Sustainable Use of Natural Resources and Traditional Medicine in Tropical Countries: Uncovering the Main Antioxidant Compounds and Antihypertensive Potential of the Diospyros comorensis Leaves as Health-Promoting Food Application for Local Population

Diospyros comorensis Hiern is a medicinal plant traditionally utilized in the management of cardiovascular disorders. Despite its common use, the pharmacological properties and phytochemical composition remain unexplored. This study aimed to evaluate the vasorelaxant, diuretic, and antioxidant activities, as well as toxicity and phytochemical profiling, of a methanol-water extract of D. comorensis leaves (MDCR) and a decoction of D. comorensis leaf (DDCR) extract. The main phytochemicals were quantified using High-Performance Liquid Chromatography (HPLC). Antioxidant capacity was assessed using DPPH and FRAP assays. The vasorelaxant effect was evaluated in vitro on phenylephrine-precontracted aortic rings. Diuretic activity was determined by measuring Wistar rats' urine output and electrolyte levels (Na+, Cl-, and K+). Toxicity was assessed using Swiss mice. The extracts showed a total phenolic content (TPC) of 29,693.02 +/- 3493.75 mg GAE/100 g DW (Folin-Ciocalteu method), which was markedly higher than the total phenolics quantified by HPLC (3743.12 +/- 457.32 mg/100 g DW, representing 76.38% of the total bioactive fraction). Among the quantified constituents, ellagic acid (56.36%) was the main compound. Both extracts exhibited marked antioxidant capacity along with significant vasorelaxant effects on phenylephrine-precontracted rat aorta rings, with EC50 values of 3.83 +/- 0.81 & micro;g/mL for MDCR and 4.87 +/- 0.79 & micro;g/mL for DDCR. Acute toxicity was not observed with either extract. The identified compounds may be involved in the observed antioxidant and pharmacological effects. These results show experimental evidence useful to support the traditional use of D. comorensis leaves in managing high blood pressure and highlight the antihypertensive potential of this Comorian endemic species. Further studies are necessary to characterize the biological mechanisms involved and relative bioactive substances. Reporting the pharmacological activities of D. comorensis may contribute to the sustainable use of natural resources in the Comoros Islands and Madagascar.