Elicitor-mediated enhancement of secondary metabolite accumulation and biological activity in Microchirita involucrata in vitro root cultures

Microchirita involucrata (family Gesneriaceae) has recently been reassigned to the genus Microchirita ; however, its biological properties and potential applications remain unexplored in Thailand. Although the species is valued for its compact growth habit and attractive floral morphology, its phytochemical potential has received little attention. This study established an in vitro culture platform for M. involucrata , identified explants with high secondary metabolite potential, optimized metabolite accumulation through elicitation, and evaluated the biological activities of elicited root cultures. Thin-layer chromatography (TLC) screening revealed that root tissues contained the highest number of antioxidant-active bands; therefore, in vitro –derived root segments were selected for elicitation using methyl jasmonate (MeJA), chitosan (CHT), and β-cyclodextrin (CD), applied individually and in combination (MeJA + CD and CHT + CD). CD alone and combined treatments significantly enhanced antioxidant activity. Root tissue extracts exhibited higher antioxidant capacity, whereas culture medium extracts showed markedly stronger lipoxygenase (LOX) inhibitory and antibacterial activities. Culture media derived from CD and combined elicitor treatments displayed the highest LOX inhibition, with values ranging from 72.04% to 94.35%. Among all treatments, the MeJA + CD–elicited culture medium extract demonstrated the strongest antibacterial activity, with minimum inhibitory and bactericidal concentrations of 0.78 mg/mL against Staphylococcus aureus . Against Escherichia coli , the corresponding MIC and MBC values were 1.56 and 3.13 mg/mL, respectively. Overall, these findings provide new insights into elicitor-induced secondary metabolism in M. involucrata in vitro root cultures, supporting its relevance as a source of biologically active metabolites.