Estimation of phytochemicals and antioxidant activity in Hibiscus sabdariffa L.

The present study was aimed to understanding functional properties of various parts of H. sabdariffa, a popular vegetable in Andaman and Nicobar Islands. Flowers were found to be rich in polyphenol, tannin and flavonoids. Anthocyanin content was highest in calyces while ascorbic acid and carotenoids in fruits. Reducing sugar and total carbohydrate were maximum in calyces, non-reducing sugar in flower and free amino acids in leaf extracts. Oxalate and nitrate were highest in calyces while phytate in mature seeds and saponin in fruits. Strong correlation was observed between antioxidant activity and ascorbic acid content (r2= 0.76; p<0.01) in H. sabdariffa extracts. Flavonoids and tannin contents in H. sabdariffa parts showed strong correlation (r2= 0.92; p<0.05). The findings support health benefits of H. sabdariffa and suggest for further analysis using HPLC for extraction of functional items with high antioxidant activity.