Cytotoxicity of Enterolobium timbouva Plant Extract and Its Isolated Pure Compounds

Aims: The present study aimed to evaluate the cytotoxic activities of the aqueous alcohol extract of Enterolobium timbouva leaves as well as its isolated pure compounds.
Place and Duration of Study: Department of Pharmacognosy, Faculty of pharmacy, Ain Shams University, between March 2010 and May 2012.
Methodology: In vitro Cytotoxic study was conducted for the aqueous methanol extract and the isolated pure single compounds to determine the IC50 by sulphorhodamine B (SRB) assay.
Results: Phytochemical investigation of the extract resulted in the isolation and structural determination of ten phenolic compounds isolated for the first time from entitled genus viz; 3,4-Dihydroxy-Cinnamic acid (Caffeic acid) (1); Quercetin-3-O-β-D-glucopyranoside (Isoquercitrin) (2); Quercetin-3-O-β-D-galacto-pyranoside (Hyperin) (3); Kaempferol-3-O-β-D–glucopyranoside (Astragalin) (4); Hesperetin-7-O-rutinoside (Hesperidin) (5); Quercetin 3-O-rutinoside (Rutin) (6); Quercetin (7); Kaempferol (8); 7-methoxycoumarin (Herniarin) (9); and Chrysin (10). The aqueous alcohol extract exhibited potent cytotoxic activity against diffferent cancer cell lines with IC50 values of 2.67 μg/mL against MCF-7 cell line, 3.89 μg/ml against HCT116 cells, 4 μg/mL against HEp2 cells, 4.5 μg/mL against HeLa cells, 1.7 μg/mL against PC-3 cells, and 5.7 μg/mL against Huh-7 cells. In vitro cytotoxic assay of the isolated pure compounds against Huh-7 cell Line showed that compounds 1, 9 and 10 are the only tested compounds exhibiting potent cytotoxic activity with IC50 of 3 μg/mL, 0.76 μg/mL, and 18.51 μg/mL respectively. The rest of tested compounds exhibited IC50 exceeding 1000 μg/mL which reflects their safety.
Conclusion: The current study indicated that the phenolic compounds isolated from Enterolobium timbouva leaves are promising molecules with potentially useful cytotoxic activity profiles. This confirms that this terrestrial plant has great value as a source of lead compounds with pharmaceutical applications.