Antimalarial activities of butanol and ethylacetate fractions of Combretum nigricans leaf

Objective: To evaluate the antimalarial activity of the ethylacetate and butanol fractions of Combretum nigricans(C. nigricans) leaf extract in mice. Methods: C. nigricans solvent(butanol and ethylacetate) fractions were screened for their phytochemical constituents using standard procedures illustrated by Harborne and Evans. The Peters' 4-day suppressive test against early malaria infection, Rane's curative test against established malaria and prophylactic test for residual activity were employed for evaluating the antimalarial potential in mice. Results: The phytochemical screening revealed the presence of alkaloids, terpenoids, saponins, and flavonoids in both fractions at different intensity. Both fractions exhibited significant antimalarial activity in all test models(P<0.05). The ethylacetate fraction of C. nigricans had better chemosuppressive and curative effects compared to the butanol fraction, which however, elicited a better chemoprophylactic effect. The chemosuppressive effect of C. nigricans ethylacetate fraction(200-800 mg/kg) was 77.6%, 69.1% and 86.1%; curative effect was 62.3%, 71.3% and 72.4%; while the chemoprophylactic activity was 32.1%, 48.6% and 61.2% respectively. C. nigricans butanol fraction(200-800 mg/kg) had 40.3%, 54.1% and 69.1% chemosuppression; 26.2%, 36.9% and 34.5% curative effect; and 48.4%, 70.0% and 87.4% chemoprophylaxis. Conclusions: Both solvent fractions of C. nigricans possess antimalarial activity, and may be useful at different stages of malaria therapy.

Comparative analysis of chemical constituents, antimicrobial and antioxidant activities of ethylacetate extracts of Polygonum cuspidatum and its endophytic actinomycete, Streptomyces sp. A0916

The present study investigated the chemical composition of ethylacetate extracts from an endophytic actinomycete Streptomyces sp. A0916 and its host Polygonum cuspidatum. A comparative analysis of the antimicrobial and antioxidant properties of the extracts was also conducted. 32 compounds of P. cuspidatum and 23 compounds of Streptomyces sp. A0916 were isolated and identified by GC/MS. Antimicrobial activities of the extracts were evaluated using eight microbial strains(3 Gram-positive bacteria, 3 Gram-negative bacteria, and 2 fungi). The Streptomyces sp. A0916 extracts showed a wide range of antimicrobial activities and presented greater antimicrobial effectiveness than the P. cuspidatum extracts. The minimum inhibitory concentration(MIC) of Streptomyces sp. A0916 extracts against the ampicillin-resistant strain Enterococcus faecium SIIA843 was 32 μg·m L-1. Furthermore, the extracts had greater antimicrobial effect against Gram-positive bacteria than Gram-negative bacteria. Finally, the antioxidant activity of the Streptomyces sp. A0916 extracts was equal to that of the P. cuspidatum extracts. In conclusion, our results suggest that the endophytic actinomycetes of the medicinal plants are an important source of bioactive substances.

紫山姜体外抗氧化及抗癌活性研究(英文)

AIM:Ethylacetate extract of Alpinia purpurata was evaluated for its potential in vitro antioxidant and antican-cer activity.METHODS:The antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl(DPPH) free radical scav-enging method,hydroxyl radical activity,superoxide radical scavenging activity,nitric oxide radical scavenging activity,hy-drogen peroxide radical scavenging activity and reducing power activity.The viability of OAW42 cells was evaluated by MTT assay.RESULTS:A.purpurata exhibited potential antioxidant activity with a concentration-dependent manner.The extract showed potential anticancer activity at the 48th hour with IC50 of 130.20 μg·mL·1 and exhibited a dose-dependent decrease in cell count for all the concentrations tested.CONCLUSION:The results suggested that long term consumption of A.purpurata exhibited antioxidant and anticancer activity and could be further exploited for their anticancer properties.