Anti-Inflammatory Potential of Phenolic Compounds Isolated From Entada africana Guill. & Perr. Used in the Republic of Benin

In West African medicine, Entada africana Guill. & Perr. from the family of Fabaceae is used to treat inflammatory conditions in the management of fractures, wounds, and sprains in the northern region of the Republic of Benin. The aim of the present study was to isolate and elucidate phenolic compounds from a hydroalcoholic leaf extract from E. africana and to identify compounds with anti-inflammatory activity in vitro. Eleven compounds were purified from three fractions, which have shown strong to medium anti-inflammatory activity. The isolated compounds were characterized by HRESI-MS and NMR methods as gallic acid (1), ethyl gallate (2), 5,7-dihydroxychromen-4-one (3), 3′,4′,7-trihydroxyflavone (4), dihydrokaempferol-7-O-glucoside (5), catechin (6), quercetin-3-O-[β-apiosyl-(1‴→2″)-β-glucoside] (7), quercetin-3-O-glucoside (8), naringenin-7-O-glucoside (9), aromadendrin (10), and myricetin-3-O-glucoside (11). Nine of the major phenolic compounds were tested using TNF-α stimulated human keratinocytes (HaCaT) as skin inflammation model to identify molecules, which may explain the use of the plant leaves as an anti-inflammatory remedy by assessing the release of proinflammatory cytokines IL-8 and IL-6. The hydroacoholic leaf extract of E. africana exerted a medium inhibitory effect on the release of IL-8. 3′,4′,7-trihydroxyflavone, aromadendrin, dihydrokaempferol-7-O-glucoside and ethyl gallate demonstrated a strong to medium effect on the release of IL-6. For the release of IL-8, 3′,4′,7-trihydroxyflavone demonstrated a medium activity. This study provides for the first time a detailed screening of phenolic compounds occurring in the hydroethanolic leaf extract of E. africana. Additionally, it is shown that E. africana contains active compounds which may justify its traditional medicinal use as an anti-inflammatory remedy to treat inflammatory and pain-related skin conditions in the Republic of Benin.

Dihydrochalcones as antitumor agents

Dihydrochalcones are a class of secondary metabolites, possessing several biological properties such as antitumor, antioxidant, antibacterial, antidiabetic, estrogenic, anti-inflammatory, antithrombotic, antiviral, neuroprotective and immunomodulator properties; therefore, they are currently considered promising candidates in the drug discovery process. This review intend to debate their pharmacological actions with a particular attention to their antitumor activity against a panel of cancer cell-lines and to the description of the inhibition mechanisms of cell proliferation such as the regulation of angiogenesis, apoptosis, etc etc.

Anti-HCV Tannins From Plants Traditionally Used in West Africa and Extracted With Green Solvents

Millions of people are still infected with hepatitis C virus (HCV) nowadays. Although recent antivirals targeting HCV proteins are very efficient, they are not affordable for many people infected with this virus. Therefore, new and more accessible treatments are needed. Several Ivorian medicinal plants are traditionally used to treat “yellow malaria”, a nosological category including illness characterized by symptomatic jaundice such as hepatitis. Therefore, some of these plants might be active against HCV. An ethnobotanical survey in Côte d’Ivoire allowed us to select such medicinal plants. Those were first extracted with methanol and tested for their anti-HCV activity. The most active ones were further studied to specify their IC50 and to evaluate their toxicity in vitro. Greener solvents were tested to obtain extracts with similar activities. Following a phytochemical screening, tannins of the most active plants were removed before re-testing on HCV. Some of these tannins were identified by UPLC-MS and pure molecules were tested against HCV. Out of the fifteen Ivorian medicinal plants selected for their putative antiviral activities, Carapa procera DC. and Pericopsis laxiflora (Benth. ex Baker) Meeuwen were the most active against HCV (IC50: 0.71 and 0.23 μg/ml respectively) and not toxic for hepatic cells. Their crude extracts were rich in polyphenols, including tannins such as procyanidins A2 which is active against HCV. The same extracts without tannin lost their anti-HCV activity. Replacing methanol by hydro-ethanolic solvent led to tannins-rich extracts with similar antiviral activities, and higher than that of aqueous extracts.

The Protective Impact of Salsola imbricata Leaf Extract From Taif Against Acrylamide-Induced Hepatic Inflammation and Oxidative Damage: The Role of Antioxidants, Cytokines, and Apoptosis-Associated Genes

Salsola imbricata is a herbal plant native to Saudi Arabia, known for its antioxidative and anti-inflammatory properties. This study explored the protective effects of an ethanolic leaf extract of Salsola imbricata against the oxidative stress and hepatic injury caused by acrylamide. Rats received intragastric administrations of 20 mg/kg of body weight of acrylamide to induce hepatic injury, or 300 mg/kg of body weight of Salsola ethanolic extract orally for 7 days before acrylamide administration. The treatments were continued for 3 weeks. Blood and liver samples were collected from all the groups, and the following biochemical parameters were tested: serum ALT (alanine aminotransferase), AST (aspartate aminotransferase), GGT (gamma glutaryl transferase), urea, albumin, total proteins, catalase, SOD (superoxide dismutase), reduced glutathione (GSH), nitric oxide (NO), and MDA (malondialdehyde). Quantitative real-time PCR (qRT-PCR) was used to examine the expression of Nrf2 (Nuclear factor-erythroid factor 2-related factor 2), HO-1 (Hemoxygenase-1), COX-2 (Cyclooxgenase-2), TGF-β1 (transforming growth factor-beta1), Bax, and Bcl2 (B-cell lymphoma 2), which are associated with oxidative stress, fibrosis, apoptosis, and anti-apoptotic effects. The annexin and survivin immunoreactivity were examined at the immunohistochemical level. Pretreatment with the Salsola ethanolic extract reduced the negative impact of acrylamide on ALT, AST, GGT, urea, albumin, and total proteins. The Salsola ethanolic extract reversed acrylamide's effects on serum and tissue antioxidants. Nrf2/HO-1 expression was downregulated, while COX-2 and TGF-β1 were upregulated in the acrylamide-administered group and normalized by the pre-administration of Salsola ethanolic extract to the acrylamide experimental group. The immunoreactivity of annexin and survivin was restored in the experimental group administered Salsola ethanolic extract plus acrylamide. In conclusion, Salsola ethanolic extract inhibits and regulates the side effects induced in the liver by acrylamide. Salsola induced its impacts by regulating inflammation, oxidative stress, and apoptosis-/anti-apoptosis-associated genes at the biochemical, molecular, and cellular levels. Salsola is recommended as oxidative stress relievers against environmental toixicity at high altitude areas.

Therapeutic Potentials of Antiviral Plants Used in Traditional African Medicine With COVID-19 in Focus: A Nigerian Perspective

The coronavirus disease 2019 (COVID-19) pandemic is caused by an infectious novel strain of coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which was earlier referred to as 2019-nCoV. The respiratory disease is the most consequential global public health crisis of the 21st century whose level of negative impact increasingly experienced globally has not been recorded since World War II. Up till now, there has been no specific globally authorized antiviral drug, vaccines, supplement or herbal remedy available for the treatment of this lethal disease except preventive measures, supportive care and non-specific treatment options adopted in different countries via divergent approaches to halt the pandemic. However, many of these interventions have been documented to show some level of success particularly the Traditional Chinese Medicine while there is paucity of well reported studies on the impact of the widely embraced Traditional African Medicines (TAM) adopted so far for the prevention, management and treatment of COVID-19. We carried out a detailed review of publicly available data, information and claims on the potentials of indigenous plants used in Sub-Saharan Africa as antiviral remedies with potentials for the prevention and management of COVID-19. In this review, we have provided a holistic report on evidence-based antiviral and promising anti-SARS-CoV-2 properties of African medicinal plants based on in silico evidence, in vitro assays and in vivo experiments alongside the available data on their mechanistic pharmacology. In addition, we have unveiled knowledge gaps, provided an update on the effort of African Scientific community toward demystifying the dreadful SARS-CoV-2 micro-enemy of man and have documented popular anti-COVID-19 herbal claims emanating from the continent for the management of COVID-19 while the risk potentials of herb-drug interaction of antiviral phytomedicines when used in combination with orthodox drugs have also been highlighted. This review exercise may lend enough credence to the potential value of African medicinal plants as possible leads in anti-COVID-19 drug discovery through research and development.

Traditional uses, phytochemistry, and pharmacological activities of Cochlospermum tinctorium A. Rich (Cochlospermaceae): a review

Background

The plant Cochlospermum tinctorium A. Rich is a sub-shrub that belongs to the family Cochlospermaceae. The plant has been used in traditional medicine for the treatment of malaria, rickets, stomachache, diarrhea, gastric ulcer, parasitic infestations, liver diseases, fever, pain, inflammation, infectious diseases, epilepsy, snake bite, burns, orchitis, labour, menstrual problems, and many other diseases. This review summarizes the traditional uses, phytochemistry, and pharmacological activities of Cochlospermum tinctorium.

Main text

To date, few bioactive molecules have been identified and isolated from the plant such as 7,3-dimethyldihydroquercelin, 5,4-dimethylquercelin, cochloxanthine, dihydrocochloxanthine, arjunolic acid, 3-O-E-p-coumaroylalphitolic acid, alphitolic acid, 1-hydroxytetradecan-3-one, 3-bisabolen, 2-tridecanone, 3-hexadecanone, 1-dodecanol, l-tetradecanol, 2-pentdecanone, 3-octadecanone, 1-hydroxy-3-hexadecanone, 1-nonadecanol, l-O-acetyl-3-hexadecanone, and l-hydroxy-3-oetadecanone. The literature related some of the reported ethnomedicinal uses of the plant to these compounds found in the different parts of the plant.

Conclusion

The comprehensive information documented in this review about the importance of the C. tinctorium may provide an opportunity for research advancement in drug discovery and a better understanding of the medicinal benefits of the plant.