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.Virtually nothing is known about the physiological importance of thesebromophenols.However, their antialgal activity suggests that they may playa role in the regulation of epiphytes and endophytes.4.2 Seaweeds of Indian CoastsSeveral seaweeds have shown a wide range of bioactive properties.1,42-49Hemolytic and antimicrobial activities are reported in seaweeds collected106 Bioactive Marine Natural Productsfrom Mandapam, Tamil Nadu, the Gulf of Manner and Back Bay, India.50The extracts of seaweeds, in general, are found active against Gram-negativemicrobes.The extract of Enteromorpha compressa, Cladophoropsis zollinger,Padina gymnospora, Sargassum wightii and Gracilaria corticata are foundactive against the Gram-positive cultures of Bacillus.High order of hemolyticactivity is shown by the extracts of Cladophoropsis zoolingeri and Grateloupialithophila.Extracts of 25 seaweeds from the Indian coast have been put through abroad biological screen which includes tests for antiviral, antibacterial,antifungal, antiprotozoal, antifertility activities, and a wide range ofpharmacological activities.Significant activity is found in 13 seaweeds, themost promising activity being 100% antifertility (antiimplantation) activityobserved in three species.51 The seaweeds which showed biological activitiesare: Caulerpa racemosa (Chlorophyceae) collected from Malvan in Novemberexhibited hypotensive activity (90 mm, 5 mg/kg), LD50 93.75 (mg/kg inmice), Cladophora pinnulata (Chlorophyceae) from Baga, Goa, in Decemberwas found toxic, LD50 8.25 (mg/kg, in mice).Codium elongatum(Chlorophyceae) collected from Cabo de Rama, Goa, India, in Februaryshowed antiviral activity (50%, 1 mg), LD50 681 (mg/kg, in mice).Enteromorpha spp.(Chlorophyceae) collected from Cabo de Rama, Goa,India, Showed diuretic activity (112%, 170 mg/kg), LD50 681 (mg/kg inmice).The other green algae, Caulerpa surtularioides collected from Malvan,Maharashtra in November, Chaetomorpha media from Vengurla, Maharashtrain May; Enteromorpha intestinalis from Chaopora, Goa, in February andUlva fasciata from Baga, Goa in December were found devoid of activity.The alga Trichodesmium erythraeum (Cyanophyta) collected from Mandovi,Goa, in March exhibited diuretic activity (104%, 170 mg/kg), LD50 681 (mg/kg, in mice), whereas the alga Trichodesmium erythraeum (Cyanophyta)from Aguada, Goa, in April was found devoid of activity.The brown algaeStoechospermum marginatum collected from Dona Paula, Goa in Decembershowed spasmolytic activity (50%, 50 µg/ml), LD50 more than 1000 (mg/kg,in mice), Padina tetrastromatica collected from Baga, Goa, in January exhibitedspasmogenic activity (50 µg/ml) and antifertility activity (100%, 200 mg/kg),LD50 464 (mg/kg, in mice); Sargassum tenerrimum from Baga, Goa, inDecember showed CNS depressant activity (89 mg/kg), LD50 178 (mg/kg inmice).The brown algae Chnoospora implexa collected from Mandapam,Tamilnadu, in March, Dictyota bartayresiana from Anjuna, Goa, in Januaryand Spatoglossum asperum from Baga, Goa, in December did not show anyactivity.The red algae which exhibited activity are: Acantophora specifera fromBaga, Goa, in February showed antifertility activity (100%, 200 mg/kg inmice), LD50 more than 1000 (mg/kg, in mice), Chondria armata from Baga,Goa, in December exhibited hypotensive activity (40 mm, 1 mg/kg, 200 min)LD50 178 (mg/kg, in mice); Corallina spp.from Anjuna, Goa, in JanuaryBioactivity of Marine Organisms 107showed spasmogenic and oxytocic activities (50 µg/ml), LD50 681 (mg/kg,in mice) and Hypnea musciformis from Baga, Goa, in December showeddiuretic activity (130%, 250 mg/kg), LD50 more than 1000 (mg/kg, in mice),Gelidiella acerosa from Eravali, Tamilnadu, in December showed antifertilityactivity (100%, 100 mg/kg, in mice).The red algae Gelidiella spp.collectedfrom Baga, Goa, in November, Gracilaria corticata from Baga, Goa, inNovember and Hypnea musciformis var.cervicornis from Malvan, Maharashtrain November did not show any activity.The sea grasses Diplanthera universecollected from Mandapam, Tamilnadu, in March and Thalassia hemprichiifrom Mandapam, Tamilnadu, in March did not show any activity.Several members of the red, brown and green algae, which were screened,are reported to show a broad spectrum of biological activities.Some of thespecies that were examined were also tested earlier by other workers, butnone of the activities were observed.For instance, extracts of Chondruscrispus and Gelidium cartilagineum have been found to be active againstinfluenza B and mumps virus.This activity has been attributed to the presenceof galactan unit in the polysaccharides, agar and carrageenan present in boththe species.Based on this, one may expect Hypnea musciformis, Gelidiellaspp.and Gracilaria corticata which are well-known sources of thesepolysaccharides to exhibit similar activity.Unfortunately, the extracts ofthese algae have not been tested against the above virus.However, they havebeen found inactive against Ranikhet disease virus, Vaccinia virus and Semilikiforest virus.The absence of the antiviral activity may be attributed to thevarying solubility behaviour of the sulphated polysaccharide, responsible forthe activity in aqueous ethanolic solutions or to the well known variation inphytoconstituents depending upon the ecological factors prevailing at thetime of collection and upon the growth stage of the plant.The last reasoncould also be applicable to the differences in activity of two different samplesof Enteromorpha spp.and Hypnea musciformis collected at differentplaces.The extract of Sargassum tenessimum was not found to have anychemotherapeutic activity though the species of this genus have been reportedto possess antibiotic effects due to the presence of antibiotic substancessarganin-A and sarganin-B.This activity, however, seems to be seasonal, andhas been reported to decrease directly with plant vigour as a function oflatitude.52Acute poisoning from seaweeds has not been reported in the literature,but it has been mentioned that Caulerpa, one of the most popular ediblealgae in the Philippines is considered toxic during the rainy season.Thistoxicity has been attributed to the presence of caulerpicin which has beenfound to have neurotropic effects.3 Unfortunately, the test for this activityhas not been performed for the extract from Caulerpa racemosa which wascollected during the pre-monsoon season [ Pobierz caÅ‚ość w formacie PDF ]