Antimicrobial and Antioxidant activity of Anaphalis lawii (Hook.f.) Gamble

Abstract

The present study was undertaken to investigate antimicrobial and  antioxidant activities of leaf and flower extracts of Anaphalis lawii (Hook.f.) Gamble (Compositae). The powdered leaves and flowers were extracted with methanol in soxhlet extraction assembly. The antimicrobial activity of leaf extract (LE) and flower extract (FE) were determined against a panel of 9 bacteria and 2 fungi by Agar well diffusion method. Antioxidant activity of LE and FE was screened by DPPH free radical scavenging, Ferric reducing and Metal chelating activity. Total phenolic content and flavonoid content of extracts was determined by Folin-Ciocalteu method and Aluminium  chloride colorimetric estimation method respectively. Both LE and FE  caused inhibition of test bacteria and fungi in a concentration dependent manner. Gram positive bacteria were more susceptible to LE and FE when compared to Gram negative bacteria. On comparing with Candida albicans,
susceptibility to extracts were found higher in Cryptococcus neoformans. The LE and FE dose dependently scavenged DPPH free radical with IC50 value of 6.01 and 5.20ìg/ml respectively. An increase in the absorbance of reaction mixture with increase in concentrations of extracts showed  reducing potential of LE and FE in ferric reducing assay. In metal chelating assay, both LE and FE caused chelation of ferrous ion with IC50 value of 180.98 and 152.89ìg/ml respectively. The phytochemical analysis revealed the presence of flavonoids, saponins and tannins in both the extracts. Total phenolic and flavonoid contents were high in FE than LE. Overall, FE showed potent antioxidant and antimicrobial activity when compared with LE and it could be related to the high phenolic and flavonoid content in FE. Further studies on isolation of active principles from extracts and testing their bioactivities are to be carried out.