A cytotoxic 5alpha,8alpha-epidioxysterol from a soft coral Sinularia species

The Invasive Anemone Condylactis sp. of the Coral Reef as a Source of Sulfur- and Nitrogen-Containing Metabolites and Cytotoxic 5,8-Epidioxy Steroids

The Condylactis-genus anemones were examined for their proteinaceous poisons over 50 years ago. On the other hand, the current research focuses on isolating and describing the non-proteinaceous secondary metabolites from the invasive Condylactis anemones, which help take advantage of their population outbreak as a new source of chemical candidates and potential drug leads. From an organic extract of Condylactis sp., a 1,2,4-thiadiazole-based alkaloid, identified as 3,5-bis(3-pyridinyl)-1,2,4-thiadiazole (1), was found to be a new natural alkaloid despite being previously synthesized. The full assignment of NMR data of compound 1, based on the analysis of 2D NMR correlations, is reported herein for the first time. The proposed biosynthetic precursor thionicotinamide (2) was also isolated for the first time from nature along with nicotinamide (3), uridine (5), hypoxanthine (6), and four 5,8-epidioxysteroids (7–10). A major secondary metabolite (−)-betonicine (4) was isolated from Condylactis sp. and found for the first time in marine invertebrates. The four 5,8-epidioxysteroids, among other metabolites, exhibited cytotoxicity (IC50 3.5–9.0 μg/mL) toward five cancer cell lines.

Cytotoxic Compounds from Alcyoniidae. An Overview of the Last 30 Years

The octocoral family Alcyoniidae represents a rich source of bioactive substances with intriguing and unique structural features. This review aims to provide an updated overview of the compounds isolated from Alcyoniidae and displaying potential cytotoxic activity. In order to allow a better comparison among the bioactive compounds, we focused on molecules evaluated in vitro by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, by far the most widely used method to analyze cell proliferation and viability. Specifically, we surveyed the last thirty years of research, finding 153 papers reporting on 344 compounds with proven cytotoxicity. The data were organized in tables to provide a ranking of the most active compounds, to be exploited for the selection of the most promising candidates for further screening and pre-clinical evaluation as anti-cancer agents. Specifically, we found that (22S,24S)-24-methyl-22,25-epoxyfurost-5-ene-3β,20β-diol (16), 3β,11-dihydroxy-24-methylene-9,11-secocholestan-5-en-9-one (23), (24S)-ergostane-3β,5α,6β,25 tetraol (146), sinulerectadione (227), sinulerectol C (229), and cladieunicellin I (277) exhibited stronger cytotoxicity than their respective positive control and that their mechanism of action has not yet been further investigated.

Model Application of Entomopathogenic Fungi as Alternatives to Chemical Pesticides: Prospects, Challenges, and Insights for Next-Generation Sustainable Agriculture

In the past few decades, the control of pests and diseases of cultivated plants using natural and biological measures has drawn increasing attention in the quest to reduce the level of dependence on chemical products for agricultural production. The use of living organisms, predators, parasitoids, and microorganisms, such as viruses, bacteria, and fungi, has proven to be a viable and sustainable pest management technique. Among the aforementioned, fungi, most importantly the insect-pathogenic species, have been in use for more than 150years. These include the most popular strains belonging to the genera Beauveria, Metarhizium, Isaria, Hirsutella, and Lecanicillium. Their application is usually through an inundative approach, which inherently involves exposure of the fungal spores to unfavorable humidity, temperature, and solar radiation conditions. These abiotic factors reduce the persistence and efficacy of these insect-pathogenic fungi. Despite these limitations, over 170 strains have been formulated as mycopesticides and are available for commercial use. In the last few decades, numerous studies have suggested that these species of entomopathogenic fungi (EPF) offer far more benefits and have broader ecological functions than hitherto presumed. For instance, aside from their roles as insect killers, it has been well established that they also colonize various host plants and, hence, provide other benefits including plant pathogen antagonism and plant growth promotion and serve as sources of novel bioactive compounds and secondary metabolites, etc. In this light, the potential of EPF as alternatives or perhaps as supplements to chemical pesticides in plant protection is discussed in this review. The paper highlights the numerous benefits associated with endophytic fungal entomopathogen and host plant associations, the mechanisms involved in mediating plant defense against pests and pathogens, and the general limitations to the use of EPF in plant protection. A deeper understanding of these plant host-fungus-insect relationships could help unveil the hidden potentials of fungal endophytes, which would consequently increase the level of acceptance and adoption by users as an integral part of pest management programs and as a suitable alternative to chemical inputs toward sustainable crop production.

Antibacterial and Cytotoxic Potential of Two Steroids from the Indonesian Soft Coral Sinularia polydactila

Background: Soft corals of the genus Sinularia are well recognized as a rich source of steroidal compounds. These constituents have been reported as possessing antitumor, antimicrobial, and antiviral activities. Objectives: This study was designed to isolate and elucidate antibacterial and cytotoxic compounds from the soft coral Sinularia polydactila. Methods: Structure elucidation of steroids was determined based on spectroscopic data through 1D and 2D NMR analyses and mass spectrometry, with the results compared to data in the literature. Antibacterial activity was determined using four human bacterial pathogens, namely B. subtilis (ATCC 6633), P. aeruginosa (ATCC 27853), S. aureus (ATCC 25923), and E. coli (ATCC 25922). Cytotoxic activity was evaluated using the human colon cancer cell HCT 116 and brine shrimp lethality assay (BSLA). Results: Two steroids (Compounds 1 - 2) were isolated from the Indonesian soft coral Sinularia polydactila. (22R,23R,24R)-22,23-methylene-24-methylcholest-6-en-5α,8α-epidioxy-3β-ol (1) and 5α,8α-Epidioxy-24(R)-methylcholesta-6,22-dien-3α-ol (2) showed moderate activity against colon carcinoma cancer HCT 116 at the concentrations of 24.8 and 27.3 μg/mL, respectively. Furthermore, compounds 1 and 2 showed cytotoxic activity using the brine shrimp lethality assay with the concentrations of 57.1 and 121.3 3 μg/mL, respectively. Compound 2 showed moderate activity against S. aureus and B. subtilis at the 250 μg/mL concentration. Conclusions: Two steroids isolated from soft coral Sinularia polydactila were found to possess moderate cytotoxic and antibacterial activities.

Chemical constituents from the South China sea soft coral Sinularia humilis

A new diterpenoid with an unusual capnosane skeleton, sinuhumilol A (1), alone with twelve known diverse compounds (2-13), were isolated from the South China Sea soft coral Sinularia humilis. Their structures and stereochemistry were elucidated by extensive spectroscopic analysis, quantum chemical calculations, and/or by the comparison of the spectroscopic data with those reported in the literature. In bioassay, compound 11 exhibited interesting specific cytotoxicity against the human colon adenocarcinoma cell line HT-29 with IC₅₀ value of 12.5 µM.

Chemical Diversity of Soft Coral Steroids and Their Pharmacological Activities

The review is devoted to the chemical diversity of steroids produced by soft corals and their determined and potential activities. There are about 200 steroids that belong to different types of steroids such as secosteroids, spirosteroids, epoxy- and peroxy-steroids, steroid glycosides, halogenated steroids, polyoxygenated steroids and steroids containing sulfur or nitrogen heteroatoms. Of greatest interest is the pharmacological activity of these steroids. More than 40 steroids exhibit antitumor and related activity with a confidence level of over 90 percent. A group of 32 steroids shows anti-hypercholesterolemic activity with over 90 percent confidence. Ten steroids exhibit anti-inflammatory activity and 20 steroids can be classified as respiratory analeptic drugs. Several steroids exhibit rather rare and very specific activities. Steroids exhibit anti-osteoporotic properties and can be used to treat osteoporosis, as well as have strong anti-eczemic and anti-psoriatic properties and antispasmodic properties. Thus, this review is probably the first and exclusive to present the known as well as the potential pharmacological activities of 200 marine steroids.

Secondary Metabolites and the Risks of Isaria fumosorosea and Isaria farinosa

Isaria fumosorosea and Isaria farinosa are important entomopathogenic fungi with a worldwide distribution and multiple host insects. However, the concerns about the safety risks of myco-pesticides have been attracting the attention of researchers and consumers. Secondary metabolites (SMs), especially the mycotoxins, closely affect the biosafety of Isaria myco-insecticides. In the last forty years, more than seventy SMs were identified and isolated from I. fumosorosea and I. farinose. The SMs of I. fumosorosea include the mycotoxins of non-ribosomal peptides (NRPs) (beauvericin and beauverolides), terpenes (trichocaranes and fumosorinone), lactone compounds (cepharosporolides), acids (dipicolinic acid and oxalic acid), etc. Meanwhile, the NRP mycotoxins (cycloaspeptides) and the terpene compounds (farinosones and militarinones) are the main SMs in I. farinosa. Although several researches reported the two Isaria have promised biosafety, the bioactivities and the safety risks of their SMs have not been studied in detail so far. However, based on existing knowledge, most SMs (i.e., mycotoxins) do not come from Isaria myco-insecticide itself, but are from the host insects infected by Isaria fungi, because only the hosts can provide the conditions for fungal proliferation. Furthermore, the SMs from Isaria fungi have a very limited possibility of entering into environments because many SMs are decomposed in insect cadavers. The biosafety of Isaria myco-insecticides and their SMs/mycotoxins are being monitored. Of course, SMs safety risks of Isaria myco-insecticides need further research.

Microalgal Microscale Model for Microalgal Growth Inhibition Evaluation of Marine Natural Products

Marine organisms especially sessile invertebrates, such as soft corals, gorgonians and sponges, can survive in the competitive environment mainly relying on their second metabolites with chemoecological effects including allelopathy and algal growth inhibition. It is well known that the microscale models are urgently needed in marine chemoecology assessment to evaluate the algal growth inhibition activity of trace quantity natural products. In this work, a microalgal growth inhibition model was established for microalgal inhibition evaluation of marine natural products with 96-well microplate by automatic fluorescence observation using microplate reader. Subsequently, this model was applied to bioassay-guided isolation and preliminary bioactivity screening of the secondary metabolites from soft corals, gorgonians, sponges and their symbiotic microbes collected from the South China Sea. As a result, fifteen compounds (1‒15) were found to exhibit microalgal growth inhibition activities against at least one of marine microalgae, Karenia mikimotoi, Isochrysis galbana, and Heterosigma akashiwo. Specifically, altersolanol C (13) demonstrated potent activity against K. mikimotoi with the 96h-EC₅₀ value of 1.16 µg/mL, more than four times stronger than that of the positive control K₂Cr₂O₇. It was suggested that the microalgal growth inhibition microscale model is suitable for bioassay-guided isolation and preliminary bioactivity screening of marine natural products.

Casbane Diterpenes from Red Sea Coral Sinularia polydactyla

The soft coral genus Sinularia is a rich source of bioactive metabolites containing a diverse array of chemical structures. A solvent extract of Sinularia polydactyla resulted in the isolation of three new casbane diterpenes: sinularcasbane M (1), sinularcasbane N (2) and sinularcasbane O (3); in addition, known metabolites (4–5) were isolated. Compounds were elucidated on the basis of spectroscopic analyses; the absolute configuration was confirmed by X-ray analysis.

Cytotoxic 5α,8α-epidioxy sterols from the marine sponge Monanchora sp

Three new sterols, 5α,8α-epidioxy-24-norcholesta-6,9(11),22-trien-3β-ol (1), 5α,8α-epidioxy-cholesta-6,9(11),24-trien-3β-ol (2), and 5α,8α-epidioxy-cholesta-6,23-dien-3β,25-diol (3), with four known sterols (4-7) were isolated from a marine sponge Monanchora sp. Their chemical structures were elucidated by extensive spectroscopic analysis. Compounds 1 and 3-7 showed moderate cytotoxicity against several human carcinoma cell lines including renal (A-498), pancreatic (PANC-1 and MIA PaCa-2), and colorectal (HCT 116) cancer cell lines.

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.

New sinularianin sesquiterpenes from soft coral Sinularia sp

Four new sesquiterpenes, sinularianins C–F (3–6), together with known sinularianins A (1) and B (2) were identified from a South China Sea soft coral Sinularia sp. Compounds 1–6 were evaluated for inhibition of NF-κB activation using the cell-based HEK293 NF-κB luciferase reporter gene assay. Compounds 1 and 4 were exhibited a potent effect with inhibitory rates of 41.3% and 43.0% at the concentration of 10 µg/mL, respectively.

Ecology- and Bioassay-Guided Drug Discovery for Treatments of Tropical Parasitic Disease: 5α,8α-Epidioxycholest-6-en-3β-ol Isolated from the Mollusk Dolabrifera dolabrifera Shows Significant Activity against Leishmania donovani

An ecology- and bioassay-guided search employed to discover compounds with activity against tropical parasitic diseases and cancer from the opisthobranch mollusk, Dolabrifera dolabrifera, led to the discovery of antileishmanial properties in the known compound, 5α,8α-epidioxycholest-6-en-3β-ol (1). Compound 1 was identified through nuclear magnetic resonance spectroscopy (1H, 13C) and mass spectrometry. The compound was concentrated in the digestive gland of D. dolabrifera, but was not detected in other body parts, fecal matter or mucus. Compound 1 showed an IC50 of 4.9 μM towards the amastigote form of Leishmania donovani compared with an IC50 of 281 μM towards the control Vero cell line, a 57.3-fold difference, and demonstrated no measurable activity against Plasmodium falciparum, Trypanosoma cruzi, and the breast cancer cell line, MCF-7.

Peroxy natural products

This review covers the structures and biological activities of peroxy natural products from a wide variety of terrestrial fungi, higher plants, and marine organisms. Syntheses that confirm or revise structures or stereochemistries have also been included, and 406 references are cited.

A new 5α,8α-Epidioxysterol from the soft coral Sinularia gaweli

A new sterol, (22R,23R,24R)-5α,8α-epidioxy-22,23-methylene-24-methyl-cholest-6,9(11)-dien-3β-ol (1), and two known sterols, (22R,23R,24R)-5α,8α-epidioxy-22,23-methylene-24-methylcholest-6-en-3β-ol (2) and 24-methylenecholestane-1α,3β,5α, 6β,11α-pentol (3), were isolated from the soft coral Sinularia gaweli. The structure of sterol 1 was established by spectroscopic methods and by comparison of the spectral data with those of known analogues. The cytotoxicity of sterols 1–3 towards various tumor cells is reported.

Polyoxygenated sterols from the South China Sea soft coral Sinularia sp

Chemical investigation of the ethanol extract of soft coral Sinularia sp. collected from the South China Sea led to the isolation of three new polyoxygenated sterols, (3S,23R,24S)-ergost-5-ene-3β,23α,25-triol (1), (24S)-ergostane-6-acetate-3β,5α,6β,25-tetraol (2), (24S)-ergostane-6-acetate-3β,6β,12β,25-tetraol (3) together with three known ones (4-6). The structures, including relative configurations of the new compounds (1-3), were elucidated by detailed analysis of spectroscopic data (IR, UV, NMR, MS) and by comparison with related reported compounds. The absolute configuration of 1 was further determined by modified Mosher's method. Compound 5 exhibited moderate cytotoxicity against K562 cell line with an IC(50) value of 3.18 μM, but also displayed strong lethality toward the brine shrimp Artemia salina with a LC(50) value of 0.96 μM.

Growth inhibition of human gynecologic and colon cancer cells by Phyllanthus watsonii through apoptosis induction

Phyllanthus watsonii Airy Shaw is an endemic plant found in Peninsular Malaysia. Although there are numerous reports on the anti cancer properties of other Phyllanthus species, published information on the cytotoxicity of P. watsonii are very limited. The present study was carried out with bioassay-guided fractionation approach to evaluate the cytotoxicity and apoptosis induction capability of the P. watsonii extracts and fractions on human gynecologic (SKOV-3 and Ca Ski) and colon (HT-29) cancer cells. P. watsonii extracts exhibited strong cytotoxicity on all the cancer cells studied with IC(50) values of ≤ 20.0 µg/mL. Hexane extract of P. watsonii was further subjected to bioassay-guided fractionation and yielded 10 fractions (PW-1→PW-10). PW-4→PW-8 portrayed stronger cytotoxic activity and was further subjected to bioassay-guided fractionation and resulted with 8 sub-fractions (PPWH-1→PPWH-8). PPWH-7 possessed greatest cytotoxicity (IC(50) values ranged from 0.66-0.83 µg/mL) and was selective on the cancer cells studied. LC-MS/MS analysis of PPWH-7 revealed the presence of ellagic acid, geranic acid, glochidone, betulin, phyllanthin and sterol glucoside. Marked morphological changes, ladder-like appearance of DNA and increment in caspase-3 activity indicating apoptosis were clearly observed in both human gynecologic and colon cancer cells treated with P. watsonii especially with PPWH-7. The study also indicated that P. watsonii extracts arrested cell cycle at different growth phases in SKOV-3, Ca Ski and HT-29 cells. Cytotoxic and apoptotic potential of the endemic P. watsonii was investigated for the first time by bioassay-guided approach. These results demonstrated that P. watsonii selectively inhibits the growth of SKOV-3, Ca Ski and HT-29 cells through apoptosis induction and cell cycle modulation. Hence, P. watsonii has the potential to be further exploited for the discovery and development of new anti cancer drugs.

Freshwater Clam Extract Decreased Hemorrhagic Shock–Induced Liver Injury by Attenuating TNF-α Production

Freshwater clam ( Corbicula fluminea), a popular edible shellfish in Asia, is said to have beneficial effects on liver function. However, scientific evidence for such benefit is limited. In this study, the authors aimed to assess the treatment effects of freshwater clam extract (FCE) administration after hemorrhagic shock (HS) in rats. The authors randomly divided animals into three groups. After inducing HS in rats in the HS + FCE ( n = 12) and HS groups, the authors fed 20 mg/kg FCE orally to rats in the HS group only. The authors neither induced HS in nor fed FCE to rats ( n = 8) in the vehicle group. The authors measured the blood levels of white blood cells (WBC), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and tumor necrosis factor-alpha (TNF-α) at several time points during the experiment. After 48 hr, the authors sacrificed the rats and harvested the livers for hematoxylin and eosin (HE) staining. The HS significantly decreased mean arterial pressure (MAP), increased blood AST, ALT, and LDH levels and induced liver injury in rats. Treatment with FCE increased MAP level and decreased AST, ALT, LDH, and TNF-α levels after hemorrhage. The HE staining showed diminished organ injury in the FCE-treated group. In conclusion, the administration of posttreatment FCE suppressed the release of pro-inflammatory TNF-α production after HS and decreased the levels of markers of liver injury associated with HS in rats. These beneficial effects suggest that FCE is a potential immunomodulator.

Chemical examination of the Sponge Phycopsis sp

Two new compounds 7alpha,8alpha-epoxy theonellin isothiocyanate (1) and 5alpha,8alpha-epidioxyergosta-6Z,22Z,25-trien-3beta-ol (2) along with two known compounds, theonellin isothiocyanate (3) and theonellin formamide (4) have been isolated from the sponge Phycopsis sp. Compound 2 showed cytotoxic activity against HL-60 and U937 human cancer cell lines with IC(50) values of 5.96+/-0.02 and 31.72+/-0.55 microg/ml, respectively.

(1)H and (13)C NMR assignments for two new steroids from the coral Chromonephthea sp

Two new steroids isolated from EtOH extracts of the South China Sea soft coral Chromonephthea sp. were identified. One-dimensional (1D) and two-dimensional (2D) NMR experiments including COSY, HSQC, HMBC and NOESY were used for the determination of their structure.

5alpha,8alpha-Epidioxysterols from the gorgonian Eunicella cavolini and the ascidian Trididemnum inarmatum: isolation and evaluation of their antiproliferative activity

Three new (1, 4, 9) and nine previously reported (2, 3, 5-8, 10-12) 5alpha,8alpha-epidioxysterols were isolated from the organic extracts of the gorgonian Eunicella cavolini and the ascidian Trididemnum inarmatum. The structures and relative configurations of 1-12 were established on the basis of detailed NMR spectroscopic analyses and comparison with the literature. The growth inhibitory effects of 1-12 were evaluated against MCF-7 human breast cancer cells. Compound 1, bearing a cyclopropyl moiety in the side chain, exhibited the highest antiproliferative activity.

Bioactive peroxides as potential therapeutic agents

Present review describes research on more than 280 natural anticancer agents isolated from terrestrial and marine sources and synthetic biologically active peroxides. Intensive searches for new classes of pharmacologically potent agents produced by terrestrial and marine organisms have resulted in the discovery of dozens of compounds possessing high cytotoxic, antibacterial, antimalarial, and other activities as an important source of leads for drug discovery.

5,8-Epidioxysterols and related derivatives from a Chinese soft coral Sinularia flexibilis

Chromatographic separation of the methanolic extract of the marine soft coral, Sinularia flexibilis, resulted in the isolation and characterization of four new sterols, 5alpha,8alpha-epidioxygorgosta-6-en-3beta-ol (1), 5alpha,8alpha-epidioxygorgosta-6,9(11)-dien-3beta-ol (2), 22alpha,28-epidioxycholesta-5,23(E)-dien-3beta-ol (3) and its C-22 epimer (4), along with nine known sterols. The structures of the new compounds were determined on the basis of extensive spectroscopic data (IR, MS, 1H and 13C NMR, HMQC, HMBC, and NOESY) analyses.

Apoptosis-inducing active components from Corbicula fluminea through activation of caspase-2 and production of reactive oxygen species in human leukemia HL-60 cells

The anti-cancer effects and possible mechanisms of the freshwater clam (Corbicula fluminea Muller) and its active compounds (FME) on cell viability in human leukemia HL-60 cells were investigated. This study demonstrated that FME was able to inhibit cell proliferation in a concentration- and time-dependent manner. Treatment with FME caused induction of caspase-2, caspase-3, caspase-6, caspase-8, and caspase-9 activity in a time-dependent manner, but not affect caspase-1 activity; it induced the proteolysis of DNA fragmentation factor (DFF-45) and poly(ADP-ribose) polymerase (PARP). Induction of cell death by FME was completely prevented by a pan-caspase inhibitor, Z-Val-Ala-Asp-fluoromethyl ketone (Z-VAD-FMK) and a caspase-2 inhibitor, Z-Val-Asp-Val-Ala-Asp-FMK (Z-VDVAD-FMK). Furthermore, treatment with FME caused a rapid loss of mitochondrial transmembrane potential, stimulation of generation of reactive oxygen species (ROS), release of mitochondrial cytochrome c into cytosol, and GSH depletion. Anti-oxidants such as N-acetylcysteine, catalase, superoxide dismutase, allopurinol, and pyrrolidine dithiocarbamate, but not diphenylene iodonium, significantly inhibited FME-induced cell death. In addition, the results showed that FME-induced apoptosis was accompanied by up-regulation of Bax and Bad, and down-regulation of Bcl-2 and Bcl-XL. Taken together, induction of apoptosis on HL-60 cells by FME was mainly associated with ROS production, GSH depletion, mitochondrial dysfunction, and caspase activation.

Cytotoxic constituents of Diadema setosum

5,8-Epidioxycholest-6-en-3-ol (1), cholesterol (2), glycerol 1-palmitate (3) and glycerol 1,3-dioleate-2-stearate (4) were isolated from the methanol extract of the sea urchin Diadema setosum, which was collected from the Halong sea, Vietnam. Chemical structures were established based on extensive 1D, 2D-NMR, FAB-MS, El-MS spectroscopic data and GC-MS analysis. The NMR spectral data of compound 1 were reassigned by using HMQC and HMBC. Compound 1 was found to have strong cytotoxic effect against various cancer cell lines, such as KB (IC50, 2.0 microg/mL), FL (ICso, 3.93 microg/mL), and Hep-2 (IC50, 2.4 microg/mL) by in vitro assay.

Marine pharmacology in 2000: antitumor and cytotoxic compounds

During 2000, marine antitumor pharmacology research aimed at the discovery of novel antitumor agents was published in 85 peer-reviewed articles. The purpose of this article is to present a structured review of the antitumor and cytotoxic properties of 143 marine natural products, many of them novel compounds that belong to diverse structural classes, including polyketides, terpenes, steroids and peptides. The organisms yielding these bioactive compounds comprised a taxonomically diverse group of marine invertebrate animals, algae, fungi and bacteria. Antitumor pharmacological studies were conducted with 19 marine natural products in a number of experimental and clinical models that defined or further characterized their mechanisms of action. Potentially promising in vitro cytotoxicity data generated with murine and human tumor cell lines were reported for 124 novel marine chemicals with as yet undetermined mechanisms of action. Noteworthy is the fact that marine anticancer research clearly remains a multinational effort, involving researchers from Austria, Australia, Brazil, Canada, England, France, Germany, Greece, Indonesia, Italy, Japan, New Zealand, Russia, Spain, South Korea, Switzerland, Taiwan, the Netherlands and the United States. Finally, this 2000 overview of the marine pharmacology literature highlights the fact that the discovery of novel marine antitumor agents continued at the same high level of research activity as during 1998 and 1999.