Antimicrobial agents and chemotherapy,2010年54(10):4306-4313 ISSN：0066-4804
[Yang, Zhaoqing; Meng, Hao; Fan, Qi] Kunming Med Univ, Dept Parasitol, Kunming 650500, Yunnan Province, Peoples R China.;[Cui, Liwang; Miao, Jun] Penn State Univ, Dept Entomol, University Pk, PA 16802 USA.;[Zhang, Rongping; Meng, Hao] Kunming Med Univ, Sch Pharmaceut Sci, Kunming 650500, Yunnan Province, Peoples R China.;[Yang, Henglin] Yunnan Inst Parasit Dis, Puer 665000, Yunnan Province, Peoples R China.;[Su, Xinzhuan] NIAID, Lab Malaria & Vector Res, NIH, Bethesda, MD 20892 USA.
[Cui, LW] Penn State Univ, Dept Entomol, 501 ASI Bldg, University Pk, PA 16802 USA.
Quinine resistance (QNR) in Plasmodium falciparum has been detected in many regions of the world where malaria is endemic. Genetic polymorphisms in at least four genes are implicated in QN susceptibility, and their significance often depends on the genetic background of the parasites. In this study, we have culture-adapted 60 P. falciparum clinical isolates from the China-Myanmar border and assessed their in vitro responses to QN. Our results showed that >50% of the parasite isolates displayed reduced sensitivity to QN, with a half-maximal inhibitory concentration (IC50) above 500 nM. Genotyping of pfcrt found that an overwhelming proportion of the parasite population had the chloroquine-resistant genotype, whereas pfmdr1 mutation genotypes and gene amplification were rare. Genotyping of the P. falciparum Na+/H+ exchanger gene (pfnhe1) at the minisatellite ms4760 locus identified 10 haplotypes. Haplotype 7, which harbors three copies of the DNNND repeat, was the most predominant, accounting for nearly half of the parasite isolates. Correlation studies did not reveal significant associations of the polymorphisms in pfcrt and pfmdr1 genes with QN response. However, the ms4760 haplotypes were highly associated with in vitro QN responses. In particular, parasite isolates with an increased DNNND copy number tended to have significantly reduced QN susceptibility, whereas parasite isolates with a higher NHNDNHNNDDD copy number had increased QN susceptibility. This study provided further support for the importance of pfnhe1 polymorphisms in influencing QNR in P. falciparum.
NATURAL PRODUCT RESEARCH AND DEVELOPMENT,2005年17(04):457-459 ISSN：1001-6880
[Reanmongkol Wantanaouking Pisit; Douking Pisit] Faculty of Phannaceutical Sciences, Prince of Songkla University;[赵永娜; 张荣平#Bouking Pisit] Faculty of Pharmaceutical Sciences, Kunming Medical College
Acute toxicity and antinociceptive effect of the aqueous extract from Laggera pterodonta (AELP) were studied in mice. Antinociceptive activity was determined using writhing,hot plate and formalin tests in mice. The LD50 value of intraperitoneally injected aqueous extract of L. pterodonta in mice was 1.19 g/kg. Although the aqueous extract of L. pterodonta at an oral administration of 200 ～ 400 mg/kg had an antinociceptive effect on writhing responses induced by acetic acid, it was ineffective on nociceptive responses in the hot plate test. The extract of L. pterodonta significantly decreased the frequency of licking behavior within a unit of time at the late phase without affecting that of the early phase in the formalin test. These results suggest that the aqueous extract from L. pterodonta possesses peripheral analgesic effect mediated by anti-inflammatory action.