Multi-targeted effects of untapped resources from the Mauritian endemic flora

The Mauritian endemic plants represent untapped resources, which must be probed into to establish therapeutic activities. This study aimed at determining a broad spectrum of in vitro bioactivities of twelve endemic plants. Total phenolics, flavonoids and proanthocyanidins were determined spectrophotometrically and by High Performance Liquid Chromatography (HPLC). Broth microdilution assay investigated the antibacterial effects of the extracts while their inhibitory effects on xanthine oxidase and acetylcholinesterase were evaluated. Cytotoxicity was studied against the human breast cancer cell line, Hs578T using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide. The highest level of total phenolics was measured in Badula multiflora while maximum total flavonoid and proanthocyanidin content were found in Eugenia orbiculata and Diospyros tesselleria respectively. A complex HPLC chromatogram indicating the presence of epigallocatechin gallate, kaempferol and quercetin in these extracts further emphasized the phenolic richness. Diospyros and Eugenia species had minimum inhibitory concentration values lower than 100 μg/ml against six Gram-negative and one Gram-positive bacteria. Eight extracts had better antimicrobial activity than at least one of the antibiotics used. Badula multiflora showed xanthine oxidase inhibition (IC50 0.08 ± 0.020 mg/ml) comparable to allopurinol (0.04 ± 0.001 mg/ml) (p < 0.05). Diospyros tessellaria, Diopyros neraudii and Erythroxylum macrocarpum were significantly better inhibitors of acetylcholinesterase than galantamine hydrobromide (p < 0.05). Badula multiflora, Croton vaughanii, Diospyros neraudi, Eugenia elliptica and Psidia terebinthina extracts exerted pronounced cytotoxicity against Hs578T cells in a dose-dependent manner. This study brings into the limelight the potential of these selected endemic plants and calls for further investigation of the bioactive components in relation to the activities.