Acute and subacute toxicity profile of ethanolic stem bark extract of Albizia coriaria Welw. ex Oliv. in Wistar albino rats

Albizia coriaria (Fabaceae) crude extracts are key ingredients of several licensed and unlicensed herbal products in East Africa. However, there is limited and often contradicting information regarding its toxicity. We therefore evaluated the acute and subacute toxicity of the ethanolic stem bark extract of A. coriaria in mature healthy Wistar albino rats following Lorke's method and OECD guidelines 407. The LD50 of the ethanolic stem bark extract of A. coriaria was 2000 mg/kg. The acute toxicity signs observed included piloerection, hyperventilation, lethargy, and loss of righting reflex. There was a significant increase in aspartate aminotransferase, alkaline phosphatase, red blood cells and haemoglobin in rats after 28 days at the dose of 500 mg/kg. Histological analyses revealed multifocal random parenchymal necrosis and scattered periportal mononuclear inflammatory cells infiltration in the liver, interstitial nephritis in the kidney and multifocal lymphoid accumulation in the peribronchiolar and perivascular lung tissue at 500 mg/kg. The ethanolic stem bark of A. coriaria was therefore moderately toxic to the rats when administered in a single high oral dose within 24 h. The extract caused a dose dependent toxicity with significant damage to the kidney, liver and lung tissues at a dose of 500 mg/kg after 28 days. Herbal medicines containing A. coriaria extracts should be consumed cautiously due to likelihood of toxicity particularly at higher doses greater than 500 mg/kg.

Dataset on the geographical distribution of species of the genus Solanum, subgenus Leptostemonum in Uganda

The dataset includes the diversity, occurrence points and a distribution map of species of the subgenus Leptostemonum in Uganda. The data was obtained following field surveys carried out in various parts of Uganda. These were guided by distribution data retrieved from Makerere University Herbarium and Flora of Tropical East Africa (FTEA). At each sampling site, species name, altitude and habitat type were recorded. Occurrence points were geocoded using a hand-held GPS (a ≤ 5M Germin S90 GPS). The distribution map was generated using ArcMap 10.7.1 software. The dataset consists of 172 occurrence points representing 18 species of subgenus Leptostemonum that occur in Uganda. The data can be used to assess the effect of climate change on the diversity and distribution of these species. The data set is also important for informing resource users, conservationists and policy makers about the biodiversity hotspots of these economically important species.

Bioactivity and toxicity of coumarins from African medicinal plants

Introduction: Coumarins are naturally occuring metabolites from plants and a few micro-organisms. They have been widely used in the food and drug industry in their natural or synthetic forms. Numerous coumarins possess several biological activities such as anti-inflammatory, anti-ulcers, anti-tumour, anti-microbial, anti-coagulant. The aim of this study was to assess the bioactivity, and toxicity of coumarins from African medicinal plants. Methods: We searched online databases and search engines such as PubMed, Google Scholar and Web of Science for key terms such as coumarins, toxicity, bioavailability, bioactivity with appropriate Boolean operators. Only full-length research articles published in English between 1956 to 2023 were reviewed. Results: We recorded 22 coumarins from 15 plant species from Africa. Most of the plant species (33%) were from North Africa. These were followed by East Africa at 21%, then West, and Central Africa at 18.2% each. Most of the coumarins (21.3%) were isolated from the entire plant and the leaves (19.1%) and most of them (46.7%) had some antimicrobial activity. Five coumarins viz osthole, pseudocordatolide C & calanolide, chartreusin and esculetin had either antitumor or anticancer activity. Six coumarins had varying levels and types of toxicity ranging from inhibiting blood clotting as anticoagulants, to cytotoxic effects, causing hyperventilation, tremor, & photophobia, pulmonary haemorrhage, carcinogenic activity, severe neurotoxicity, hepato- and phototoxicity. Conclusion: Several African medicinal plants are sources of various coumarins that possess several biological activities as well as toxicities. This calls for more research into their safety and efficacy because of their wide spread applications as therapeutic agents.

Ex vivo and in vitro antiplasmodial activity and toxicity of Caesalpinia decapetala (Roth) Alston (Fabaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is among the most prevalent and devastating parasitic diseases globally with most cases reported in Sub-Saharan Africa. One of the major reasons for the high malaria prevalence is the ever-increasing emergence of resistant strains of malaria-causing parasites to the currently used antimalarial drugs. This, therefore, calls for the search for antimalarial compounds with alternative modes of action. Plants used in traditional medicine for the treatment of malaria offer possible sources of such compounds. Caesalpinia decapetala has been used traditionally for the treatment of various diseases including malaria. However, the antiplasmodial activity of the plant has never been reported.

AIM OF THE STUDY

To determine the ex vivo and in vitro antiplasmodial activities of the extracts of the roots, stem bark and leaves of Caesalpinia decapetala.

METHODOLOGY

The roots, stem bark and leaves of Caesalpinia decapetala (Roth) Alston (Caesalpiniaceae) were collected and air-dried under a shade then extracted consecutively with dichloromethane and methanol (1:1 (v/v) (4 × 0.8 L). The extracts were tested for antiplasmodial activities against four strains of Plasmodium falciparum (W2, DD2, 3D7, and D6) and fresh P. falciparum field isolates using the SYBR green I assay. The mean fifty percent inhibition concentration (IC50) was determined for each assay. An acute oral toxicity test was done based on the Organization for Economic Cooperation and Development (OECD 425) guidelines using Swiss albino mice.

RESULTS

The leaves and stem bark extracts showed good antiplasmodial activities with IC50 values of 4.54 and 4.86 μg/mL, respectively, when tested against the fresh field isolates ex vivo. Similarly, the roots extract showed an IC50 value of 6.49 μg/mL when tested against field isolates ex vivo. The roots extract showed the highest antiplasmodial activities among the samples when tested against W2 (IC50 = 6.12 μg/mL), DD2 (IC50 = 8.17 μg/mL), and D6 (IC50 = 16.02 μg/mL) strains of P. falciparum whereas the leaves showed the highest activity (IC50 = 9.3 μg/mL) when tested against the 3D7 strain of P. falciparum. No mortality was observed for the mice treated with 2000 mg/kg of the leaves and stem bark extracts. The mouse treated with 2000 mg/kg of the roots extracts regained weight by day 12 of the observation period.

CONCLUSION

Caesalpinia decapetala has the potential to suppress the growth of P. falciparum thereby contributing to combating the recurrent emergence of antimalarial drug resistance.

Application of the herbal chemical marker ranking system (Herb MaRS) to the standardization of herbal raw materials: a case study

INTRODUCTION

Phytochemical standardization of herbal materials involves establishing consistent levels of one or more active ingredients or markers. It ensures the authenticity and quality of herbal materials, extracts, and their products. This research aimed to apply the herbal chemical marker ranking system (Herb MaRS) originally proposed for quality assurance of complex herbal products to establish markers for controlling the quality of herbal raw materials.

METHODS

The assessment of compounds for suitability as markers was based on the Herb MaRS, with minor modifications as follows: for more objective scoring, evidence of biological activity of the potential marker compound(s) was determined at three levels based on the number of symptoms of the disease condition a compound can treat or alleviate: (i) one symptom (1 point), two symptoms (2 points), and 3 or more symptoms (3 points). The reported concentrations of the compounds were also scored as follows: concentration not determined (0 points), concentration ≥ 5 ppm (1 point), concentration ≥ 50 ppm (2 points) and availability of analytical standards (1 point). Finally, the compounds were scored for the availability of an analytical method (1 point). The compounds were scored from 0 to 8, where 8 indicated the most suitable chemical marker.

RESULTS

The selected markers were as follows: aromadendrine, α-terpineol, globulol, and 1,8-cineol (in Eucalyptus globulus Labill. ); aloin, aloe emodin, acemannan (in Aloe barbadensis (L.) Burm.f. ), lupeol, lupenone, betulinic acid, betulin, and catechin (in Albizia coriaria Oliv.); mangiferin, catechin, quercetin, and gallic acid (in Mangifera indica L.); polygodial (in Warburgia ugandensis Sprague); azadirachtin, nimbin, nimbidin (in Azadirachta indica A. Juss. ); and 6,8,10-gingerols, and 6-shogaol (in Zingiber officinalis Roscoe).

CONCLUSIONS

Herb MaRS can be efficiently applied to select marker compounds for quality control of herbal materials. However, for herbs whose phytochemicals have not been sufficiently researched, it is difficult to establish evidence of activity, and there are no analytical standards and/or methods; this is the case for plants exclusively used in Africa. The markers identified should be incorporated into chromatographic fingerprints, their quantitative methods developed, and evaluated for applicability at the various stages of the production chain of herbal medicines; then, they can be included in future local plant monographs. There is also a need to build local capacity to isolate marker compounds, particularly those that are not sold by current vendors.

Network analysis and molecular docking studies of quercetin as a potential treatment for prostate cancer

Globally, the prevalence of prostate cancer is only the second to lung cancer. In Africa however, the commonest cancer among men is cancer of the prostate. The use of natural compounds from plants such as quercetin is being explored as a potential cure. Quercetin is a plant-based flavonoid that has anti-inflammatory, antioxidant and anticancer properties. Although quercetin has been extensively studied, its chemo preventive mode of action is not well-understood. The molecular targets and potential mechanisms underlying the action of quercetin against prostate cancer were identified and validated using network pharmacology and molecular docking methods. The biological targets of quercetin and targets associated with prostate cancer were obtained through database mining. Overlapping targets associated with quercetin and prostate cancer were identified and used to construct a compound-disease target (C-D) network and the targets were subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and protein-protein interaction analysis (PPI). A disease target- pathway network was constructed and then merged with C-D network to form a compound-disease_target-pathway (C-D-P) network. Hub targets were obtained from the C-D-P and PPI networks. The binding affinities between quercetin and the retrieved hub targets were identified. Pathway enrichment analysis showed that prostate cancer associated quercetin targets were mainly linked with pathways such as the cancer signaling pathways (HIF-1 and ErbB) and hepatitis B. Basing on the PPI and C-D-P network analysis STAT3, TP53, MAPK1, MAPK3 and KRAS were identified as the main targets and were subjected to molecular docking. The results showed quercetin's ability to stably bind to the key targets. In conclusion, this study showed the potential molecular targets and mode of action of quercetin in prostate cancer treatment. This can potentially inform the future use of quercetin in the treatment of prostate cancer.

Chemometric Classification of Mangifera indica L. Leaf Cultivars, Based on Selected Phytochemical Parameters; Implications for Standardization of the Pharmaceutical Raw Materials

Introduction

Mangifera indica leaves are among the most common materials employed in manufacturing herbal medicinal products. Despite the phytochemical variation of M. indica cultivars, there are no monographs to guide the cultivation, processing, and authentication of the materials.

Methods

This study characterized 15 Ugandan M. indica leaf varieties, with reference to extraction index (EI), total phenolic content (TPC), antioxidant activity (AOA), and mangiferin concentration (MC). In addition, HPLC fingerprints were established to evaluate the overall phytoequivalence of the materials. Then, using hierarchical clustering (HC) and principal component analysis (PCA), the materials were assigned quality grades.

Results

The mean EI was 9.39 ± 1.64% and varied among the varieties (P=0.001); the TPC varied significantly (P < 0.0001), from 183.29 ± 2.36 mg/g (Takataka) to 79.47 ± 0.58 mg/g (Apple mango). AOA ranged from 16.81 ± 2.85 μg/mL (Doodo red) to 87.85 μg/mL (Asante). MC varied significantly (P < 0.0001), from 105.75 ± 0.60 mg/g (Kate) to 39.53 ± 0.30 mg/g (Asante). HC gave four major grades: A to D (A, varieties with the highest TPC, MC, and AOA). These parameters reduced to below average from group B to group D. The chromatographic fingerprints were visually similar, but the number of peaks varied, from 19 (Kawanda green) to 29 (Kawanda wide), with 23.5 ± 2.9 average peaks. Whole fingerprints were less similar (r < 0.8) than common peak fingerprints (r > 0.9, P < 0.001). PCA grouped the fingerprints into five clusters; loading plots for PC 1 and 2 revealed two important compounds, one at Rt = 15.828 minutes (mangiferin) and the other at 6.021 minutes. Using the standardized common fingerprints, unknown field samples clustered closely with Koona, Kate, and Kawanda green varieties.

Conclusions

The EI, TPC, MC, and AOA values can be utilized to monitor consistency in the quality of materials and the production process. The grades generated can be used to select materials for cultivation and manufacturing. Where minimum concentrations are set, materials of different concentrations are used to dilute or concentrate each other. The HPLC fingerprints can be utilized to authenticate the materials. More samples from different agroecological regions of the country should be tested to cater to climatic variations in order to develop GMP-compliant botanical identification methods.

Medicinal plants used for treatment of malaria by indigenous communities of Tororo District, Eastern Uganda

BACKGROUND

Malaria remains the leading cause of death in sub-Saharan Africa. Although recent developments such as malaria vaccine trials inspire optimism, the search for novel antimalarial drugs is urgently needed to control the mounting resistance of Plasmodium species to the available therapies. The present study was conducted to document ethnobotanical knowledge on the plants used to treat symptoms of malaria in Tororo district, a malaria-endemic region of Eastern Uganda.

METHODS

An ethnobotanical study was carried out between February 2020 and September 2020 in 12 randomly selected villages of Tororo district. In total, 151 respondents (21 herbalists and 130 non-herbalists) were selected using multistage random sampling method. Their awareness of malaria, treatment-seeking behaviour and herbal treatment practices were obtained using semi-structured questionnaires and focus group discussions. Data were analysed using descriptive statistics, paired comparison, preference ranking and informant consensus factor.

RESULTS

A total of 45 plant species belonging to 26 families and 44 genera were used in the preparation of herbal medicines for management of malaria and its symptoms. The most frequently mentioned plant species were Vernonia amygdalina, Chamaecrista nigricans, Aloe nobilis, Warburgia ugandensis, Abrus precatorius, Kedrostis foetidissima, Senna occidentalis, Azadirachta indica and Mangifera indica. Leaves (67.3%) were the most used plant part while maceration (56%) was the major method of herbal remedy preparation. Oral route was the predominant mode of administration with inconsistencies in the posology prescribed.

CONCLUSION

This study showed that the identified medicinal plants in Tororo district, Uganda, are potential sources of new antimalarial drugs. This provides a basis for investigating the antimalarial efficacy, phytochemistry and toxicity of the unstudied species with high percentage use values to validate their use in the management of malaria.

In Vitro Anti-Venom Potentials of Aqueous Extract and Oils of Toona ciliata M. Roem against Cobra Venom and Chemical Constituents of Oils

There are high mortality and morbidity rates from poisonous snakebites globally. Many medicinal plants are locally used for snakebite treatment in Uganda. This study aimed to determine the in vitro anti-venom activities of aqueous extract and oils of Toona ciliata against Naja melanoleuca venom. A mixture of venom and extract was administered intramuscularly in rats. Anticoagulant, antiphospholipase A2 (PLA2) inhibition assay, and gel electrophoresis for anti-venom activities of oils were done. The chemical constituents of the oils of ciliata were identified using Gas chromatography-tandem mass spectroscopy (GC-MS/MS). The LD50 of the venom was 0.168 ± 0.21 µg/g. The venom and aqueous extract mixture (1.25 µg/g and 3.5 mg/g) did not cause any rat mortality, while the control with venom only (1.25 µg/g) caused death in 1 h. The aqueous extract of T. ciliata inhibited the anticoagulation activity of N. melanoleuca venom from 18.58 min. to 4.83 min and reduced the hemolytic halo diameter from 24 to 22 mm. SDS-PAGE gel electrophoresis showed that oils completely cleared venom proteins. GC-MS/MS analysis showed that the oils had sesquiterpene hydrocarbons (60%) in the volatile oil (VO) and oxygenated sesquiterpenes (48.89%) in the non-volatile oils (NVO). Some major compounds reported for the first time in T. ciliata NVOs were: Rutamarin (52.55%), β-Himachalol (9.53%), Girinimbine (6.68%) and Oprea1 (6.24%). Most compounds in the VO were reported for the first time in T. ciliata, including the major ones Santalene (8.55%) and Himachal-7-ol (6.69%). The result showed that aqueous extract and oils of T. ciliata have anti-venom/procoagulant activities and completely neutralized the venom. We recommend a study on isolation and testing the pure compounds against the same venom.

Ethnobotanical study of medicinal plants utilized in the management of candidiasis in Northern Uganda

Background

The emergence of resistant Candida species to antifungal drugs has led to resurgence in herbal usage globally. However, little is known about anti-candida plants. This study explored ethnomedicinal plants as treatment option for candidiasis in Pader, Northern Uganda.

Methods

A cross-sectional survey of potential anti-candida plants was conducted using questionnaires, focus group discussions and field observations in March 2022. Sixty-three respondents were selected by snowball technique. The frequencies of respondents/responses were analyzed, associations of respondents’ socio-demographics with indigenous knowledge of herbal usage established by Chi-square (χ²) test using SPSS 27. Informant Consensus Factor was computed to establish level of agreement on herbal usage, and thematic analysis done for focus group discussions.

Results

Candidiasis is still common and troublesome in Pader. All herbalist had equal chances of receiving and treating candidiasis patients irrespective of herbalist’s gender, age, education level, occupation, marital status and religion (p > 0.05). About 39.7% of herbalists received candidiasis patients weekly (p < 0.01). All herbalists had knowledge on candidiasis. Death (56.8%) and discomfort (36.8%) were the major health risks of oropharyngeal candidiasis (OPC) and vulvovaginal candidiasis (VVC), respectively. A total of 32 potential anti-candida plant species in 18 families were identified. Families of Fabaceae (9 species) and Asteraceae (5 species) had most plant species. Trees (50.0%) and herbs (43.8%) were the dominant life forms. The commonest plants by frequency of mention were: Momordica foetida (26), Sansevieria dawei (20), Khaya anthotheca (15), Piliostigma thonningii (10), Clerodendrum umbellatum (7), Hallea rubrostipulata (5) and unidentified plant, ‘Agaba/daa layata’ in Acholi dialect (5). Plant parts mainly used were roots (56.3%) and stem barks (15.6%) harvested majorly by cutting (46.9%) and uprooting (12.5%). Most respondents (females, 95%) preferred herbal to western medication (p < 0.01) due to its perceived effectiveness. There was high consensus among herbalists on herbal remedies for OPC and VVC (FIC = 0.9).

Conclusions

 Pader communities have diverse indigenous knowledge on candidiasis and prefer herbal medicines to orthodox treatment for candidiasis. However, the herbalists use unsustainable harvesting techniques like uprooting whole plants and cutting main roots. Hence, the need to document such indigenous knowledge before being lost for community usage and scientific validation.

Antibiotic-resistance in medically important bacteria isolated from commercial herbal medicines in Africa from 2000 to 2021: a systematic review and meta-analysis

Background

Antimicrobial resistance is swiftly increasing all over the world. In Africa, it manifests more in pathogenic bacteria in form of antibiotic resistance (ABR). On this continent, bacterial contamination of commonly used herbal medicine (HM) is on the increase, but information about antimicrobial resistance in these contaminants is limited due to fragmented studies. Here, we analyzed research that characterized ABR in pathogenic bacteria isolated from HM in Africa since 2000; to generate a comprehensive understanding of the drug-resistant bacterial contamination burden in this region.

Methods

The study was conducted according to standards of the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). We searched for articles from 12 databases. These were: PubMed, Science Direct, Scifinder scholar, Google scholar, HerbMed, Medline, EMBASE, Cochrane Library, International Pharmaceutical Abstracts, Commonwealth Agricultural Bureau Abstracts, African Journal Online, and Biological Abstracts. Prevalence and ABR traits of bacterial isolates, Cochran’s Q test, and the I² statistic for heterogeneity were evaluated using MedCalcs software. A random-effects model was used to determine the pooled prevalence of ABR traits. The potential sources of heterogeneity were examined through sensitivity analysis, subgroup analysis, and meta-regression at a 95% level of significance.

Findings

Eighteen studies met our inclusion criteria. The pooled prevalence of bacterial resistance to at least one conventional drug was 86.51% (95% CI = 61.247–99.357%). The studies were highly heterogeneous (I² = 99.17%; p < 0.0001), with no evidence of publication bias. The most prevalent multidrug-resistant species was Escherichia coli (24.0%). The most highly resisted drug was Ceftazidime with a pooled prevalence of 95.10% (95% CI = 78.51–99.87%), while the drug-class was 3^rd generation cephalosporins; 91.64% (95% CI = 78.64–96.73%). None of the eligible studies tested isolates for Carbapenem resistance. Extended Spectrum β-lactamase genes were detected in 89 (37.2%) isolates, mostly Salmonella spp., Proteus vulgaris, and K. pneumonia. Resistance plasmids were found in 6 (5.8%) isolates; the heaviest plasmid weighed 23,130 Kilobases, and Proteus vulgaris harbored the majority (n = 5; 83.3%).

Conclusions

Herbal medicines in Africa harbor bacterial contaminants which are highly resistant to conventional medicines. This points to a potential treatment failure when these contaminants are involved in diseases causation. More research on this subject is recommended, to fill the evidence gaps and support the formation of collaborative quality control mechanisms for the herbal medicine industry in Africa.

Herbal medicine used for the treatment of diarrhea and cough in Kampala city, Uganda

BACKGROUND

Globally, diarrheal and respiratory diseases are among the main causes of mortality and morbidity. In Uganda, cities are facing proliferation of trade in herbal medicines (HM), including those for diarrhea and/or cough. Information on the economic, and the ethnopharmacological aspects of these HM is scarce, deterring the sector from achieving optimal capacity to support national development. We profiled the anti-diarrhea and/or anti-cough HM, and the basic economic aspects of HM trade in Kampala city, to support ethnopharmacological knowledge conservation and strategic planning.

METHODS

A cross-sectional survey was conducted on 65 herbalists using semi-structured questionnaires. This was supplemented by an observational survey using a high-resolution digital camera. Data were collected following the guidelines for research on HM, established by Uganda National Drug Authority, and World Health organization.

RESULTS

Eighty-four plant species from 41 families were documented. Fabaceae and Myricaceae had the highest number of species (9, 10.7% each). Citrus limon (L.) Osbeck was the most commonly cited for cough, with a relative frequency of citation (RFC) of 1.00, and its relative medical importance was not significantly different from the other top 5 species except for Azadirachta indica A.Juss (RFC = 0.87). Entada abyssinica A. Rich (RFC = 0.97) was the most cited for diarrhea. Trees (34, 40.5%) were mostly used, and mainly harvested from wild habitats (55.2%) in 20 districts across Uganda. These HM were mainly sold as powders and concoctions, in markets, shops, pharmacies, and roadside or mobile stalls. The highest prices were Uganda Shillings (UGX) 48,000 ($13.15)/kg for Allium sativum L, and UGX 16,000 ($4.38)/kg for C. limon. All participants used HM trade as a sole source of basic needs; majority (60.0%) earned net monthly profit of UGX. 730,000 ($200) ≤ 1,460,000 ($400). The main hindrances to HM trade were the; disruptions caused by the COVID-19 pandemic (n = 65, 100%), and the scarcity of medicinal plants (58, 89.2%).

CONCLUSION

There is a rich diversity of medicinal plant species traded in Kampala to treat diarrhea and cough. The HM trade significantly contributes to the livelihoods of the traders in Kampala, as well as the different actors along the HM value chain throughout the country.

African and Asian Medicinal Plants as a Repository for Prospective Antiviral Metabolites Against HIV-1 and SARS CoV-2: A Mini Review

Introduction: The worldwide burden of viral infections has triggered a resurgence in the search for new and more efficient antiviral drugs. Scientists are also repurposing existing natural compounds such as the antimalarial drug artemisinin from Artemesia annua L. as potential drug candidates for some of the emerging and re-emerging viral infections such as covid-19

Aim: The aim of this review was to analyse the existing literature to explore the actual or potential natural antiviral compounds from African and Asian medicinal plants as lead compounds in the drug discovery process.

Methods: We searched the literature on African and Asian medicinal plant species as antiviral agents for HIV-1 and the novel coronavirus (SARS-CoV-2) in various databases and search engines such as Web of Science, Google Scholar and PubMed. The search was limited to in vitro, in vivo, and clinical studies and excluded in silico studies.

Results: We present 16 plant species with actual or potential antiviral activity against HIV-1 and SARS-CoV-2. These plant species span the continents of Africa and Asia where they are widely used for treating several other ailments.

Conclusion: Natural compounds from plants can play a significant role in the clinical management of HIV/AIDS and the covid-19 pandemic. More research needs to be conducted to investigate the potential toxicities of the various compounds and their efficacies in clinical settings.

Pharmacological Assessment of the Antiprotozoal Activity, Cytotoxicity and Genotoxicity of Medicinal Plants Used in the Treatment of Malaria in the Greater Mpigi Region in Uganda

We investigated the potential antimalarial and toxicological effects of 16 medicinal plants frequently used by traditional healers to treat malaria, fever, and related disorders in the Greater Mpigi region in Uganda. Species studied were Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis, and Zanthoxylum chalybeum. In addition, the traditional healers indicated that P. hadiensis is used as a ritual plant to boost fertility and prepare young women and teenagers for motherhood in some Ugandan communities where a high incidence of rapidly growing large breast masses in young female patients was observed (not necessarily breast cancer). We present results from various in vitro experiments performed with 56 different plant extracts, namely, 1) an initial assessment of the 16 species regarding their traditional use in the treatment of malaria by identifying promising plant extract candidates using a heme biocrystallization inhibition library screen; 2) follow-up investigations of antiprotozoal effects of the most bioactive crude extracts against chloroquine-resistant P. falciparum K1; 3) a cytotoxicity counterscreen against human MRC-5SV2 lung fibroblasts; 4) a genotoxicity evaluation of the extract library without and with metabolic bioactivation with human S9 liver fraction; and 5) an assessment of the mutagenicity of the ritual plant P. hadiensis. A total of seven extracts from five plant species were selected for antiplasmodial follow-up investigations based on their hemozoin formation inhibition activity in the heme biocrystallization assay. Among other extracts, an ethyl acetate extract of L. calostachys leaves exhibited antiplasmodial activity against P. falciparum K1 (IC50 value: 5.7 µg/ml), which was further characterized with a selectivity index of 2.6 (CC50 value: 14.7 µg/ml). The experiments for assessment of potential procarcinogenic properties of plant extracts via evaluation of in vitro mutagenicity and genotoxicity indicated that few extracts cause mutations. The species T. asiatica showed the most significant genotoxic effects on both bacterial test strains (without metabolic bioactivation at a concentration of 500 µg/plate). However, none of the mutagenic extracts from the experiments without metabolic bioactivation retained their genotoxic activity after metabolic bioactivation of the plant extract library through pre-incubation with human S9 liver fraction. While this study did not show that P. hadiensis has genotoxic properties, it did provide early stage support for the therapeutic use of the medicinal plants from the Greater Mpigi region.

A Review of the Toxicity and Phytochemistry of Medicinal Plant Species Used by Herbalists in Treating People Living With HIV/AIDS in Uganda

Introduction: Despite concerns about toxicity, potentially harmful effects and herb-drug interactions, the use of herbal medicines remains widely practiced by people living with HIV/AIDS (PLHIV) in Uganda. Objective: The objective of the paper was to comprehensively review the literature on the toxicity and chemical composition of commonly used medicinal plant species in treating PLHIV in Uganda. Methods: We reviewed relevant articles and books published over the last sixty years on ethnobotany, antiviral/anti-HIV activity, toxicity, phytochemistry of Vachellia hockii, Albizia coriaria, Bridelia micrantha, Cryptolepis sanguinolenta, Erythrina abyssinica, Gardenia ternifolia, Gymnosporia senegalensis, Psorospermum febrifugium, Securidaca longipendunculata, Warburgia ugandensis and Zanthoxylum chalybeum and their synonyms. We searched PubMed, Web of Science, Scopus, Science Direct and Google Scholar. Discussion: Most of the plant species reviewed apart from P. febrifugium, S. longipedunculata and C. sanguinolenta lacked detailed phytochemical analyses as well as the quantification and characterization of their constituents. Crude plant extracts were the most commonly used. However, purified/single component extracts from different plant parts were also used in some studies. The U87 human glioblastoma was the most commonly used cell line. Water, ethanol, methanol and DMSO were the commonest solvents used. In some instances, isolated purified compounds/extracts such as Cryptolepine and Psorospermin were used. Conclusion: Cytotoxicity varied with cell type, solvent and extract type used making it difficult for direct comparison of the plant species. Five of the eleven plant species namely, A. coriaria, C. sanguinolenta, G. ternifolia, P. febrifugium and Z. chalybeum had no cytotoxicity studies in animal models. For the remaining six plant species, the crude aqueous and ethanol extracts were mainly used in acute oral toxicity studies in mice. Herbalists reported only A. coriaria and W. ugandensis to cause toxic side effects in humans. However, selective cytotoxic plant extracts can potentially be beneficial as anticancer or anti-tumour drugs.

Antiinflammatory Medicinal Plants from the Ugandan Greater Mpigi Region Act as Potent Inhibitors in the COX-2/PGH2 Pathway

Our study investigates 16 medicinal plants via assessment of inhibition of proinflammatory enzymes such as cyclooxygenases (COX). The plants are used by traditional healers in the Greater Mpigi region in Uganda to treat inflammation and related disorders. We present results of diverse in vitro experiments performed with 76 different plant extracts, namely, (1) selective COX-2 and COX-1 inhibitor screening; (2) 15-LOX inhibition screening; (3) antibacterial resazurin assay against multidrug-resistant Staphylococcus aureus, Listeria innocua, Listeria monocytogenes, and Escherichia coli K12; (4) DPPH assay for antioxidant activity; and (5) determination of the total phenolic content (TPC). Results showed a high correlation between traditional use and pharmacological activity, e.g., extracts of 15 out of the 16 plant species displayed significant selective COX-2 inhibition activity in the PGH₂ pathway. The most active COX-2 inhibitors (IC₅₀ < 20 µg/mL) were nine extracts from Leucas calostachys, Solanum aculeastrum, Sesamum calycinum subsp. angustifolium, Plectranthus hadiensis, Morella kandtiana, Zanthoxylum chalybeum, and Warburgia ugandensis. There was no counteractivity between COX-2 and 15-LOX inhibition in these nine extracts. The ethyl acetate extract of Leucas calostachys showed the lowest IC₅₀ value with 0.66 µg/mL (COX-2), as well as the most promising selectivity ratio with 0.1 (COX-2/COX-1). The TPCs and the EC₅₀ values for DPPH radical scavenging activity showed no correlation with COX-2 inhibitory activity. This led to the assumption that the mechanisms of action are most likely not based on scavenging of reactive oxygen species and antioxidant activities. The diethyl ether extract of Harungana madagascariensis stem bark displayed the highest growth inhibition activity against S. aureus (MIC value: 13 µg/mL), L. innocua (MIC value: 40 µg/mL), and L. monocytogenes (MIC value: 150 µg/mL). This study provides further evidence for the therapeutic use of the previously identified plants used medicinally in the Greater Mpigi region.

Ethnobotanical study of selected medicinal plants traditionally used in the rural Greater Mpigi region of Uganda

ETHNOPHARMACOLOGICAL RELEVANCE

This study provides the first report on selected traditional medicinal plant use, including parts used and methods of preparation, in the Greater Mpigi region of Uganda. This data supports the conservation of local traditional ecological knowledge and will facilitate future drug discovery research.

AIM OF THE STUDY

Our study aimed to conserve culturally and scientifically-valuable medical knowledge of 16 plant species traditionally used in the Greater Mpigi region in Uganda, namely Albizia coriaria, Cassine buchananii, Combretum molle, Erythrina abyssinica, Ficus saussureana, Harungana madagascariensis, Leucas calostachys, Microgramma lycopodioides, Morella kandtiana, Plectranthus hadiensis, Securidaca longipedunculata, Sesamum calycinum subsp. angustifolium, Solanum aculeastrum, Toddalia asiatica, Warburgia ugandensis and Zanthoxylum chalybeum. An additional objective of the study was an ethnological investigation of the socio-cultural background and medical understanding of diseases treated by traditional healers in the study area.

MATERIALS AND METHODS

A pilot survey in the study area revealed that 16 plant species were frequently used in treatment of a variety of medical disorders. In order to obtain more complete information, we conducted a broader ethnobotanical survey using structured interviews with 39 traditional healers from 29 villages, specifically asking about the traditional uses of these 16 medicinal species.

RESULTS

Results of the survey confirmed a high level of traditional use of these species in the Greater Mpigi region. In addition, various other traditional uses and methods of preparation were recorded, most of them for the first time. In total, 75 different medical disorders treated with the plants were documented.

CONCLUSIONS

Conservation of traditional knowledge for future generations is vital, as loss has already been recorded due to multiple causes. The need for novel and more effective drugs derived from natural products is more important than ever, making future studies on herbal remedies both justified and urgently required. The traditional healers surveyed in this project also have expectations of the research - they would like to be updated about any resulting studies into the pharmacological efficacy of medicinal plants so that the research findings can inform their confidence in each herbal remedy.

Medicinal plants species used by herbalists in the treatment of snakebite envenomation in Uganda

Background

There are high mortality and morbidity rates due to poisonous snakebites globally with sub-Saharan Africa having some of the highest cases. However, traditional medicine practitioners (TMP) have been treating snakebites in Uganda for long despite the fact that few studies have been conducted to document such vital and rich indigenous traditional knowledge before it is lost. This study aimed to document the medicinal plant species used by experienced TMP in treating snakebite envenomation in selected post-conflict parts of Uganda. An ethnopharmacological survey was conducted in Kitgum, Serere, Kaberamaido and Kaabong districts in Uganda. Twenty-seven TMP with expertise in treating snakebites were purposively identified using the snowball technique and interviewed using semi-structured questionnaires. Data were analysed using simple descriptive statistics.

Results

Sixty plant species from 28 families were documented with high consensus among the isolated indigenous Ik tribe of Kaabong district. Most of the plant species used were from the Asteraceae and Fabaceae families with eight species each. The genus Echinops was the most well-represented with three species. The most commonly used plant species were of citation were Steganotaenia araliaceae (16), Microglossa pyrifolia (Lam.), Gladiolus dalenii Van Geel (13), Aframomum mildbraedii Loes. (11), Jasminum schimperi Vatke and Cyathula uncinulata (Schrad) Schinz (10) and Crinum macowanii Baker and Cyphostemma cyphopetalum (Fresen.) Desc. ex Wild & R.B. Drumm (10). S. araliaceae which was mentioned by all the TMP in the Ik community was used for first aid. Most of the plant species were harvested from the wild (68.75%) and were herbs (65.0%) followed by trees (23.3%). The most commonly used plant parts were roots (42.6%) and leaves (25.0%). Thirteen different methods of preparation and administration were used. Most of the medicines were administered orally (61.2%) and topically (37.6%). The commonest methods of oral application were cold water infusions (32.5%) and decoctions (21.7%).

Conclusions

TMP widely use several medicinal plant species for treating snakebite envenomation in the selected post-conflict regions of Uganda

Indigenous traditional knowledge of medicinal plants used by herbalists in treating opportunistic infections among people living with HIV/AIDS in Uganda

ETHNOPHARMACOLOGICAL RELEVANCE

Currently, more than two thirds of the world's 36.9 million people living with HIV/AIDS reside in Sub-Saharan Africa. Opportunistic infections (OI) associated with HIV are the single most important cause of mortality and morbidity among HIV/AIDS patients in poor countries. There is widespread use of medicinal plant species to manage the HIV infection and it's associated OI in Uganda, even by patients already on antiretroviral drugs (ARV). However, much of this information remains undocumented and unverified.

AIM OF STUDY

The aim of this study was to systematically and comprehensively document the traditional indigenous knowledge and practices associated with the management of HIV/AIDS infections by herbalists in Uganda.

METHODS

Ethnobotanical data were collected using semi-structured interviews and questionnaires. Ninety traditional medicine practitioners (TMP) or herbalists were interviewed in Arua, Dokolo, Mbale, Bushenyi, Iganga, Rakai, Luwero and Kaabong districts to gather information on the plant species used. Data were analysed and presented using descriptive statistics and the Informant Consensus Factor.

RESULTS

We documented 236 medicinal plant species from 70 families and 201 genera. Acacia was the most widely represented genus with five species. The most frequently used medicinal plant species for treating various OI were Erythrina abyssinica (45), Warburgia ugandensis (43), Zanthoxylum chalybeum (38), Acacia hockii (37), Mangifera indica (36), Aloe vera (35), Albizia coriaria (34), Azadirachta indica (32), Psorospermum febrifugum (27) Vernonia amygdalina (22) and Gymnosporia senegalensis (21). Some of the plant species were used for treating all the OI mentioned. There is a high degree of consensus among the TMP on which plant species they use for the different OI, even though they are geographically separated. Herbalists contribute to the widespread practice of simultaneously using herbal medicines and ARV. Some TMP are also engaged in dangerous practices like injecting patients with herbs and encouraging simultaneous use of herbs and ARV. Although the TMP relied on biomedical laboratory diagnoses for confirming the patients' HIV sero status, they were familiar with the signs and symptoms of HIV/AIDS.

CONCLUSION

There is wide spread use of a rich diversity of medicinal plants species and practices by TMP to manage OI in HIV/AIDS patients in Uganda.

Treatment-seeking behavior and practices among caregivers of children aged ≤5 y with presumed malaria in rural Uganda

BACKGROUND

We aimed to determine the rate of herbal medicine usage and the treatment-seeking patterns of children aged ≤5 y with presumed or confirmed malaria in an endemic area of Uganda.

METHODS

We interviewed guardians of 722 children aged 6 months to 5 y, who had experienced an episode of presumed malaria in the previous 3 months, about the illness history.

RESULTS

Overall, 36.1% of patients took herbal medicines but most also sought modern medical care; 79.2% received Artemether-Lumefantrine (AL), but only 42.7% received the correct AL dose. Of the 36.6% of patients treated in drug shops, 9.8% had a diagnostic test and 30.2% received the correct dose of AL. Antibiotics were frequently provided with AL at drug shops (62%) and formal health centers (45%). There were no significant differences in the self-reported outcomes associated with different treatments.

CONCLUSION

Almost all of the patients who took herbal medicine also took modern antimalarials, so further research is needed to explore potential interactions between them. Although formal health facilities provided the correct diagnosis and dose of AL to a majority of children with malaria, many children still received inappropriate antibiotics. Quality of care was worse in drug shops than in formal health facilities.

Medicinal Plants used during Antenatal Care by Pregnant Women in Eastern Uganda

Plants are commonly used during the antenatal stage in pregnancy to manage different ailments in Africa. In Uganda, both medicinal and food plants are used to handle common pregnancy related conditions. An ethnobotanical survey was conducted in Iganga district, eastern Uganda. Seven traditional birth attendants (TBA) and 46 mothers were interviewed. Data was collected using structured questionnaires and household interviews. The TBAs were identified using snowball sampling. A total of 33 plant species, belonging to 23 families were documented. Out of these, the pregnant mothers used 45.5 % as both food and medicine. The most frequently used plant life form was herbs (58.8%). The leaves are the most commonly used plant parts (59%). Most of the plants (58.8%) were semi cultivated and were being domesticated in crop fields and home gardens. Most of the plants were used to manage anaemia and for child development and good health among the pregnant women. The pregnant women and TBAs in Namungalwe sub County have diverse knowledge on medicinal and nutri-medicinal plants in the management of common pregnancy related diseases, which can be used to supplement modern antenatal services, inspite of the ban of the activities of TBA. Further research on the bioavailability of nutrients, efficacy and safety of the medicinal plants used by pregnant women should be done.

Medicinal plants used in malaria treatment by Prometra herbalists in Uganda

ETHNOPHARMACOLOGICAL RELEVANCE

The aim of the survey was to document medicinal plants used in malaria treatment by Prometra (Promocion de la medicina tradicional amazonica) Traditional Medical Practitioners (TMPs) of Uganda and for search of new antiplasmodial herbal medicines (HMs) for further phytochemical analysis.

MATERIALS AND METHODS

In this study, semi structured guided open and close ended questionnaires were used. Focus group discussions were conducted and key informants were chosen within the TMPs who helped in further discussions of how the herbal remedies where collected, prepared and administered.

RESULTS

A sample size of 51 respondents was randomly selected among the TMPs with the help of their leader. 86 species distributed over 81 genera and 39 families were reportedly being used as herbal remedies in malaria treatment. The TMPs use symptoms like high temperature, shivering, among others in malaria diagnosis an indication that they understand malaria. They emphasized the use of leaves and bark in treatment because they can regenerate and therefore ensure sustainable use of plants rather than the use of roots which would be destructive. These TMPS treat and also advise their patients on preventive measures against malaria attacks like sleeping under mosquito nets, clearing bushes near homesteads, among others which is an indication that they help in the prevention and mitigation of malaria incidences and prevalence in the areas where they live. The Informant Consensus Factor (FIC) value of 0.8 demonstrated that the TMPs of Prometra-Uganda tend to agree with each other in terms of the plant species they use in malaria treatment an indication of quality control in as far as administration of the herbal remedies. Vernonia amygdalina Delile, Bidens pilosa L., Justicia betonica L. were highly cited as being used in malaria treatment with frequencies of mention of 38, 28 and 25, respectively.

CONCLUSION

TMPs of Prometra-Uganda understand and treat malaria using the available plant diversity from their huge forest and the herbal gardens within Buyija forest. The healers are very keen at plant conservation which is a good practice. Species like Justica betonica may be investigated further for antiplasmodial assays to justify its efficacy.