The importance of various polysaccharides as an anti-tumor agent has a long historical
background [1]. Ornithogalum bungei Boiss. (Hyacinthaceae), is an Iranian native plant distributed in Golestan province
[2]. The initial screening of cytotoxic activities of the extracts from different parts
of the plant showed the promising result for the bulbs. Therefor in the present study
detailed investigation of cytotoxic effects of the bulb extracts on human hepatocarcinoma
cell line (HepG2), prostate cancer cell line (PC3) and Human myelogenous leukemia
(K562) were carried out as well as isolation and structure elucidation the active
compounds. The method was based on bio-assay guided fractionation. AF3400024ter each
step of chromatography all fractions were assayed on the mentioned cells. Finally
two new water-soluble polysaccharides, OBP1 and OBP2 with molecular weights of 56.2 kDa and 97.9 kDa respectively, were isolated. Purification
of the polysaccharides was carried out using hot water extraction and further purification
methods such as DEAE-cellulose A52 and Sephadex G-100 columns. The linkages of polysaccharides
were determined by using methylation method. OBP1 was composed of glucose (Glc), galactose (Gal), arabinose (Ara) and mannose (Man)
in a molar ratio of 10.8:3.52:3.72:1.97 and OBP2 was composed of glucose (Glc), galactose (Gal), arabinose (Ara), mannose (Man) and
glucoronic acid (GlcA) in a molar ratio of 7.48:4.01:3.09:4.13:5.05. The uronic acid
content of OBP2 was about 20%. Two polysaccharides exhibited significant cytotoxic activity in a
concentration- independent manner against HepG2, K562 and PC3 cells. Results suggested
that these polysaccharides could be a potential natural cytotoxic agents.
