In Vitro α-Amylase Inhibition and Antioxidant Activities of Methanolic Extract of Amaranthus Caudatus Linn.

OBJECTIVES: The present study was aimed to investigate the α-amylase inhibition and antioxidant activities of methanolic extract of Amaranthus caudatus Linn (MeAc). METHODS: Methanolic extract of Amaranthus caudatus was screened for α-amylase inhibition activity by CNPG3 method (2-chloro-p-nitrophenyl-α-D-maltotrioside) and antioxidant activity was evaluated by 1,1-diphenyl-2-picryl-hydrazile (DPPH) free radical scavenging, superoxide dismutase (SOD) scavenging, hydroxyl free radical scavenging, nitric oxide (NO) radical scavenging, and 2.2'-azinobis-3-ethylbenzothiazole-6-sulfonic acid (ABTS) radical scavenging assays. MeAc was also screened for non enzymatic hemoglycosylation. RESULTS: The methanolic extract of Amaranthus caudatus showed potent α-amylase inhibition activity (IC(50) 19.233 µg/ml). MeAc showed significant antioxidant activity in all the in vitro antioxidant models. Furthermore, the MeAc was found to be extremely effective in scavenging ABTS radical activity (IC(50) 48.75±1.1 µg/ml) when compared to DPPH (IC(50) 77.5±0.4 µg/ml), SOD (IC(50) 62.5±2.1 µg/ml), hydroxyl (IC(50) 88.50±1.8 µg/ml) and NO (IC(50) 67.5±2.2 µg/ml) scavenging activity. CONCLUSIONS: The methanolic extract of A. caudatus showed potent α-amylase inhibition and antioxidant activities.