LAUSR

Abstract Efficient plant extraction techniques that provide high yields of the desired molecules are important. This study focused on the optimization of the processing conditions for a microwave-assisted extraction (MAE) to obtain a maximal yield of prominent pentacyclic triterpenes from Centella asiatica. Response surface methodology (RSM) was tested in the experiments to improve the extraction conditions. The proportions of liquid-to-solid ( X 1 ), ethanol concentration ( X 2 ), microwave power ( X 3 ), and irradiation time ( X 4 ) were defined as the independent variables. The responses were the recovery of madecassoside, asiaticoside, and its sapogenin triterpene acids. The target compound-rich extract was intensified using Diaion HP-20 resin. The results showed that all the independent MAE variables are important for the isolation of specific compounds (p  X 1 , X 2 , X 3 and X 4 were 10 mL/g, 58 % (v/v), 300 W and 3.4 min, respectively. The efficient macroporous resin method was successful at enriching the triterpenes in concentrated extracts. Both MAE crude extract and enriched samples exerted inhibitory effects on matrix metalloproteinases (MMPs)-3 and 9 secretions against ultraviolet B (UVB)-irradiated human dermal fibroblasts (HDFs). The MAE results, when enriched, are beneficial for increasing the amounts of the targeted active ingredients. These findings demonstrate the feasibility of extracting and enriching the target triterpenes.