Ethnopharmacological Study of Medicinal Plants Used for the Treatment of Cardiovascular Diseases and Their Associated Risk Factors in sub-Saharan Africa

Potential Benefits of In Silico Methods: A Promising Alternative in Natural Compound's Drug Discovery and Repurposing for HBV Therapy

Hepatitis B virus (HBV) is an important global public health issue. The World Health Organization (WHO) 2024 Global Hepatitis Report estimated that the global prevalence of people living with HBV infection is 254 million, with an estimated prevalence incidence of 1.2 million new HBV infections yearly. Previous studies have shown that natural compounds have antiviral inhibition potentials. In silico methods such as molecular docking, virtual screening, pharmacophore modeling, quantitative structure-activity relationship (QSAR), and molecular dynamic simulations have been successfully applied in identifying bioactive compounds with strong binding energies in HBV treatment targets. The COVID-19 pandemic necessitated the importance of repurposing already approved drugs using in silico methods. This study is aimed at unveiling the benefits of in silico techniques as a potential alternative in natural compounds' drug discovery and repurposing for HBV therapy. Relevant articles from PubMed, Google Scholar, and Web of Science were retrieved and analyzed. Furthermore, this study comprehensively reviewed the literature containing identified bioactive compounds with strong inhibition of essential HBV proteins. Notably, hesperidin, quercetin, kaempferol, myricetin, and flavonoids have shown strong binding energies for hepatitis B surface antigen (HBsAg). The investigation reveals that in silico drug discovery methods offer an understanding of the mechanisms of action, reveal previously overlooked viral targets (including PreS1 Domain of HBsAg and cccDNA (Covalently Closed Circular DNA) regulators, and facilitate the creation of specific inhibitors. The integration of in silico, in vitro, and in vivo techniques is essential for the discovery of new drugs for HBV therapy. The insights further highlight the importance of natural compounds and in silico methods as targets in drug discovery for HBV therapy. Moreover, the combination of natural compounds, an in silico approach, and drug repurposing improves the chances of personalized and precision medicine in HBV treatment. Therefore, we recommend drug repurposing strategies that combine in vitro, in vivo, and in silico approaches to facilitate the discovery of effective HBV drugs.

An Ethnobotanical Survey and Pharmacological and Toxicity Review of Medicinal Plants Used in the Management of Obesity in the North Central Zone of Nigeria

Introduction: Obesity is increasing worldwide. Due to the unavailability of affordable obesity drugs in most parts of Nigeria, many overweight and obese people rely on medicinal plants to manage obesity. Thus, the aim of this study is to document medicinal plants traditionally used in the treatment and management of obesity in the North Central Zone of Nigeria, determine the plants to which pharmacological assessment of their use in obesity management has not been reported, and assess their toxicity based on the literature. Methods: Semistructured questionnaires and interviews were used to assess sociodemographic information of the 700 herb sellers/practitioners (100 for each state) who consented to participate in the study. Information gathered on plants that are traditionally used in the management of obesity included administration/dosage, method of preparation, plant part used, method of growth, and plant type. The field study was conducted over a one-year period, from March 2018 to March 2019. Reports of pharmacological activity pertaining to obesity as well as toxicity of the plants were obtained from the literature via scientific databases (Scopus, Web of Science, PubMed, Google Scholar, SciFinder, AJOL, PubChem, and other web sources) after the field survey. Results: A total of 39 families and 70 plant species were used to treat or manage obesity. The majority of plant species used resulted in the family Leguminosae. The relative frequency of citation (RFC) and percentage values for the five most frequently used plants were as follows: Citrus aurantifolia (0.0500; 3.56%), Citrus limon (0.0457; 3.26%), Garcinia kola (0.0429; 3.05%), Zingiber officinale (0.0429; 3.05%), and Allium sativum (0.0414; 2.95%). The majority of the medications were prepared as decoctions (50.5%), and cultivated plants (62.86%) were in the majority of plants used. Results showed that 23 plants have no pharmacological report for antiobesity activities while among the five frequently used plants, only Garcinia kola was reported toxic in preclinical models. Conclusions: This paper provides a valuable compilation of the plants used in obesity treatment in the study area by indigenous healers, highlights plants with no reported pharmacological activity pertaining to obesity, and indicates the toxicity profile of used plants. However, further studies on the mechanism of action are warranted, especially where no reports were obtained.

In vivo hypotensive effect of a chemically characterised extract from the leaves of Lippia alba (Mill.) N.E.Br

Lippia alba (erva-cidreira) is often mentioned in Brazilian ethnopharmacological studies. Although its leaves have been used to treat hypertension, few studies have evaluated its hypotensive effects. This work aimed to evaluate the haemodynamic effects of Lippia alba methanolic extract and to characterise its chemical composition. Normotensive rats received an intravenous injection of L. alba extract. Systolic, diastolic, mean arterial pressures, and electrocardiographic data were analysed.1H-qNMR and LC-MS were used to assess the chemical composition. L. alba extract had significant hypotensive effects on systolic, diastolic, and mean arterial pressure. Acteoside was identified as major compound (292.6 ± 2.7 mg/g). Sixty-one other compounds were tentatively identified, mainly phenylethanoids, flavonoids, and iridoids. L. alba extract reduces systolic, diastolic, mean arterial pressure, and appears to be associated with a reduction in heart rate. Acteoside, a known hypotensive compound, may be responsible for these effects, but other structurally similar minority compounds may also contribute.

Antibacterial Activity of Phyto-Synthesized Silver Nanoparticles From Dryopteris cristata Against Staphylococcus aureus ATCC 28923 and Escherichia coli ATCC 28922

Introduction Nanotechnology has emerged as a vital field, particularly in synthesizing nanoparticles. Silver nanoparticles (AgNPs) are recognized for their strong antimicrobial properties against various pathogens, including Staphylococcus aureus and Escherichia coli, due to their small size and high surface area. Green synthesis using plant extracts offers an eco-friendly alternative. The rise of multidrug-resistant bacteria underscores the urgent need for new antimicrobial agents. This study investigates the antibacterial activities of Dryopteris cristata AgNPs (DC-AgNPs) against S. aureus and E. coli, employing antimicrobial susceptibility testing (AST), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assessments, along with nanoparticle characterization. Materials and method The antimicrobial activity ofDC-AgNPs was evaluated using clinical isolates of E. coli and S. aureus. Bacterial inoculums were standardized to 0.5 MacFarlard (1.5 × 108 CFU/mL) and tested via a modified agar-well diffusion method. The MIC and MBC were determined using broth microdilution and sub-culturing methods, respectively. Characterization of the nanoparticles was conducted using Ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results and conclusion D. cristata was identified as the plant used to synthesize AgNPs, confirmed by the University of Ilorin, Nigeria. Phytochemical screening revealed the presence of tannins, flavonoids, glycosides, and phenolics. The AgNPs were synthesized by adding the aqueous extract to silver nitrate, resulting in a color change. Characterization via UV-Vis spectrophotometry confirmed nanoparticle formation. Antimicrobial testing showed that DC-AgNPs effectively inhibited S. aureus and E. coli, with minimum inhibitory concentrations of 125 μg and 250 μg, respectively, indicating their potential as antimicrobial agents.

Impact of Indoor Air Pollutants on the Cardiovascular Health Outcomes of Older Adults: Systematic Review

Indoor air pollution accounts for approximately 3.8 million inopportune deaths annually at global level. Due to spending more time indoors, children and older adults are especially susceptible to the health risks of indoor air pollution. This review seeks to summarise existing knowledge on the cardiovascular health effects of three common indoor air pollutants, namely carbon monoxide (CO), particulate matter (PM2.5 and PM10), and Nitrogen dioxide (NO2), focusing on older adults. We systematically reviewed the literature (PROSPERO CRD42024479220) on PubMed, Google Scholar, Scopus, Web of Science and Embase. The search yielded 20,914 records. Two independent reviewers screened the articles using titles, abstracts, and full-length articles written in English. Upon a detailed assessment of all the records, the review considered 38 full-length articles. Several studies reported mortality, myocardial infarction, stroke, increased hospitalisation and increased emergency room visits due to exposure to indoor air pollution. A few studies reported arrhythmias, hypertension and Ischaemic heart disease due to exposure to indoor air pollutants. The increased mortality, morbidity, hospitalization, and emergency rooms visits resulting from indoor air pollution associated CVDs makes indoor air pollution a health risk for older adults. There is, therefore, a need to synthesize information on studies relate d to how the selected indoor air pollutants affected the cardiovascular health of older adults.

Antihypertensive Effects of Lindera erythrocarpa Makino via NO/cGMP Pathway and Ca2+ and K+ Channels

Studies have demonstrated the therapeutic effects of Lindera plants. This study was undertaken to reveal the antihypertensive properties of Lindera erythrocarpa leaf ethanolic extract (LEL). Aorta segments of Sprague-Dawley rats were used to study the vasodilatory effect of LEL, and the mechanisms involved were evaluated by treating specific inhibitors or activators that affect the contractility of blood vessels. Our results revealed that LEL promotes a vasorelaxant effect through the nitric oxide/cyclic guanosine 3',5'-monophosphate pathway, blocking the Ca2+ channels, opening the K+ channels, and inhibiting the vasoconstrictive action of angiotensin II. In addition, the effects of LEL on blood pressure were investigated in spontaneously hypertensive rats by the tail-cuff method. LEL (300 or 1000 mg/kg) was orally administered to the rats, and 1000 mg/kg of LEL significantly lowered the blood pressure. Systolic blood pressure decreased by -20.06 ± 4.87%, and diastolic blood pressure also lowered by -30.58 ± 5.92% at 4 h in the 1000 mg/kg LEL group. Overall, our results suggest that LEL may be useful to treat hypertensive diseases, considering its vasorelaxing and hypotensive effects.

Research on Moringa (Moringa oleifera Lam.) in Africa

While Moringa oleifera Lam. is gaining importance in Africa, especially sub-Saharan Africa, it is unclear whether research is following the quick pace of its development on the continent. Therefore, this article analyzes the landscape of research dealing with moringa in Africa. This systematic review draws upon 299 eligible articles identified through a search carried out on the Web of Science in April 2023. Research on M. oleifera is rather recent in Africa but interest is increasing among scholars. While the research field is multidisciplinary and cross-sectoral, the literature seems to focus on biological and environmental sciences. Moreover, research is performed mainly in South Africa, Nigeria, Egypt, and Ghana. The analysis suggests a significant potential contribution of moringa to food security and nutrition, climate change mitigation/adaptation, farming systems resilience, and livelihoods. Its versatility and diverse applications and uses make moringa particularly interesting for developing countries, such as African ones. However, this review also underscores some factors hindering its development. Therefore, there is a need to strengthen research on moringa to unlock its potential in Africa. Investments in research, innovation, and development can help address the many challenges that Africa faces and contribute to the transition towards sustainable and resilient food systems.

Ethnomedicinal uses, phytochemistry, and pharmacology of the genus Sarcophyte: a review

Although medicinal plants have been used by ethnic communities since ancient times to prevent and treat various diseases, only a few have been scientifically documented. Therefore, due to their rare availability and lack of comprehensive scientific information, we reviewed the ethnomedicinal uses, phytochemistry, and pharmacological activities of plants within the genus Sarcophyte. To do this, we used specific search terms and phrases to retrieve relevant information from online sources published in English from 2000 to July 2023. The results showed that there are only two plants in the genus Sarcophyte (Sarcophyte sanguinea Sparrm. and Sarcophyte piriei Hutch.), which are traditionally used to treat a wide range of diseases, especially cancer, and skin, gastrointestinal, and urinogenital tract ailments in humans, and to cure animals in ethnoveterinary practices. It was noted that 13 secondary metabolites have been isolated from the two plants, the most prominent of which are flavonoids (diinsininol, diinsinin, and naringenin). The antioxidant activity of S. piriei is reported based on the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50: 4.26 ± 0.22 μg/mL) and 2 -2'-Azino-di-[3-ethylbenzthiazoline sulfonate (ABTS) radicals (IC50: 4.62 ± 0.14 μg/mL), chelating iron (IC50: 1.82 ± 0.01 μg/mL, 3.50 ± 0.09 μg/mL), and nitric oxide (IC50: 9.97 ± 0.88 μg/mL, 9.09 ± 0.11 μg/mL). The methanolic stem extracts of S. piriei possess antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Vibrio fluvialis, and Enterococcus avium, with minimum inhibitory concentration (MIC) values ranging from 0.16 to 0.625 mg/mL, and a minimum bactericidal concentration (MBC) of 1.25 to 5 mg/mL. Cytotoxic effects of the extracts from the two plant species were also demonstrated. Sarcophyte piriei possesses therapeutic potential as evidenced by the inhibitory effects of the aqueous rhizome extract on edema (1,000 mg/kg) and prostaglandin synthesis (IC50 = 0.2 mg/mL). In addition, diinsininol and diinsinin were isolated from S. sanguinea inhibited prostaglandin synthesis (IC50: 9.20 µM, 13.14 µM) and platelet-activating factor-induced exocytosis. Therefore, based on this review, further scientific research is needed to demystify the links between traditional medicinal uses, various secondary metabolites, and the pharmacology of the two plants.

Ethnomedicinal Knowledge of Plants Used in Nonconventional Medicine in the Management of Diabetes Mellitus in Kinshasa (Democratic Republic of the Congo)

Background

People with diabetes, herbalists, and traditional medicine practitioners (TMPs) from Kinshasa use plants to treat diabetes, but no study has inventoried the plants used by these populations. The present study was conducted to identify the plants used in Kinshasa to treat diabetes mellitus.

Methods

The survey conducted in the form of a semistructured interview between March 2005 and August 2006 made it possible to collect ethnobotanical information from people with diabetes (n = 126), herbalists (n = 80), and TMPs (n = 120).

Results

The 326 subjects consulted (sex ratio M/F = 0.6, age 51 ± 7 years, and experience: 17 ± 5 years) provided information on 71 plants, most of which are trees (35%), belonging to 38 families dominated by Fabaceae (19.7%) and indicated in 51 other cases of consultation dominated by malaria (12%). From these 71 plants derived, 86 antidiabetic recipes were administered orally, where the leaf is the most used part (>50%) and the decoction (>46%) is the most common mode of preparation. This study reports for the first time the antidiabetic use of 11 species, among which Tephrosia vogeliiX (0.08), Chromolaena corymbosaX (0.06), and Baphia capparidifoliaX (0.06) present the highest consensus indexes (CI) and Marsdenia latifoliaW (UVp = 0.08) and Rauvolfia manniiX (UVp = 0.06) present the highest UVs.

Conclusion

The results show that Kinshasa people treat diabetes using several plants. Some are specific to the ecological environment; others are used in other regions. Pharmacological studies are underway to assess the therapeutic efficacy of these plants.

A Review of the Popular Uses, Anatomical, Chemical, and Biological Aspects of Kalanchoe (Crassulaceae): A Genus of Plants Known as "Miracle Leaf"

Species of the genus Kalanchoe have a long history of therapeutic use in ethnomedicine linked to their remarkable healing properties. Several species have chemical and anatomical similarities, often leading to confusion when they are used in folk medicine. This review aims to provide an overview and discussion of the reported traditional uses, botanical aspects, chemical constituents, and pharmacological potential of the Kalanchoe species. Published scientific materials were collected from the PubMed and SciFinder databases without restriction regarding the year of publication through April 2023. Ethnopharmacological knowledge suggests that these species have been used to treat infections, inflammation, injuries, and other disorders. Typically, all parts of the plant are used for medicinal purposes either as crude extract or juice. Botanical evaluation can clarify species differentiation and can enable correct identification and validation of the scientific data. Flavonoids are the most common classes of secondary metabolites identified from Kalanchoe species and can be correlated with some biological studies (antioxidant, anti-inflammatory, and antimicrobial potential). This review summarizes several topics related to the Kalanchoe genus, supporting future studies regarding other unexplored research areas. The need to conduct further studies to confirm the popular uses and biological activities of bioactive compounds is also highlighted.

Phytochemical Screening, Antioxidant, and Antimicrobial Activities of Seven Underinvestigated Medicinal Plants against Microbial Pathogens

Background

Plants are a rich source of therapeutic compounds that have tremendous applications in the pharmaceutical industry. This study aimed to identify the phytochemicals present in the seven selected medicinal plants as well as their antioxidant and antimicrobial activities.

Methods

Phytochemical screening, total phenolic, and flavonoid contents were determined using standard methods. The antioxidant activity of plant extracts was determined using 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), and nitric oxide (NO) radical scavenging assays. The antimicrobial activity of the plant extracts was determined by the broth microdilution method.

Results

The results of phytochemical analysis showed the presence of phenols, flavonoids, and steroids in all plant extracts. The extract of Psychotria peduncularis showed the highest total phenolic and flavonoid contents (5.57 ± 0.22 mg GAE/g and 1.38 ± 0.06 mg QE/g, respectively). All plant extracts showed very strong antioxidant activity against DPPH and NO radical scavenging with IC50 values ranging from 0.55 to 49.43 µg/mL and 0.65 to 13.7 µg/mL, respectively. The extracts of Tristemma mauritianum and P. peduncularis displayed significant antibacterial activity with MIC values ranging from 16 to 1024 µg/mL. T. mauritianum extract showed bactericidal activity against all tested species. The extracts of Alsophila manianna and P. peduncularis showed significant antifungal activity (MIC = 64 µg/mL) against Candida albicans strain.

Conclusion

The screened extracts of medicinal plants used in our study can be used as potential antioxidant and antimicrobial agents, and resources for the development of new drugs.