Green extraction of polyphenolic-polysaccharide conjugates from Pseuderanthemum palatiferum (Nees) Radlk.: Chemical profile and anticoagulant activity.

In this study, pressurized liquid extraction (PLE) of polyphenolic-polysaccharide (PP) from Pseuderanthemum palatiferum (Nees) Radlk. leaves was carried out and compared with a conventional technique using 0.1 M sodium hydroxide. The extracts were purified according to the method reported previously to obtain PP conjugates which were further studied about chemical profiles and anticoagulant activity. Fourier-transform infrared spectroscopy (FTIR), UV-Vis, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and spectrophotometry analysis were used to characterize the selected PP conjugates. The results showed that PP conjugates comprised of carbohydrate, phenolic, and protein constituents with the yield ranged from 2.76% to 14.34%. Seven mono sugars containing in all conjugates were determined using high-performance liquid chromatography (HPLC), namely, arabinose, fucose, galactose, glucose, mannose, rhamnose, and xylose. PP conjugates obtained from PLE at 150 °C (PP-PLE5) exhibited better anticoagulant activity than those found at 200 °C and comparable to that of the conventional technique. On gel permeation chromatography, PP-PLE5 showed a broad molecular mass from 6 to 642 kDa. From the obtained results, PLE can be used as a green effective technique for the recovery of PP conjugate from P. palatiferum leaves.