Effect of different extraction techniques on quantification of oleanolic and ursolic acid in Lamii albi flos

The classic techniques such as: maceration (ME), Soxhlet (SE) and heat reflux extraction (HRE) were compared with modern techniques: ultrasonic extraction (UE), microwave-assisted extraction (MAE) and accelerated solvent extraction (ASE) for their extraction efficiency of two triterpenic acids from Lamii albi flos. Quantifications of oleanolic and ursolic acid in obtained extracts were performed by HPLC method on a RP-18 column with use of mobile phase consisting of acetonitrile–water–1% phosphoric acid (85:15:0.5, v/v/v), the flow rate was 0.8 mL/min and temperature was 10 °C.MAE in closed system was the most effective technique. The best results for ursolic acid were obtained with use of MAE in closed system for 10 min and 100% of generator power. Oleanolic acid was better extracted with use of milder conditions (30% generator power and 30 min). Ultrasonic assisted extraction proved to be noteworthy, alternative method due to its simplicity, inexpensive equipment and relatively good extraction efficiency.

► Extraction techniques of two triterpenic acids from Lamium album were compared.
► Quantifications of oleanolic and ursolic acid were performed by HPLC method.
► MAE in closed system was the most effective technique.
► UE proved to be alternative method due to low cost and good extraction efficiency.