Estimation of anti-oxidant activity and quantification of specific phenols and flavonoids in Asphodelus tenuifolius Cavan. (Onion weed) using HPLC

Asphodelus tenuifolius Cavan. commonly known as onion weed is a member of family Asphodelaceae. Plants growing at Spalwan and Sungal areas of Kathua and Jammu districts of Jammu region (J&K, India) were studied for the biochemical constituents of their leaves. Analyses were carried out qualitatively as well as quantitatively. Various phytochemicals like phenols, alkaloids, flavonoids and glycosides showed their presence in colorimetric tests. The extracts of freshly dried leaves prepared in 5 different solvents- chloroform, acetone, ethanol, methanol and water were then subjected to spectrophotometric analysis. Results showed these leaves to be potent source of phenolics and flavonoids in general. In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to evaluate their antioxidant properties. Ethanolic extracts analyzed revealed higher total anti-oxidant activities (IC₅₀ = 25000 µg/ml) in Spalwan compared to that in Sungal (IC₅₀ = 66000 µg/ml). Specifically, eight secondary metabolites were narrowed down for quantification from 16 samples using five solvents. These include p-Coumaric acid (p-CA), Quercetin hydrate (QH), Caffeic acid (CA), Kaempferol (KA), Rutin hydrate (RH), Apigenin (AP), Gallic acid (GA) and Catechin (CH). The first three were completely absent in the extracts of all solvents. Of the remaining 5, Quercetin hydrate was found in all the solvents in maximum quantity across populations while others exhibited variable response. Accordingly, one-way ANOVA showed significant differences in quantities of these metabolites. All these bioactives have a wider utility in the food and pharmaceutical industries which can play a pivotal role in the improvement of human health. Hence, Asphodelus tenuifolius Cavan. may be a promising source of pharmaceuticals and food in future.