Lignans are a class of secondary metabolites derived from the oxidative dimerization of two phenylpropanoid units. This review covers the source, chemistry and bioactivities of natural lignans, and highlights the total syntheses of some lignans and asymmetric syntheses of their motifs.

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.

Unfavorable fishy odour is an inevitable problem in aquatic products. In the present study, headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) analysis of volatiles from untreated samples and three deodorized samples (under the optimal conditions) of Paphia undulata enzymatic hydrolysate revealed that the compounds contributing to the distinctive odor were 1-octen-3-ol, n-hexanal, n-heptanal, 2,4-heptadienal, and 2,4-decadienal, whereas n-pentanal, n-octanal, n-octanol, benzaldehyde, 2-ethylfuran and 2-pentylfuran were the main contributors to the aromatic flavor. The deodorizing effects of activated carbon (AC) adsorption, yeast extract (YE) masking and tea polyphenol (TP) treatment on a P. undulata enzymatic hydrolysate were investigated using orthogonal experiments with sensory evaluation as the index. The following optimized deodorization conditions were obtained: AC adsorption (35 mg mL −1 , 80℃, 40 min), YE masking (7 mg mL −1 , 45℃, 30 min) and TP treatment (0.4 mg mL −1 , 40℃, 50 min). AC adsorption effectively removed off-flavor volatile aldehydes and ketones. YE masking modified the odor profile by increasing the relative contents of aromatic compounds and decreasing the relative contents of aldehydes and ketones. The TP treatment was not effective in reducing the odor score, but it significantly reduced the relative content of aldehydes while increasing that of alkanes. It is also notable that TP effectively suppressed trimethylamine (TMA) formation in a P. undulate hydrolysate solution for a period of 72 h.