Extraction of tannins and saponins from plant sources and their effects on in vitro methanogenesis and rumen fermentation

Abstract

This study was aimed to extract tannins from Swietenia mahagony and saponins from Sapindus rarak by using different solvents, and to test their extracts on in vitro rumen fermentation and methanogenesis. Solvents used for extraction were water, methanol, acetone and their combinations. Tannin and saponin extracts were added into each incubation bottle containing Brachiaria humidicola grass and Indigofera sp. legume (1:1 w/w) according to the following treatments (in four replicates): R1: control substrate, R2: R1 + 0.5 mg/ml tannin extract, R3: R1 + 1 mg/mL tannin extract, R4: R1 + 0.5 mg/mL saponin extract, R5: R1 + 1 mg/mL saponin extract, R6: R1 + 0.5 mg/mL tannin extract + 0.5 mg/mL saponin extract, and R7: R1 + 1 mg/mL tannin extract + 1 mg/mL saponin extract. Results revealed that 75% water + 25% methanol was the best solvent to extract tannins from S. mahagony whereas 100% methanol was the best to extract saponins from S. rarak. The highest gas production and the lowest methane emission were obtained in R7. It can be concluded that combination of tannin and saponin extracts were potential in mitigating ruminal methane emissions.