Extraction of Kratom (Mitragyna speciosa) leaf compounds by enzymatic hydrolysis-assisted process: Yield, characteristics and its in vitro cytotoxicity in cell lines

This study aimed to develop an antioxidative compound extraction method for Kratom (Mitragyna speciosa) leaves using cellulase and pectinase, in combination and alone. The enzymatic hydrolysis-assisted process (EA) successfully enhanced antioxidant extraction from kratom leaves. The single enzymatic hydrolysis-assisted process (SEA) with 6% cellulase (C6) provided the highest extraction yield. The mixed enzymatic hydrolysis-assisted process (MEA) was then developed using C6, mixed with different concentrations of pectinase. Based on the high extraction yield, the MEA using 6% cellulase and 2% pectinase (C6+P2) was selected for further studies in comparison with that from relevant SEA and the control (without EA). Different extraction processes altered the characteristics and antioxidative activities of resulting extracts. The antioxidative activity of C6+P2 was dramatically enhanced in the gastrointestinal tract model system. Fourier transform infrared (FT-IR) spectrometer results confirmed significant content of phenolic compounds, proteins, and polysaccharides in C6+P2. From in vitro cytotoxicity study, C6+P2 showed an IC50 value of 22.86 and 4.76µg/mL in RAW264.7 and Caco-2 cells, respectively. The bioactive compounds from C6+P2 should be identified in further studies to facilitate their application in the food and pharmaceutical industries.