Phenolic profile, antioxidant and enzyme inhibitory activities of Stachys annua subsp. annua var. annua

The antioxidant and enzyme inhibitory activities of different solvent extracts of Stachys annua (L.) subsp. annua var. annua were determined. Specific phenolics were also determined by RP-HPLC. Methanol extract was found to be rich in phenolics (35.36 mg gallic acid equivalent/g extract). Antioxidant activities of the extracts were determined by using different complementary test systems including phosphomolybdenum, β-carotene bleaching, radical scavenging activity, reducing power, and metal chelating effect. Inhibitory activities of the extracts on acetyl cholinesterase, butyryl cholinesterase, tyrosinase, α-amylase, and α-glucosidase were also investigated. Ethyl acetate extract was found superior to the others especially in terms of its inhibitory activity on butyryl cholinesterase, tyrosinase, and α-glucosidase (6.32 mg galantamine equivalent/g extract, 23.95 mg kojic acid equivalent/g extract, 6.18 mmol acarbose equivalent/g extract, respectively), whereas the water extract exhibited the weakest activity. These findings suggest that S. annua extracts might be considered as an alternative antioxidative and enzyme inhibitory agents.