Formation of (2E)-4-Hydroxy-2-nonenal and (2E)-4-Hydroxy-2-hexenal by Plant Enzymes: A Review Suggests a Role in the Physiology of Plants

It is demonstrated that (3Z)-nonenal (NON) and (3Z)-hexenal (HEX) are oxidized in a cascade by lipoxygenase (LOX) and hydroperoxide peroxygenase (HP peroxygenase) into (2E)-4-hydroxy-2- nonenal (HNE) and (2E)-4-hydroxy-2-hexenal (HHE), respectively. In turn, HNE inactivates LOX terminating the cascade. The hydroxy-alkenals produced serve to inhibit plant pathogens, which initiated the cascade. In addition to LOX, other unknown oxygenases may be involved in the cascade.

Isolation and structural elucidation of cytotoxic compounds from the root bark of Diospyros quercina (Baill.) endemic to Madagascar

Objective:To isolate and characterize the cytotoxic compounds from Diospyros quercina(Baill.)G.E.Schatz&Lowry(Ebenaceae).Methods:An ethno-botanical survey was conducted in the south of Madagascar from July to August 2010.Bio-guided fractionation assay was carried out on the root bark of Diospyros quercina,using cytotoxicity bioassay on murine P388 leukemia cell lines as model.The structures of the cytotoxic compounds were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry.Results:Biological experiments resulted in the isolation of three bioactive pure compounds(named TR-21,TR-22,and TR-23)which exhibited very good in vitro cytotoxic activities with the IC_(50)values of(0.017 5±0.0060)μg/mL,(0.089±0.005)μg/mL and(1.027±0.070)μg/mL respectively.Thus,they support the claims of traditional healers and suggest the possible correlation between the chemical composition of this plant and its wide use in Malagasy folk medicine to treat cancer.Conclusions:The ability of isolated compounds in this study to inhibit cell growth may represent a rational explanation for the use of Diospyros quercina root bark in treating cancer by Malagasy traditional healers.Further studies are,therefore,necessary to evaluate the in vivo antineoplastic activity of these cytotoxic compounds as effective anticancer drugs.

Vlultifunctional immune responses of HMBPP-specific Jy2Vδ2 T cells in M. tuberculosis and other infections

Vy2Vδ2 T （also known as Vy9Vδ2 T） cells exist only in primates, and in humans represent a major yδ T-cell sub-population in the total population of circulating yδ T cells. Results from recent studies suggest that while （E）-4-hydroxy-3-methyl-but-2-enyl pyrophosphate （HMBPP） phosphoantigen from Mycobacterium tuberculosis （Mtb） and other microbes activates and expands primate Vy2Vδ2 T cells, the Vy2Vδ2 T-cell receptor （TCR） recognizes and binds to HMBPP on antigen-presenting cells （APC）. In response to HMBPP stimulus, Vy2V82 TCRs array to form signaling-related nanoclusters or nanodomains during the activation of Vy2V82 T cells. Primary infections with H MBPP-producing pathogens drive the evolution of multieffector functional responses in Vy2Vδ2 T cells, although Vy2V82 T cells display different patterns of responses during the acute and chronic phases of Mtb infection and in other infections. Expanded Vy2Vδ2 T cells in primary Mtb infection can exhibit a broader TCR repertoire and a greater clonal response than previously assumed, with different distribution patterns of Vδ,2Vδ2 T-cell clones in lymphoid and non-lymphoid compartments. Emerging in vivo data suggest that HMBPP activation of Vy2W2 T cells appears to impact other immune cells during infection.

New phenolic compounds from the leaves of Artocarpus heterophyllus

One new 2-arylbenzofuran derivative, artocarstilbene B（1）, one new benzaldehyde derivative,（E）-3,5-dihydroxy-4-（3-methylbut-1-enyl）benzaldehyde（2）, as well as 18 known compounds（3–20） were obtained from the leaves of Artocarpus heterophyllus. Their structures were elucidated on the basis of extensive spectroscopic techniques including 2D NMR and HR-ESIMS. Many compounds exhibited moderate to weak inhibitory activity against the proliferation of the PC-3, NCI-H460, and A549 cancer cell lines.