Phenolic compounds profile and hypoglycaemic, anti-inflammatory and antioxidant properties of aqueous leaf extract of Androstachys johnsonii Prain: In vitro study

• Androstachys johnsonii is a well-known medicinal plant used in traditional medicine for the treatment of diabetic complications. • The development of diabetic complications is linked to oxidative stress and inflammation arising from hyperglycaemia. • The aqueous leaf extract of Androstachys johnsonii contains up to 34 phenolic compounds (majorly flavonoids). • Phenolic compounds in medicinal plants exhibit hypoglycaemic, hypoglycaemic, and anti-inflammatory properties. Androstachys johnsonii Prain has been identified through ethnobotanical studies as a medicinal plant used in traditional medicine to treat medical complications, including diabetes mellitus (DM). The development of DM complications involves hyperglycaemia and excessive production of free radicals and inflammatory cytokines. This study investigates the hypoglycaemic, antioxidant, and anti-inflammatory properties of the aqueous extract of A. johnsonii , to reveal the possible pathways through which the extract can possibly treat DM complications. A total of 34 phenolic compounds (majorly flavonoids) was identified in the plant extract through the Ultra-High Performance Liquid Chromatography Mass Spectrometry (UHPLC-MS) analysis. Total polyphenols were 403.28 ± 12.75 mg gallic acid equivalent (GAE)/g with 88.35 ± 2.16 mg catechin equivalent (CE)/g of flavanols and 6.96 ± 3.10 mg quercetin equivalent (QE)/g flavonols. For antioxidant capacity determination, ferric reducing antioxidant power (FRAP) (1342.68 ± 3.41 mg ascorbic acid equivalent (AAE)/g), 2,2-diphenyl-1-pycrylhydrazyl (DPPH) (571.57 ± 0.55 mg Trolox equivalent (TE)/g), and Trolox equivalent antioxidant capacity (TEAC) (478.88±0.09 mg Trolox equivalent (TE)/g) values were obtained. The extract demonstrated a concentration-dependent anti-inflammatory activity on RAW macrophage cells. The highest concentration of the extract increased glucose uptake and utilisation in C3A hepatocarcinoma cells. The extract showed a significant concentration-dependent ( P < 0.05) increase in α-glucosidase inhibition and a significantly ( P < 0.05) lower pancreatic lipase inhibition. These results suggest the potential therapeutic effect of A. johnsonii in the treatment of DM.