The effect of 9,11-secosterol, a newly discovered compound from the soft coral Gersemia fruticosa, on the growth and cell cycle progression of various tumor cells in culture

Deep-Sea Sponges and Corals off the Western Coast of Florida-Intracellular Mechanisms of Action of Bioactive Compounds and Technological Advances Supporting the Drug Discovery Pipeline

The majority of natural products utilized to treat a diverse array of human conditions and diseases are derived from terrestrial sources. In recent years, marine ecosystems have proven to be a valuable resource of diverse natural products that are generated to defend and support their growth. Such marine sources offer a large opportunity for the identification of novel compounds that may guide the future development of new drugs and therapies. Using the National Oceanic and Atmospheric Administration (NOAA) portal, we explore deep-sea coral and sponge species inhabiting a segment of the U.S. Exclusive Economic Zone, specifically off the western coast of Florida. This area spans ~100,000 km2, containing coral and sponge species at sea depths up to 3000 m. Utilizing PubMed, we uncovered current knowledge on and gaps across a subset of these sessile organisms with regards to their natural products and mechanisms of altering cytoskeleton, protein trafficking, and signaling pathways. Since the exploitation of such marine organisms could disrupt the marine ecosystem leading to supply issues that would limit the quantities of bioactive compounds, we surveyed methods and technological advances that are necessary for sustaining the drug discovery pipeline including in vitro aquaculture systems and preserving our natural ecological community in the future. Collectively, our efforts establish the foundation for supporting future research on the identification of marine-based natural products and their mechanism of action to develop novel drugs and therapies for improving treatment regimens of human conditions and diseases.

Designed whole-cell-catalysis-assisted synthesis of 9,11-secosterols

A method for the synthesis of 9,11-secosteroids starting from the natural corticosteroid cortisol is described. There are two key steps in this approach, combining chemistry and synthetic biology. Stereo- and regioselective hydroxylation at C9 (steroid numbering) is carried out using whole-cell biocatalysis, followed by the chemical cleavage of the C-C bond of the vicinal diol. The two-step method features mild reaction conditions and completely excludes the use of toxic oxidants.

Marine Terpenoids from Polar Latitudes and Their Potential Applications in Biotechnology

Polar marine biota have adapted to thrive under one of the ocean’s most inhospitable scenarios, where extremes of temperature, light photoperiod and ice disturbance, along with ecological interactions, have selected species with a unique suite of secondary metabolites. Organisms of Arctic and Antarctic oceans are prolific sources of natural products, exhibiting wide structural diversity and remarkable bioactivities for human applications. Chemical skeletons belonging to terpene families are the most commonly found compounds, whereas cytotoxic antimicrobial properties, the capacity to prevent infections, are the most widely reported activities from these environments. This review firstly summarizes the regulations on access and benefit sharing requirements for research in polar environments. Then it provides an overview of the natural product arsenal from Antarctic and Arctic marine organisms that displays promising uses for fighting human disease. Microbes, such as bacteria and fungi, and macroorganisms, such as sponges, macroalgae, ascidians, corals, bryozoans, echinoderms and mollusks, are the main focus of this review. The biological origin, the structure of terpenes and terpenoids, derivatives and their biotechnological potential are described. This survey aims to highlight the chemical diversity of marine polar life and the versatility of this group of biomolecules, in an effort to encourage further research in drug discovery.

Purified compounds from marine organism sea pen induce apoptosis in human breast cancer cell MDA-MB-231 and cervical cancer cell Hela

Marine organisms are an important source of chemical compounds which are appropriate for use as therapeutic agents. Among them, Sea pens produce valuable chemical compounds being used as anti-cancer drugs. The aim of this study was to investigate anti-cancer property of extracted and purified compounds from marine organism Sea pen and evaluate their effects on inducing of apoptosis. The extracts were prepared from dried colony of Virgularia gustaviana. The compounds (3β)-Cholest,5en,3ol (cholesterol) (15 mg), Hexadecanoic acid (2.5 mg) and 2-Hexadecanol (10.7 mg) were identified by GC-MS and NMR. The cytotoxic effects of the compounds were evaluated on Hela and MDA-Mb-231 human cancer cell lines with MTT assay. Immunocytochemistry and Western Blot analyses were used to evaluate the expression of apoptosis related markers Caspase 3, Caspase 8, Bax and BCL2 in cancer cells after treating with three compounds. The purified compounds reduced viability of human breast cancer cell line MDA-MB-231 and human cervical cancer cell line Hela concentration-dependently. 2-Hexadecanol reduced significantly the viability of both cancer cell lines in comparison to the other purified compounds. Treatment of cancer cells with the three purified compounds increased the expression of caspase-3, caspase-8 and Bax proteins and decreased the relative Bcl-2/Bax ratio, demonstrating induction of apoptosis as possible mechanism of action. According to the results, three purified compounds inhibit the growth of cancer cells by inducing of apoptosis pathway; an effect which needs to be further investigated in the future studies.

Gersemiols A-C and Eunicellol A, Diterpenoids from the Arctic Soft Coral Gersemia fruticosa

Three new diterpenes named gersemiols A-C (1-3) and a new eunicellane diterpene, eunicellol A (4), have been isolated together with the known sesquiterpene (+)-α-muurolene (5) from the Arctic soft coral Gersemia fruticosa. The name gersemiane was assigned to the rare and unnamed diterpene skeleton of compounds 1-3 corresponding to 4-isopropyl-1,5,8a-trimethyltetradecahydrophenanthrene. The chemical structures were elucidated on the basis of extensive spectroscopic analysis (HR-ESIMS, 1D and 2D NMR) as well as coupling constant calculations for the determination of the relative configurations. All compounds were tested for their antimicrobial activity against several bacteria and fungi and eunicellol A was found to exhibit moderate and selective antibacterial activity.

9,11-Secosteroids with cytotoxic activity from the South China Sea gorgonian coral Subergorgia suberosa

Nine new 9,11-secosterols (1-9), containing the same 3β,6α,11-trihydroxy-9,11-seco-5α-cholest-7-en-9-one steroidal nucleus, whereas possessing an array of structurally diverse side chains, along with fourteen known 9,11-secosterol compounds (10-23), were isolated from the South China Sea gorgonian coral Subergorgia suberosa, of which 3/4, 5/6, 7/8, and the known compounds 11/12, 20/21 were five pairs of inseparable C-24 epimers. Their structures were established by the extensive analyses of 1D and 2D NMR spectra, high-resolution chemical ionization mass spectrometry (HRCIMS), and by the comparison with literature data. Cytotoxic effect of these metabolites against the growth of HeLa cell lines was evaluated. The result showed that the inhibitory effect of compounds 1-23 varied considerably depending on the nature of the side chain in spite of sharing the same steroidal nucleus. Compound 19, featuring both the absence of hydroxyl group and the presence of double bond in the stigmasterol side chain, exhibited the most potent cytotoxicity with IC50 being 15.1 μM. The preliminary structure activity relationship studies identified some important structural features considerably influencing the biological effect deserved, providing valuable information for chemists and pharmacologists to design and synthesize more effective antitumor agents bearing the 9,11-secosteroid framework.

Cytotoxic and cytolytic cnidarian venoms. A review on health implications and possible therapeutic applications

The toxicity of Cnidaria is a subject of concern for its influence on human activities and public health. During the last decades, the mechanisms of cell injury caused by cnidarian venoms have been studied utilizing extracts from several Cnidaria that have been tested in order to evaluate some fundamental parameters, such as the activity on cell survival, functioning and metabolism, and to improve the knowledge about the mechanisms of action of these compounds. In agreement with the modern tendency aimed to avoid the utilization of living animals in the experiments and to substitute them with in vitro systems, established cell lines or primary cultures have been employed to test cnidarian extracts or derivatives. Several cnidarian venoms have been found to have cytotoxic properties and have been also shown to cause hemolytic effects. Some studied substances have been shown to affect tumour cells and microorganisms, so making cnidarian extracts particularly interesting for their possible therapeutic employment. The review aims to emphasize the up-to-date knowledge about this subject taking in consideration the importance of such venoms in human pathology, the health implications and the possible therapeutic application of these natural compounds.

Secosteroids and norcembranoids from the soft coral Sinularia nanolobata

Two new 9,11-secosteroids, 22α-acetoxy-24-methylene-3β,6α,11-trihydroxy-9,11-seco-cholest-7-en-9-one (1) and 11-acetoxy-24-methylene-1β,3β,6α-trihydroxy-9,11-seco-cholest-7-en-9-one (2), as well as two known norcembranoids, 5-epi-sinuleptolide (3) and sinuleptolide (4), were isolated from the soft coral Sinularia nanolobata. The structures of these metabolites were elucidated on the basis of extensive spectroscopic analysis. The anti-HCMV (human cytomegalovirus) activity of 1–4 and its cytotoxicity against selected cell lines were evaluated.

Synthesis of cytotoxic novel 9,11-secosterol analogs: Structure/activity studies

In an effort to determine the pharmaceutical utility and the structural requirements for activity against tumor cell lines, 30 novel 9,11-secosterol analogues with different side chains and degrees of oxidation at C-9 were synthesized starting from hecogenin. Evaluation of the synthesized compounds for cytotoxicity against KB, HeLa and MCF-7 cell lines revealed that some important structural features are required for activity. The presence of a cholesterol-type side chain, which appears to play a major role in determining the biological activity, the existence of a ketone functional at C-9 is also crucial for anticancer activity whereas hydroxyl/ketone function at C-22 on the side chain did not increase cytotoxicity.

9,11-Secosterols with antiproliferative activity from the gorgonian Eunicella cavolini

Four new 9,11-secosterols (2, 4-6), along with two previously reported ones (1, 3) were isolated from the organic extract of the gorgonian Eunicella cavolini. The structures and relative configurations of the isolated natural products were established on the basis of detailed NMR spectroscopic analysis. Metabolites 1 and 2 were found to strongly inhibit the growth of LNCaP human prostate adenocarcinoma cells and the estrogen-dependent growth of MCF-7 human breast adenocarcinoma cells.

Cold-water marine natural products

Marine natural products isolated from organisms collected from cold-water habitats are described. Emphasis is on bioactive compounds from tunicates, sponges, microbes, bryozoans, corals, algae, molluscs and echinoderms. Synthetic studies of several important classes of cold-water compounds are highlighted.

Secosteroids of marine origin

This review describes the isolation from marine organisms of all secosteroids reported in the literature from 1972 to 2004. Secosteroids are highly oxidized metabolites with bond cleavage in the rings of the steroid tetracyclic nucleus. All secosteroids are grouped in accordance with their ring joined to side chain as 5,6-, 9,11-, 9,10- 8,9-, 8,14- and 13,17-secosteroids and the structures and the synthetic works, where available, are reported. Furthermore, this review gives details on the biological activities of the isolated secosteroids (e.g. antiproliferative, antifouling, antiinflammatory, antimicrobial, ichthyotoxic and antiviral).

Challenges and rewards of research in marine natural products chemistry in Brazil

Brazil is blessed with a great biodiversity, which constitutes one of the most important sources of biologically active compounds, even if it has been largely underexplored. As is the case of the Amazon and Atlantic rainforests, the Brazilian marine fauna remains practically unexplored in the search for new biologically active natural products. Considering that marine organisms have been shown to be one of the most promising sources of new bioactive compounds for the treatment of different human diseases, the 8000 km of the Brazilian coastline represents a great potential for finding new pharmacologically active secondary metabolites. This review presents the status of marine natural products chemistry in Brazil, including results reported by different research groups with emphasis on the isolation, structure elucidation, and evaluation of biological activities of natural products isolated from sponges, ascidians, octocorals, and Opistobranch mollusks. A brief overview of the first Brazilian program on the isolation of marine bacteria and fungi, directed toward the production of biologically active compounds, is also discussed. The current multidisciplinary collaborative program under development at the Universidade de São Paulo proposes to establish a new paradigm toward the management of the Brazilian marine biodiversity, integrating research on the species diversity, ecology, taxonomy, and biogeography of marine invertebrates and microorganisms. This program also includes a broad screening program of Brazilian marine bioresources, to search for active compounds that may be of interest for the development of new drug leads.

Short synthesis of novel 9,11-secosterols

Starting from ergosterol two novel 9,11-secosterols with modified side chains (1a) and (1c) were synthesized via eight main transformations.