IN VITRO FREE RADICAL SCAVENGING POTENTIAL OF ACORUS CALAMUS L. RHIZOME FROM KUTTANAD WETLANDS, KERALA, INDIA

摘要

Objective: The present study was aimed to carry out phytochemical screening and to assess the in vitro free radical scavenging ability of methanolic and aqueous extracts of Acorus calamus (Sweet flag) rhizome collected from Kuttanad wetlands, forming part of Vembanad-Kol wetland system, one of the Ramsar sites in Kerala, India. Methods: The antioxidant potential of the rhizome was evaluated by using six in vitro assays, namely 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl radical, superoxide radical, reducing power, lipid peroxidation and metal ion chelating assay. The phenolic and flavanoid contents of methanolic and aqueous extracts were also analysed. Results: The total phenolic contents of aqueous and methanolic extracts were 19.86 mg/g and 12.17 mg/g respectively. Similarly the flavonoid contents were 8.33 mg/g and 2.56 mg/g. The methanolic extract of the rhizome showed higher hydroxyl radical scavenging activity of 86.83 %, superoxide radical activity of 44.16 %, and also higher reducing power activity. The aqueous extract was a better scavenger of DPPH free radicals with 34.51 %, lipid peroxidation with 49.91 %, and metal ions chelating assays with 39.85 % activity. Conclusion: The methanolic extract of A. calamus rhizome is a good free radical scavenger in case of reducing power, superoxide radical scavenging and hydroxyl radical scavenging assays. On the other hand, aqueous extract showed better radical scavenging ability in metal ion chelating, lipid peroxidation and DPPH radical scavenging assays