Systematic Review of Chemical Compounds with Immunomodulatory Action Isolated from African Medicinal Plants.

A robust, well-functioning immune system is the cornerstone of good health. Various factors may influence the immune system's effectiveness, potentially leading to immune system failure. This review aims to provide an overview of the structure and action of immunomodulators isolated from African medicinal plants. The research was conducted according to PRISMA guidelines. Full-text access research articles published in English up to December 2023, including plant characteristics, isolated phytochemicals, and immuno-modulatory activities, were screened. The chemical structures of the isolated compounds were generated using ChemDraw® (version 12.0.1076), and convergent and distinctive signaling pathways were highlighted. These phytochemicals with demonstrated immunostimulatory activity include alkaloids (berberine, piperine, magnoflorine), polysaccharides (pectin, glucan, acemannan, CALB-4, GMP90-1), glycosides (syringin, cordifolioside, tinocordiside, aucubin), phenolic compounds (ferulic acid, vanillic acid, eupalitin), flavonoids (curcumin, centaurein, kaempferin, luteolin, guajaverin, etc.), terpenoids (oleanolic acid, ursolic acid, betulinic acid, boswellic acids, corosolic acid, nimbidin, andrographolides). These discussed compounds exert their effects through various mechanisms, targeting the modulation of MAPKs, PI3K-Akt, and NF-kB. These mechanisms can support the traditional use of medicinal plants to treat immune-related diseases. The outcomes of this overview are to provoke structural action optimization, to orient research on particular natural chemicals for managing inflammatory, infectious diseases and cancers, or to boost vaccine immunogenicity.

Antiulcer Effect of Aqueous Ethanolic Extracts of Pseudocedrela kotschyi (Schweinf) Harms (Meliaceae) and Ximenia americana L. (Olacaceae).

Purpose: This study aimed to provide pharmacological evidence of Pseudocedrela kotschyi and Ximenia americana in preventing or healing peptic ulcers claimed by traditional healers in Burkina Faso. Methods: The trunk bark of Pseudocedrela kotschyi and the roots bark of Ximenia americana (Olacaceae) were macerated in mixed ethanol/water (80:20), respectively, to obtain dried extracts. Two models of hydrochloric acid (HCl, 0.3 M/ethanol, 60%) and hypothermic stress-induced peptic ulcer were used. The cytoprotective effect of individual or combined plant extracts was assessed at 1; 10; 30mg/kg. bw. Then, the healing effect of the extracts at 10mg/kg.bw was evaluated within 21 days of treatment on the hydrochloric acid-induced ulcer model. The extracts' antioxidant activity and phenolic content were assessed to support the plant extracts' efficiency. Results: The extracts of P. kotschyi and X. americana at 10 mg/kg.bw reduced ulceration index in hydrochloric acid- and hypothermic stress-ulcer models by more than 83% and 65%, respectively. The extract from X. americana at 10mg/kg.bw allowed complete ulcer healing but not the association of the two plant extracts. The plant extracts had IC50of inhibition of DPPH radical lower than 5µg/mL and total ferric reducing antioxidant power of more than 77 mg EQAA/100mg. The total polyphenolic content was 64.82 ±0.99 and 53.75 ±1.39 mg EGA/g of dried extract of P. kotschyi and X. americana, respectively. Conclusion: X. americana extract is better than the combined two plant extracts in gastric cytoprotection and ulcer healing. Further investigations are needed to highlight mechanism-based effects.