Nano-Chitosan as a Biotic Elicitor for Enhancing Secondary Metabolite Production in Basil Callus Cultures (Ocimum Basilicum L.)

Abstract

Ocimum basilicum L. is one of the important medicinal and aromatic plants, widely known for its high content of phenolic compounds and flavonoids with significant antioxidant properties. The present study was conducted to investigate the effect of nano-chitosan on biomass accumulation, phytochemical production and antioxidant activity in basil callus cultures. Callus cultures were induced using leaf explants cultured on Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg/L 6-benzylaminopurine (BAP). The nano-chitosan was applied at 0, 5, 10, 25, 50, 75 and 100 mg L-1. After 6 weeks elicitation, biomass accumulation, total phenolic content, total flavonoid content, antioxidant activity and major phenolic compounds were assessed.
Nano-chitosan significantly boosted callus growth and phytochemicals. The maximum biomass, phenolic content and flavonoid content was observed at 50 mg/L nano-chitosan. Antioxidant activities of elicited cultures were determined by DPPH, ABTS and FRAP and showed significant increase. HPLC analysis showed an increase in the accumulation of rosmarinic acid, chicoric acid, caffeic acid, quercetin, kaempferol and apigenin after treatment with nano-chitosan. Correlation analysis revealed a positive correlation among phenolic content, flavonoid content and antioxidant activity.These results suggest that under carefully regulated in vitro conditions, nano-chitosan can be utilized as an efficient elicitor to enhance phytochemical output in basil callus cultures.The results suggest the possible use of nano-chitosan as a sustained elicitation approach for commercial phytochemical synthesis under controlled in vitro settings and offer important information for its application in medical plant biotechnology.