Evaluation of nutritive and nutraceutical value of wild non-conventional leafy herbs in Assam, North East India

Abstract

In recent times, there is increasing interest in lesser known, under-utilised food plants. Assam and N. E. India is known for hundreds of such plants and not much is known about them particularly their nutritive values. Therefore, the present study was carried out to evaluate the basic nutritional parameters, dietary antioxidants and in vitro antioxidant activity of five wild non-conventional leafy vegetables traditionally consumed by the indigenous people as supplement to staple food. The species studied were Polygonum perfoliatum, Sphenoclea zeylanica, Ludwigia adscendens, Oenanthera javanica and Alternanthera philoxeroids. Except P. perfoliatum, the others are semi-aquatic or aquatic. Results revealed that crude protein content varied from 15.64 to 28.38 %. Total carbohydrates content was low, in the range of 7.9 to 15.33%, so also, lipid varied from 2.01 to 3.44 %. Crude fibre and ash contents were impressive, the variation ranging between 13.41 to 25.36 % and 7.42 to 19.37 %, respectively. Free amino acid contents were high in the range of 3.21 to 10.25 mg/g. Dietary antioxidants were assessed in terms of phenolics and flavonoids, their range of variation being 3.12 to 5.20 mg GAE/g and 2.83 to 3.50 mg RE/g, respectively. In-vitro antioxidant activity based on DPPH reduction exhibited promising result with IC50 value varying from 3.84 to 1.08 mg/mL. The present study reinforces the emerging reports that lesser known, non-conventional leafy vegetables are promising with respect to nutritive and nutraceutical values and can contribute to combating malnutrition particularly for protein, minerals and crude fibre.