Identification and Structure-Activity Relationship of Recovered Phenolics with Antioxidant and Antihyperglycemic Potential from Sugarcane Molasses Vinasse.

Sugarcane molasses vinasse is the residue of the fermentation of molasses and the water and soil environmental pollutants from distilleries. However, its recycling value has been neglected. The chemical analysis of the molasses vinasse led to the isolation of a new benzoyl chloride called 2,3,4-trihydroxy-5-methoxy benzoyl chloride, as well as thirteen known compounds, including six benzoic acids. The structure of the new benzoyl chloride was elucidated on the basis of extensive spectroscopic analysis. The antioxidant activity of all isolated compounds was measured using the ORAC assay. Moreover, we compared the cellular antioxidant activity (CAA) and inhibitory activity against α-amylase and α-glucosidase for structure-activity analysis. The results showed that only vanillic acid had CAA (8.64 µmol QE/100 µmol in the no PBS wash protocol and 6.18 µmol QE/100 µmol in the PBS wash protocol), although other benzoic acid derivatives had high ORAC values ranging between 1879.9 and 32,648.1 µmol TE/g. Additional methoxy groups at the ortho-positions of the p-hydroxy group of benzoic acids enhanced the inhibition of α-glucosidase but reduced the ORAC activity unless at the para-position. This work indicated that phenolics, especially phenolic acids in the sugarcane molasses vinasse, possessed potential antioxidant and antihyperglycemic activity, which improved the utilization rate of resources and reduced the discharge of pollutants.

Structural features, interaction with the gut microbiota and anti-tumor activity of oligosaccharides.

Some oligosaccharides are regarded as biological constituents with benefits to human health in an indirect way. They enter the intestinal tract to be fermented by the gut microbiota, causing changes in the abundance and composition of the gut microbiota and producing fermentation products such as short-chain fatty acids (SCFAs). In this review, the structural features and biological activities of eight common natural oligosaccharides were summarized, including human milk oligosaccharides (HMOS), xylo-oligosaccharides (XOS), arabinoxylo-oligosaccharides (AXOS), isomaltooligosaccharides (IMOS), chitin oligosaccharides (NACOS), mannan-oligosaccharides (MOS), galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS). Furthermore, XOS were selected to explain the anti-tumor mechanism mediated by gut microbiota. The review aims to reveal primary structural features of natural functional oligosaccharides related to the biological activities and also provide an explanation of the anti-tumor activity of functional oligosaccharides mediated by the gut microbiota.

Marine unsaturated fatty acids: structures, bioactivities, biosynthesis and benefits.

Unsaturated fatty acids (UFAs) are an important category of monounsaturated and polyunsaturated fatty acids with nutritional properties. These secondary metabolites have been obtained from multitudinous natural resources, including marine organisms. Because of the increasing numerous biological importance of these marine derived molecules, this review covers 147 marine originated UFAs reported from 1978 to 2018. The review will focus on the structural characterizations, biological properties, proposed biosynthetic processes, and healthy benefits mediated by gut microbiota of these marine naturally originated UFAs.

Two New Secondary Metabolites from Tephrosia purpurea.

Further investigation of Tephrosia purpurea led to the isolation of a new prenylated flavone, isoglabratephrin B (1) and a new 1,2-ethanedione benzofuran derivative, purpdione B (2). The structures of the new isolates were elucidated on the basis of extensive spectroscopic analysis.

Marine nucleosides: structure, bioactivity, synthesis and biosynthesis.

Nucleosides are glycosylamines that structurally form part of nucleotide molecules, the building block of DNA and RNA. Both nucleosides and nucleotides are vital components of all living cells and involved in several key biological processes. Some of these nucleosides have been obtained from a variety of marine resources. Because of the biological importance of these compounds, this review covers 68 marine originated nucleosides and their synthetic analogs published up to June 2014. The review will focus on the structures, bioactivities, synthesis and biosynthetic processes of these compounds.

A new 1,2-ethanedione benzofurane derivative from Tephrosia purpurea.

A new 1,2-ethanedione benzofurane derivative, purpdione (1), was isolated from Tephrosia purpurea, together with seven known flavonoids, purpurenone (2), pongamol (3), ovalitenin A (4), karanjin (5), lanceolatin B (6), tachrosin (7) and villosinol (8). The new structure was elucidated based on the analysis of its spectroscopic data. The structures of the known compounds were identified by comparing their spectroscopic data with those reported in the literature. The isolates exhibited marginal ability to inhibit the settlement of barnacle (Balanus reticulatus).

New antioxidative secondary metabolites from the fruits of a Beibu Gulf mangrove, Avicennia marina.

Further chemical investigation of the fruits of the mangrove, Avicennia marina, afforded three new phenylethyl glycosides, marinoids J-L (1-3), and a new cinnamoyl glycoside, marinoid M (4). The structures of isolates were elucidated on the basis of extensive spectroscopic analysis and by comparison of the data with those of related secondary metabolites. The antioxidant activity of the isolates was evaluated using the cellular antioxidant assay (CAA), and compounds 1-4 showed antioxidant activities, with EC50 values ranging from 23.0 ± 0.71 µM to 247.8 ± 2.47 µM.

Two new thyminenol derivatives from the marine sponge Haliclona sp.

Investigation of the marine sponge Haliclona sp. led to the isolation of two new thyminenol derivatives, named cis-thyminenol (1) and trans-thyminenol (2). The structures of the new isolates were elucidated on the basis of extensive spectroscopic analysis.

Two new avermectin derivatives from the Beibu Gulf gorgonian Anthogorgia caerulea.

Two new avermectin derivatives, avermectins B1c and B1e (1 and 2, resp.), as well as two known compounds, avermectin B2a (3) and ivermectin A1a (4), were isolated from a Beibu Gulf gorgonian coral, Anthogorgia caerulea. The structures of the new compounds were established by detailed spectroscopic analysis and by comparison with spectral data of related known compounds. Compounds 1-4 showed moderate antifouling activities against the larval settlement of Balanus amphitrite.

Four new Jacaranone analogs from the fruits of a Beibu Gulf mangrove Avicennia marina.

Four new jacaranone analogs, marinoids F-I (1-4), were isolated from the fruits of a Beibu Gulf mangrove Avicennia marina. The structures were elucidated based on analysis of spectroscopic data. Marinoids F and G are shown to be diastereoisomers of chlorocornoside, a new halogen containing marine secondary metabolite. The antioxidant activity of the isolates was evaluated using a cellular antioxidant assay, and 4 showed good antioxidant activity (EC50 = 26 µM).

A new diketopiperazine from South China Sea marine sponge Callyspongia sp.

Further chemical investigation on the marine sponge Callyspongia sp. collected from South China Sea led to the isolation of a new diketopiperazine, named callysponine A (1), as well as four known diketopiperazines, namely cyclo-(Gly-Pro) (2), cyclo-(Thr-Pro) (3), cyclo-(Ile-Pro) (4) and cyclo-(Pro-Pro) (5). The new structure was determined on the basis of NMR and MS analysis, and the absolute stereochemistry was defined by analysis of the coupling constants and optical rotation. The structures of the known compounds were identified by comparing their spectroscopic data with those reported in the literature. Compounds 1-5 did not inhibit the growth of HepG2 (hepatoma carcinoma cell), A549 (lung carcinoma cell) and HeLa (cervical cancer cell) cell lines.

A new diketopiperazine from the gorgonian coral Menella kanisa.

Chemical investigation on the gorgonian Menella kanisa collected from Beibu Gulf led to the isolation of a new diketopiperazine, named menazepine A (1), as well as three known diketopiperazines, namely cyclo(4-hydroxyprolylleucyl) (2), cyclo(Pro-Leu) (3) and cyclo(4-hydroxyprolylphenylalanyl) (4). The structure of the new diketopiperazine was elucidated on the basis of extensive spectroscopic analysis and by comparing the data with those of related metabolites. Compounds 1-4 were also evaluated for brine shrimp lethality.

Natural products from the genus tephrosia.

The genus Tephrosia, belonging to the Leguminosae family, is a large pantropical genus of more than 350 species, many of which have important traditional uses in agriculture. This review not only outlines the source, chemistry and biological evaluations of natural products from the genus Tephrosia worldwide that have appeared in literature from 1910 to December 2013, but also covers work related to proposed biosynthetic pathways and synthesis of some natural products from the genus Tephrosia, with 105 citations and 168 new compounds.

Dibenzylbutane lignans from the stems of Schisandra bicolor.

Further investigation of the stems of Schisandra bicolor led to the isolation of a new dibenzylbutane lignan, named schibicolignan A (1), as well as five known compounds, namely bis[dibenzylbutane] (2), machilin A (3), macelignan (4), saururenin (5) and sphenanlignan (6). The structure of the new lignan was elucidated on the basis of extensive spectroscopic analysis. Antioxidant activity of 1-6 was also evaluated.