Bioactive compounds fractionated from endophyte Streptomyces SUK 08 with promising ex-vivo antimalarial activity

Objective: To determine ex vivo antimalarial activity and cytotoxicity of endophytic Streptomyces SUK 08 as well as the main core structure fractionated from its crude extract. Methods: The activities of SUK 08 crude extract were evaluated by using the Plasmodium lactate dehydrogenase assay and synchronization test against rodent malaria parasite Plasmodium berghei, instead of human malarial parasite Plasmodium falciparum. The cytotoxicity of the crude extract was determined by MTT assay. The crude extract was analyzed by thin-layer chromatography and gas chromatography–mass spectrophotometry. Results: The ethyl acetate crude extract showed very promising antimalarial activity with IC50 of 1.25 mg/mL. The synchronization tests showed that ethyl acetate extraction could inhibit all stages of the Plasmodium life cycle, but it was most effective at the Plasmodium ring stage. On the basis of a MTT assay on Chang Liver cells, ethyl acetate and ethanol demonstrated IC50 values of >1.0 mg/mL. The IC50 of parasitemia at 5% and 30% for this extract was lower than chloroquine. Thin-layer chromatography, with 1: 9 ratio of ethyl acetate: hexane, was used to isolate several distinct compounds. Based on gas chromatography–mass spectrophotometry analysis, three core structures were identified as cyclohexane, butyl propyl ester, and 2,3-heptanedione. Structurally, these compounds were similar to currently available antimalarial drugs. Conclusions: The results suggest that compounds isolated from Streptomyces SUK 08 are viable antimalarial drug candidates that require further investigation

Micronucleus analysis in buccal swabs of paddy farmers from the East Coast of Malaysia

Pesticide exposure may cause genotoxic effects by inducing the formation of micronucleus (Mn). Mn are fragments of chromosomes that remains after cells division. The increase in Mn may increase the risk of cancer formation. Our study aimed to determine the effects of lifestyle and pesticide exposure on the formation of Mn in epithelial cells from buccal swabs among paddy farmers in Malaysia. About 40 farmers who were exposed to pesticides were chosen as subjects and 30 personnels whose not directly exposed to pesticides, were chosen as the control group. Demographic and anthropometric data were obtained from questionnaires developed. Analysis of Mn formation was done using Giemsa staining (10% v/v) and the frequency of Mn formation was scored from 1000 cells per sample. Kruskal-Wallis test done between Mn frequency with age group showed a significant increase (p < 0.05) in Mn frequency in farmers as compared to the control in the age group of 30-39 , 40-49 years, and 50-59 years. Significant increased (p < 0.05) were observed between Mn frequency groups of normal BMI, pre-obese, and grade 1 obese as compared to control. Significant increase of Mn frequency (p < 0.01) was also seen among smokers and farmer’s group (15.39 ± 3.34) as compared to controls (4.76 ± 1.26). The maximum numbers of Mn found in farmers are 7 Mn per cell whereas for control group is only 3 Mn. However, most farmers had only 1 Mn (81.75 ± 6.42%) and 2 Mn (15.28 ± 5.14%). Mn frequency with the duration of exposure to pesticides in a month and the use of PPE revealed no significant difference (p = 0.27). In conclusion, the increased frequency of Mn was influenced by age, gender, BMI and smoking status of farmers besides commonly repeated duration of exposures and the use of PPE. Further studies are needed to analyze the causes of an increased in Mn among farmers