Phytochemical and antioxidant activity of roselle (Hibiscus Sabdariffa L.) petal extracts

Abstract

Roselle (Hibiscus sabdariffa L.) is known for delicacy and also for medicinal properties. The present work aim to study the phytochemical screening of Hibiscus sabdariffa for various medicinally important compounds and their quantification. The results showed that alkaloids, anthocyanins, flavonoids, saponins, steroids, sterols and tannins are present in petals of the H. sabdariffa. Anthocyanin content was highest while the contents of phenols and flavonoids were lowest. HPLC analysis revealed two phenolic acids, 16 flavonoids and four anthocyanins in petal of H. sabdariffa. The major compounds were gossypetin, hibiscetin, quercetin and sabdaretin (flavonoids) while delphinidin 3-O-sambubioside and cyanidin 3-O-sambubioside were the major anthocyanins. The antioxidant activity of the investigated extract has a scavenging ability of DPPH radical scavenging activity (around 97 %). The IC50 values of H. sabdariffa extract was 0.24 mg/ml while that of ascorbic acid used as the reference control was 0.35 mg/ml. This indicated that the compounds constituting mainly petals of H. sabdariffa, such as anthocyanins, flavonoids and phenolic acid contribute to the antioxidative activity. Our findings provide evidence that the petal extract of H. sabdariffa is a potential source of natural antioxidants, and this justify its uses in folkloric medicines.