Isolasi senyawa flavonoid dari ekstrak etanol kelopak bunga Rosella (Hibiscus Sabdariffa Linn) menggunakan metode sonikasi

Abstract

Rosella (Hibiscus sabdariffa L.) is a plant belonging to the Malcaveae family and can grow in tropical areas such as Indonesia. Rosella flower petals contain flavonoid secondary metabolite compounds such as anthocyanins. The purpose of this study was to isolate, test, and characterise flavonoid compounds in rosella petals. Isolation was carried out using the sonication method at 42 kHz for 15 minutes with 96% ethanol solvent with a yield weight of 39.117% and the weight of hydrolyzate from hydrolysis using 2N HCl of 42.117%. The hydrolyzate was partitioned with water and chloroform in a ratio of 1:1, and then a flavonoid phytochemical test was carried out to obtain a change in the colour of the solution to red-brown, which indicates that it is positive for flavonoids. Furthermore, the isolation of compounds using preparative KLT was observed with UV light at λ245 nm and λ366 nm. The results obtained showed that at λ245 nm, a green colour was obtained with Rf 0.72, and at λ366 nm, a purple colour was obtained with Rf 0.86. Identification with a UV-Vis spectrophotometer obtained a maximum at λ268.9 nm with an absorbance value of 0.182. FT-IR results showed a typical absorption of the C=C stretching group at wave number 1644.930 cm1 and the C-OH stretching group at wave number 1045.9 cm^-1.