Inhibitory effects of four plants flavonoids extracts on fatty acid synthase.

Fatty acid synthase (FAS) had been found overexpress and hyperactive in most cancers. Pharmacological inhibitors of FAS activity preferentially repress cancer cell proliferation and induce cancer cell apoptosis without affecting nonmalignant fibroblasts. These made FAS an excellent drug target for cancer therapy. The activity of FAS in 11 different kinds of cancer cells, including esophageal carcinoma (EC109, EC8712, H5E973), gastric carcinoma (N87, BGC823), lung carcinoma (A549, 95-D), hepatoma (HepG2), uterine cervix cancer (HeLa) and leukaemia (K562, U937) were compared using spectrophotometric method. We selected the cell line with the highest FAS activity as cell model to study the inhibitory effect of the flavonoids extracts on FAS. Four plants including Canavium album Raeuseh leaves, Bombax ceiba Linn, Brassica albograbra Bailey, and Citrus reticulata Blanco were selected for extracting flavonoids. The results showed significantly different FAS activity among different cancer cells. The FAS activity is the lowest in gastric cancer cell N87 (15.91 ± 3.61 U/mg protein) and the highest in lung cancer cell A549 (127.36 ± 10.14 U/mg protein). The cancer cell A549 was used as cell model to test the inhibitory effort of flavonoids extracts on FAS. Results showed that the flavonoids extracts of Citrus reticulata Blanco and Canavium album Raeuseh leaves have higher inhibitory effect on FAS activity compared with the universally used FAS inhibitor C75 and both extracts inhibit cancer cell proliferation when added to cultured cancer cells. These studies provided a good cell model for testing the inhibitory effect on FAS activity and suggested that Citrus reticulata Blanco rind and Canavium album Raeuseh leaves are good biomaterials for separating and purifying natural flavonoids FAS inhibitors and exploring their inhibitory mechanisms.

[Construction of prokaryotic expression vector for MAP30 gene and study of PCR methods for rapid identification of recombinant].

Based on the sequence reported by Lee-Huang,S, we cloned the MAP30 gene of Momordica charantia (balsam pear) into a prokaryotic expression vector pET28a (+). A method by using PCR for rapid identification of positive clone was developed. Result showed this screening method can be used to detect positive colonies from samples of bacterial, purified plasmid, liquid culture,and liquid culture treated with mixture of phenol/Chloroform. The result from liquid-culture-treated- PCR (LCT-PCR) is very close to that of by plasmid-PCR. LCT-PCR is reliable and much easier to used than plasmid-PCR, therefore the LCT-PCR can be used for clone screening during the molecular cloning.