Anthocyanin isolation from Hibiscus sabdariffa L. flowers by extraction, macroporous D101 resin purification, and biological evaluation

This study aimed to improve the purity of anthocyanins in the extract from Hibiscus sabdariffa L. (H. sabdariffa L.) by macroporous D101 resin. Thereby, we determined the main components, thermal stability properties, and some biological activities of anthocyanin mixture from Hibiscus flowers. The main anthocyanin identified in the anthocyanin sample was Cyanidin-3-O-sambubioside. In the purification stage with D101 resin, the anthocyanin fraction had the highest purity of 72.18 % compared with 12.07 % of that of the extract. Purified anthocyanins have very good color stability at low temperatures and in mildly alkaline media. The high antioxidant capacity of anthocyanins was recorded by methods of the free radical scavenging capacity of 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), and Ferric-reducing antioxidant power (FRAP) with IC50 values of 93.14 +/- 0.93 mu g/mL, 75.51 +/- 0.71 mu g/mL and 73.26 +/- 0.93 mu g/mL, respectively. The total antioxidant activity (RP) of anthocyanin sample was dose-dependent, the absorbance increased from 0.149 (100 mu g/mL) to 0.873 (500 mu g/mL). Anthocyanin also can inhibit both Gram (+) and Gram (-) bacteria of Staphylococcus aureus and Escherichia coli, as well as the mold Aspergillus flavus. Research has also shown potential anti-inflammatory in vitro of anthocyanins. These findings provide evidence that the purified anthocyanin from H. sabdariffa L. is a potential source of natural antioxidants, anti-bacteria, and anti-inflammatory in functional food and medicine.