Antioxidant and Antibacterial Activities of Phytochemicals in Methanolic Extracts of Five Underutilized Leafy Vegetables

Abstract

Leafy vegetables are important for their nutritive and medicinal values. However, many of them are less explored and underutilized. The present study evaluates the antioxidant and antibacterial activities present in five underutilized leafy vegetables such as Alternanthera philoxeroides, Boerhavia diffusa, Enydra(=Enhydra) fluctuans, Glinus oppositifolius and Suaeda maritima. Methanolic extracts from leafy edible parts of these plants possessed diverse phytochemicals. Of these plants, the polyphenol contents like total phenolic (TPC), total flavonoid (TFC) and total tannin (TTC) were the highest in E. fluctuans with significant variations concerning other plants. Also, the antioxidant activities of E. fluctuans were greater comparing other plants; the parameters were the total antioxidant activity (TAA), ferric reducing power assay and ability to scavenge DPPH, ABTS and superoxide radicals. The effect of varying extract-quantities revealed the highest antibacterial activity of the E. fluctuans extracts with substantial inhibition zones against six bacterial strains. Accordingly, the E. fluctuans extracts showed the lowest MIC (2.75±0.35 mg ml-1) and MBC (3.50±0.71 mg ml-1), albeit with significant variations with ampicillin. The study highlights that these plants are the untapped repertoires of natural antioxidants and antimicrobials for dietary and therapeutic uses.