Phytochemical analysis, antioxidant activity and identification of bioactive constituents from three wild medicinally important underutilized plants of Ladakh, India using GCMS and FTIR based metabolomics approach

Abstract

Underutilized wild medicinal plants have been used in various traditional system of medicine including Chinese, Turkish, African and Brazilian in the treatment of pain, purgative, constipation, tonic, hemostatic, headaches, arthritis, backache, rheumatism, and eczema. The aim of the present study is to quantify and identify the bioactive constituents of three ethnobotanically important wild plants of cold desert Ladakh including Rheum spiciforme, Rumex patientia, and Sonchus oleraceus. Using spectrophotometry, total phenol, flavonoid, phytosterol and antioxidant activity was analyzed. Rheum spiciforme has highest phenol content (77.2 mg/g), Rumex patientia was highest in phytosterol (133.3 mg/g) and flavonoids (88.7 mg/g). Sonchus oleraceus showed highest antioxidant activity by DPPH (IC50 = 39.51 μg/mL) and FRAP assay (98.93 mg/g). GCMS and FTIR metabolomics approach is used for the identification of secondary metabolites for further use in pharmaceutical preparations. FTIR analysis of the plant extract shows the presence of functional groups such as carboxylic acids, aromatics, alkanes, alcohols, phenols, aliphatic amines, alkenes and amine groups. GCMS analysis of methanolic extract revealed 29 different bioactive compounds with high content of 1-Naphthalenol, methylcarbamate (13.22%), Cyclopentadecane (12.43%) in Rheum spiciforme, 22 peak with high content of Benzene, 1,1′-sulfonylbis[4-chloro- in Rumex patientia (31.18%) and 13 compounds identified with the highest % area of compound 2,2-Dimethoxybutane in Sonchus oleraceus (19.33%). The functional groups and identified compounds have various health benefits including antioxidant, anti-inflammatory, immunomodulatory and antifungal activity which could be used for production of food supplements and novel drugs.