Metabolites of Marine Invertebrates

Over 500 metabolites have been isolated from sponges.1-13,71-80 Several of these have unusual structures with interesting biological activities. Despite much speculation on the biogenesis of these metabolites, there has been only limited experimental evidence. The main difficulty in the biosynthetic studies is the slow rate of metabolism of these marine invertebrates. Accumulation of metabolites occur over a number of years, rather than in weeks or months. The turnover of metabolites may also...

Bioactive Marine Peptides 31 Marine Algae

Bioactive Peptides And Origin

Certain varieties of Lyngbya majuscula,19-27 a toxic marine blue-green alga found in warm water have been implicated as the causative agents of Swimmer's'itch, a form of contact dermatitis. Lyngbyatoxin-A ( 1)28-5 was isolated from L. majuscula and the gross structure was determined as the prenylated cyclic dipeptide. The configuration at the C-14 quaternary carbon in (1) was subsequently shown to be (R) by degradation of (1) to dimethyl 2(S)-2-ethyl-2-methylglutarate.36 Lyngbyatoxin-A (1)...

Bioactive Metabolites of Marine Invertebrates

The chapter deals with the bioactive metabolites of the marine invertebrates. The chemistry and biological activity of the bioactive steroids, terpenoids, isoprenoid and non-isoprenoid compounds, quinones, brominated compounds, nitrogen heterocyclics and nitrogen-sulphur heterocyclics from marine invertebrates have been discussed. The chapter also reviews the bioactive secondary metabolites isolated in recent past from the marine sponges, jelly fish, sea anemones, corals, bryozoans, molluscs,...

Pyridoacridine Alkaloids

Mass Spectra Alkaloid Salt

Marine pyridoacridine alkaloids have been the subject of intense study due to their significant biological activities.4-13 Over 75 pyridoacridine alkaloids have been isolated and characterized from marine source and it is expected that more of these alkaloids will be isolated in future. Almost all known pyridoacridine alkaloids are reported to have significant cytotoxicity. The compounds of this group also display several specific biological properties, such as inhibition to topoisomerase...

Paralytic Shellfish Poisoning

Epi Gonyautoxin

Paralytic shellfish poisoning PSP 2225 is one of the most severe forms of food poisoning caused by ingestion of seafood. It is acute and often fatal. There is no effective way to destroy the toxins or to treat the patients. Therefore, it poses serious health problems. Deterring shellfish consumption causes economic problems. The history of the poisoning goes back to prehistoric days and the incidents due to the consumption of toxic shellfish are well documented. The problem exists along both...

Concluding Remarks

There is no specific technique that could be followed for the separation of the constituents of the complex mixture present in the ethanolic or methanolic extract of a marine organisms since the chemical nature of the bioactive compounds is not known. However, a broad separation of the mixture can be achieved by fractionation with organic solvents. If the separation is effective, the biological activity may concentrate in a particular fraction. The abundance of salts carried over from seawater...

Bioactivity of Marine Organisms

The green, brown and red algae have been extensively screened for antibacterial and antifungal activity.1 The active principles isolated from Symphycladia gracillis, Rhodomela larix and Polysiphonia lanosa39'41 are 2,3-dibromobenzyl alcohol, 4,5-disulphate dipotassium salt, 2,3-dibromo-4,5-dihydroxybenzaldehyde, 2,3-dibromo-4,5-dihydroxybenzyl alcohol, 3,5-dibromo-p-hydroxybenzyl alcohol, and 5-bromo-3,4-dihydroxybenzaldehyde. Virtually nothing is known about the physiological importance of...

Screening Models and Activity

Excellent accounts of various models are published6,25 for screening antibacterial, antifungal, antileishmanial, anthelmintic, antitapeworm, antimalarial, antiviral, antiinflammatory, analgesic, antiallergic, antiarhythmic, hypolipidaemic, hypoglycemic, antihypertensive, diuretic adaptogenic, immunomodulatory, hepatoprotective, choleretic, anticholesteric, CNS, activities and toxicity. 3.1 Antibacterial and Antifungal Activities The need for effective antibacterial and antifungal drug has been...

Bioactive Metabolites of Marine Sponges

Kalihinol From Sponges

Marine sponges are a good source of unusual sterols. Some of these sterols have phylogenetic significance. These sterols are also of interest to understand the function of biological membranes. The sulphated and alkaloidal sterols exhibit antimicrobial activity. Halistanol 38 82 from Halichondria mooriei and the sterols 39-41 from Toxadocia zumi83 inhibited the growth of Staphylococcus aureus and Bacillus subtitis at 100 g disc and 50 g disc. A hydroxy sterol 42 with unusual features is...

Bioactive Metabolites

Chemical Structure21 Hydroxylase

The bioactive metabolites isolated from marine animals could be divided into steroids, terpenoids, isoprenoids, nonisoprenoids, quinones, brominated compounds, nitrogen heterocyclics, and nitrogen sulphur heterocyclics. The bioactive compounds isolated from marine animals, which have steroidal nucleus are insect moulting hormones, sterols and saponins. Karlson22 found that an extract of crustacean Cragon vulgaris was active in the insect Calliphora test. Horn et al23 isolated crustecdysone 1, R...

Marine Invertebrates of the Andaman and Nicobar Islands

About 50 species of marine sponges occur in these Islands and only a few of them have been investigated. Even their classification is in a confused state. Several bioactive metabolites of considerable interest have been isolated from Agelas species182 183 found in the Andaman and Nicobar Islands. A. nata the only species reported to occur remains to be investigated. Four species of Cliona, C. ensifera, C. lobata, C. mucronata and C. quadrata occur in the Andaman Islands. However, none of these...

Marine Bacteria and Fungi

Antibacterial Compounds Marine Organisms

Bacteria and fungi are prime producers of the antagonistic substances in terrestrial environment. A similar role in the oceans from these organisms is expected. Indeed, this had been found true. Antibiotic, antiviral, antifungal, and antiyeast activities of these organisms had been reported.75 Besides, a few growth stimulant properties which may be useful in studies on wound healing, carcinogenic properties, and in the study of cancers are reported. Among the many bacteria showing antimicrobial...