Inhibition of proliferation of human carcinoma cell lines by phenolic compounds from a bearberry-leaf crude extract and its fractions

Abstract

Phenolic compounds were extracted from the leaves of bearberry, a potential functional food ingredient, using 80% (v/v) aqueous ethanol after which the resultant crude extract was applied to a Sephadex LH-20 column. A fraction comprising low-molecular-weight phenolics (LMW fraction) and sugars was eluted from the column with 95% (v/v) ethanol. A tannin fraction was then obtained after switching the mobile phase to acetone/water (1:1, v/v). Phenolic compounds present in the crude extract and its two fractions showed antiproliferative activities in a concentration-dependent manner against five carcinoma cell lines, namely MCF-7 (estrogen receptor-positive breast carcinoma), DU-145 (androgen receptor-negative prostate carcinoma), HT-29 (colon carcinoma), SK-MEL-5 and MDA-MB-435 (melanoma; skin carcinoma). IC50 data revealed that the tannin fraction was best at retarding cell proliferation in the tested cancer cell lines. The greatest inhibition at 1.5 μg fraction/mL assay was observed for the HT-29 colon carcinoma cell line. The proliferation of SK-MEL-5 skin carcinoma cells was also strongly inhibited by both the crude extract and LMW fraction. MDA-MB-435 cells were found to be the least sensitive for the materials tested, particularly for the LMW fraction.

Keywords

• Bearberry leaves
• Arctostaphylos uva-ursi
• Phenolics
• Carcinoma cells
• Proliferation
• Anticancer activity