Genotoxic Potential of Shrimp Pastes (Belacan) Extracts Using <i>Umu</i>Test

This study was conducted to observe the genotoxic effects of aqueous, methanol, hexane and dichloromethane extracts of “belacan” (shrimp paste) taken from three local districts in Melaka, Malaysia (Kelemak, Batang Tiga & Pantai Puteri). The umu test which was used as the screening test was conducted with and without the presence of metabolic activation system. Without the presence of metabolic activation system, aqueous extracts from Kelemak showed mutagenicity activity at 5 mg/ml with IR (Induction Rate) = 1.52 ± 0.57 and the methanol extracts showed mutagenic activities at 0.625 mg/ml and 5 mg/ml, which the IR was the highest at 5 mg/ml (2.08 ± 0.09). On the other hand, samples from Batang Tiga, Melaka showed mutagenic effects at all five concentrations for the dichloromethane extract, with IR = 2.09 ± 0.64 as the highest value at 1.25 mg/ml. Methanol extracts also showed positive results at 1.25 mg/ml and 2.5 mg/ml with IR = 1.70 ± 0.33 and IR = 2.12 ± 0.51 respectively, and aqueous extract at 0.625 mg/ml with IR = 1.54 ± 0.48 and 5 mg/ml with IR = 1.74 ± 0.50. There was a significant difference of the mean values of IR between the four different types of “belacan” extracts from Batang Tiga (p < 0.05). All four “belacan” extracts from Pantai Puteri, Melaka did not show any mutagenic effect. With the presence of metabolic activation system, there was no mutagenic effect observed in all four extracts from the three districts. Further study to analyze the contents in the food samples should be done in the future to determine the possible contents in the food samples that might be responsible for the mutagenic activities.

Piper betle leaf extract enhances the cytotoxicity effect of 5-fluorouracil in inhibiting the growth of HT29 and HCT116 colon cancer cells

Objective： The combination effect of Piperbetle （PB） and 5-fluorouracil （5-FU） in enhancing the cytotoxic potential of 5-FU in inhibiting the growth of colon cancer cells was investigated. Methods： HT29 and HCT116 cells were subjected to 5-FU or PB treatment. 5-FU and PB were then combined and their effects on both cell lines were observed after 24 h of treatment. PB-5-FU interaction was elucidated by isobologram analysis. Apoptosis features of the treated cells were revealed by annexin V/PI stain. High-performance liquid chromatography （HPLC） was performed to exclude any possible chemical interaction between the compounds. Results： In the presence of PB extract, the cytotoxicity of 5-FU was observed at a lower dose （IC^0 12.5 pmol/L） and a shorter time （24 h） in both cell lines. Both cell lines treated with 5-FU or PB alone induced a greater apoptosis effect compared with the combination treatment. Isobologram analysis indicated that PB and 5-FU interacted synergistically and antagonistically in inhibiting the growth of HT29 and HCT116 cells, respectively. Conclusions： In the presence of PB, a lower dosage of 5-FU is required to achieve the maximum drug effect in inhibiting the growth of HT29 cells. However, PB did not significantly reduce 5-FU dosage in HCT116 cells. Our result showed that this interaction may not solely contribute to the apoptosis pathway.

Toxic effects of Litsea elliptica Blume essential oil on red blood cells of Sprague-Dawley rats

Litsea elliptica Blume leaves have been traditionally used as medicinal herbs because of its antimutagenicity,chemopreventative and insecticidal properties. In this study,the toxic effects of L. elliptica essential oil against Sprague-Dawley rat’s red blood cells (RBCs) were evaluated. L. elliptica essential oil was given by oral gavage 5 times per week for 3 treated groups in the doses of 125,250,and 500 mg/(kg body weight),respectively,and the control group received distilled water. Full blood count,RBC osmotic fragility,RBC morphological changes,and RBC membrane lipid were analyzed 28 d after the treatment. Although L. elliptica essential oil administration had significantly different effects on hemoglobin (Hb),mean cell hemoglobin concentration (MCHC),mean cell volume (MCV),and mean cell hemoglobin (MCH) in the experimental groups as compared to the control group (P<0.05),the values were still within the normal range. L. elliptica induced morphological changes of RBC into the form of echinocyte. The percentage of echinocyte increased significantly among the treated groups in a dose-response manner (P<0.001). The concentrations of RBC membrane phospholipids and cholesterol of all treated groups were significantly lower than those of control group (P<0.001). However,the RBC membrane osmotic fragility and total proteins of RBC membrane findings did not differ significantly between control and treated groups (P>0.05). It is concluded that structural changes in the RBC membrane due to L. elliptica essential oil administration did not cause severe membrane damage.