PHYTOCHEMICAL SCREENING AND ANTIOXIDANT POTENTIAL OF RHEUM WEBBIANUM ROYLE FROM NALTAR VALLEY, GILGIT-BALTISTAN, PAKISTAN

Abstract

The study revealed the phytochemical screening and antioxidant potential of Rheum webbianum Royal an important medicinal plant from Naltar Valley, Gilgit-Baltistan, Pakistan. The grinded material of root and aerial part plant were subjected to methanol extraction followed by sequential fractionation with ethyl acetate, dichloromethane, and n-hexane.Qualitative phytochemical screening revealed the presence of alkaloids, flavonoids, and phenolic compounds in the root and aerial parts of plant, while carbohydrates were exclusively detected in roots. Steroids were absent in root extract. The antioxidant potential was in`2vestigated using DPPH free radical scavenging assay, with all extracts showing significant activity. The ethyl acetate root fraction exhibited the highest antioxidant activity (94.2%), followed by dichloromethane (91.3%) and n-hexane (90.4%) root fractions. The percentage inhibition of aerial part revealed moderate potential as compare to root. Among the fractions of aerial parts dichloromethane fraction showed highest percentage of inhibition (85.3%), followed by n-hexane (83%), methane (81.6%) and ethyl acetate showed relatively low inhibition (70.97%). The strong correlation between phenolic, flavonoid content and antioxidant capacity suggests the extract as major contributors to the observed bioactivity. These findings prove and validate the traditional medicinal uses of R. webbianum and highlights its potential as a natural source of antioxidants for pharmaceutical applications. The superior activity of root extracts, particularly the ethyl acetate fraction, suggest further investigation into isolation of bioactive compounds and their mood of action. The study contributes to the scientific validation of tradition knowledge while emphasizing the conservation value of medicinal plants in the Karakoram region.