Abstract
The plant based natural products have always been a rich source of bioactive molecules for drug discovery. The tender shoots of Calamus leptospadix Griff., an edible medicinal plant was extracted using methanol, water and ethanol as three different solvents to study the effect of the extracting solvents and temperature on their antioxidant, antidiabetic and antibacterial properties and total phenolic and flavonoid contents. The antioxidant properties were determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and ferric reducing antioxidant power (FRAP) assay. The α-glucosidase inhibitory assay was carried out to determine the antidiabetic potential. The antibacterial properties of the extracts were determined against four strains of bacterial species viz. Bacillus subtilis, Streptococcus pneumoniae, Escherichia coli and Citrobacter freundii using Broth macro dilution method. The methanolic extracts of the plant were found to possess the highest total phenolic and total flavonoid contents. In the antioxidant assays, the cold methanolic extract was found to exhibit the highest DDPH radical scavenging activity and ferric-reducing antioxidant power. In the antidiabetic assay, the extract exhibited better α-glucosidase inhibitory potential than that of the positive control acarbose. It was also found to be effective against both gram-positive and gram-negative strains in the antibacterial assay. A flavan-type compound 4-(5,7-dimethoxychroman-2-yl)phenol was isolated from the most bioactive cold methanolic extract of the plant and characterised from its XRD, 1H and 13C NMR, HRMS and IR data.