Determination of anthocyanin content in two varieties of Hibiscus Sabdariffa from Selangor, Malaysia using a combination of chromatography and spectroscopy

Abstract

The calyces of Hibiscus sabdariffa have been used by many communities as herbal tea. Their anthocyanin contents have been reported as the key component in anti-obesity studies. This present work reported results of anthocyanin content of calyces in two varieties of H. sabdariffa collected from Sabak Bernam, Selangor, Malaysia. The samples have been authenticated in the Herbarium, Institute of Bioscience, University Putra Malaysia prior to the study. The samples were processed and the ground dry raw material and its aqueous extract were analyzed using Fourier Transform Infrared (FTIR) and Two-Dimensional Infrared (2DIR). The short hybrid calyces (FT11-15A) raw material spectrum showed more than 80% similarity with long wild variety calyces (FT11-15B) when using “Compare” in analysis. The differences of both samples were obviously shown in their aqueous extract spectra. The peak at 1672 cm-1 and 841 cm-1 showed that tri-substituted double bond in FT11-15B aqueous extract was not present in FT11-15A aqueous extract spectra, whereby a double peak was assigned at 1221 cm-1 referred to anti symmetry stretching of aromatic and vinyl =C-O-C- with other =C-O- and 1192 cm-1 is assigned In-plane δ C-H in FT11-15A aqueous extract. The peak at 1071 cm-1 assigned as bonding C-H in plane bending of phenyl of both samples was the only peak comparable with standard delphinidin and cyanidin which are used for qualification and quantification of sample content. Aqueous extract spectra of both samples showed higher number of peaks detected compared with raw material spectra, which was attributed to the higher solubility of anthocyanins in water. The 2DIR correlation spectroscopy is advantageous in enhancing the qualitative analysis of herbal products. The anthocyanin content in both varieties of H. sabdariffa in descending amount is delphinidin-3-O-sambubioside (DS), cyanidin-3-O-sambubioside (CS), delphenidin-3-O-glucoside (DG) and lastly cyanidin-3-O-glucoside (CG). FT11-15A has more content of DS and DG of raw material and CG of water extract plus TFA than FT11-15B, whereby, FT11-15B has more content of CS, CG of raw material and DS, DG, CS of water extract plus TFA than FT11-15A.