Metabolite profiling, antioxidant activity, and glycosidase inhibition property of the mesocarp tissue extracts of sugar date palm [Phoenix sylvestris (L.) Roxb.] fruits

摘要

Phoenix sylvestris is an underutilized seasonal fruit in West Bengal, India. Methanol extract and extracts after alkaline hydrolysis of the mesocarp tissue of full-mature edible fruits of P. sylvestris were analyzed by GC-MS following a metabolomics approach. The fractions were tested for their antioxidant and inhibitory properties against the two key enzymes involved in diabetes, -amylase, and -glucosidase. Total 71 metabolites belonging to organic acids, amino acids, sugars, sugar alcohols, fatty acids, and phenols were identified in the methanol extract and in fractions after saponification. All the extracts and fractions showed high antioxidant, -glucosidase, and -amylase inhibitory activities. Sugars like raffinose (IC50 = 0.36 M), sucrose (IC50 = 0.51 M), trehalose (IC50 = 0.85 M), and phenols like taxifolin (IC50 = 0.31 M), benzoic acid (IC50 = 2.74 M) inhibited only the enzyme -amylase. Phenolic components which inhibited both the enzymes were caffeic acid (IC50 = 1.42 M for -amylase and IC50 = 1.8 M for -glucosidase), 3, 4-dihydroxy benzoic acid (IC50 = 0.23 M for -amylase and IC50 = 2.58 M for -glucosidase), and quinic acid (IC50 = 4.91 M for -amylase and IC50 = 4.95 M for -glucosidase). Ferulic acid (IC50 = 0.52 M) and 4-hydroxycinnamic acid (IC50 = 0.23 M) inhibited only -glucosidase. This study suggested that the metabolites present in the fruit mesocarp tissue showed the potential antioxidant activity and properties to inhibit the enzymes -amylase and -glucosidase. Further in vivo study is to be carried out to prove the efficacy of the fruits.Abbreviations: FM: crude methanol extract; SI: ethyl acetate extract after alkaline hydrolysis step I; SII: ethyl acetate extract after alkaline hydrolysis step II