West African medicinal plants and their constituent compounds as treatments for viral infections, including SARS-CoV-2/COVID-19.

OBJECTIVES: The recent emergence of the COVID-19 pandemic (caused by SARS-CoV-2) and the experience of its unprecedented alarming toll on humanity have shone a fresh spotlight on the weakness of global preparedness for pandemics, significant health inequalities, and the fragility of healthcare systems in certain regions of the world. It is imperative to identify effective drug treatments for COVID-19. Therefore, the objective of this review is to present a unique and contextualised collection of antiviral natural plants or remedies from the West African sub-region as existing or potential treatments for viral infections, including COVID-19, with emphasis on their mechanisms of action. EVIDENCE ACQUISITION: Evidence was synthesised from the literature using appropriate keywords as search terms within scientific databases such as Scopus, PubMed, Web of Science and Google Scholar. RESULTS: While some vaccines and small-molecule drugs are now available to combat COVID-19, access to these therapeutic entities in many countries is still quite limited. In addition, significant aspects of the symptomatology, pathophysiology and long-term prognosis of the infection yet remain unknown. The existing therapeutic armamentarium, therefore, requires significant expansion. There is evidence that natural products with antiviral effects have been used in successfully managing COVID-19 symptoms and could be developed as anti-COVID-19 agents which act through host- and virus-based molecular targets. CONCLUSION: Natural products could be successfully exploited for treating viral infections/diseases, including COVID-19. Strengthening natural products research capacity in developing countries is, therefore, a key strategy for reducing health inequalities, improving global health, and enhancing preparedness for future pandemics.

Traditional medicines for COVID-19: Perspectives from clinical pharmacologists.

There has been high interest in the use of traditional medicines for COVID-19 from early in the course of the pandemic. Significant advances in the science of ethnopharmacology have helped to introduce chemical entities identified from natural sources into modern medicine. However, the wider integration of natural products into the modern drug discovery process will require enhanced collaboration amongst the pharmaceutical industry, academic research units, regulatory bodies, ethics review committees and local, regional, continental and international organizations. Revisiting this topic holds promise of benefit for both the current and future pandemics.

Evaluation of the Microbial Load and Heavy Metal Content of Two Polyherbal Antimalarial Products on the Ghanaian Market.

The use of herbal products has increased and become more popularized globally; however, limited studies coupled with questions related to the quality and safety of these herbal products have been raised. Herbal products with hope of their nontoxicity may play a role of alternative to overcome the problems of multi-drug resistant pathogens. Medicinal plants used as raw materials for production may have quality and safety issues due to proximity to wastewater application of fungicides and pesticides, which may be directly deposited superficially or absorbed by the plant system. Therefore, possible contamination of some Ghanaian herbal products cannot be ignored, as it may severely affect human life in the process of treatment. Aim. To evaluate the microbial load and the presence of toxic heavy metals in Mist Amen Fevermix and Edhec Malacure, two polyherbal products used in the treatment of uncomplicated malaria in Ghana. Methods. Thermo Elemental M5 Atomic Absorption Spectrophotometer (AAS) fitted with graphite furnace and an auto sampler was used to determine the heavy metal contents of the herbal products. The herbal samples were evaluated for the microbial load by using the appropriate culture media. Results and Analysis. Mist Amen Fevermix and Edhec Malacure complied with the safety limits evaluated for all different microbial counts and contamination. The following heavy metals were present in Mist Amen Fevermix and Edhec Malacure Mixture: Fe, Ni, K, Zn, Hg, Cu, Mn, Cr, Cd, Pb, Fe, Cu, K, and Na. Ni was below detectable limit in Edhec Malacure. Conclusion. Mist Amen Fevermix and Edhec Malacure may be assured of safety. The products contained heavy metals, but all were within acceptable limit established by the FAO/WHO. The levels of microbial contamination were below the maximum acceptable limit.

Albizia zygia root extract exhibits antipsychotic-like properties in murine models of schizophrenia.

BACKGROUND: The root extract of Albizia zygia (DC.) J.F. Macbr. (Leguminosae) is used to manage mental disorders in African traditional medicine. However, its value, particularly, against negative and cognitive symptoms of schizophrenia have not been evaluated. AIM: The aim of this study was to evaluate the antipsychotic properties of the hydroethanolic root extract of Albizia zygia (AZE) against positive, negative and cognitive symptoms of schizophrenia in animal models. MATERIALS AND METHODS: The effects of AZE (30-300 mg kg-1) were evaluated against apomorphine-induced cage climbing as well as ketamine -induced hyperlocomotion, -enhanced immobility, -impaired social interaction and novel object recognition. The propensity of AZE to induce catalepsy and to attenuate haloperidol-induced catalepsy were also investigated. RESULTS: AZE 30-300 mg kg-1 significantly reduced apomorphine-induced climbing behaviour as well as ketamine-induced hyperlocomotion, immobility and object recognition deficits (at least P < 0.05). Moreover, the extract showed no cataleptic effect but significantly inhibited haloperidol-induced catalepsy at a dose of 30 mg kg-1 (P < 0.05). CONCLUSION: The root extract of Albizia zygia exhibited an antipsychotic-like activity in mice with potential to alleviate positive, negative and cognitive symptoms of schizophrenia.

Antiinflammatory properties of betulinic acid and xylopic acid in the carrageenan-induced pleurisy model of lung inflammation in mice.

This study investigated the antiinflammatory properties of betulinic acid (BA) and xylopic acid (XA) extracted from Margaritaria discoidea and Xylopia aethiopica, respectively. M. discoidea and X. aethiopica are plants native in Ghana and the West-African region and used traditionally to treat different pathologies including inflammatory conditions. The antiinflammatory effect of BA and XA was established by an in vivo assay using the carrageenan-induced pleural inflammation model in mice. Also, the ability of BA and XA to increase catalase, superoxide dismutase, glutathione levels and decrease lipid peroxidation level in reactive oxidative assays was assessed. In addition, the ability of XA and BA to prevent potential lung tissue damage was quantified. Pretreatment with BA and XA reduced significantly, signs of inflammation: neutrophil infiltration, oedema, and alveoli septal thickening in carrageenan-treated lung tissue. Additionally, BA or XA pretreatment lowered the degree of lipid peroxidation in the lung tissue while increasing the levels of catalase, superoxide dismutase, and glutathione in vivo. Comparatively, XA was more efficacious than BA in the prevention of lung tissue damage. BA and XA derived from X. aethiopica and M. discoidea possess antiinflammatory and in vivo antioxidant activities in mice pleurisy model. The effect of these compounds gives credence to the traditional use in the management of inflammatory conditions of the airway.

A novel triterpene from the roots of Paullinia pinnata: 6α-(3'-methoxy-4'-hydroxybenzoyl)-lup-20(29)-ene-3-one.

Paullinia pinnata L. (Sapindaceae) is an endemic West African plant that is extensively used in traditional medicine to treat various diseases. Previous phytochemical analysis by various groups led to the isolation of several novel lupene-based triterpenene derivatives along with other classes of compounds. As part of our continued phytochemical studies on the roots of this plant, we have now identified yet another novel triterpene, 6a-(3'-methoxy-4'-hydroxybenzoyl)-lup-20(29)-ene-3-one. The identification of the compound through comprehensive spectroscopic studies is discussed.

The immunostimulatory and antimicrobial property of two herbal decoctions used in the management of HIV/AIDS in Ghana.

BACKGROUND: HIV/AIDS is a pandemic retarding economic growth and destroying human capital globally. This study therefore investigated the perceived efficacy of Betula alba (BA) and Sutherlandia frutescens (SF) decoctions used in the management of HIV/AIDS in Ghana. MATERIALS AND METHODS: A study on the records of HIV/AIDS patients attending Habibi Herbal Clinic, Kumasi, Ghana, was conducted to obtain information on the initial viral load presented during their maiden visit and results after treatment with the herbal decoctions. The decoctions were assessed for immunostimulatory property in cyclophosphamide-induced immunosuppressed ICR mice. Total white blood cell count, as well as lymphocyte and neutrophil counts were determined and their effects compared with Levamisole. The decoctions were also screened for antimicrobial activity by the micro dilution method. RESULTS: The two herbal decoctions used significantly reduced (P ≤ 0.001) the patients' viral loads (47.42 ± 17.28 % to 13.69 ± 12.42 %; n=16). BA (1, 2, and 4 mg/kg) and SF (0.4, 0.8, and 1.6 mg/kg) caused significant increment (P ≤ 0.001) in total WBC and lymphocyte count in mice comparable to that produced by 2.5 mg/kg Levamisole. The decoctions also exhibited antimicrobial activity against gram negative and gram positive bacteria as well as Candida albicans (MIC 0.607 to 3.062 mg/ml). Phytochemicals present in both plants include saponins, terpenoids and coumarins. CONCLUSION: The Betula alba and Sutherlandia frutescens decoctions have interesting immunostimulatory and antimicrobial properties and hence could be useful in the management of HIV/AIDS and associated opportunistic infections.

Flavonoid glycosides from the stem bark of Margaritaria discoidea demonstrate antibacterial and free radical scavenging activities.

One new flavonoid glycoside, along with three known flavonoid glycosides were isolated from the stem bark of Margaritaria discoidea, which is traditionally used in the management of wounds and skin infections in Ghana. The new flavonoid glycoside was elucidated as hydroxygenkwanin-8-C-[α-rhamnopyranosyl-(1 → 6)]-ß-glucopyranoside (1) on the basis of spectroscopic analysis. The isolated compounds demonstrated free-radical scavenging as well as some level of antibacterial activities. Microorganisms including Staphylococcus aureus are implicated in inhibiting or delaying wound healing. Therefore, any agent capable of reducing or eliminating the microbial load present in a wound as well as decreasing the levels of reactive oxygen species may facilitate the healing process. These findings therefore provide some support to the ethnopharmacological usage of the plant in the management of wounds.