Evaluation of the inhibitory effects and the mechanism of terpenoids on Toxoplasma gondii tachyzoites.

BACKGROUND: Currently, symptomatic toxoplasmosis is treated with a combination of sulfadiazine and pyrimethamine. However, significant adverse effects and drug resistance have been reported. Terpenoids are widely found in nature, with numerous studies demonstrating that they have effective inhibitory effects on a variety of parasites. METHODS: In this study, we employed intermediates or derivatives of lindenane sesquiterpenoids to evaluate their intracellular and extracellular inhibitory effects on Toxoplasma gondii tachyzoites and their cytotoxicity on macrophages. RESULTS: We demonstrated that two of these target terpenoids could effectively reduce the number of extracellular tachyzoites, probably by inducing tachyzoite apoptosis through altering tachyzoites mitochondrial membrane potential and calcium homeostasis. In addition, the two target terpenoids were able to promote intracellular tachyzoites elimination, possibly by enhancing macrophage activities. CONCLUSIONS: Two derivatives of lindenane sesquiterpenoids with low cytotoxicity to macrophages demonstrated direct and indirect antitoxoplasma effects.

Chloroplast Genome Sequences and Comparative Analyses of Combretaceae Mangroves with Related Species.

In the Combretaceae family, only two species of Lumnitzera and one species of Laguncularia belong to mangroves. Among them, Lumnitzera littorea (Jack) Voigt. is an endangered mangrove plant in China for the limited occurrence and seed abortion. In contrast, Lumnitzera racemosa Willd. is known as the most widespread mangrove plant in China. Laguncularia racemosa C. F. Gaertn., an exotic mangrove in China, has the fast growth and high adaptation ability. To better understand the phylogenetic positions of these mangroves in Combretaceae and in Myrtales and to provide information for studies on evolutionary adaptation for intertidal habitat, the complete chloroplast (cp) genomes of Lu. racemosa and La. racemosa were sequenced. Furthermore, we present here the results from the assembly and annotation of the two cp genomes, which were further subjected to the comparative analysis with Lu. littorea cp genomes we published before and other eleven closely related species within Myrtales. The chloroplast genomes of the three Combretaceae mangrove species: Lu. littorea, Lu. racemosa, and La. racemosa are 159,687 bp, 159,473 bp, and 158,311 bp in size. All three cp genomes host 130 genes including 85 protein-coding genes, 37 tRNAs, and 4 rRNAs. A comparative analysis of those three genomes revealed the high similarity of genes in coding-regions and conserved gene order in the IR and LSC/SSC regions. The differences between Lumnitzera and Laguncularia cp genomes are the locations of rps19 and rpl2 genes in the IR/SC boundary regions. Investigating the effects of selection events on shared protein-coding genes showed a relaxed selection had acted on the ycf2, ycf1, and matK genes of Combretaceae mangroves compared to the nonmangrove species Eucalyptus aromaphloia. The phylogenetic analysis based on the whole chloroplast genome sequence with one outgroup species strongly supported three Combretaceae mangroves together with other two Combretaceae species formed a cluster in Combretaceae. This study is the first report on the comparative analysis of three Combretaceae mangrove chloroplast genomes, which will provide the significant information for understanding photosynthesis and evolution in Combretaceae mangrove plants.

Isolation and characterization of phenolic compounds from the leaves of Salix matsudana.

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclooxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (1), together with five known flavonoids--luteolin (2), isoquercitrin (3), 7-methoxyflavone (4), luteolin 7-O-glucoside (5), 4',7-dihydroxyflavone (6)--and two phenolic glycosides, leonuriside A (7) and piceoside (8). Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies, high resolution ESI mass spectroscopic analyses and comparisons with literature data. The isolated compounds 1-8 were tested for their inhibitory activities against COX-1 and COX-2. Compounds 1, 5 and 6 were found to have potent inhibitory effect on COX-2 and compounds 3-5 exhibited moderate inhibition against COX-1.

[The confirmation of putative natural hybrid species Meconopsis x cookei G. Taylor (Papaveraceae) based on nuclear ribosomal DNA ITS region sequence].

The Nuclear Ribosomal DNA internal transcribed spacers (ITS) region sequences from a putative natural hybrid species Meconopsis x cookei and its possible parents M. punicea and M. quintuplinervia were obtained by using direct sequencing method. The sequence length of ITS region (including ITS1, 5.8S and ITS2) is 667 bp for M. punicea, 668 bp for M. x cookei, and 668 bp for M. quintuplinervia. The sequences were aligned by the software Clustal X, and the bases per locus were compared by using software with manual method. The aligned sequence length is 688 bp, of which ITS1 is 254 bp, 5.8S is 162 bp, and ITS2 is 252 bp. 16 variable loci were detected from the aligned sequence, approximately 2.40% to the whole sequence length, of which ITS1 has nine variable loci (56.25%), ITS2 has six variable loci (37.50%), and 5.8S has one variable locus (6.25%). The results show that M. x cookei have two kinds of ITS sequences contributed from two species M. puniceaa and M. quintuplinervia, i.e. the variation of ITS gene among M. x cookei, M. punicea and M. quintuplinervia is congruence with the Mendel's genetics law. Therefore, the molecular evidences indicate that M. x cookei is a hybrid origin from M. punicea and M. quintuplinervia.