Composition of polysaccharides from Alectryon tomentosus F. Muell. leaves with potential cytotoxic and antimicrobial activities

Cold and hot water soluble polysaccharides (CWP and HWP) of Alectryon tomentosus were obtained from defatted powdered leaves samples, pre-extracted with 80% ethanol. The CWP and HWP were subjected to hydrolysis and silylation followed by gas liquid chromatography (GLC) to establish its monosaccharide composition. They were found to be rich in rhamnose, galactose, and arabinose by 16.99, 19.03, and 9.71% versus 30.06, 13.14, and 8.07% for CWP and HWP, respectively. The CWP and HWP were evaluated for their cytotoxic and antimicrobial activity using SulphoRhodamine-B (SRB) cell survival assay and agar well diffusion method, respectively. The HWP showed significant cytotoxic activities against breast cancer cells (MCF-7) and liver cancer cells (HepG2) at IC50=3.83 and 12.20g/dL, respectively, whereas the CWP showed an appreciable cytotoxic activity against colon cancer cells (HCT 116) at IC50=23.92g/dL. CWP exhibited a significant antimicrobial activity against Bacillus subtilis (Gram-positive bacteria).