Antibacterial and anti‐proliferative activity of Isolated Fractions of Aqueous extract from the rhubarb stem

Abstract

Medicinal uses of rhubarb roots have often been reported. The aim of this current research is to evaluate the anti‐bacterial and anti‐proliferative effects of the rhubarb stem. Aqueous extract from rhubarb stem was fractionated using DEAE Sephadex (anion exchange) followed by Sephadex G25 (gel filtration). Fractions were monitored by assaying for their antibacterial activity on the periodontal pathogen Aggregatibacter actinomycetemcomitans. The fraction from gel filtration column having antibacterial activity was used for further studies. Purity of the active compound was confirmed by the presence of a single major peak in HPLC. The purified active compound was found to have broad spectrum antibacterial activity. It inhibited growth of the Gram negative bacteria, E. coli and A. actinomycetemcomitans as well as the Gram positive bacteria, B subtilis. Its anti‐proliferative activity was tested on the breast cancer cell line, MCF‐7. It was observed that proliferation of the tumor cells was inhibited by 60 % while the cell viability was not affected. The purified compound was partially characterized based on its 1H and 13C NMR spectra. Preliminary analysis indicated that this compound is carbohydrate but the exact identity of the sugar has not yet been determined. This research helped to discover a compound in rhubarb stem that has antibacterial and anti‐tumor activity but very little cytotoxic effect. This research was supported by the Long Island University Intramural Research Support Program.