Cembranoids from the Vietnamese soft coral Sarcophyton ehrenbergi

Using various chromatographic separations, two new cembranoids, ehrenbergols F and G (1 and 2), along with three known analogs ehrenbergol D (3), (+)-isosarcophine (4) and sinulariol Z₂ (5) were isolated from the soft coral Sarcophyton ehrenbergi. The structural elucidation was done by extensive analysis of the 1 D and 2 D NMR, HR-ESI-QTOF-MS as well as CD experiments. In addition, compounds 1 (IC₅₀ of 38.38 ± 2.89 µM), 3 (IC₅₀ of 37.14 ± 3.22 µM) and 4 (IC₅₀ of 45.01 ± 2.49 µM) revealed moderate inhibitory activity on LPS-induced NO production in RAW264.7 cells, whereas 2 (IC₅₀ of 73.32 ± 1.95 µM) and 5 (IC₅₀ of 64.48 ± 4.93 µM) exhibited weak effect.

Cytotoxic and α-Glucosidase Inhibitory Xanthones from Garcinia mckeaniana Leaves and Molecular Docking Study

A new racemic xanthone, garmckeanin A (1), and eight known analogs 2-9 were isolated from the ethyl acetate (AcOEt) extract of the Vietnamese Garcinia mckeaniana leaves. Their structures were determined by MS and NMR spectral analyses and compared with the literature. The AcOEt extract showed good cytotoxicity against cancer cell lines KB, Lu, Hep-G2 and MCF7, with IC₅₀ values of 5.40-8.76 μg/mL, and it also possessed α-glucosidase inhibitory activity, with an IC₅₀ value of 9.17 μg/mL. Garmckeanin A (1) exhibited inhibition of all cancer cell lines, with an IC₅₀ value of 7.3-0.9 μM. Allanxanthone C (5) successfully controlled KB growth, with an IC₅₀ value of 0.54 μM, higher than that of the positive control, ellipticine (IC₅₀ 1.22 μM). Norathyriol (8) was a promising α-glucosidase inhibitor, with an IC₅₀ value of 0.07 μM, much higher than that of the positive control, acarbose (IC₅₀ 161.0 μM). The interactions of the potential α-glucosidase inhibitors with the C- and N-terminal domains of human intestinal α-glucosidase were also investigated by molecular docking study. The results indicated that bannaxanthone D (2), garcinone E (4), bannaxanthone E (6), and norathyriol (8) exhibit higher binding affinity to the C-terminal than to the N-terminal domain through essential residues in the active sites. In particular, compound 8 could be assumed to be the most potent mixed inhibitor.

Alkaloids From Zanthoxylum nitidum and Their Cytotoxic Activity

Zanthoxylum nitidum (Roxb.) DC (Rutaceae) is a traditional medicine used for the treatment of various diseases like toothache, gingivitis, fever, colic vomiting, diarrhea, and cholera. Three new alkaloids, zanthocadinanine C (1), 7-methoxy-8-demethoxynitidine (2), and zanthonitiside I (3) were isolated from the stems and twigs of Z. nitidum. Their structures were determined on the basis of extensive spectroscopic, including 1-dimensional and 2-dimensional nuclear magnetic resonance and mass spectroscopy data. Compounds 1–3 were evaluated for cytotoxic activity against 5 human cancer cell lines, KB, MCF-7, LNCaP, HepG-2, and LU-1. Compound 2 showed significant cytotoxic activity against all tested human cancer cell lines with IC50 values ranging from 10.3 to 12.6 µM.

Cytotoxic steroid derivatives from the Vietnamese soft coral Sinularia brassica

Using various chromatographic separations, six ergostane-type steroids, including one new compound sinubrassione (1), and two pregnene-type steroid glycosides, including one new compound sinubrassioside (7), were isolated from methanol extract of the Vietnamese soft coral Sinularia brassica. The structure elucidation was confirmed by spectroscopic methods including 1D, 2D NMR and HR-ESI-MS. The cytotoxic activities of all the isolated compounds against three human cancer cell lines were also evaluated using MTT-based colorimetric assays.

Examples of probable host-pathogen co-adaptation/co-evolution in isolated farmed animal populations in the mountainous regions of North Vietnam

In Vietnam, for a number of specific geographical and historical reasons, the mountainous areas have preserved an exceptional diversity of wild and domestic animal species of high socioeconomic interest. This endemic genetic diversity fosters a rapid response to environmental change in mostly isolated local communities and, in particular, fosters the constant adaptation of ecosystems common to humans and farmed and wild animal populations and pathogens. During a 2-year study carried out in several mountainous regions of North Vietnam near the Chinese border, we surveyed 1697 breeders in 249 villages and gathered 5815 biological samples among the four main domesticated species of food animals: chickens, cattle, buffaloes, and goats. Serological analyses were carried out by ELISA on 726 sera in order to assess the prevalence of antibodies specific to two major diseases suspected to be present in the region: avian influenza (AI) and peste des petits ruminants (PPR). The results reported here reveal the presence of antibodies specific to AI, but not the H5N1 highly pathogenic strain, and the presence of antibodies specific to PPR, confirming that this disease, never previously described in Southeast Asia, is present in this region, with no mortality and little or no evidence of clinical cases. These are probably situations of co-evolutive epidemiological equilibrium between pathogen populations, which may have lost their virulence, and animal populations that have acquired genetic resistances over generations, either naturally or through genetic introgression from related wild species better adapted to such pathogens. These results suggest the need for more research, both short-term and, more globally, long-term.