Effect of solvent extraction on phenolic content, antioxidant and α- amylase inhibition activities of Swertia chirata

Swertia chirata is an indigenous medicinal plant of temperate Himalaya which has been widely used in herbal and folk medicine. The study aimed to evaluate the phenolic content, antioxidant and andiabetic potential of S. chirata in different solvents. The edible portion (stem) of the plant was extracted with distilled water and different concentrations of methanol, ethanol and acetone to determine total phenolic content (TPC), antioxidant properties by ferric reducing antioxidant power (FRAP), total antioxidant capacity (TAC), DPPH free radical scavenging activities and antidiabetic property by inhibition of %-amylase. All the extracts showed antioxidant and antidiabetic properties although they varied significantly (P<0.05) among the different extractions. TPC varied between 20 ± 2 mg GAE/100g (ethanol 100%) to 221 ± 12 mg GAE/100g (water extracts), FRAP ranged between 18 ± 4 mg AAE/100g (acetone 100%) to 162 ± 4 mg AAE/100g (water extracts) and TAC ranged between 139 ± 17 mg AAE/100g (acetone 100%) to 707 ± 71 mg AAE/100g (acetone 50%). DPPH radical scavenging and alpha amylase inhibition activities were determined in dose dependent manner ranging between 3-15 mg/mL and 7-21 mg/mL respectively. Acetone 50% showed the most prominent dose dependent scavenging of DPPH radical while alpha amylase inhibition by ethanol 100%, methanol 100% and acetone 100% were comparable with each other. The study revealed the influence of solvent extraction on phenolic compound, antioxidant and %-amylase inhibition activities of S. chirata. These findings support the use of the plant as a traditional and folk medicine.