Chemical profile and scavenging activity of four extracts from Hibiscus sabdariffa L. calyx

Objective Hibiscus sabdariffa L., also known as roselle and karkadeh, is commonly used in traditional medicine and has many applications on food, pharmaceutical and cosmetic industries. More than 100 cultivars of H. sabdariffa are found. Despite the fact that Sudan is considered as one of the principal producer of H. sabdariffa there has been limited systematic study on the efficiency of different solvent extraction on its bioactive molecules. Therefore, this study was designed to investigate the chemical constituents of H. sabdariffa calyx using acetone, ethanol (EtOH), 50% EtOH and water as extraction solvents and their impact on the DPPH free radical scavenging activity. Results Results showed that the total polyphenol, flavonoids and vitamin C contents of the dried calyces were significantly (P < 0.05) affected by the solvent extraction used. HPLC analysis using 16 standards revealed the presence of 11–13 compounds in the four extracts with the 50% EtOH extract recovered the highest concentrations of identified compounds. Moreover, the 50% EtOH extract revealed highest DPPH free radical scavenging activity (IC50 1.544 ± 0.3 µg/mL). Based on these results, maceration the calyx on 50% EtOH was therefore suggested for optimal extraction of bioactive compounds with high antiradical activity from H. sabdariffa calyx.