Abstract

Leptocarpha rivularis is a medicinal plant that grows in southern Chile and is used to treat some diseases. Previous studies have demonstrated the presence of flavonoids, alkaloids, and terpenes, which can be extracted with green technologies such as supercritical fluid extraction. The objective was to evaluate the pharmacological activity of L. rivularis stem extracts according to the content of bioactive compounds (flavonoids, alkaloids, and terpenes) obtained by sequential supercritical extraction. This extraction technique is based on sequential stages with an increase in solvent polarity with each stage. The supercritical extraction was carried out in three sequential stages at 60°C: Stage 1: 25 MPa con CO2 pure, stage 2: 50 MPa con CO2 pure, and stage 3: 50 MPa and CO2 + ethanol (5%wt). The total content of flavonoids, alkaloids, and terpenes was quantified by spectrophotometry. Antioxidant capacity was determined by the FRAP and DPPH methods. The inhibitory capacity of the enzyme acetylcholinesterase was determined by the Ellman method. The highest yield of flavonoids (370 mg quercetin/kg dry solid) and alkaloids (4.2 mg atropine/kg dry solid) was found in Stage 3. At the same time, the highest yield of terpenes (256 mg linalool/kg dry solid) was found in stage 2. Stage 3, with the highest yield of flavonoids and alkaloids, showed the highest antioxidant and acetylcholinesterase inhibitory capacity. Sequential supercritical extraction resulted in a suitable technique to obtain L. rivularis stem extracts with high acetylcholinesterase inhibitory and antioxidant capacity.