The cytotoxic activity of PM 701 (a clean and sterile natural product) and fractions obtained thereof was assessed against human cancer cell lines, namely, hepatocellular carcinoma (HEPG2), colon carcinoma (HCT 116) and human glioma (U251) cells by using sulforhodamine B assay. PM 701 was extracted with methyl alcohol to give PMF fraction that was chromatographed on a Si gel column to yield seven fractions (frs: M2-
M8). PMF and its sub-fractions demonstrated a variable and notably high cytotoxic activity against the tested cell lines (IC50 0.5-10 g/mL). Fractions M2 and M5 were found to demonstrate the most potent activity against HEPG2 cell line (IC50 0.54 g/mL for each), followed by fraction M8 (IC50 1.01 g/mL). The effect of the different
fractions against normal human foreskin cell line (HFS) was also evaluated. Isolation and
identification of the active cytotoxic compounds are now in progress in our laboratories.