Bioefficacy of Mauritian Endemic Medicinal Plants: Assessment of Their Phenolic Contents and Antioxidant Potential

Abstract

The role of free radicals in the etiology and development of a wide range of clinical disorders has continued to fuel the suggestion that phenolic antioxidants can offer a realistic promise to reduce the incidence of a number of pathologies involving oxidative stress. In this study, the total phenol, flavonoid, and proanthocyanidin contents of the Mauritian medicinal plants Crinum mauritianum. Lodd. (Asteraceae), Gaertnera psychotroides. DC (Rubiaceae), Psidia terebinthina. A.J. Scott (Asteraceae), and Tylophora coriacea. Marais. (Monimiaceae) were assessed and contrasted with their antioxidant potential. The antioxidant propensity was evaluated by the ability of the extracts to scavenge hypochlorous acid and hydroxyl radical and the ABTS^{⋅ +} radical including their abilities to inhibit microsomal lipid peroxidation. The endemic plants Badula multiflora. A. DC. (Myrsinaceae), Croton vaughanii. L. (Euphorbiaceae), Erythroxylum macrocarpum. Lam. (Erythroxylaceae), Ochna mauritiana. Lam. (Ochnaceae), Tambourissa cordifolia. Lorence. (Monimiaceae), and Turraea rigida. Vent. (Meliaceae) were similarly investigated. Badula multiflora. and Erythoxylum macrocarpum. showed highest antioxidant activity in the TEAC and FRAP assay. Badula multiflora., Ochna mauritiana., and Gaertnera psychotroides. were very potent scavengers of hypochlorous acid and inhibited microsomal lipid peroxidation induced by 2,2′-azobis.(2-amidinopropane) hydrochloride (AAPH), suggesting that the inhibition was intrinsically linked to peroxyl radical scavenging. The antioxidant activity of Gaertnera psychotroides., Tylophora coriacea., Psidia terebinthina., and Crinum mauritianum. may account for the therapeutic effects of these extracts, in particular, in conditions characterized by inflammation and oxidative mechanisms. While these polyphenolic-rich endemics are good sources of natural prophylactic antioxidants, there is an urgent need for sustainable conservation programs for their protection.

Keywords:

• Antioxidant
• endemic medicinal plants
• flavonoids
• lipid peroxidation
• proanthocyanidins
• total phenols
• degenerative diseases
• nutraceuticals
• phytopharmacenticals