Fig. 2

Analytical HPLC chromatogram of C1, C2 and C3 showing single peaks at 10.487, 8.644 and 10.994 min, and compound structures. Chromatographic conditions: Vision Ht C18 column (5 μm; 10  ×  250 mm, Agilent USA). Mobile phase A (Millipore H₂O) and mobile phase B (acetonitrile) in gradients: 0–5 min; 15% B in A (isocratic run), 5–27 min; 15–100% B (gradient mode), 27–32 min; 15% B in A (for column equilibration). Flow rate; 1 ml/min, injection volume 20 µl. All compounds showed UV maxima at 280 nm (characteristic of polyphenolic compounds). 7-O-galloyl catechin (C1), catechin (C2), and methyl gallate (C3)