Differential effect of vitamins and plant growth regulators on sesquiterpene lactones and phenolic acids accumulation of Inula britannica L. shoot cultures

Abstract

Inula britannica L. is of great importance for Traditional Chinese and Kampo medicinal practices.Shoot cultures of Bulgarian accessions of the plant were developed and an experiment for elucidation of the combined effect of vitamins and auxin and cytokinin on their biomass formation, physiological status and secondary metabolite productivity was conducted. While Gamborg vitamins stimulated plant height, the Murashige and Skoog formulation increased leaf area and root length. Addition of benzyl adenine strongly stimulated axillary rosettes formation, however it suppressed aerial and root length and caused callusogenesis at explant base, this effect being slightly alleviated by 1-Naphthaleneacetic acid addition. Murashige and Skoog vitamins stimulated phenolic acids in the control and benzyl adenine treatments, while Gamborg—in the combined benzyl adenine and 1-Naphthaleneacetic acid ones. The capacity of production of britannin through gaillardin was stimulated by Gamborg vitamins in plant growth regulators free plants, but auxin and cytokinin supplementation reversed this effect. Plant growth regulators treatments generally lowered lipid peroxidation as compared with the controls at both vitamin supplementations. Elevation of hydrogen peroxide was related to preservation of lower malondyaldehyde levels, which was indicative of hydrogen peroxide role as a mediator to alleviate long-term lipid peroxidation in vitro. In all samples the chlorophyll a/b ratios remained at comparable levels indicating the physiological flexibility of the plant irrespectively of the different plant tissue manipulations. The results are indicative of the relations between growth, development and secondary metabolite productivity in I. britannica L. shoot cultures. The species showed a potential to target desired phytopharmaceuticals by modification of growth and development in vitro. The comparative study of vitamins and plant growth regulators treatments on Inula britannica L. shoot cultures showed their differential effect on biomass formation, physiological status and secondary metabolite formation.