, not enough reported research data have been published to gain thorough mechanistic insights and clinical applications. Additionally, we discuss the possibility of the utilization of potential phytochemicals from fruits like Persea americana and Punica granatum in anticancer research, as well as future directions.

Excitatory amino acids, possible causative agents of nodding syndrome in eastern Africa

BACKGROUND

Nodding syndrome (NS) is one type of epilepsy and a progressive disease characterized by nodding symptoms with children in sub-Saharan Africa. The burden for NS children is heavy, not only mentally but financially for themselves and their families, and yet, the cause and cure of NS remain unknown. The kainic acid-induced model in experimental animals is a well-known epilepsy model that is useful for studying human diseases. In this study, we examined similarities of clinical symptoms and histological brain changes between NS patients and kainic acid-treated rats. In addition, we argued for kainic acid agonist as one of the causes of NS.

METHODS

Clinical signs in rats were studied after kainic acid administration, and histological lesions including the expression of tau protein and gliosis, were examined at 24 h, 8 days, and 28 days after dosing.

RESULTS

Kainic acid-induced epileptic symptoms were observed in rats, including nodding accompanied by drooling and bilateral neuronal cell death in the hippocampus and piriform cortex regions. In the regions that exhibited neuronal cell death, an increase in tau protein expression and gliosis were found immunohistochemically. The symptoms and brain histology were similar in the NS and kainic acid-induced rat models.

CONCLUSION

The results suggest that kainic acid agonist may be one of the causative substances for NS.

Diversity and biological activities of medicinal plants of Santiago island (Cabo Verde)

Plants continue to constitute key elements of medical practice in West African countries. The Cabo Verde archipelago hosts a great diversity of medicinal plants and local markets are considered important sites for trading plants harvested by rural communities. This study has two main goals: (i) to assess the medicinal uses of native species in Santiago, the biggest island of the archipelago, and (ii) to evaluate the antioxidant, antimicrobial and antidiabetic/antihyperglycemic activities of two native trees (Tamarix senegalensis and Sideroxylon marginatum) used in traditional medicine and traded in local markets. Our results revealed that on Santiago Island, 24 native plants are used in traditional medicine. The main uses of these species (e.g., forage, timber, food and fibres), their medicinal applications, the plant parts used, their mode of administration and conservation status are presented here for the first time. Moreover, the pharmacological characterization of two native tree species revealed that hydroethanolic extracts were richer in phenolic compounds and more active than their aqueous counterparts. All the studied extracts revealed significant antioxidant properties (DPPH and FRAP assays) and were generally moderately active against Gram-positive bacteria. All the extracts inhibited the activities of the carbohydrate digestive enzymes α-glucosidase and α-amylase in a dose-dependent manner. For α-glucosidase, the detected inhibitory activity (IC₅₀ values from 2.0 ± 0.2 μg/mL to 9.9 ± 1.2 μg/mL) was significantly higher than that of acarbose, suggesting that extracts of both species can delay glucose absorption, thereby assisting in slowing down the progression of diabetes. Our findings highlight the crucial importance that medicinal plants have for the Cabo Verdean population, while also raising awareness on the need for sustainable use and conservation of native flora, and of tree species traded in local markets in particular.

Propagation of Medicinal Plants for Sustainable Livelihoods, Economic Development, and Biodiversity Conservation in South Africa

South Africa is blessed with vast plant resources and unique vegetation types. Indigenous South African medicinal plants have been well-harnessed to generate income in rural communities. Many of these plants have been processed into natural products to heal a variety of diseases, making them valuable export commodities. South Africa has one of the most effective bio-conservation policies in Africa, which has protected the South African indigenous medicinal vegetation. However, there is a strong link between government policies for biodiversity conservation, the propagation of medicinal plants as a source of livelihood, and the development of propagation techniques by research scientists. Tertiary institutions nationwide have played a crucial role in the development of effective propagation protocols for valuable South African medicinal plants. The government-restricted harvest policies have also helped to nudge natural product companies and medicinal plant marketers to embrace the cultivated plants for their medicinal uses, and thus have helped support the South African economy and biodiversity conservation. Propagation methods used for the cultivation of the relevant medicinal plants vary according to plant family and vegetation type, among others. Plants from the Cape areas, such as the Karoo, are often resuscitated after bushfires, and propagation protocols mimicking these events have been established through seed propagation protocols with controlled temperatures and other conditions, to establish seedlings of such plants. Thus, this review highlights the role of the propagation of highly utilized and traded medicinal plants in the South African traditional medicinal system. Some valuable medicinal plants that sustain livelihoods and are highly sought-after as export raw materials are discussed. The effect of South African bio-conservation registration on the propagation of these plants and the roles of the communities and other stakeholders in the development of propagation protocols for highly utilized and endangered medicinal plants are also covered. The role of various propagation methods on the bioactive compounds' composition of medicinal plants and issues of quality assurance are addressed. The available literature, media online news, newspapers, and other resources, such as published books and manuals, were scrutinized for information.

Desert Endemic Plants in Algeria: A Review on Traditional Uses, Phytochemistry, Polyphenolic Compounds and Pharmacological Activities

Due to their robust antioxidant capabilities, potential health benefits, wide variety of biological activities, and strong antioxidant qualities, phenolic compounds are substances that have drawn considerable attention in recent years. The main goal of the review is to draw attention to saharian Algerian medicinal plants and the determination of their bioactivity (antioxidant, anti-cancer, and anti-inflammatory importance), and to present their chemical composition as well as in vivo and in vitro studies, clinical studies, and other studies confirming their real impact on human health. Research results have revealed a rich variety of medicinal plants used to treat various disease states in this region. Based on in vivo and in vitro studies, biological activity, and clinical studies, a list of 34 species of desert plants, belonging to 20 botanical families, useful both in preventive actions and in the treatment of neoplastic diseases has been established, and polyphenolic compounds have been identified as key to the health potential of endemic diseases and desert plants. It has been shown that people who follow a diet rich in polyphenols are less prone to the risk of many cancers and chronic diseases, such as obesity and diabetes. In view of the increasing antioxidant potential of these plant species, as well as the increasing trade in herbal products from the Sahara region, phytosanitary and pharmaceutical regulations must change in this respect and should be in line with Trade Related Aspects of Intellectual Property Rights (TRIPS), and the sustainable use and development of plant products must be addressed at the same time.

The Potential of Rhizobacteria to Mitigate Abiotic Stress in Lessertia frutescens

Lessertia frutescens is a multipurpose medicinal plant indigenous to South Africa. The curative ability of the medicinal plant is attributed to its rich phytochemical composition, including amino acids, triterpenoids, and flavonoids. A literature review of some of the phytochemical compounds, particularly amino acids, in L. frutescens shows a steady decrease in concentration over the years. The reduction of the phytochemical compounds and diminishing biological activities may be attributed to drought and salt stress, which South Africa has been grappling with over the years. Canavanine, a phytochemical which is associated with the anticancer activity of L. frutescens, reduced slightly when the plant was subjected to salt stress. Like other legumes, L. frutescens forms a symbiotic relationship with plant-growth-promoting rhizobacteria, which facilitate plant growth and development. Studies employing commercial plant-growth-promoting rhizobacteria to enhance growth and biological activities in L. frutescens have been successfully carried out. Furthermore, alleviation of drought and salt stress in medicinal plants through inoculation with plant growth-promoting-rhizobacteria is well documented and effective. Therefore, this review seeks to highlight the potential of plant-growth-promoting rhizobacteria to alleviate the effect of salt and drought in Lessertia frutescens.

Ethnobotanical Survey of Plants Used by Subsistence Farmers in Mitigating Cabbage and Spinach Diseases in OR Tambo Municipality, South Africa

Annually, significant crop losses are reported due to diseases caused by phytopathogens. Most subsistence farmers cannot afford the high cost of chemical treatments thereby resulting in the increasing dependence on plant extracts to manage crop diseases. In this study, we documented plants used for the management of cabbage and spinach diseases in OR Tambo Municipality, Eastern Cape Province. An ethnobotanical survey using semi-structured questionnaires was used to document plants and plant parts used by the subsistence farmers in managing cabbage and spinach diseases. Semi-structured questionnaires were administered to 41 consenting subsistence farmers from November to December in 2021, using snowball sampling. The collected data were subjected to descriptive statistical and ethnobotanical analyses. A total of 17 plants belonging to 10 families were identified by the participants as being used in mitigating cabbage and spinach diseases. Tulbaghia violacea, Aloe ferox, and Capsicum annuum had the highest use value of 0.32 each, whereas Tulbaghia violacea had the highest relative frequency of citation of 0.39. This current study revealed the importance of plants in managing crop diseases in local communities. It provides baseline data for future pharmacological evaluations in authenticating the efficacies of the identified plants in managing crop diseases.

Ethnoveterinary Practices and Ethnobotanical Knowledge on Plants Used against Cattle Diseases among Two Communities in South Africa

Ethnoveterinary practices and ethnobotanical knowledge serve as potential therapeutic approaches used to manage and prevent cattle diseases within poor communities in developing nations. Most of the knowledge and practices remain inadequately documented and threatened with extinction in the future. This study aimed to explore the ethnoveterinary practices and knowledge on plants used to treat cattle diseases in two communities of the Ramotshere Moiloa local municipality, South Africa. A semi-structured interview guide, snowball, and purposive technique were used to collect data and recruit 90 participants. Three ethnobotanical indices (informant consensus factor (Fic), use-value (UV), and relative frequency of citation (RFC) were used for quantitative analysis. A total of 64 medicinal plants from 32 families (dominated by Compositae, Fabaceae, and Asparagaceae) were used to treat 27 cattle diseases. The plants with a high frequency of citation and RFC were Gomphocarpus fruticosus (75, 0.83), Opuntia ficus-indica (74, 0.82), Schkuhria pinnata and Portulaca oleracea (73, 0.81), Solanum lichtensteinii (70, 0.77), and Senna italica. In addition, Schkuhria pinnata and Aloe greatheadii (0.077) had the highest UV. About 28.13% of 64 identified plants were documented as ethnoveterinary medicine for treating cattle ailments, for the first time. The remedies were mainly either prepared as a decoction (52.04%), ground, or prepared as an infusion (16.33%). The plants were administered either orally (69.79%) or topically (30.2%). The ailments with a high frequency of citations were: wounds and constipation (76); arthralgia and retained placenta (69); and lumpy skin disease (68). The categories with the highest number of plants used were gastrointestinal problems (53), skin problems (33), respiratory problems (25), and fertility/reproduction disorders (21). The highest Fic score was cited for tick-borne diseases (1), followed by musculoskeletal systems (Fic = 0.89), and general system infection (Fic = 0.88). The current findings contribute to the documentation and preservation of valuable knowledge from indigenous communities for extensive use. Additionally, ethnoveterinary uses of Portulaca oleracea, Securidaca longipedunculata, and Plumbago zeylanica were recorded for the first time. Further scientific evaluation of the most cited and indigenous/native plants is recommended to establish their therapeutic potential and possible integration into the conventional veterinary sector for the welfare of cattle.

Ethnobotanical Survey of Local Flora Used for Medicinal Purposes among Indigenous People in Five Areas in Lagos State, Nigeria

Traditional medicine is typically the most accessible primary healthcare for a large proportion of the people in Nigeria. However, its potential remains under-explored, especially with regards to their documentation. This research investigated and documented the use of medicinal plants in the management of various health conditions/diseases among local populations in Lagos State. This study was conducted in five (5) locations of Lagos State i.e., Alimosho, Badagry, Eti-Osa, and Epe (including Ijebu and Imota). Ethnobotanical information from 100 participants was obtained using semi-structured questionnaires. Frequency of citation (FC), relative frequency of citation (RFC), fidelity level (FL), and informant consensus factor (ICF) were used to assess the importance of plants utilised for various health conditions/diseases. We identified 183 plants from 61 plant families with the highest number (24) of plants belonging to Fabaceae. Based on the high FC, the top-five popular plants used for managing health conditions/diseases in the study areas were Mangifera indica (95%), Waltheria indica (93%), Zingiber officinale (87%), Alchornea cordifolia (83%) and Ipomoea involucrata (81%). Furthermore, Rauvolfia vomitoria, Urena lobata and Waltheria indica were recognised as the most adaptable plants, as they were used to treat five different health conditions/diseases. The most commonly used life-forms were herbs (34%) and woody species (shrubs; 30%, and trees; 22%). The most regularly used plant parts were leaves. The calculated RFC values for all medicinal plant species ranged from 0.01 to 0.95, while FL values ranged from 7.14 to 100%. We found 14 health conditions/diseases, with ICF values ranging from 0.88 to 0.95. Insomnia, insanity, convulsion, nervousness, and muscle relaxants had the lowest (ICF = 0.88) agreement, while malaria/fevers, stomach, and respiratory-related diseases had the most (ICF = 0.95) agreement. The documented therapeutic uses of the plants provide basic data for further research aimed at pharmacological and conservation studies of the most important flora existing in the study areas.

Characterisation of the indigenous knowledge used for gastrointestinal nematode control in smallholder farming areas of KwaZulu-Natal Province, South Africa

BACKGROUND

The use of indigenous knowledge (IK) to control gastrointestinal nematodes has been known since ancient times. The objective of the study was to characterise the use of indigenous knowledge to control gastrointestinal nematodes in goats.

METHODS

A structured questionnaire was used to collect data from farmers. Chi-square was used to compute associations; the generalized linear model was used for mean rank scores.

RESULTS

Roundworms were the most common gastrointestinal nematode (GIN) affecting goats reared in the bushland vegetation type than grasslands. Twelve plant species were commonly used to control GIN in goats, with Cissus quadrangularis Linn. singled out as the most widely used plant with a use-value of 0.97, followed by Albizia anthelminthica Brongn. (0.66), Cissus rotundifolia (Forssk.) Vahl (0.63), Vachellia xanthophloea (Benth.) P.J.H. Hurter (0.59), Aloe marlothii A. Berger (0.58), Sclerocarya birrea (A. Rich.) Hochst (0.54), Gomphocarpus physocarpus E. Mey (0.53), Aloe maculata All. (0.50), Trichilia emetica Vahl (0.47), Aloe ferox Mill. (0.43), Vernonia neocorymbosa Hilliard (0.25) and Schkuhria pinnata (Lam) Kuntze ex Thell (0.16). C. rotundifolia, V. xanthophloea, S. birrea and T. emetica were dominant plant species used to control GIN in goats reared in the grassland vegetation. A. maculata, A. ferox and V. neocorymbosa were dominant in the bushland vegetation type.

CONCLUSION

The study revealed that ethnoveterinary plants are widely used in grassland and bushland vegetation types to control GIN in goats. Scientific validation of their efficacy and safety should be carried out to provide a cheaper alternative, thus improving the community livelihoods and development.

Medicinal-Cosmetic Potential of the Local Endemic Plants of Crete (Greece), Northern Morocco and Tunisia: Priorities for Conservation and Sustainable Exploitation of Neglected and Underutilized Phytogenetic Resources

Medicinal-aromatic plants (MAPs) are important sources for the development of new valuable products of interest to human and animal health, and are also used as ornamentals for the horticulture industry. However, the increased global demand and the uncontrolled exploitation of these plants constitute a threat to their sustainability. To date, few scientific investigations have focused on MAPs valorization and their domestication. The purpose of this study was to evaluate for the first time the medicinal-cosmetic potential of 399 local endemic Mediterranean plants confined to Crete (223 taxa), the Mediterranean coast-Rif of Morocco (94), and Tunisia (82). The new methodological scheme was developed by experts through three multidisciplinary co-creative workshops and was adjusted by end-users to point-scoring of nine attributes evaluating the potential of the targeted neglected and underutilized plants (NUPs) in the medicinal-cosmetic sector. The results were demonstrated as percentage of the maximum possible score. These assessments were further linked and discussed with respect to feasibility and readiness timescale evaluations for sustainable exploitation of the focal NUPs. A great diversity of local endemic NUPs (30 taxa, 11 families) were associated with interesting medicinal-cosmetic properties (>35% up to 94.44%). Among them, 8 taxa showed the highest medicinal-cosmetic potential (>55% of maximum possible score), half of which are threatened with extinction. Although ex-situ conservation efforts and applied research work are needed to safeguard and unlock the full potential of the local endemic NUPs evaluated herein, the proposed multifaceted evaluation scheme revealed that some local endemic NUPs of the studied regions can be sustainably exploited in short- or medium-term, following successful examples of Cretan NUPs e.g., Origanum dictramnus. The sustainable exploitation of high scored taxa of the studied regions can be fastened through targeted species-specific research bridging extant research gaps and facilitating conservation and stakeholder attraction.

Constraints to Cultivation of Medicinal Plants by Smallholder Farmers in South Africa

Growing demand for therapeutic products from indigenous medicinal plants has led to increased interest in its cultivation, which presents a viable option for improving smallholder farmers’ livelihoods, as well as sustaining the availability of these resources for future generations. Serious bottlenecks however exist for subsistent farmers in the cultivation of these valuable plants. It was pertinent to probe whether the cultivation of medicinal plants provides feasible solutions to rural poverty, while effectively conserving threatened indigenous biodiversity. The paper employed a comprehensive review of existing literature to explore issues constraining smallholder farmers from involvement in a potentially lucrative plant value chain. Findings indicate challenges such as inadequate domestication of valuable plants species, continued over-harvesting from wild populations, poor knowledge of required agronomic practices, low efficacy perception regarding derivatives from cultivated plants, among others. These constraints occur alongside the conservation-oriented strategy driven by international conservation agencies and wholly adopted by the South African government. Recommendations to improve smallholder involvement in the cultivation of medicinal plants include support to research and extension, targeted inducement to smallholders, contracting and off-take agreements, aimed at promoting an alternative poverty-alleviation-focused economic development strategy. The review adds to the conceptual discourse related to plant diversity, resource conservation, poverty alleviation, and economic development

Phytodentistry in Africa: prospects for head and neck cancers

Background

Orthodox dentistry has undergone significant changes in recent times with the introduction of various omics and molecular targeted therapies both at the experimental/trial and clinical implementation level. Although, significant milestones have been achieved in the molecular dentistry field in the past decade, there remains a dearth of application of phytopharmacological innovation in personalized and targeted therapies for dental diseases.

Main body

From time immemorial, plant products have long been an integral aspect of dental practice ranging from chewing sticks/herbal kinds of toothpaste to dental/impression materials. The current era of precision medicine seeks to apply a multipronged molecular and bio-computational approaches to solve fundamental medical problems that have hitherto remained difficult. Remarkable changes in the molecular/omics era, have transformed empirical therapies into personalized/individualized ones. Furthermore, the combinatorial application and the widespread introduction of high-throughput molecular tools such as pharmacogenomics, phytopharmacology, metabolomics, mathematical modelling, and genetic engineering inter alia, has tremendously improved the diagnostic and therapeutic landscape of medicine. Additionally, the variable molecular epidemiology of diseases among different population and emerging molecular evidence warrants the use of customized novel theranostic techniques. Unfortunately, the footprint of such emerging application is sparse in dental diseases such as maxillofacial cancers.

Conclusion

Hence, this review seeks to evaluate the potential application of phytopharmacological approaches to head and neck cancers in a resource-limited environment, such as Africa.

Medicinal Plants for Mitigating Pain and Inflammatory-Related Conditions: An Appraisal of Ethnobotanical Uses and Patterns in South Africa

In South Africa, traditional medicine remains the first point of call for a significant proportion of the population seeking primary healthcare needs. This is particularly important for treating common conditions including pain and inflammation which are often associated with many disease conditions. This review focuses on the analysis of the trend and pattern of plants used for mitigating pain and inflammatory-related conditions in South African folk medicine. An extensive search was conducted using various scientific databases and popular ethnobotanical literature focusing on South African ethnobotany. Based on the systematic analysis, 38 sources were selected to generate the inventory of 495 plants from 99 families that are considered as remedies for pain and inflammatory-related conditions (e.g., headache, toothache, backache, menstrual pain, and rheumatism) among different ethnic groups in South Africa. The majority (55%) of the 38 studies were recorded in three provinces, namely, KwaZulu-Natal, Limpopo, and Western Cape. In terms of the number of mentions, the most popular plants used for pain and inflammatory-related conditions in South Africa were Ricinus communis L. (10), Aloe ferox Mill. (8), Pentanisia prunelloides subsp. latifolia (Hochst.) Verdc. (8), Dodonaea viscosa Jacq var. angustifolia (L.f) Benth. (8), (L.) W.T.Aiton. (7) Ruta graveolens L. (7), and Solanum aculeastrum Dunal. (7). The top five plant families represented were Asteraceae (13%), Fabaceae (8%), Apocynaceae (4.3%), Asparagaceae (4%), and Lamiaceae (4%). An estimated 54% of the recorded plants were woody (trees and shrubs) in nature, while the leaves (27%) and roots (25%) were the most dominant plant parts. The use of plants for alleviating pain and inflammatory-related conditions remains popular in South African folk medicine. The lagging ethnobotanical information from provinces such as North West, Gauteng, and Free State remains a gap that needs to be pursued meticulously in order to have a complete country-wide database.

Multi-modular engineering of Saccharomyces cerevisiae for high-titre production of tyrosol and salidroside

Tyrosol and its glycosylated product salidroside are important ingredients in pharmaceuticals, nutraceuticals and cosmetics. Despite the ability of Saccharomyces cerevisiae to naturally synthesize tyrosol, high yield from de novo synthesis remains a challenge. Here, we used metabolic engineering strategies to construct S. cerevisiae strains for high-level production of tyrosol and salidroside from glucose. First, tyrosol production was unlocked from feedback inhibition. Then, transketolase and ribose-5-phosphate ketol-isomerase were overexpressed to balance the supply of precursors. Next, chorismate synthase and chorismate mutase were overexpressed to maximize the aromatic amino acid flux towards tyrosol synthesis. Finally, the competing pathway was knocked out to further direct the carbon flux into tyrosol synthesis. Through a combination of these interventions, tyrosol titres reached 702.30 ± 0.41 mg l-1 in shake flasks, which were approximately 26-fold greater than that of the WT strain. RrU8GT33 from Rhodiola rosea was also applied to cells and maximized salidroside production from tyrosol in S. cerevisiae. Salidroside titres of 1575.45 ± 19.35 mg l-1 were accomplished in shake flasks. Furthermore, titres of 9.90 ± 0.06 g l-1 of tyrosol and 26.55 ± 0.43 g l-1 of salidroside were achieved in 5 l bioreactors, both are the highest titres reported to date. The synergistic engineering strategies presented in this study could be further applied to increase the production of high value-added aromatic compounds derived from the aromatic amino acid biosynthesis pathway in S. cerevisiae.

A Review of Ethnoveterinary Knowledge, Biological Activities and Secondary Metabolites of Medicinal Woody Plants Used for Managing Animal Health in South Africa

Globally, the use of ethnoveterinary medicine as remedies for animal health among different ethnic groups justify the need for a systematic exploration to enhance their potential. In addition, the increasing popularity and utilisation of woody plants remain common in traditional medicine, which may be attributed to their inherent benefits. The current review was aimed at analysing ethnoveterinary surveys, biological activities, and secondary metabolites/phytochemical profiles of the woody plants of South Africa. Eligible literature (period: 2000 to 2020) were retrieved from different databases such as Google Scholar, PubMed, Sabinet, and Science Direct. Based on the inclusion and exclusion criteria, 20 ethnoveterinary surveys were eligible and were subjected to further analysis. We identified 104 woody plant species from 44 plant families that are used in the treatment of different diseases in animals, particularly cattle (70%) and goats (20%). The most mentioned (with six citations) woody plants were Terminalia sericea Burch. ex DC and Ziziphus mucronata Willd., which were followed by plants with five (Cussonia spicata Thunb., Pterocarpus angolensis DC and Vachellia karroo (Hayne) Banfi & Galasso) or four (Acokanthera oppositifolia (Lam.) Codd, Cassia abbreviata Oliv., and Strychnos henningsii Gilg) individual mentions. The most dominant families were Fabaceae (19%), Apocynaceae (5.8%), Rubiaceae (5.8%), Anacardiaceae (4.8%), Combretaceae (4.8%), Euphorbiaceae (4.8%), Malvaceae (4.8%), Rhamnaceae (4.8%), and Celastraceae (3.8%). Bark (33%), leaves (29%), and roots (19%) were the plant parts dominantly used to prepare remedies for ethnoveterinary medicine. An estimated 20% of woody plants have been screened for antimicrobial, anthelmintic, antioxidant, and cytotoxicity effects. Phytochemical profiles established a rich pool of valuable secondary metabolites (phenolic, flavonoids and condensed tannins) that may be responsible for the exerted biological activities. Overall, the significant portion of woody plants lacking empirical evidence on their biological effects indicates a major knowledge gap that requires more research efforts.

Studies on Activities and Chemical Characterization of Medicinal Plants in Search for New Antimalarials: A Ten Year Review on Ethnopharmacology

Malaria is an endemic disease that affected 229 million people and caused 409 thousand deaths, in 2019. Disease control is based on early diagnosis and specific treatment with antimalarial drugs since no effective vaccines are commercially available to prevent the disease. Drug chemotherapy has a strong historical link to the use of traditional plant infusions and other natural products in various cultures. The research based on such knowledge has yielded two drugs in medicine: the alkaloid quinine from Cinchona species, native in the Amazon highland rain forest in South America, and artemisinin from Artemisia annua, a species from the millenary Chinese medicine. The artemisinin-based combination therapies (ACTs), proven to be highly effective against malaria parasites, and considered as “the last bullet to fight drug-resistant malaria parasites,” have limited use now due to the emergence of multidrug resistance. In addition, the limited number of therapeutic options makes urgent the development of new antimalarial drugs. This review focuses on the antimalarial activities of 90 plant species obtained from a search using Pubmed database with keywords “antimalarials,” “plants” and “natural products.” We selected only papers published in the last 10 years (2011–2020), with a further analysis of those which were tested experimentally in malaria infected mice. Most plant species studied were from the African continent, followed by Asia and South America; their antimalarial activities were evaluated against asexual blood parasites, and only one species was evaluated for transmission blocking activity. Only a few compounds isolated from these plants were active and had their mechanisms of action delineated, thereby limiting the contribution of these medicinal plants as sources of novel antimalarial pharmacophores, which are highly necessary for the development of effective drugs. Nevertheless, the search for bioactive compounds remains as a promising strategy for the development of new antimalarials and the validation of traditional treatments against malaria. One species native in South America, Ampelozyzyphus amazonicus, and is largely used against human malaria in Brazil has a prophylactic effect, interfering with the viability of sporozoites in in vitro and in vivo experiments.

Ethnoveterinary Knowledge and Biological Evaluation of Plants Used for Mitigating Cattle Diseases: A Critical Insight Into the Trends and Patterns in South Africa

Cattle farming is a traditional agricultural system that contribute to the rural economic, social and cultural values of the communities. Cattle as common with other livestock, are affected by many diseases that cause mortality and economic losses. In many rural households, the use of plants and associated knowledge are popular for managing cattle diseases especially in areas experiencing challenges with conventional veterinary medicine. Evidence on the documentation of indigenous knowledge and biological evaluation of plants used against cattle diseases remain understudied and fragmented. The aim of the review is to collate and analyse the ethnoveterinary knowledge and biological evaluation of plants used against cattle diseases in South Africa. Different scientific databases were systematically explored to extract data from 37 eligible studies. A total of 310 medicinal plants from 81 families used to treat 10 categories of cattle diseases across seven (7) provinces in South Africa. Leguminosae (Fabaceae), Compositae (Astereceae), Asparagaceae, and Xanthorrhoeaceae were the most frequently used plant families. Common plant parts used were leaves and roots. Twenty-seven (27) combination remedies involving 2–6 plants were identified as treatment regimes against cattle diseases. Common preparation methods were infusion and decoction while the administration mode was predominantly unspecified (52%) while oral and topical contributed 26 and 22%, respectively. In terms of diseases, the most treated ones were general systems infection, reproduction disorders and gastrointestinal problems. Currently, an estimated 21% of the 310 plants have been evaluated for diverse biological activities using relevant bioassays related to cattle diseases. Antibacterial activity remained the most studied biological activity. Evidence from the review revealed the significance of ethnoveterinary medicine against cattle diseases especially in rural areas of South Africa. Nevertheless, the use of plants for cattle diseases among other ethnic groups, particularly in the Northern Cape and Western Cape, remain under-studied.

Therapeutic perspectives of the black cumin component thymoquinone: A review

The dietary phytochemical thymoquinone (TQ), belonging to the family of quinones, mainly obtained from the black and angular seeds of Nigella sativa, is one of the promising monoterpenoid hydrocarbons, which has been receiving massive attention for its therapeutic potential and pharmacological properties. It plays an important role as a chemopreventive and therapeutic agent in the treatment of various diseases and illnesses. The aim of this review is to present a summary of the most recent literature pertaining to the use of TQ for the prevention and treatment of various diseases along with possible mechanisms of action, and the potential use of this natural product as a complementary or alternative medicine. Research findings indicated that TQ exhibits numerous pharmacological activities including antioxidant, anti-inflammatory, cardioprotective, hepatoprotective, antidiabetic, neuroprotective, and anticancer, among others. Conclusions of this review on the therapeutic aspects of TQ highlight the medicinal and folk values of this compound against various diseases and ailments. In short, TQ could be a novel drug in clinical trials, as we hope.

Soil nutrient status of KwaZulu-Natal savanna and grassland biomes causes variation in cytokinin functional groups and their levels in above-ground and underground parts of three legumes

Cytokinins (CKs) are involved in several developmental stages in the life-cycle of plants. The CK content in plants and their respective organs are susceptible to changes under different environmental conditions. In the current study, we profiled the CK content in the above and underground organs of three legumes (Lessertia frutescens, Mucuna pruriens and Pisum sativum) grown in soils collected from four locations (Ashburton, Bergville, Hluhluwe and Izingolweni) in KwaZulu-Natal province, South Africa. The quantified CK contents in the three legumes were categorized on the basis of their side chains (isoprenoid, aromatic and furfural) and modifications (e.g. free bases and glucosides). Legume and soil types as well as their interaction significantly influenced the concentrations of CKs. Lessertia frutescens, Mucuna pruriens and Pisum sativum had CK content that ranged from 124-653, 170-670 and 69-595 pmol/g DW, respectively. Substantial quantity (> 600 pmol/g DW) of CK were observed in plants grown in Bergville (above-ground part of Lessertia frutescens) and Izingolweni (underground part of Mucuna pruriens) soils. A total of 28 CK derivatives observed in the legumes comprised of isoprenoid (22), aromatic (5) and furfural (1) side-chain CKs. However, the 16 CK derivatives in Mucuna pruriens were isoprenoid-type based on the side-chain. Generally, a higher ratio of cis-zeatin (cZ) relative to the trans-zeatin (tZ) was evident in the above-ground part of Lessertia frutescens and Pisum sativum for the four soil treatments. In terms of functional and physiological importance of the CKs, the free bases (active form) and ribosides (translocation form) were the most abundant CK in Lessertia frutescens and Pisum sativum. However, N-glucoside, a deactivation/detoxicification product was the most dominant CK in Mucuna pruriens from Hluhluwe and Izingolweni soils. The total CKs in the underground parts of the legumes had a positive significant correlation with the total phosphorus and nitrogen content in the plant as well as the soil nitrogen. Overall, the CK profiles of the legumes were strongly influenced by the soil types.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-021-01021-2.

Natural Products Modulating Angiotensin Converting Enzyme 2 (ACE2) as Potential COVID-19 Therapies

The 2019 coronavirus disease (COVID-19) is a potentially fatal multisystemic infection caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Currently, viable therapeutic options that are cost effective, safe and readily available are desired, but lacking. Nevertheless, the pandemic is noticeably of lesser burden in African and Asian regions, where the use of traditional herbs predominates, with such relationship warranting a closer look at ethnomedicine. From a molecular viewpoint, the interaction of SARS-CoV-2 with angiotensin converting enzyme 2 (ACE2) is the crucial first phase of COVID-19 pathogenesis. Here, we review plants with medicinal properties which may be implicated in mitigation of viral invasion either via direct or indirect modulation of ACE2 activity to ameliorate COVID-19. Selected ethnomedicinal plants containing bioactive compounds which may prevent and mitigate the fusion and entry of the SARS-CoV-2 by modulating ACE2-associated up and downstream events are highlighted. Through further experimentation, these plants could be supported for ethnobotanical use and the phytomedicinal ligands could be potentially developed into single or combined preventive therapeutics for COVID-19. This will benefit researchers actively looking for solutions from plant bioresources and help lessen the burden of COVID-19 across the globe.

Microbial biodiversity of natural toothbrushes in Mali

Different oral hygiene practices are used to overcome endemic diseases such as dental caries and oral infections. In Mali (Africa), natural plant-based toothbrushes are used for eliminating bacterial biofilm. The repertoire of microorganisms associated with natural toothbrushes is unknown. The aim of our study is to study microbial flora in particular the methanogenic archaea associated with natural toothbrushes recently recognized as responsible for periodontitis and peri-implantitis. We investigated the methanogens and bacteria associated with 15 different natural plant toothbrushes collected in Bamako local market (Mali). Microbiological investigations consisted in culturing the bacteria on agar plates and searching archaea using molecular techniques. No archaea were demonstrated by molecular biology but 50 bacterial species, including 33 aero-anaerobic and 17 aerobic species, were isolated from natural toothbrushes. We isolated Pseudomonas sp., Staphylococcus sp. and Klebsiella pneumoniae, which are acknowledged as opportunistic human pathogens. This study has highlighted the likely impact of the use of natural toothbrushes in the spread of potentially pathogenic bacteria in the human oral cavity.

Ethnobotanical Study on Plant Used by Semi-Nomad Descendants' Community in Ouled Dabbeb-Southern Tunisia

Thanks to its geographic location between two bioclimatic belts (arid and Saharan) and the ancestral nomadic roots of its inhabitants, the sector of Ouled Dabbeb (Southern Tunisia) represents a rich source of plant biodiversity and wide ranging of ethnobotanical knowledge. This work aims to (1) explore and compile the unique diversity of floristic and ethnobotanical information on different folk use of plants in this sector and (2) provide a novel insight into the degree of knowledge transmission between the current population and their semi-nomadic forefathers. Ethnobotanical interviews and vegetation inventories were undertaken during 2014–2019. Thirty informants aged from 27 to 84 were interviewed. The ethnobotanical study revealed that the local community of Ouled Dabbeb perceived the use of 70 plant species belonging to 59 genera from 31 families for therapeutic (83%), food (49%), domestic (15%), ethnoveterinary (12%), cosmetic (5%), and ritual purposes (3%). Moreover, they were knowledgeable about the toxicity of eight taxa. Nearly 73% of reported ethnospecies were freely gathered from the wild. The most commonly used plant parts were leaves (41%) followed by flowers and inflorescence (16%). We reported the use and collection of non-renewable parts (underground storage organs and roots) for 20 ethnospecies. Interestingly, a comparison with the available literature in Tunisia and neighboring countries reveals 13 new useful plants as well as 17 plants with new uses and demonstrates an important reservoir of traditional ethnobotanical heritage that is still sustained by respondents stemming from the semi-nomadic lifestyle of their ancestors (74% of cited taxa). These data could set a basis for further phytochemical and pharmacological research and conservative approach of the most relevant plant species including endemic overused and endangered taxa.

Ethnomedicinal uses, biological activities, phytochemistry and conservation of African ginger (Siphonochilus aethiopicus): A commercially important and endangered medicinal plant

ETHNOPHARMACOLOGICAL RELEVANCE

In sub-Saharan Africa, African ginger (Siphonochilus aethiopicus) is used for treating common illnesses including colds, coughs, inflammation and related symptoms. The available literature survey on this plant provided scarce anecdotal information, particularly in western and eastern Africa, with a few reports on its bioactivity. In addition, the indigenous knowledge and conservation strategies of this economically important and critically endangered species are currently fragmented.

AIM OF THE REVIEW

This review entails a critical appraisal of existing literature on the ethnomedicinal uses, biological activities, phytochemicals, research opportunities and prospects for the sustainable use of S. aethiopicus.

MATERIALS AND METHODS

This review was conducted using a comprehensive literature search on the ethnomedicinal uses, biological activities and phytochemistry of S. aethiopicus throughout its distributional range. The conservation status and associated bio-economy potential of African ginger were also assessed. We searched different online databases (e.g. Google Scholar, ScienceDirect, PubMed and Scopus) for peer-reviewed journals, conference outputs, international, regional and national organizational reports, published books and theses.

RESULTS

We established that S. aethiopicus is used to treat a wide variety of ailments such as respiratory problems (including cough, influenza), pain, inflammation and malaria. Extracts of African ginger are used as an ingredient in some commercialised products for nutraceutical, cosmeceutical and pharmaceutical purposes. The rhizome extract demonstrated anti-asthmatic, anti-inflammatory, and antiplasmodial activities, which led to the development of a patented novel extract for treating asthma and allergies. Phytochemical analysis of leaf, root and rhizome extracts of African ginger revealed the presence of flavonoids, phenolic acids, volatile and essential oils as the major constituents. These phytochemicals are known to possess bioactivities such as antimicrobial and anti-inflammatory activities. Particularly, the bioactive compounds, siphonochilone and eucalyptol, found in the roots and rhizomes have demonstrated potential to be used in remedies for treating asthma and allergic reactions. Furthermore, extracts of S. aethiopicus contained natural anti-inflammatory mediators with potential to combat and manage chronic inflammation. This plant is classified on the Red List of South African Plants as a critically endangered plant. Its high risk of extinction due to its unsustainable harvesting and exploitation necessitates its rapid propagation and cultivation to meet its increasing demand.

CONCLUSIONS

The review highlights the therapeutic potential of S. aethiopicus and rational prioritization of this plant species with the potential for isolating new bioactive compounds. In the light of the use of this plant extract in traditional medicine and many commercial products, there is a heightened need to explore the mechanism(s) of action of the identified extracts and bioactive compounds in order to fully understand their pharmacokinetics and probably elucidate the pathways of their activities.

Reproductive Toxicity of Theobroma cacao: Increase in Survival Index, Nongenotoxic, and Proimplantation Potential

Unsweetened natural cocoa (UNCP) was evaluated for reproductive toxicity in rats. A preliminary genotoxic potential was evaluated by the DNA comet assay test using C57Bl/6 mice. Both therapeutic dose (TD; 900 mg/kg) and high dose (HD; 9000 mg/kg) of UNCP were used. White Wistar rats were used in two experimental groups. The females received UNCP 15 days before crossing with untreated males. The males received UNCP for 48 days before mating with untreated females. Subacute toxicity was observed during a 14-day oral administration of UNCP. Results show that a high tail DNA% was observed with methyl mesylate administration in all tissues analysed. The lowest tail DNA% value was observed in the liver (1.64 ± 0.26) and kidney (1.63 ± 0.30) during UNCP (TD) administration. UNCP did not induce observable physical congenital malformations on the pubs of treated female and male rats, lacks genotoxic potential, and did not adversely affect pregnancy index, pub weights, and survival index, but UNCP exhibited proimplantation potential (p > 0.05).

The genetic legacy of fragmentation and overexploitation in the threatened medicinal African pepper-bark tree, Warburgia salutaris

The pepper-bark tree (Warburgia salutaris) is one of the most highly valued medicinal plant species worldwide. Native to southern Africa, this species has been extensively harvested for the bark, which is widely used in traditional health practices. Illegal harvesting coupled with habitat degradation has contributed to fragmentation of populations and a severe decline in its distribution. Even though the species is included in the IUCN Red List as Endangered, genetic data that would help conservation efforts and future re-introductions are absent. We therefore developed new molecular markers to understand patterns of genetic diversity, structure, and gene flow of W. salutaris in one of its most important areas of occurrence (Mozambique). In this study, we have shown that, despite fragmentation and overexploitation, this species maintains a relatively high level of genetic diversity supporting the existence of random mating. Two genetic groups were found corresponding to the northern and southern locations. Our study suggests that, if local extinctions occurred in Mozambique, the pepper-bark tree persisted in sufficient numbers to retain a large proportion of genetic diversity. Management plans should concentrate on maintaining this high level of genetic variability through both in and ex-situ conservation actions.

Ethnobotanical Survey of Plants Used for Treating Cough Associated with Respiratory Conditions in Ede South Local Government Area of Osun State, Nigeria

In many developing countries, community members depend on their local flora for treating diverse ailments including those affecting the respiratory system. This is often attributed to the high cost and limited access to health care facilities. This present study focused on the documentation of plant species used against cough associated with the respiratory diseases in Ede South Local Government Area of Osun State. The survey was conducted using semi-structured interviews among 100 participants. Information obtained was analyzed using different ethno-botanical indices including relative frequency of citation (RFC) and fidelity level (FL). A total of 87 plant species from 39 families, which was mostly represented by Fabaceae, were reported in the study area. Crinum jagus was the most popular plant used against cough and approximately 32% of the plants have been reported as cough remedies for the first time. However, some of the documented plants have been reported for the treatment of cough and related respiratory diseases in several countries. In terms of the life-form, trees constituted the highest proportion of the medicinal plants (37%), while leaves (36%) were the predominant plant part prescribed for cough. Decoction was the main method of preparing the plants, which were all administered orally. Approximately 63% of the plants were exclusively sourced from the wild. The current study revealed the richness and widespread use of plant species for managing cough associated with respiratory diseases in the study area. The generated inventory contributes to the expanding database of valuable plant resources with medicinal potential in Nigeria and Africa.

An Ethnobotanical Study of Traditional Knowledge and Uses of Medicinal Wild Plants among the Marakwet Community in Kenya

Traditional plant knowledge and uses of medicinal wild plants were investigated among the Marakwet community in Kenya. Data were collected through interviews with seven traditional healers and 157 questionnaires for local community members. Traditional names of the plants by traditional healers and local community members were prepared as a checklist. Loss of traditional medicinal names of plants was ascertained with up to 60% overlapping in their nomenclature. The traditional medicinal plants treated 41 diseases within the region, of which local community members understood common ones for treating stomachache (94.8%), diarrhea (70.7%), chest problems (65.5%), and typhoid (63.8%). It was also clear that there was low knowledge index of medicinal plants by the local community members (23.6%) based on knowledge of traditional healers. Clearly, medicinal plants for treatment of malaria, diabetes, tetanus, and pneumonia were recognized by over 40% of the local community members, while plants treating arteriosclerosis, meningitis, arthritis, trachoma, smallpox, rheumatic fever, and gout were known by less than 10% of the respondents. Among plants, the use of roots for treatment was known by over 67% of the local community members compared to fruits, bark, bulb, and flowers (<10%). This low traditional medicinal knowledge in a community relies on the traditional medicinal plants, calling for an urgent need to document the information and perpetuate this knowledge from one generation to another. This can be achieved by collecting the information and developing a database of medicinal plants for future research and potential development of new drugs.

Diversity and Conservation through Cultivation of Hypoxis in Africa—A Case Study of Hypoxis hemerocallidea

Africa has the largest diversity of the genus Hypoxis, accounting for 61% of the current globally accepted taxa within the genus, including some endemic species. Using Hypoxis hemerocallidea as a case study, this review addresses the conservation concerns arising from the unsustainable, wild harvesting of a number of Hypoxis species. Hypoxis hemerocallidea is one of the wild-harvested, economically important, indigenous medicinal plants of southern Africa, with potential in natural product and drug development. There are several products made from the species, including capsules, tinctures, tonics and creams that are available in the market. The use of H. hemerocallidea as a “cure-all” medicine puts an important harvesting pressure on the species. Unsustainable harvesting causes a continuing decline of its populations and it is therefore of high priority for conservation, including a strong case to cultivate the species. Reviewing the current knowledge and gaps on cultivation of H. hemerocallidea, we suggest the creation of a platform for linking all the stakeholders in the industry.

Potential of Smoke-Water and One of Its Active Compounds (karrikinolide, KAR1) on the Phytochemical and Antioxidant Activity of Eucomis autumnalis

Eucomis autumnalis (Mill.) Chitt. subspecies autumnalis is a popular African plant that is susceptible to population decline because the bulbs are widely utilized for diverse medicinal purposes. As a result, approaches to ensure the sustainability of the plants are essential. In the current study, the influence of smoke-water (SW) and karrikinolide (KAR₁ isolated from SW extract) on the phytochemicals and antioxidant activity of in vitro and greenhouse-acclimatized Eucomis autumnalis subspecies autumnalis were evaluated. Leaf explants were cultured on Murashige and Skoog (MS) media supplemented with SW (1:500, 1:1000 and 1:1500 v/v dilutions) or KAR₁ (10⁻⁷, 10⁻⁸ and 10⁻⁹ M) and grown for ten weeks. In vitro regenerants were subsequently acclimatized in the greenhouse for four months. Bioactive phytochemicals in different treatments were analyzed using ultra-high performance liquid chromatography (UHPLC-MS/MS), while antioxidant potential was evaluated using two chemical tests namely: DPPH and the β-carotene model. Smoke-water and KAR₁ generally influenced the quantity and types of phytochemicals in in vitro regenerants and acclimatized plants. In addition to eucomic acid, 15 phenolic acids and flavonoids were quantified; however, some were specific to either the in vitro regenerants or greenhouse-acclimatized plants. The majority of the phenolic acids and flavonoids were generally higher in in vitro regenerants than in acclimatized plants. Evidence from the chemical tests indicated an increase in antioxidant activity of SW and KAR₁-treated regenerants and acclimatized plants. Overall, these findings unravel the value of SW and KAR₁ as potential elicitors for bioactive phytochemicals with therapeutic activity in plants facilitated via in vitro culture systems. In addition, it affords an efficient means to ensure the sustainability of the investigated plant. Nevertheless, further studies focusing on the use of other types of antioxidant test systems (including in vivo model) and the carry-over effect of the application of SW and KAR₁ for a longer duration will be pertinent. In addition, the safety of the resultant plant extracts and their pharmacological efficacy in clinical relevance systems is required.

Ethnobotanical uses, biological activities and chemical properties of Kei-apple [Dovyalis caffra (Hook.f. & Harv.) Sim]: An indigenous fruit tree of southern Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Dovyalis caffra (Hook.f. & Harv.) Sim (commonly called Kei-apple) is an indigenous fruit tree that has medicinal values for various ethnic groups in southern Africa.

AIM OF THE REVIEW

This review aims to provide a critical appraisal of the existing knowledge on the ethnobotanical value, biological activities and phytochemicals of Dovyalis caffra. In addition, the potential of producing a functional health product from Kei-apple due to its therapeutic effects and rich pool of phytochemicals was explored.

METHODS

A detailed literature search was conducted using various online search engines, such as Scopus, Google Scholar, Mendeley and Web of Science. Additional information was sourced from ethnobotanical literature focusing on southern African flora.

RESULTS

Dovyalis caffra has diverse uses in local and popular medicine, specifically for relieving pain and rheumatism in humans. Ethno-veterinary potential of Kei-apple has also been documented in East Africa. Non-medicinal uses of the tree include its role in biological hedging and as a traditional herb for African magical purpose. Regarding its biological activities, polar extracts from the seeds exhibited noteworthy antibacterial (minimum inhibitory concentration of 1 μg/ml against Staphylococcus aureus) activity. Quantitative analysis (e.g. GC-MS, HPLC) indicated the presence of a rich (>80) pool of chemicals, including sterols, phenolic acids and fatty acids from different parts of the plant while 11 compounds have been isolated from its leaves and twigs.

CONCLUSIONS

Dovyalis caffra has been tested for various biological activities and the extracts (seeds in particular) demonstrated promising antibacterial potential. A lack of alignment between the ethno-medicinal uses and existing biological screenings was observed, indicting the need for anti-inflammatory and anti-rheumatism potential of Dovyalis caffra to be explored. In vivo validation of antibacterial and anti-parasitic activities against clinical bacterial strains and parasites, respectively is required. Other areas that need investigation are safety evaluations and development of integrated cultivation approach in order to fully explore the plant's potential.

Conservation and sustainable use of the medicinal Leguminosae plants from Angola

Leguminosae is an economically important family that contains a large number of medicinal plants, many of which are widely used in African traditional medicine. Angola holds a great socio-cultural diversity and is one of the richest floristic regions of the world, with over 900 native Leguminosae species. This study is the first to assess the medicinal uses of the legumes in Angola and provides new data to promote the conservation and the sustainable use of these unique resources. We document the ethnobotanical knowledge on Angola by reviewing the most important herbarium collections and literature, complemented by recent field surveys. Our results revealed that 127 native legume species have medicinal uses and 65% of them have other important uses by local populations. The species with most medicinal applications are Erythrina abyssinica, Bauhinia thonningii and Pterocarpus angolensis. The rich flora found in Angola suggests an enormous potential for discovery of new drugs with therapeutic value. However, the overexploitation and the indiscriminate collection of legumes for multiple uses such as forage, food, timber and medical uses, increases the threats upon the native vegetation. Efforts to assess the conservation status of these species are urgently needed, and future actions should promote the sustainable use of medicinal plants in Angola together with the implementation of conservation strategies.

Propensity of Tagetes erecta L., a Medicinal Plant Commonly Used in Diabetes Management, to Accumulate Perfluoroalkyl Substances

It has been extensively demonstrated that plants accumulate organic substances emanating from various sources, including soil and water. This fact suggests the potentiality of contamination of certain vital bioresources, such as medicinal plants, by persistent contaminants, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutane sulfonate (PFBS). Hence, in this study, the propensity of Tagetes erecta L. (a commonly used medicinal plant) to accumulate PFOA, PFOS, and PFBS was determined using liquid chromatography/tandem mass spectrometry (LC⁻MS/MS-8030). From the results, PFOA, PFOS, and PFBS were detected in all the plant samples and concentration levels were found to be 94.83 ng/g, 5.03 ng/g, and 1.44 ng/g, respectively, with bioconcentration factor (BCF) ranges of 1.30 to 2.57, 13.67 to 72.33, and 0.16 to 0.31, respectively. Little evidence exists on the bioaccumulative susceptibility of medicinal plants to these persistent organic pollutants (POPs). These results suggest that these medicinal plants (in particular, Tagetes erecta L., used for the management of diabetes) are also potential conduits of PFOA, PFOS, and PFBS into humans.