Enhancement of Biomass and Secondary Metabolite Production of St. John's Wort (Hypericum perforatum L.) under a Controlled Environment

Abstract

There is increasing interest in growing medicinal plants under controlled environments for phytopharmaceutical products, partly because it provides safety and efficacy. However, few studies on medicinal plant production under controlled environments have been reported. In the current study, St. John's wort, a traditional medicinal plant with antidepressive properties, was grown in a controlled environment system (CES) and in the field in summer (FS) and winter (FW) . Despite the higher planting density in the CES-treatment, plants showed the greater biomass and secondary metabolite production than those of the plants in both the FS-treatment or FW-treatment. Total dry mass per plant in the CES-treatment was 2.4 and 2.1 times greater than those of plants in the FS-and FW-treatments, respectively. Leaf net photosynthetic rate and chlorophyll a concentration were higher in the CES-treatment than in the FS-treatment or FW-treatment. The hypericin, pseudohypericin and hyperforin contents (mg plant-1) in leaf tissues in the CES-treatment were 6.1, 5.6 and 10.6 times greater, respectively, than those in the FW-treatment. Therefore growing medicinal plants under a controlled environment appears to provide high biomass and secondary metabolite production.