From the MeOH extract of the Vietnamese sea cucumber Holothuria edulis, eight triterpene glycosides (1−8), including one new compound namely holothurin A5 (1), were isolated by using various chromatographic separations. Their structures were established by spectroscopic experiments including 1D, 2D NMR and HR-ESI-MS.Holothurin A5 (1) has a hydroperoxy group at C-25. To the best of our knowledge, this is the first report of this group in triterpene saponins obtained from sea cucumbers to date.In addition, the in vitro cytotoxicity against five human cancer cell lines (HepG2, KB, LNCaP, MCF7 and SK-Mel2) of all isolated compounds was also evaluated using SRB assays.

Soft corals are marine invertebrates possessing a vast range of terpenoid metabolites. These terpenes, mainly cembranoids, represent the main chemical defense tools of animal against its natural predators. Cembranoids, which have 14-membered macrolic skeleton, are well known to exhibit a wide range of biological activities including neuroprotective, antimicrobial, Ca-antagonistic, antiinflammatory and antitumor properties.1-3) The antitumor effect of cembranes is, however, one of the most important activities of this class of natural products.1-3) Among soft corals, Sarcophyton species is one of the most abundant coral reef animals with a high cembranoid content. In the course of our ongoing studies on marine natural products, we have investigated on the S. mililatensis and found four new cembranoid diterpenes as (Ϫ)-7b-hydroxy-8a-methoxydeepoxysarcophytoxide (1), (ϩ)-7b,8b-dihydroxydeepoxysarcophytoxide (2), (Ϫ)-17-hydroxysarcophytonin A (3) and sarcophytol V (4), along with two known compounds (ϩ)-sarcophine (5) and sarcophytoxide (6). Their structures were established on the basis of NMR and MS spectral experiments.Osteoporosis is characterized by a reduced bone mass, which results in increased bone fragility and fracture risk. Many osteoporotic patients have already lost a substantial amount of bone; therefore, a method of increasing bone mass by stimulating new bone formation is required. Osteoblasts are the active mature bone cells that synthesize the organic matrix and regulate its mineralization. To investigate whether compounds isolated from S. mililatensis could stimulate the function of osteoblasts, alkaline phosphatase (ALP) activity, collagen content, and calcium deposition were assessed in the pre-osteoblastic target cell line, MC3T3-E1, which has been a well-characterized as an in vitro model for osteoblast differentiation. Results and DiscussionsCombined chromatographic methods led to the isolation of four new cembranoid diterpenes 1-4 from the methanolic extract of the soft coral S. mililatensis. (d 124.5, 126.4, 136.5, 142.6). All the protons were assigned to relevant carbons by an HSQC experiment. The 1 H-1 H COSY experiment allowed to assign the proton-proton correlations of H-2/H-3, H 2 -5/H 2 -6/H-7, H 2 -9/H 2 -10/H-11 and H 2 -13/H 2 -14. These data together with the HMBC cross peaks between H-2/C-1, H 3 -18/C-3, H 3 -18/C-4, H 3 -18/C-5, H 3 -19/C-7, H 3 -19/C-8, H 3 -19/C-9, H 3 -20/C-11, H 3 -20/C-12, H 3 -20/C-13 and H 2 -13/C-1 confirmed the connectivities from C-1 to C-14 of the 14-membered ring. The position of the C-17 methyl group was confirmed by the HMBC correlations from H 3 -17 to C-1, C-15 and C-16. The HMBC Science and Technology; 18 Hoang Quoc Viet, Nghiado, Caugiay, Hanoi, Vietnam: and b College of Pharmacy, Chungnam National University; Daejeon 305-764, Korea. Received December 31, 2007; accepted H COSY, HSQC, HMBC, and ROESY. To investigate the bioactivities of compounds, which act on bone metabolism, we studied the effects of compounds on the function of osteobl...

Microbial cells have extensively been utilized to produce value-added bioactive compounds. Based on advancement in protein engineering, DNA recombinant technology, genome engineering, and metabolic remodeling, the microbes can be re-engineered to produce industrially and medicinally important platform chemicals. The emergence of co-culture system which reduces the metabolic burden and allows parallel optimization of the engineered pathway in a modular fashion restricting the formation of undesired byproducts has become an alternative way to synthesize and produce bioactive compounds. In this study, we present genetically engineered E. coli-based co-culture system to the de novo synthesis of apigetrin (APG), an apigenin-7-O-β-D-glucopyranoside of apigenin. The culture system consists of an upstream module including 4-coumarate: CoA ligase (4CL), chalcone synthase, chalcone flavanone isomerase (CHS, CHI), and flavone synthase I (FNSI) to synthesize apigenin (API) from p-coumaric acid (PCA). Whereas, the downstream system contains a metabolizing module to enhance the production of UDP-glucose and expression of glycosyltransferase (PaGT3) to convert API into APG. To accomplish this improvement in titer, the initial inoculum ratio of strains for making the co-culture system, temperature, and media component was optimized. Following large-scale production, a yield of 38.5 µM (16.6 mg/L) of APG was achieved. In overall, this study provided an efficient tool to synthesize bioactive compounds in microbial cells.

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Eight compounds were isolated from the leaves of Clerodendrum inerme, including one new rearranged abietane diterpene, crolerodendrum B (1). Their structures were determined by means of spectroscopic methods including one-dimensional and two-dimensional nuclear magnetic resonance (1-D and 2-DNMR), high-resolution electrospray ionisation mass spectrometry (HR-ESI-MS) and circular dichroism (CD). The DPPH radical scavenging and cytotoxic activities of isolated compounds against MCF7 (breast), HCT116 (colon) and B16F10 (melanoma) cancer cell lines were evaluated. Compounds 1, 3 and 4 exhibited strong DPPH radical-scavenging effects (ED values of 17.6 ± 2.1, 10.1 ± 0.8 and 11.3 ± 0.3 μM, respectively) and 4 showed strong cytotoxicity against the HCT116 cell line (IC = 3.46 ± 0.01 μM).

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Nine cembranoid diterpenes 1-9, including four new compounds, crassumols D-G (1-4), were isolated from the methanol extract of the Vietnamese soft coral Lobophytum crassum. Spectroscopic methods were used to elucidate the structures of these compounds. Compound 5 exhibited a potent inhibitory effect on tumor necrosis factor-alpha (TNFα)-induced nuclear factor-kappa B (NF-κB) transcriptional activation in HepG2 cells and significantly inhibited the mRNA expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in a dose-dependent manner.

Inflammation is important in biomedical research, because it plays a key role in inflammatory diseases including rheumatoid arthritis and other forms of arthritis, diabetes, heart disease, irritable bowel syndrome, Alzheimer’s disease, Parkinson’s disease, allergies, asthma, and even cancer. In the present study, we describe the inhibitory effect of crude extracts and steroids isolated from the starfish Astropecten polyacanthus on pro-inflammatory cytokine (Interleukin-12 (IL-12) p40, interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α)) production in lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs). Among those tested, compounds 5 and 7 showed potent inhibitory effects on the production of all three pro-inflammatory cytokines with IC50 values ranging from 1.82 ± 0.11 to 7.00 ± 0.16 μM. Potent inhibitory activities were also observed for compound 1 on the production of IL-12 p40 and IL-6 with values of 3.96 ± 0.12 and 4.07 ± 0.13 μM, respectively, and for compounds 3 and 4 on the production of IL-12 p40 with values of 6.55 ± 0.18 and 5.06 ± 0.16 μM, respectively. Moreover, compounds 2 (IC50 = 34.86 ± 0.31 μM) and 6 (IC50 = 79.05 ± 2.05 μM) exhibited moderate inhibitory effects on the production of IL-12 p40, whereas compounds 3 (IC50 = 22.80 ± 0.21 μM) and 4 (IC50 = 16.73 ± 0.25 μM) moderately inhibited the production of TNF-α and IL-6, respectively.