The mangrove flora is a diverse group of salt-tolerant plants growing in tropical and subtropical intertidal estuarine zones. This review summarizes the source, chemistry and bioactivities of natural products from true mangrove species worldwide. It includes 349 metabolites and 150 references. The molecular phylogeny and chemotaxonomy of true mangrove plants is discussed.

Thirteen limonoids with a new carbon skeleton, the xylogranatins F-R (1-13), have been isolated from the seeds of a Chinese mangrove, Xylocarpus granatum; two recently reported compounds, xylogranatins C and D were also isolated. Their structures were elucidated on the basis of spectroscopic data and chemical methods. The absolute configurations of these compounds were determined by using the modified Mosher MTPA ester method and by quantum chemical circular dichroism (CD) calculations. Xylogranatins F-Q are the first aromatic B-ring limonoids found in nature. They belong to two substructural classes, of which one (1-3) contains a pyridine ring while the other one (4-12) contains a central furan core. Xylogranatins C and R can be considered to be key biosynthetic intermediates, while xylogranatin D, the only limonoid found so far with a carbon skeleton that conatains a C(30)-C(9) linkage, is apparently an artifact. The structures of these compounds suggest a new biogenetic pathway to tetranortriterpenoids. Xylogranatins F, G and R were found to exhibit marked antifeedant activity against the third instar larvae of Mythimna separata (Walker) at a concentration of 1 mg mL(-1). The most potent compound tested was xylogranatin G. Its AFC(50) (concentration for 50 % antifeedant activity) values at the exposure times of 24 and 48 h were 0.31 and 0.30 mg mL(-1), respectively.

Two unique 8,9,30-phragmalin ortho esters, xyloccensins O (1) and P (2), were isolated from the mangrove plant Xylocarpus granatum. They are a new type of ortho ester of phragmalin. The structures were determined by spectroscopic and single-crystal X-ray diffraction techniques. The biogenetic pathway to these new phragmalins was also proposed. [structure: see text]

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A novel inherently conducting polymer, high-quality polyfluoranthene (PFA) film with electrical conductivity of 10(-2) S cm(-1), was first synthesized electrochemically by direct anodic oxidation of fluoranthene in a middle strong Lewis acid-boron trifluoride diethyl etherate. The oxidation potential onset of fluoranthene in this medium was measured to be only 1.07 V vs SCE, which was much lower than that in acetonitrile + 0.1 mol L(-1) tetrabutylammonium tetrafluoroborate (1.68 V vs SCE). This PFA film showed good redox activity and stability even in concentrated sulfuric acid. Moreover, the fluorescence properties of PFA were greatly improved in comparison with those of the monomer. Dedoped PFA films were partly soluble in polar solvents such as CH(2)Cl(2), acetone, tetrahedrofuran, and dimethyl sulfoxide. The structure and morphology of the polymer were investigated by UV-vis spectroscopy, infrared spectroscopy, and scanning electron microscopy, respectively. The results of quantum chemistry calculations of fluoranthene monomer and (1)H NMR spectroscopy of dedoped PFA films indicated that the polymerization mainly occurred at C((3)), C((4)), C((13)), and C((14)) positions.

Blocking the staphyloxanthin biosynthesis process has emerged as a new promising antivirulence strategy. Previously, we first revealed that CrtN is a druggable target against infections caused by pigmented Staphylococcus aureus (S. aureus) and that naftifine was an effective CrtN inhibitor. Here, we identify a new type of benzofuran-derived CrtN inhibitor with submicromolar IC50 values that is based on the naftifine scaffold. The most potent analog, 5m, inhibits the pigment production of S. aureus Newman and three MRSA strains, with IC50 values of 0.38-5.45 nM, without any impact on the survival of four strains (up to 200 μM). Notably, compound 5m (1 μM) could significantly sensitize four strains to immune clearance and could effectively attenuate the virulence of three strains in vivo. Moreover, 5m was determined to be a weak antifungal reagent (MIC > 16 μg/mL). Combined with good oral bioavailability (F = 42.2%) and excellent safety profiles, these data demonstrate that 5m may be a good candidate for the treatment of MRSA infections.

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