Optimization of Callus Induction with Enhancing Production of Phenolic Compounds Production and Antioxidants Activity in Callus Cultures of Nepeta binaloudensis Jamzad (Lamiaceae)

Abstract

Background: World Health Organization (WHO) reported that more than 80% of people in the world use herbal traditional medicines nowadays. Many endemic medicinal plants, especially Nepeta species, are facing to extinction as a result of high harvesting, limited distribution, and habitat destruction.Tissue culture is a successful method for plant secondary metabolites production. Nepeta binaloudensis is a medicinal plant belonging to family Lamiaceae. Objective: Our study was focused on devising an optimum procedure for callus induction and phenolic compounds production in N. binaloudensis. First, we are focused on finding suitable explants and media for callus induction. Then, subsequent experiments were conducted to find an optimal concentration of plant growth regulators (PGRs) and reducedglutathione for maximum biomass production, and phenolic compounds production in calli. Material and Method: In this study, the usage of whole plant grown in Hoagland nutrient solution, were used as a source of explants. Also, different media including, ½ MS, MS, and B5 and different combination of PGRs (NAA and BAP) were used for optimization of calli induction. Results: Based on the results of the first experiment, leaf-originated explants, and macro half strength MS (½ MS) medium were used for the next experiments. The highest FW (Fresh Weight) and DW (Dry Weight) of calli were observed in ½ MS medium, supplemented with 2 μM/L reduced-glutathione, 2 mg.L-1 BAP, and 2 mg.L-1 NAA. The maximum amount of total phenolic, flavonoid, tannin contents and free-radical scavenger were observed in calli which were grown in ½ MS medium supplemented with 2 μM/L reduced-glutathione, 2 mg.L-1 BAP, and 2 mg.L-1 NAA. Conclusion: Our study finds the optimum condition for calli induction and phenolic compounds production in N. binaloudensis.