Riming Huang

Diketopiperazines from marine organisms.

Diketopiperazines (DKPs), which are cyclic dipeptides, have been detected in a variety of natural resources. Recently, the interest in these compounds increased significantly because of their remarkable bioactivity. This review deals with the chemical structures, biosynthetic pathways, and biological activities of DKPs from marine microorganisms, sponges, sea stars, tunicates (ascidians), and red algae. The literature has been covered up to December 2008, and a total 124 DKPs from 104 publications have been discussed and reviewed. Some of these compounds have been found to possess various bioactivities including cytotoxicity, and antibacterial, antifungal, antifouling, plant‐growth regulatory, and other activities.

A New 1,4-Diazepine from South China Sea Marine Sponge Callyspongia Species

A new 1,4-diazepine, callysponine (1), was isolated from a South China Sea Callyspongia sp. marine sponge, together with four known proline-based diketopiperazines: cyclo-(S-Pro-R-Leu) (2), cyclo-(S-Pro-R-Val) (3), cyclo-(S-Pro-R-Ala) (4), and cyclo-(S-Pro-R-Tyr) (5). The new structure was determined on the basis of NMR and MS analysis, and the absolute stereochemistry was defined by NOESY spectroscopy and optical rotation. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported in the literature. Callysponine (1) did not inhibit the growth of HepG2 (hepatoma carcinoma cell), A549 (lung carcinoma cell), and HeLa (cervical cancer cell) cell lines.

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.

Chemical and Biological Aspects of Marine Sponges of the Genus Xestospongia

Contents1. Introduction2. Chemical Constituents2.1. Alkaloids2.2. Quinones2.3. Terpenoids2.4. Sterols2.5. Fatty Acids3. Biological Activities3.1. Cardiovascular Activity3.2. Cytotoxic and Antitumor Activities3.3. HIV Protease Inhibitory Activity3.4. Other Enzyme Inhibitory Activities3.5. Antimicrobial and Insecticidal Activities3.6. Other Activities4. Concluding Remarks1. Introduction. – Marine sponges (phylum Porifera) are sessile marine filterfeeders that have developed efficient defense mechanisms against foreign attackerssuch as viruses, bacteria, or eukaryotic organisms, by production of secondarymetabolitestorepelthem[1].Theyareamongtherichestsourcesofpharmacologicallyactive chemicals isolated from marine organisms. The Xestospongia species (classDesmospongia, order Haplosclerida, family Petrosiidae), known as barrel sponges, arelarge and common members of the coral reef communities at depths greater than 10 m,all over the Indo-Pacific Ocean and the Caribbean Sea. Since the 1970s, with thedevelopment of the investigations of marine natural products, the analysis of thechemical constituents of Xestospongia sponges has been carried out consecutively allover the world, particularly in the USA, Japan, and Australia. Xestospongia spongeshave been established as a rich source of diverse secondary metabolites, including

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.

Four New Cyclohexylideneacetonitrile Derivatives from the Hypocotyl of Mangrove (Bruguiera gymnorrhiza)

Four new cyclohexylideneacetonitrile derivatives 1–4, named menisdaurins B–E, as well as three known cyclohexylideneacetonitrile derivatives—menisdaurin (5), coclauril (6), and menisdaurilide (7)—were isolated from the hypocotyl of a mangrove (Bruguiera gymnorrhiza). The structures of the isolates were elucidated on the basis of extensive spectroscopic analysis. Compounds 1–7 showed anti-Hepatitis B virus (HBV) activities, with EC50 values ranging from 5.1 ± 0.2 μg/mL to 87.7 ± 5.8 μg/mL.

Two new cyclic tetrapeptides from deep-sea bacterium Bacillus amyloliquefaciens GAS 00152

Two new cyclic tetrapeptides from deep-sea bacterium Bacillus amyloliquefaciens GAS 00152

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 taurine derivative from South China Sea marine sponge Axinella sp.

A new (1) and two known (2 and 3) acylated taurine derivatives were isolated from the South China Sea marine sponge Axinella sp. The structures of the compounds were determined on the basis of spectral analysis. Compounds 1–3 did not inhibit the growth of hepatoma carcinoma cell (HepG2), lung carcinoma cell (A549), human breast carcinoma (MCF-7), no-small cell lung cancer (NCI-H460) and human nasopharyngeal carcinoma cell lines.

Alkaloids from corals.

Alkaloids, which are generally basic N‐containing compounds, have been found in a variety of natural sources. Recently, the interest in alkaloids from corals increased significantly due to their remarkable bioactivities. This review deals with the chemical structures and biological activities of alkaloids in corals. The literature has been covered up to June 2011, and a total of 102 alkaloids from the 51 publications are discussed and reviewed. Some of these compounds showed various biological properties, such as cytotoxic, antibacterial, insecticidal, antifouling, and other activities.