A comparative evaluation: phytochemical composition and antioxidant capacity of three roselle (Hibiscus sabdariffa L.) accessions

An increased consumption and demand in international trade suggests a need for quality assurance of roselle (Hibiscus sabdariffa) products. A liquid chromatography-mass spectrometry method was developed for the determination of anthocyanin profiles of the calyces, phenolic acids and flavonoids of the leaves of Jamaica, Senegal and Malaysia accessions. Delphinidin-sambubioside, delphinidin-glucoside, cyanidin-sambubioside, cyanidin-glucoside and delphinidin were identified from the calyces of these accessions. Chlorogenic acid and its isomers, glycosylated derivatives of quercetin and kaempferol, and 5-(hydroxymethyl) furfural were identified from the leaves of these accessions. No significant differences in anthocyanins among accessions were found, except the accession from Malaysia, which contained significantly (P<0.05) higher amounts of delphinidin-glucoside and delphinidin. The total phenols determined by Folin-Ciocalteu's assay were 15.92+1.12, 17.63+0.7, and 19.25+1.10 mg g-1 for the calyces of Jamaica, Malaysia and Senegal, respectively, and 23.76+2.16, 22.28+1.77 and 20.62+1.61 mg g-1 for the leaves of Malaysia, Senegal and Jamaica, respectively, calculated as gallic acid equivalents. The Senegal accession contained a higher (P<0.05) amount of total phenols in calyces than the Jamaica accession. The antioxidant activities determined by the ABTS radical cation decolorization assay were 64.38+1.56, 60.36+3.34 and 62.49+2.69 mg g-1 for the calyces and 111.43+7.17, 121.84+12.55 and 110.68+10.27 mg g-1 for the leaves of Malaysia, Senegal and Jamaica, respectively, as Trolox equivalents. Macro- and micro-nutrient elements varied significantly (P<0.05) among accessions. This study reveals variability in phenolic, antioxidant and elemental nutrient contents and suggests that the selection of roselle accessions can influence the quality of developed products.