Methanol extracts of different species of Ocimum alleviate the peroxide radical-mediated cell injury and redox imbalance in human colon epithelial cells

Abstract

Ocimum has been identified as a potential entrant in Ayurvedic and other folk medicinal systems across the globe. In this attempt, we went on to analyse the antioxidant potential of the alcoholic extracted Ocimum plants viz., O. basilicum, Ocimum × africanum and O. basilicum var. purpurascens. Besides, the mitigating effect of these extracts was plotted in cell culture models against peroxide radical-mediated cell injury. The different extracts had higher polyphenol content with highest in O. basilicum (155.39 ± 2.14 mg GAE) and O. basilicum var. purpurascens (164.66 ± 0.39 mg GAE). Further, the IC50 value of DPPH radical scavenging was high in O. basilicum (27.25 ± 0.04 μg/mL) and O. basilicum var. purpurascens (21.59 ± 0.17 μg/mL). In cultured intestinal epithelial cells, the peroxide radical treatment-induced toxicity leads to reduced cell viability. On the contrary, pre-treatment with the various doses of the three selected taxa of Ocimum were effective and successfully prevented the toxic insults induced by the peroxide moiety in HCT-15 cells (p˂0.05). To corroborate with the improved cell viability, cells exposed to the varying doses of extracts had an increased cellular pool of reduced glutathione and concomitantly diminished lipid peroxides. Thus, the outcome underlines the effectiveness of different Ocimum taxa selected and the protective efficacy on the oxidative stress in HCT-15 cells. Among the three taxa, O. basilicum var. purpurascens was found to be the promising candidate and thus have a greater value as a therapeutic agent.