The influence of exogenous melatonin and chitosan on secondary metabolites’ production and biological activities of tissue extracts in agitated micro-shoot cultures of Ajuga integrifolia Buch. Ham. ex D.Don

Ajuga integrifolia Buch. Ham. ex D.Don (Family: Lamiaceae) is a wild crafted perennial medicinal herb. Ajuga integrifolia rapid micro-propagation was induced to get disease-free plantlets and high yield agitated micro-shoot cultures by in vitro shoot culture. Micro-shoots were supplemented with Chitosan (CHT) and Melatonin (MEL) in a dose-dependent manner to elicit the secondary metabolites and biomass accumulation. Biomass accumulation was increased [dry weight (DW 16.8 g/L)] in response to CHT (10 mg/L) comparative to control and MEL. A total of 11 bioactive compounds were quantified by HPLC. Results illustrated that MEL (5 mg/L) was optimum for accumulation of majority of bioactive compounds. However, optimum production of aucubin, harpagoside, catalpol, and 8-O-acetyl harpagoside was noted at MEL (3 mg/L) concentration, whereas maximum harpagide production showed by CHT (150 mg/L) treated cultures. Anti-inflammatory and antioxidant activities were highest by MEL (3 mg/L) and MEL (5 mg/L), respectively, correlated with phytochemical biosynthesis. According to the results, Ajuga integrifolia agitated micro-shoot cultures treated with melatonin might be an efficient bio-factory of pharmaceutically active compounds especially chlorogenic acid, rosmarinic acid, apigenin, and quercetin.