Xiao-Ling Lu

Macrolactin S, a novel macrolactin antibiotic from marine Bacillus sp.

A new 24-membered ring lactone, macrolactin S, was isolated from a culture broth of marine Bacillus sp. and its structure was established by various spectral analyses. Macrolactin S is the first macrolactin hydroxylated at C-12. Besides, the known compounds macrolactin A and macrolactin B were also isolated, which were elucidated on the basis of spectral data analyses and literature data comparison. They exhibited antibacterial activity against E. coli and S. aureus.

Marine Drugs – Macrolactins

The increasing demands for new lead compounds in pharmaceutical and agrochemical industries have driven scientists to search for new bioactive natural products. Marine microorganisms are rich sources of novel, bioactive secondary metabolites, and have attracted much attention of chemists, pharmacologists, and molecular biologists. This mini‐review mainly focuses on macrolactins, a group of 24‐membered lactone marine natural products, aiming at giving an overview on their sources, structures, biological activities, as well as their potential medical applications.

Bioactive Natural Products from the Antarctic and Arctic Organisms

Polar regions are remote and challenging areas on the earth. In view of the unique environment and the severe competition in polar regions, its considered that the ecological system might be the producer of new compounds with diversity biological activities. This review is an attempt to consolidate the studies about 97 natural products isolated from Antarctic and Arctic organisms including microbes, algae, sponges, bryozoans, and tunicates and so on published in the recent years. The emphasis is mainly about the new compounds, source organisms and biological activities, which signifies the immense competence of Antarctic and Arctic organisms as bioactive natural products producers.

Pimarane diterpenes from the Arctic fungus Eutypella sp. D-1

Two new diterpenes, libertellenone G(1) and libertellenone H(2) were isolated from the fungus Eutypella sp. D-1 isolated from the soil of high latitude of Arctic, together with two known pimarane diterpenes (3–4). The structures of 1 and 2 were elucidated from spectroscopic data (nuclear magnetic resonance, mass spectrometry and infrared). These compounds were evaluated for cytotoxic activity against seven human tumor cell lines. Compound 2 showed a range of cytotoxicity between 3.31 and 44.1 μM. Compound 1 exhibited antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus.

Recent Progress of Src SH2 and SH3 Inhibitors as Anticancer Agents

Src family tyrosine kinases (SFKs) play key roles in regulating signal transduction in cellular processes. However, hyper-activated SFKs lead to uncontrolled cell proliferation and cancers. For both Src SH2 and SH3 domains involve in the regulation of tumorigenesis signal pathways, the SH2 and SH3 inhibition strategies are expected to block the protein-protein interactions between SFKs and their corporation proteins to abolish the signal transduction. Many inhibitors of SH2 and SH3 domain have been identified. Herein, some predominant examples of these inhibitors are reviewed.

Marine Microbes-Derived Anti-Bacterial Agents

This review covers natural products isolated from marine microorganisms including bacteria, fungi and actinomycetes published in the recent years. The emphasis is mainly about new compounds, together with their anti-bacterial activities, source organisms and country of origin, biosynthetic studies as well as the mechanisms involved in their anti-bacterial activities.

Bioactive Tyrosine‐Derived Cytochalasins from Fungus Eutypella sp. D‐1

Three new cytochalasins Z24, Z25, Z26 (1–3, resp.) and one known compound, scoparasin B (4), were isolated from the fungus Eutypella sp. D‐1 isolated from the soil of high latitude of the Arctic. The structures of 1–3 were elucidated from spectroscopic data (NMR, MS). These compounds were evaluated for cytotoxic activities against several human tumor cell lines. Among them, compound 1 exhibited moderate cytotoxicity toward human breast cancer MCF‐7 cell line with IC50 of 9.33 μM.

Diketopiperazine constituents of marine Bacillus subtilis

Marine organisms, especially marine microorganisms, have been proven to be a rich source of diverse arrays of bioactive metabolites with great potential for pharmaceutical and medical applications. Marine Bacillus subtilis is a common strain species, which usually produces cyclopeptide, macrolide, indole derivatives, etc. In the course of further studies, 10 diketopiperazines: cyclo(Leu-Ile) (1) [1], cyclo(Leu-Leu) (2) [2], cyclo(Trp-Pro) (3) [3], cyclo(Leu-Pro) (4) [4, 5], cyclo(Phe-Ala) (5) [6], cyclo(PheTyr) (6) [2], cyclo(benzyl-Gly) (7) [7], cyclo(Val-Val) (8) [8], cyclo(Gla-Tyr) (9) [9], cyclo(Ala-Tyr) (10) [10], 1-(4-hydroxyphenyl)ethanone (11) [11], and macrolactin B (12) [12] have been isolated from the marine Bacillus subtilis. Among them, compound 7 is a new natural product. All the compounds have not been reported before from this species. The strain 201721 has been derived from sea sediment of East Sea of China. It was isolated on F1 medium [Glucose (6 g), peptone (5 g), and yeast extract (1 g) were dissolved in artifical seawater (1L)] with incubation for 4 days at 28°C. Due to its chemical and morphological features as well as the 16S rDNA (GenBank accession number EF417872), the strain can be identified as the genus Bacillus sp. Chemistry of Natural Compounds, Vol. 45, No. 2, 2009

Traditional Chinese Medicine - Sea Urchin

The sea urchin is an ancient, common, seafloor-dwelling marine invertebrate that belongs to the phylum Echinodermata. There are multiple species of sea urchin with resources that are widely distributed in China, where they were used in ancient times as Traditional Chinese Medicine for treating a variety of diseases. At present, it is known that the shell, spine and gonad of the sea urchin have many medicinal values determined through modern research. In this paper, we summarized the major chemical constituents and medicinal value of the sea urchin.

Description of a Sulfitobacter Strain and Its Extracellular Cyclodipeptides

A marine bacterium M44 was separated from 30 m deep seawater in the East China Sea (26° 28.3′ N 122° 29.0′ E) in 2006. 16S rDNA gene sequence comparison showed that the strain M44 was a member of the genus Sulfitobacter and highly similar to KMM 3554T. A series of experiments demonstrated that this strain M44 had many distinctive characteristics: its cells were gram-negative and mesophilic; its colonies were slightly yellowish, round, convex, and smooth; and it could grow at 10–28°C, pH 6.0–10.0, and in the presence of 0–12.5% (w/v) NaCl; the optimum growth conditions were 25°C and pH 7.0, and the optimum Na+ concentration was 2.5%. In addition, strain M44 contained 18 : 1 ω7c, 11 methyl 18 : 1 ω7c and 16 : 0 fatty acids as major fatty acids, and the genomic DNA G+C content was 58.04 mol%. According to our results of the secondary metabolites, six cyclodipeptides were isolated from the strain M44, which were Cyclo (Val-Leu), Cyclo (Phe-Val), Cyclo (Phe-Leu), Cyclo (Leu-Ile), Cyclo (Phe-Ile), and Cyclo (Trp-Pro). It is the first study of secondary metabolites isolated from this genus.