Black Rice Bran Extracts and Fractions Containing Cyanidin 3-glucoside and Peonidin 3-glucoside Induce Apoptosis in Human Cervical Cancer Cells

Abstract

Anthocyanin of pigmented rice inhibits the growth of cancer cells. The cytotoxicity and apoptosisinducing properties of local black rice (cv Cempo Ireng) extracts and fractions, which contain anthocyanin
including cyanidin 3-glucoside and peonidin 3-glucoside, on human cervical cancer cell line (HeLa cells) has
been evaluated. The pigmented rice bran was extracted and fractionated using methanol-HCl. The MTT test
was performed on HeLa cell cultures to observe the IC50 value. Preparative TLC was performed to obtain the
fractions of black rice bran. Cyanidin 3-glucoside and peonidin 3-glucoside were identified in the pigmented
rice bran extract and fractions using UHPLC. Flowcytometry analysis was performed to measure the percentage
of apoptotic cells. Our results suggest that the fractions are more toxic than the methanolic crude extract with
IC
50 values of 85.95 ± 5.56 μg/mL (the lowest one) and 408.13 ± 51.9 μg/mL, respectively. The concentration of
cyanidin 3-glucoside and peonidin 3-glucoside in the methanolic extract were 1.89 and 0.84 μg/mg, respectively.
The apoptosis induction by fractions F2 and F4 (52 and 55%) were significantly higher compared to fraction
F3 and F5 (30 and 33%) and doxorubicin (21%). Cyanidin 3-glucoside was detected in F4 (0.14 μg/ml) while
peonidin 3-glucoside in F2 (0.012 μg/ml), however both were not detected in F3 and F5.