ABSTRACT
OBJECTIVE: To investigate the cytotoxic activity against lung cancer cells of Dioscorea birmanica Prain & Burkill extract and its compounds. MATERIAL AND METHOD: Cytotoxic activity was tested against two types of lung cancer cell line (A549 and CORL-23), one type of normal lung cell (MRC-5) by sulforhodamine B assay. Bioassay guide fractionation was used for isolating cytotoxic compounds. The structure elucidation of active ingredients was proven by spectrophotometry technique. RESULTS: The results found that the ethanolic extract of Dioscorea birmanica Prain & Burkill (DBE) showed high cytotoxic activity against lung cancer cells; A 549 and COR-L23 (IC50 = 7.45 +/- 0.31, 8.71 +/- 0.29 microg/ml, respectively) but no cytotoxic activity against normal cancer cells MRC-5 (IC50 = 94.76 +/- 1.25 micro/ml). Six fractions from DBE were isolated by vaccuum liquid chromatography with ordering polarity of solvent and were coded as DB1-DB6, respectively. The fraction DB5 showed high cytotoxic against A 549 and COR-L23 (IC50 = 6.14 +/- 0.08 and 16.44 +/- 1.23 microg/ml, respectively) but less toxic to normal cell. Diosgenin-3-O-alpha-L-rhamnosyl (1-->2)-beta-D-glucopyranoside or Prosapogenin A of dioscin (DBS1) was isolated from DB5 fraction and had highest cytotoxic activity against those two types of lung cancer cells (IC50 = 1.81 +/- 0.03, 1.84 +/- 0.05 microg/ml), respectively) but less cytotoxic against normal lung cells MRC-5 (IC50 = 37.09 +/- 0.67 microg/ml). CONCLUSION: The steroid saponin from Dioscorea birmanica showed cytotoxic activity against human lung cancer cells but less toxic against normal lung cells.
