Antiproliferative effects of isoprenoids from Sarcophyton glaucum on breast cancer MCF-7 cells

Purpose: To evaluate the anticancer activity of isoprenoids of Sarcophyton glaucum on MCF-7 cells and to investigate the potential synergistic effect of doxorubicin.Methods: Isolation and purification of isoprenoids were performed by applying different planar chromatographic methods (CC and PTLC). Further analyses of the isoprenoids by nuclear magnetic resonance (NMR) and mass spectrometry (MS) carried out to identify the compounds. Sulforhodamine- B (SRB) assay was used to determine the cytotoxic activity of the compounds against the MCF-7 human cell line. Flow cytometric analysis was used to assess their impact on cell cycle of  MCF-7. Combination index (CI), when the compounds were combined with  doxorubicin, was calculated to determine possible synergism. The isoprenoid  compounds were also incubated at ¼ or ½ of their respective half-maximal  concentration (IC50) with equimolar concentrations of doxorubicin.Results: Four known isoprenoid derivatives (1-4) were identified as 10(14)-aromadendrene (1), sarcophinediol (2), ent-deoxysarcophine (3) and sarcotrocheliol acetate (4). It was observed that cells accumulated in pre-G phase as well. CI of compound 3 with doxorubicin was 0.67 and 0.79, respectively, at ¼ and ½ of IC50, indicating overt synergism. This was confirmed by re-assessing the cell cycle stages of MCF-7 cells.Conclusion: The results indicate that compound 3 exhibits promising cytotoxicity as well as synergism with doxorubicin in MCF-7 cells. This is attributed, at least partly, to its ability to generate intercellular apoptosis induction.Keywords: Sarcophyton glaucum, Combination index, Antiproliferation, Isoprenoidal derivatives, 10(14)-Aromadendrene,Sarcophinediol, Deoxysarcophine,  Sarcotrocheliol acetate, Doxorubici

Bioactivities of Lyngbyabellins from Cyanobacteria of Moorea and Okeania Genera

Cyanobacteria are reported as rich sources of secondary metabolites that provide biological activities such as enzyme inhibition and cytotoxicity. Ten depsipeptide derivatives (lyngbyabellins) were isolated from a Malaysian Moorea bouillonii and a Red Sea Okeania sp.: lyngbyabellins G (1), O (2), P (3), H (4), A (7), 27-deoxylyngbyabellin A (5), and homohydroxydolabellin (6). This study indicated that lyngbyabellins displayed cytotoxicity, antimalarial, and antifouling activities. The isolated compounds were tested for cytotoxic effect against human breast cancer cells (MCF7), for antifouling activity against Amphibalanus amphitrite barnacle larvae, and for antiplasmodial effect towards Plasmodium falciparum. Lyngbyabellins A and G displayed potent antiplasmodial effect against Plasmodium, whereas homohydroxydolabellin showed moderate effect. For antifouling activity, the side chain decreases the activity slightly, but the essential feature is the acyclic structure. As previously reported, the acyclic lyngbyabellins are less cytotoxic than the corresponding cyclic ones, and the side chain increases cytotoxicity. This study revealed that lyngbyabellins, despite being cytotoxic agents as previously reported, also exhibit antimalarial and antifouling activities. The unique chemical structures and functionalities of lyngbyabellin play an essential role in their biological activities

Mycosporine-like amino acids in six scleractinian coral species

Mycosporine-like amino acids (MAAs) were studied in stony coral species (Fungiidae) along the Eastern coast of the Red Sea. Six species - Fungia scutaria, F. danai, F. corona, F. repanda, Ctenactis echinata and Lithophyllor lobata - were examined for MAAs at water depths of 5, 10, 15 and 20 m. Protein and chlorophyll were also determined and showed higher contents in winter than in summer. Generally, the total content of MAAs in summer was found to be approximately three times greater than in winter. Overall, concentrations of MAAs were greatest at a depth of 5 m. Porphyra-334 was the most abundant MAA in F. Scutaria and F. Danai, whereas asterina-330 was either not detectable (e.g. L. lobata) or present in low concentrations (e.g. F. danai, F. repanda and C. echinata). Shinorine was not detected in F. danai or L. lobata. Both C. echinata and L. Lobata had the lowest concentrations of MAAs, presumably because of their large calcareous skeletons. The variation in MAA concentrations among seasons and water depths is probably due to a number of factors, including the intensity of solar radiation, turbidity and phylogenetic variation

Long-chain wax esterns and diphenylamine in fire coral Millepora dichotoma and Millepora platyphylla from Saudi Red Sea Coast

The characterization of the non-protein constituents of two species of fire corals Millepora dichotoma and Millepora platyphylla, exhibits very interesting results. The compounds were identified by gas chromatography-mass spectrometry (GCMS) and nuclear magnetic resonance (NMR) spectroscopy. The solvent extracts of the two species revealed four wax esters. The compounds were identified as C30H60O2, C32H64O2, C34H68O2 and C36H72O2 respectively. The presence of these compounds has been reported previously in different marine organisms as well as in marine samples. It is interesting that there were some variations in the number and nature of isomers of similar wax esters reported earlier. Long-chain wax esters are normally waxy in nature and their presence in fire coral plays a vital role in the nutrient transfer to the coral mass. They may also act as a protective coating of the nematocyst of dactylozooid. The coral species were also subjected to mild acidic hydrolysis, followed by neutralization and partitioning between water and ether. The organic phase was dried and purified by column chromatography and thin layer chromatography (TLC). Diphenylamine was revealed as the main product in one of the fractions. It is worth noting that diphenylamine is reported for the first time as a marine natural product. Diphenylamine is known to be toxic and causes allergic reactions to the skin, so it can be considered as responsible for the stinging property of fire coral.No disponibl

Antimicrobial sesquiterpenoids from Laurencia obtusa Lamouroux

Purification of the organic extract of Laurencia obtusa Lamouroux by column chromatography and preparative thin layer chromatography provided four new compounds: a eudesmane-type sesquiterpenoid [eudesma-4(15),11-diene-5,7-diol (1)], a cuparane-type sesquiterpenoid [10-hydroxycuparaldehyde (2)], and two nor-cuparanes [3-hydroxy-15-nor-cuparan-10β-ol (3) and 2-bromo-3-hydroxy-15-nor-cuparan-10β-ol (4)]. Structural identification was made possible by comparison of spectral data with those reported in the literature. Compounds 3 and 4 are significant as nor-cuparanes are rarely isolated from marine environment. 1 showed moderate anticandidal activity, whereas 2 exhibited reasonable antibacterial activity against multidrug-resistant bacteria (especially Gram-positive). All the compounds are nontoxic to Artemia salina

New cytotoxic isoprenoid derivatives from the Red Sea soft coral<i> Sarcophyton glaucum</i>

<div><p>Chemical investigation of the soft coral <i>Sarcophyton glaucum</i> collected from the Red Sea led to isolation of 11 isoprenoidal metabolites (<b>1</b>–<b>11</b>). A new sesquiterpenoid, 6-oxo-germacra-4(15),8,11-triene (<b>1</b>), a new natural cembranoid, sarcophinediol, along with two known sesquiterpenoids (<b>2</b> and <b>3</b>) and seven known cembranoids (<b>5</b>–<b>11</b>) was obtained. The structures of the compounds were established based on their NMR, MS, IR and UV spectral data. All compounds were evaluated for their cytotoxicity employing three cancer cell lines (HepG2, MCF-7 and HCT116). Compounds <b>4</b> and <b>6</b> showed significant cytotoxicity towards HepG2 with IC₅₀ values of 18.8 ± 0.07 and 19.9 ± 0.02 μM; respectively. Compounds <b>5</b>–<b>7</b> exhibited potent cytotoxicity against MCF-7 cells with IC₅₀ values of 9.9 ± 0.03, 2.4 ± 0.04 and 3.2 ± 0.02 μM, respectively. Compounds <b>1</b>, <b>4</b> and <b>5</b> showed significant activities towards HCT116 cells with IC₅₀ values of 29.4 ± 0.03, 19.4 ± 0.02 and 25.8 ± 0.03 μM, respectively.</p></div