Elicitation Strategies for Enhanced Homoplantaginin Production in Salvia plebeia R. Brown In Vitro Cultures and Evaluation of Their Anti-Inflammatory Activities

Abstract

Salvia plebeia R. Brown is a medicinal plant containing various bioactive compounds, including flavonoids, and has been reportedto exhibit diverse pharmacological effects such as anti-inflammatory, antioxidant, and hepatoprotective activities. However, previous studieson S. plebeia have mainly focused on phytochemical identification and pharmacological evaluation, while biotechnological approachesaimed at enhancing the productivity of major bioactive compounds—particularly metabolic regulation and content improvement throughelicitor treatment in in vitro culture systems—remain largely unexplored. In this study, we investigated the effects of elicitor treatmentson the accumulation of homoplantaginin, a major bioactive compound in the leaves of in vitro–cultured S. plebeia, as well as the associatedchanges in anti-inflammatory activity. In vitro–grown plantlets were treated with yeast extract at concentrations of 1, 2, and 5 mg/Land polyethylene glycol (PEG) at concentrations of 1, 2, and 5% (w/v), respectively. Homoplantaginin content was quantitatively analyzedusing high-performance liquid chromatography (HPLC), and anti-inflammatory activity was evaluated by measuring nitric oxide (NO)production inhibition in RAW 264.7 macrophage cells. As a result, the homoplantaginin content was significantly increased in the treatmentwith 2 mg/L yeast extract compared to the control, while the highest NO inhibition activity was observed in the 5% PEG treatment. These findings suggest that elicitor treatment can effectively enhance the production of bioactive compounds and anti-inflammatory activityin in vitro–cultured S. plebeian. Furthermore, this study provides fundamental data supporting the potential industrial application of S. plebeia through further elucidation of metabolic pathways and optimization of culture conditions.