Chemical Profiling and Quantification of Tannins in Phyllanthus niruri Linn. Fractionated by SFE Method

Abstract

Chemical profiles or fingerprints of polyphenolic compounds (condensed and hydrolyzable tannins) in various fractions of Phyllanthus niruri Linn extracted using supercritical carbon dioxide and various polar cosolvents, namely water, methanol, and ethanol are presented. Chemical analysis of the extracted fractions was undertaken using High Performance Liquid Chromatography (HPLC) with the in-house method. Good peak reproducibility of intra-day (R.S.D range 0.01–0.21 min) and inter-day (R.S.D range 0.5–0.8 min) was obtained for the detection of ellagitannins (hydrolyzable tannins) and flavonoids (condensed tannins). Fractions extracted using ethanol-water mixtures as cosolvent at 200 bar and 60°C exhibited an appealing behavior whereby non-polar compounds and flavonoids were able to be fractionated before the extraction of ellagitannins. Contents of three major ellagitannins, namely gallic acid (0.39–0.48% g/g), corilagin (2.42–3.00% g/g), and ellagic acid (5.94–6.48% g/g), were relatively higher compared to the commercial HEPAR-P™ standardized extract (0.21, 2.64, and 4.17% g/g, respectively). The study shows that the supercritical fluid extraction (SFE) method with the use of appropriate cosolvents is able to produce P. niruri fractions with improved yields and different chemical characteristic, which thus can be used as a rapid preparative tool for further downstream processing of plant samples.