This document summarizes various types of compounds derived from marine sources that have pharmaceutical applications. It discusses antibiotics, anti-inflammatory agents, antimicrobials, antiviral agents, anticancer agents, cardiovascular active substances, marine toxins, and their physiological effects. A wide range of compounds have been isolated from marine organisms such as sponges, algae, gorgonian corals, sea cucumbers, and cyanobacteria that show potential as antimicrobial, anticancer, anti-inflammatory, cardiovascular, and other therapeutic agents.

1. MARINE DRUGS
SATYAJIT GHOSH
B. PHARM 4TH
SEMESTER

2.  Introduction: -
Marine pharmacognosy is a sub-branch of pharmacognosy, which is mainly concerned with the naturally occurring substances of medicinal value from marine
source.
 Classification: -
Class Examples
Antibiotics Cycloeudesmol, Variabilin, Ircinin – 1
Anti-inflammatory and Antispasmodic Manoalide
Antimicrobial Holotoxin ABC, Tholepin
Cardio vascular active substances Anthopleurin, Laminine, Saxitoxins
Cytotoxic or Anticancer Ara – A, Simularin
Marine toxins Ciguatoxin, Palytoxin, Saxitoxin
 Antiviral agents: -
Drugs Notes Structure
Ara-A
Ara-A is a semisynthetic antiviral agent based on the arabinosyl nucleoside
isolated from the marine sponge Tethya crypta.

3. Eudistomins
Eudistomins are the β-carboline derivatives which are isolated from sponges
and gorgonians Eudistoma olivaceum, family Polycitoridae.
These compounds are also found in tunicates. Eudistomin compounds can be
classified into four groups, i.e. pyrrolyl substituted, pyrrolinyl-substituted,
unsubstituted and tetrahydro – β – carboline derivatives with a 1,3,7-
oxathiazepine ring.
Didemnins
Didemnin compounds are the promising antiviral and antitumor agents
isolated from Trididemnum spp, Didemnidae. A compound Didemnin B is
found to be a potential antitumor agent during its clinical trials.
Avarol and
Avarones
These two sesquiterpene benzenoids are derived from the sponge Dysidea
avara. It has exhibited strong anti-HIV activity against the human
immunodeficiency virus (HIV). It shows the greater promises in the treatment
of AIDS.
Fucoidan
Fucoidan, a sulphated polysaccharide compound extracted from brown algae
Laminaria has shown the activity against HIV and Herpes simplex viruses.

4.  Antimicrobial agents, Antibacterial agents: -
A large variety of antimicrobial agents are produced by number of marine organisms, such as sponges, algae, gorgonian corals, annelids, etc., and many of them
are active against gram +ve and gram –ve microorganisms, protozoal and fungal strains. A list of antibiotics agents derived from marine organisms are as
follows:
Antimicrobials
Organism Drugs Structure
Verongia fistularis
V. cauliformis
V. thiona
(Marine sponges)
3,5-dibromo-1-hydroxy-4-oxo-2,5- cyclohexadiene-1-
acetamide
V. aerophoba
(Marine sponge)
(-) Aeroplysinin - 1

5. V. archeri
(Marine sponge)
2,4-dibromo-3,6-dehydrobenzen-1- acetamide
Agelas oroids
(Marine sponge)
2-cyano-4,5-dibromopyrrole
Phakellia flabellate
(Marine sponge)
Bromophakellin

6. Laurencia johnstonii
(Red algae)
Laurinterol
Ptilonia australasica
(Red algae)
Bromopyrones
Delisea fimbriata
(Red algae)
Fimbrolide
Condria californica
(Red algae)
1,2,3,5,6-pentathiepane

7. Stichopus japonicus
(Sea cucumber)
Holotoxin A, B, C
Zonarol
Dictyopteris zonaroids
(Brown algae)
Tetrabromoheptanone
Bonnemaisonia hemifera
(Red algae)
4 isomers of Polyhalo – 3 – butene – 2 - one

8. Asparogopsis taxiformis
(Red algae)
Aeroplysinin – 1 (+)
Verongia aerophoba
(Sponge)
Aeroplysinin – 1 (-)
Agelas oroides
(Sponges)
2 – cyano – 4, 5 – dibromo pyrrole

9. Laurencia pacifica
L. filformis
(Red algae)
Prepacifenol
Aplysia californica
(Sea hair)
Debromolaurenterol
Eunicia mammosa
(Gorgonian corals)
Eunicin

10. Acanthella acuta Acanthelin - 1
Antibacterials
Organism Drugs Structure
Pseudomonas bromutilis
(Marine bacterium)
2, 4 – Dibromo – 6 – (3, 4, 5 tribromo pyrrole – 2 – yl)
phenol
Chondria oppositiclada
(Red algae)
Cycloeudesmol

11. Ircinia strobilina
(Sponges)
Variabilin, Ircinin – 1
Verongia archery
(Sponges)
3, 5 – dibromo – 4 – hydroxy benzene – 1 acetamide
L. filformis
(Red algae)
Chondriol
Spongia officinalis
(Marine sponge)
Furospongin

12.  Antiparasitic agents: -
Drugs Notes Structure
𝛂-Kainic Acid
α-Kainic acid isolated from the red algae, Digenia simplex shows the broad-
spectrum anthelmintic activity against the parasitic round worms, tape worms and
whip worms.
Dried powder of D. simplex has been widely used for the treatment of ascariasis.
Domoic Acid
Domoic acid is a compound chemically related to kainic acid. It has been isolated
from red algae Chondria armata and Alsidium corallinum.
It has shown prominent anthelmintic activities.
Laminarin
Laminarine is a methylated lysine derivative found in the marine red algae of the
order Laminariales as well as in brown algae.
Laminine also shows the hypotensive and smooth muscle relaxant activities, along
with its potential antiparasitic activity.

13. Bengamide F
Bengamide F is the recently isolated and characterized compound from marine
sponge. It has demonstrated a remarkable antiparasitic activity during in vitro
studies.
 Anticancer agents: -
Several compounds with anticancer and cytotoxic activities have been isolated and characterized from various marine organisms, such as marine sponges,
gorgonian corals, sea algae, sea hares and sea cucumbers.
One of the most prominent synthetic anticancer agents is cytosine arabinoside, also known as Ara-c. It originates from the natural marine substance
spongothymidine isolated from Caribbean sponge (Cryptotethya crypta). Ara-c is a potent inhibitor of the tumours in cases of sarcoma-180.
Drugs Notes Structure
Bryostatin I
Isolated from Bugula neritina a bryozoal marine organism showed highly potent
antineoplastic activity in an extremely low dose level.

14. Ara - C
It is 1 – α – D – arabinofuranosyl cytosine or cytosine arabinoside. It is present in
Caribbean sponges. It is used in treatment of acute myelogenous leukemia and
human acute leukemia.
 Antispasmodic agents: -
Drugs Notes Structure
Agelasidine A
A sesquiterpene derivative isolated from Okinawa sea sponge Agelas Spp. has
demonstrated very good antispasmodic activity in animal models.
Agelasidine A contain guanine and sulfone units.

15.  Marine toxin: -
Drugs Notes Structure
Tetrodotoxin
Tetrodotoxins is a potent neurotoxin produced by the pufferfish of family
Tetraodontidae.
It is present in other animals including Gobius crinigar, Taricha torosa, Atelopus
chiriquensis marine crabs and also produced by marine bacteria.
This dangerous toxin shows the cardiovascular and neurophysiological activity in
experimental animals.
Saxitoxin
Saxitoxin is a purine skeleton containing toxic compound produced by the butter
clam Saxidomus giganteus and California mussel Mytilus californianus.
It is also found in two toxic species of mollusk, Zolimus aeneus.
In lower doses this toxin produces a marked hypotensive effect.
Holothurin A
Holothurin A is a toxic saponin isolated from the sea cucumber of Holothurian group
Helix pomatia.
Holothurins contain triterpenoid moiety as aglycone. Holothurins are present in sea
cucumbers, belonging to family Holothuroidea of phylum Echinodermata.
Holothurins have cardiotonic and ichthyotoxic actions. They also show haemolytic
activity.
Holoxins like holotoxin A, B and C are desulphated holothurins and possess
antifungal activity.
It is recognized as a mixture of triterpenic aglycones which are linked to four sugar
molecules and a molecule of sulphuric acid as a sodium salt.
It has shown hemolytic and neurotoxic properties.

16. Aplysins
Aplysins is a group of toxic compounds isolated from Mediterranean Sea hares
Aplysia depilans.
Aplysins contains an unpleasant, colorless fluid secreted by the skin. These are the
white viscous liquid by opaline gland and purple secretion from another gland
present in sea hares.
Aplysins causes paralysis when injected into cold-blooded animals.
Lophotoxin
Lophotoxin is a diterpene lactone present in the gorgonian corals of the genus
Lophogorgia.
It produces an irreversible postsynaptic blockage at neuromuscular junction
Lyngbyatoxin
Lyngbyatoxin is an indole group of alkaloids produced by the marine cyanobacterium
Lyngbya majuscula.
It is responsible for the contact dermatitis known as ‘swimmers itch’ in the humans.
Some other organisms of the same species L. majuscula have been found to produce
totally unrelated skin irritant.

17.  Marine toxins and their physiological effects: -
Organisms Physiologic effects
Gymnodinium breve Depolarises membranes, RBC haemolysis and neurotoxic
Gonyaulax catenella
G. tamarensis
(saxitoxin)
Block membrane Na+ conductance
Haliclona rubens
(holotoxin)
Potent neuromuscular blocker
Amphidinium carterae Acetyl-choline like activity
Lophogorgia rigida
(Lophotoxin)
Neuromuscular blocker
Anacystis cyanea Neurotoxin, fast death factor
Gambier discus toxicus
(maitotoxin)
Stimulates calcium channels in insect skeletal muscles
Prymnesium parva Neurotoxin, blocks end plate transmission, haemolytic agent
Palythoa grandis
(palytoxin)
Most potent coronary vasoconstrictor
Ptychodiscus brevis
(brevetoxin)
Positive inotropic and arrhythmogenic
Babylonia japonica
(neosurugatoxin)
Potent blocker of sympathetic ganglia and specific blocker of nicotinic Ach receptors
Gambier discus toxicus
(ciguatoxin)
Respiratory depression and bradycardia
 Cardiovascular active substances:
Drug Organisms Notes
Anthopleurin
Anthopleura xanthogrammica
Anthopleura elegantissima
Anthopleura xanthogrammica produces Anthopleurin -A & B and Anthopleura
elegantissima produces Anthopleurin – C.
AP – A shows strong positive inotropic action without an effect on Na+, K+, ATPase,
pump heart rate and blood pressure in various animals.
It produces cardiotonic et in conscious dog, which is 35 times potent as compared to
digoxin with very less toxicity.

18. Eptatretin
Eptatretus stoutii
(Pacific hagfish)
It is a potent cardiac stimulant with direct stimulant action on mammalian myocardium,
which is comparable to adrenaline.
Laminine Laminaria angustata It is a basic amino acid has hypotensive effects.
D (-) Octopamine
Octopus macropus
O. vulgaris
Eledone muschata
It produces adrenergic and cardiovascular response.
Autonomium Verongia fistularis
This compound has isosteric structure of adrenaline and acetylcholine. It produces both
α and β-adrenergic effects and also exhibits cholinergic activity. This compound shows
CNS stimulant effects in mice exhibited by significant increase in spontaneous motor
activity.
Due to both adrenergic and cholinergic effects, this compound may prove to be useful in
regulating the behavior of heart.
ATX - II
Anemonia sulcata
(Sea anemone)
This is one of the polypeptides found in sea anemones. Like anthopleurin, it also has
cardiotonic effect is due to indirect action on the pump activity induced by increased Na+
transport as a result of a delayed inactivation of fast sodium current.
It slows down the voltage gated sodium channels.
Eledoisin
Eledone muschata
Eledone aldovandi
It is a powerful hypotensive compound obtained from posterior salivary glands of
cephalopod Eledone moschata. It also shows strong vasodilator effects.
Asterosaponins Acanthaster planci, Asteroidae
They exert different pharmacological actions like haemolytic, anti-inflammatory
hypotensive and analgesic effects and also cytolytic action due to interference in protein
metabolism and neuromuscular blocking effects. They are inhibitors of ATPase.
 Anti-inflammatory agents: -
A series of bio-indole derivatives isolated from marine cyanobacterium Rivularia firma has shown potential anti-inflammatory activity in the models of
carrageenan-induced rat paw edema.
In another study, the butanolide derivatives obtained from Euplexaura flava have demonstrated a significant anti-inflammatory effect in a low dose of 100
ug/ml.
The sulphated polysaccharide carrageenan isolated from Irish moss, Chondrus crispus, a red alga is used as a phlogistic agent for inducing inflammation in the
rat paw oedema model for the study of anti-inflammatory activity.