Previously undescribed fridooleanene triterpenoids 2a-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien- 20-propyl-21-hex-40(Z)-enoate, 2a-hydroxy-(28,29)-frido-olean-12(13), 21(22)-dien-20-prop-2(E)-en- 21-butanoate and oxygenated labdane diterpenoids 2a-hydroxy-8(17), (12E), 14-labdatriene, 3b, 6b, 13atri hydroxy 8(17), 12E, 14-labdatriene were purified from the ethyl acetate-methanol and dichloromethane fractions of the air-dried thalli of Sargassum wightii (Sargassaceae), a brown seaweed collected from the Gulf-of-Mannar of Penninsular India. Inhibitory potential of D12 oleanenes towards protein tyrosine phosphatase-1B, the critical regulator of insulin-receptor activity were found to be significantly greater (IC50 0.1 ? 10?2 and 0.09 ? 10?2 mg/mL, respectively) than the standard sodium metavanadate (IC50 0.31 ? 10?2 mg/mL). Fridooleanene triterpenoids displayed greater antioxidant activities (IC50DPPH 0.16e0.18 mg/mL) than the commercially available antioxidants, butylated hydroxytoluene and atocopherol (IC50DPPH 0.25 and 0.63 mg/mL, respectively). In general, the oxygenated labdane diterpenoids displayed significantly lesser antioxidant and tyrosine phosphatase-1B inhibitory properties than those exhibited by the fridooleanenes. Bioactivities of the titled compounds were primarily determined by the electronic and lipophilic parameters and not by the steric descriptors. Molecular docking simulations and kinetic studies were employed to describe the tyrosine phosphatase-1B inhibitory mechanism. The previously undescribed fridooleanene triterpenoids might be used as potential anti-hyperglycaemic pharmacophore leads to reduce the risk of elevated postprandial glucose levels.
A detailed pathological survey was carried out on the commercially important edible oyster, Crassostrea madrasensis (Preston), from two distinct coastal/brackish water ecosystems of south India. Samples were collected twice a year during wet and dry seasons from 2009 to 2012. Bacterial colonies in the form of prokaryotic inclusions, protozoans (Perkinsus beihaiensis, Nematopsis sp. and ciliates Sphenophrya sp. and Stegotricha sp.), metazoans (trematodes, turbellaria, cestodes and crustaceans) and shell parasites (Polydora spp. and Cliona spp.) along with various pathological conditions (digestive tubule atrophy, ceroid bodies, haemocytic infiltration, tissue necrosis and neoplastic disorders) were observed in C. madrasensis collected from two sites. Intensity, spatial and seasonal variations in infection prevalence and pathological effects on the host were studied. The protozoan parasite, P. beihaiensis; shell parasite, Polydora spp. and pathological condition, digestive gland atrophy were most prevalent in occurrence. High-intensity infections with P. beihaiensis, larval trematodes and Polydora spp. were found to cause significant impact on host physiology. All other parasites were observed with low mean prevalence and intensity. Karapad in Tuticorin bay, the site reported with marked pollution levels, exhibited higher number of parasitic taxa and high mean prevalence and intensity for pathological conditions.
Present study reports the first record of the keeltail pomfret, Taractes rubescens (Jordan & Evermann 1887) in the south-eastern Arabian Sea based on four specimens collected from the Cochin Fisheries Harbour, Kerala, India. The results of the comparative morphometric and meristic analysis of the present and previous records are presented here. This study revealed the first record of T. rubescens in south-eastern Arabian Sea extending its known geographical range by more than 2000 km in southward direction from the Oman Coast. Further, it is an addition to the deep sea ichthyofaunal biodiversity of the west coast of India.
During the survey 1386 colonies of hard corals, belonging to 27 genera were examined to identify the occurrence of different diseases and the disease prevalence data was collected for the entire study period. The percentage occurrence of the nine major diseases, which were prevalent among the corals in the islands, was as follows: White Pox disease (12.19), White Plague (11.04), White Band (12.77), White Syndrome (17.89), Pink Spot (1.01), Dark Spot (10.25), Pink Line Syndrome (15.30), Polychaete infestation (16.23) and Crown of thorn grazing (1.23). Area- wise analysis of the disease prevalence data showed that the highest number of incidences was at Marina park (21.3%), followed by North Bay (16.13 %), Car Nicobar (13.89 %), Radhanagar Beach (13.74%), Boat Island (12.44%), Tarmugli Island (9.85%), Silver sand beach (8.07 %) and Havelock Jetty (5.63 %). Among the coral species, Acropora spp. and Porites spp. were dominantly affected. The other affected species include Platygyra spp., Gardineroseris sp., Goniastrea spp., Leptorea spp., Montipora spp., Favites spp., and Lobophyllia spp.
This paper redescribes sexually dimorphic Cruriraja andamanica based on five juvenile (four males, one female) and four adult specimens (three males, one female) collected from Andaman waters. Morphometric comparison of the present specimens with a female specimen collected off the coast of Tanzania reveals considerable dissimilarities between them. These findings, along with the wide geographical distance between collection locations, support a need for revision of the Tanzanian specimen, which, in all probability, represents a new species in the genus. The paper also addresses zoogeography of genus Cruriraja across the world’s oceans and provides a revised key to the species.
Previously undescribed aryl polyketide lactones, 4-(8-ethyl-tetrahydro-7-oxo-2H-pyran-5-yl)-propyl-4′-methylbenzoate (compound 1) and methyl-2-(12-oxo-7-phenyl-8-vinyl-1-oxa-4,9-cyclododecadien-3-yl)-acetate (compound 2) were purified from ethyl acetate-methanol fraction of the brown seaweed Sargassum wightii. The structures were proposed based on their NMR and mass spectrometric data. The antioxidative activities of the lactones were significantly greater (P < 0.05) (IC50 1,1-diphenyl-2-picrylhydrazyl radical scavenging 0.24–0.32 mg/mL) than α-tocopherol (IC50 0.63 mg/mL). The title compounds displayed considerably greater 5- lipoxygenase inhibitory activity (IC50 0.56 and 0.29 mg/mL, respectively) in conjunction with higher selectivity indices (anti-cycloxygense-1IC50/anti-cycloxygense-2IC50> 1) compared to non-steroidal anti-inflammatory drugs (SIaspirin 0.03, SIibuprofen 0.43). Putative biosynthetic pathway of title polyketide products through polyketide synthase enzyme cascade catalyzed reactions substantiated the structural attributions of the hitherto unreported aryl polyketides. This is the first report of the occurrence and characterization of two rare skeletal types, oxo-2H-pyranyl and oxa-cyclododecadienyl macrolactone featuring the aryl substituent from marine organisms with potential antioxidative and anti-inflammatory activities.