Screening culinary herbs for antioxidant and α-glucosidase inhibitory activities

Twelve commonly consumed culinary herbs were assessed for their potential effect in mitigating oxidative stress and postprandial hyperglycaemia: River Mint, Vietnamese Mint, Fish Mint, Spearmint, Sweet Basil, Thai Basil, Coriander, Lemon Verbena, Vietnamese Perilla, Rice Patty, Sawtooth and Rosemary. The radical scavenging and reducing antioxidant activity of the herbs were quite variable ranging from 31-652mg Trolox Equivalent to 35-512mg Ferrous Equivalent per gram dried leaves, respectively. The herbs were largely inactive against pancreatic -amylase, but showed strong inhibitions against yeast -glucosidase at 100g Gallic Acid Equivalent (GAE) per millilitre. Vietnamese Mint is the most potent herbs with the concentration required for 50% inhibition of activity of 6.9g Dried Leaves per millilitre. In addition, Vietnamese Mint was the only herb that produced significant inhibition of rat intestinal -glucosidases, reducing activity to 29.6% at 100gGAEmL(-1) compared with control.