Chitosan-induced Enhancement of Phenolic Compounds and Antioxidant Activity in Dendrobium fimbriatum In Vitro Cultures

Studies on the therapeutic potential of secondary metabolites derived from Dendrobium species have gained increasing attention in recent years, particularly due to their antioxidant, anticancer and anti-inflammatory properties. The inherently low production of secondary metabolites in Dendrobium species, combined with their slow growth in the wild, poses significant challenges in obtaining sufficient plant tissue for the extraction of bioactive compounds. Based on the hypothesis that supplementing plant tissue cultures with exogenous elicitors promotes biomass accumulation and enhances secondary metabolite production, this study investigated whether the biological elicitors chitosan and salicylic acid could increase total phenolic content and antioxidant activity in Dendrobium fimbriatum. In vitro shoot cultures of D. fimbriatum were treated with various concentrations of chitosan or salicylic acid for different durations. Colorimetric assays were used to assess the total phenolic content and antioxidant activity. The results showed that treating shoot tissue cultures with 100 mg/L chitosan for 30 days increased the total phenolic content from 14.73 ± 1.47 to 21.07 ± 1.01 mg GAE/g dry weight, a 30% increase. Moreover, this treatment did not affect photosynthetic pigments, suggesting there was no physiological stress. These results highlight the potential of chitosan as an effective elicitor for improving secondary metabolite production in D. fimbriatum. Future studies could focus on optimizing these conditions to further advance the production of bioactive compounds for use in herbal remedies derived from D. fimbriatum.