Search

Dipeptidyl peptidase is a crucial enzyme that regulates glucose metabolism by degrading incretins, such as glucagon-like-peptide-1, thereby reducing insulin secretion from the pancreatic β-cells. Consequently, dipeptidyl peptidase-IV inhibitors are an important remedial approach to moderate the hyperglycemic pathophysiology. A pyruvylated polysaccharide characterized as [→3)-4,6-O-(1-carboxyethylidene)-β-D-galp-(2SO3−)-(1→4)-3,6-α-L-AnGalp-(2OMe)-(1→], isolated from the marine macroalga Hydropuntia edulis, showed attenuation potential against dipeptidyl peptidase-IV (IC50 4.44 μM). The structure was elucidated using mass and one/two-dimensional nuclear magnetic resonance spectroscopic analyses of hydrolyzed polysaccharide besides glycosidic linkages obtained from partially methylated alditol acetate derivative. The isolated polysaccharide also revealed potential anti-carbolytic properties against α-amylase/α-glucosidase (IC50 45–47 μM). The results proved the candidacy of pyruvylated polysaccharide isolated from H. edulis as a potential therapeutic lead against hyperglycemia.

Dipeptidyl-peptidase-4 is a multifunctional ectoenzyme, which is implicated with hyperglycemic pathophysiology. Therefore, dipeptidyl-peptidase-4 inhibitors could be used as an attractive therapeutic strategy in blood-glucose homeostasis to attenuate the pathophysiologies of diabetes. A sulfated galactofucan characterized as [→1)-O-4-sulfonato-α-fucopyranosyl-(2→1)-O-2-sulfonato-α-fucopyranose-(3→] along with a branch of [→1)-6-O-methyl-β-galactopyranosyl-(4→] unit at the C-4 position of O-2-sulfonato-α-fucopyranose, isolated from the seaweed Padina tetrastromatica, exhibited prospective attenuation property against dipeptidyl-peptidase-4 (IC50 0.25 mg mL−1). The studied sulfated galactofucan exhibited potential inhibitory properties against carbolytic enzymes α-amylase (IC50 0.98 mg mL−1) and α-glucosidase (IC50 0.87 mg mL−1) in comparison with the standard antidiabetic agent acarbose, along with radical scavenging activities. The seaweed-originated galactofucan could be developed as a promising natural therapeutic lead against hyperglycemic disorder.

Intertidal triangular sea bell Turbinaria decurrens (Bory de Saint-Vincent) (family Sargassaceae) belongs to one of the largely abundant genus of marine brown alga. Bioactivity-directed chromatographic purification of the organic extract of T. decurrens afforded two new nor-dammarane triterpenoids named as decurrencyclic A-B. Decurrencyclic B showed superior attenuation properties against cyclooxygenase-2 (IC50 13.98 μM) and 5-lipoxygenase (IC50 3.02 μM) in contrast with decurrencyclic A. Decurrencyclic B showed higher inhibition potential against COX-2 than that revealed by the anti-inflammatory agent, ibuprofen (IC50 70.44 μM). The higher selectivity index of decurrencyclics (1.39–1.57) acknowledged their selective attenuation property against inducible cyclooxygenase-2. In-silico molecular modeling analysis of decurrencyclic B with the inflammatory enzymes showed least binding energy of −14.55 kcal mol−1. These reports have proven that decurrencyclic B could be a potential therapeutic lead for use against inflammatory pathogenesis.

Bioactivity-steered chromatographic purification of the solvent extract of marine sponge Hyrtios erectus (Thorectidae) led to the isolation of three undescribed cyanthiwigin-type diterpenoids, erectcyanthins A-C. Erectcyanthin B exhibited comparable attenuation activity against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (IC50 0.07 mM) with that displayed by anti-dyslipidemic agent atorvastatin (IC50 0.08 mM). Comparatively greater antioxidant properties of erectcyanthin B (IC50 ∼ 0.4 mM) than that displayed by erectcyanthin A (IC50 ∼ 0.5 mM), erectcyanthin C and the standard α-tocopherol (IC50 1.5–1.7 mM) against oxidants also corroborated its promising bioactivity. Erectcyanthin B exhibited considerably greater anti-inflammatory activities (IC50 0.88–1.09 mM) than other erectcyanthin analogues in the series. The potential anti-dyslipidemic activity of erectcyanthins was linearly correlated with electronic parameter (topological polar surface area ∼ 74.6) along with balanced hydrophilic-lipophilic properties (logarithmic octanol-water partition coefficient 1.76). This study recognized the anti-dyslipidemic property of erectcyanthin B as a promising pharmaceutical lead.

Heterotrophic Bacillus amyloliquefaciens (MTCC 12716) isolated from the red alga Hypnea valentiae exhibited promising antibacterial activity (minimum inhibitory concentration of ≤1.0 µg/mL) against clinically relevant pathogens. The bacterium displayed bile salt and acid tolerance up to 4 h in a simulated gastric fluid, along with a prospective antioxidant effect. This non-hemolytic bacterium was found to be sensitive to a panel of antibiotics and did not amplify the enterotoxin-specific genes. In order to analyze the possibilities of scaling up, we have optimized the growth of B. amyloliquefaciens by response surface methodology to realize maximum production of anti-infective agents in the fermentation medium and observed an increment of about 85% antibacterial activity against gastrointestinal pathogens. As probiotic treatment is useful due to its ability to recreate the natural intestinal microflora, this heterotrophic Bacillus could be contemplated to offer a prospective probiotic. Further studies are needed to assess its utility for commercial application.

This study analyzed the ethyl acetate-methanol extracts of tropical green seaweeds for phytochemical indicators and antioxidant activities. Compositional analysis of the organic extracts of green seaweeds Ulva lactuca (formerly Ulva fasciata), Halimeda macroloba, Chaetomorpha linum and Chaetomorpha antennina identified the presence of phytoconstituents, such as total phenols, terpenoids, saponins and flavanoids. U. lactuca exhibited higher levels of total phenols (59.8 mg GAE/g), saponins (1.77 %), flavanoids (2.3 %), as well as greater 2, 2-diphenyl-1-picrylhydrazylradical radical quenching activity (DPPH.IC50 0.86 mg/mL). Extracts of U. lactuca and H. macrobola showed promising antimicrobial activities against Vibrio parahaemolyticus. Proton nuclear magnetic resonance fingerprint analyses of the solvent extracts showed that higher proton integrals were present in the downfield regions in U. lactuca, which could be responsible for lowering DPPH activity. The present work supports that the renewable green seaweed U. lactuca could be used to isolate prospective bioactive leads.

An undescribed tricyclic spiroketal compound clathriketal was purified from the solvent extract of the Microcionidae sponge Clathria prolifera, and was characterised as 7-(hydroxymethyl)-13-methoxy-3,11-dimethyl-4-oxo-octahydrospiro[chromene-9,13-pyran]-11-yl propionate by spectroscopic experiments. Clathriketal exhibited significant anti-hyperglycemic property by attenuating serine protease dipeptidyl peptidase-IV (IC50 0.37 mM), and its activity was comparable with the standard diprotin A (IC50 0.31 mM). The spiroketal also exhibited significant inhibitory potentials against carbolytic enzymes α-glucosidase (IC50 0.43 mM) and α-amylase (IC50 0.41 mM). Superior antioxidant properties of clathriketal against the oxidants, 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid and 2, 2-diphenyl-1-picrylhydrazyl (IC50 ∼1.2 mM) also reinforced its promising anti-hyperglycemic activity. Considerably greater topological surface area (91.29) coupled with lesser steric parameters of clathriketal, as elucidated from the structure-activity relationship analyses could further ascribe the improved ligand-receptor interactions resulting in its prospective anti-hyperglycemic activity. Molecular docking analysis of clathriketal with dipeptidyl peptidase-IV recorded lesser binding energy (–9.63 kcal/mol), which further corroborated its prospective antihyperglycemic activity.

Two new scalarane-type sesterterpenes, hyrtioscalaranes A and B, were isolated from the organic extract of the Demosponge Hyrtios erectus through extensive chromatographic purification. Hyrtioscalarane A exhibited significantly greater attenuation property against cyclooxygense-2 (IC50 0.83 mM) than that displayed by hyrtioscalarane B (IC50 0.98 mM). The greater selectivity index of hyrtioscalaranes (> 1) than that exhibited by the commercial anti-inflammatory agent ibuprofen (0.43) further supported the higher selectivity of the former towards pro-inflammatory cyclooxygenase-2. Hyrtioscalarane A exhibited greater antioxidant activities as determined by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (IC50 0.77 mM) and 2,2-diphenyl-1-picrylhydrazyl (IC50 0.81 mM) free radical quenching properties than those displayed by hyrtioscalarane B (IC50 > 0.83 mM) and the antioxidative agent α-tocopherol (IC50 1.51 mM). The greater binding energy (–14.32 kcal/mol) and docking score (15.22 kcal/mol) of hyrtioscalarane A at the active site of cyclooxygenase-2 along with the higher electronic parameters and balanced hydrophobicity could attribute its potential anti-inflammatory activity.

Chemical analysis of the organic extract from intertidal brown seaweed Sargassum ilicifolium (family Sargassaceae) characterised an undescribed xenicane-type diterpenoid sargilicixenicane, elucidated as 3-(17-hydroxy-14-methylhept-13-en-10-yl)-6-methylhexahydro-1H-cyclonona[c]furan-4,19-diyl diacetate (compound 1). The studied compound exhibited prospective free radical quenching potential (IC50 1.2-1.4 mM) in comparison with commercial antioxidant (α-tocopherol, IC50 > 1.40 mM). Attenuation property of sargilicixenicane against pro-inflammatory enzyme, 5-lipoxygenase (IC50 4.70 mM) was comparable with that displayed by the non-steroidal anti-inflammatory agent ibuprofen (IC50 4.51 mM). Greater selectivity index displayed by the studied xenicane-type diterpenoid (1.42) than that exhibited by ibuprofen (0.44) recognised the selective attenuation potential of the former against the inducible cyclooxygenase-2 and 5-lipoxygenase enzymes. Higher electronic parameters (topological polar surface area, 82.06) and balanced hydrophobic-hydrophilic property (octanol-water partition coefficient 2.94) coupled with docking score (-11.17 kcal mol−1) and lower binding energy (-9.61 kcal mol−1) with the active site of 5-lipoxygenase supported the significant anti-inflammatory properties of the studied xenicane-type diterpenoid.

Angiotensin I-converting enzyme (ACE) catalyses the biosynthesis of angiotensin II, a potent blood vessel constrictor, from angiotensin I, and ACE inhibitors were recognised as medications for hypertension. Undescribed bis-γ-pyrone polypropionate compounds, callypyrones A and B were purified from the organic extract of Callyspongiidae sponge species Callyspongia diffusa by repeated chromatographic purification. Callypyrone A exhibited significantly greater attenuation potential against ACE (IC50 0.48 mM) than that displayed by callypyrone B (IC50 0.57 mM) and showed comparable activity with standard ACE inhibitor captopril (IC50 0.36 mM). Higher electronic parameters of callypyrone A (topological surface area of 108.36) combined with balanced hydrophilic-lipophilic parameter (octanol–water coefficient, log Pow 1.9), as deduced from the structure–activity relationship analyses, could further indicate the improved ligand–receptor interactions resulting in its prospective ACE inhibitory activity. In silico docking analyses of the callypyrones with ACE recorded lowest binding energy (–12.58 kcal mol−1) for callypyrone A, which further supported the antihypertensive potential of the compound.

The chemical analyses of ethyl acetate-methanol (EtOAc-MeOH) extract of muricid gastropod mollusk, Chicoreus ramosus from the southeastern coast of Indian peninsular led to the identification of unprecedented cembrane-type diterpenoid, which was characterized as (3E, 6E, 10E)-8a-butoxy-17(15→14), 20(12→11)-bis-abeo-cembra-3,6,10,14(17),15-pentaene (1). The structure of the studied cembrane was unambiguously assigned through the extensive spectroscopic experimentations. The antioxidant potentials of the bis-abeo cembrane as determined by in vitro 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis-3-ethylbenzothiozoline-6-sulfonic acid diammonium salt radical quenching potentials were greater (IC50 α-tocopherol (IC50 > 0.60 mg/mL). The pro-inflammatory anti-5-lipoxygenase potential of studied cembrane was higher (IC50 50 > 0.90 mg/mL).

The spineless cuttlefish Sepiella inermis encompasses a major share in the marine fisheries sector, and represents as a culinary delicacy in many cultures. Bioactivity-guided fractionation of methanol:ethyl acetate (MeOH:EtOAc, 1:1) extract of the edible parts of the species ensued in identification of two hexahydro chromenyl analogues namely, methyl 7-ethyl-hexahydro-8a-methyl-2H-chromene-4-carboxylate (1) and methyl 1-acetoxy-hexahydro-3-methyl-3-propyl-1H-isochromene-4-carboxylate (2). The isolated metabolites were checked for their radical scavenging and anti-inflammatory potentials by selective in vitro models. The isochromenyl derivative exhibited potential 2,2-diphenyl-1-picryl-hydrazil and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (IC50 −1) radical-scavenging capacities along with pro-inflammatory cyclooxygenase-2 (COX-2) (IC50 0.75 mg mL−1) and 5-lipoxygenase (5-LOX) (IC50 0.77 mg mL−1) inhibitory activities. The titled compounds displayed the selectivity indices (IC50 anti-COX-1/IC50 anti-COX-2) greater than 1.25, in comparison with synthetic anti-inflammatory drug ibuprofen (0.44), which attributed to their greater selectivity towards inducible pro-inflammatory enzyme COX-2.

Efficacy of sunflower oil (diet SF) and soybean oil (diet SB) alone and in combination with cod liver oil (diets M1-2.80:1.40:1.40, M2-2.80:2.24:0.56 and M3-2.80:0.56:2.24; cod liver oil:sunflower oil:soybean oil) as lipid supplements (5.6%) in formulated diets (crude fat ∼9.79%) for juvenile Scylla serrata (weight=0.28±0.07 g, carapace width=9.7±0.1 mm) were compared with diet CL, containing cod liver oil alone as the lipid supplement (6 diets × 24 crabs stocked individually, randomized block design). Growth performance, nutrient (protein and lipid) intake and gain of crabs fed M1, M2 and M3 were higher (P≤0.05) than the crabs fed SF and SB, but were not significantly different (P≥0.05) from crabs fed CL. Dietary fatty acids (FAs) are found to influence the FA profile of test crabs. Higher tissue levels of 16:1n-7, 18:1n-9 and 18:1n-7 reflected the essential FA deficiency in crabs fed diets supplemented only with vegetable oils. Results confirmed that S. serrata could utilize vegetable oil supplements in the formulated diets as a partial replacement (50%) of cod liver oil without compromising growth and survival. Partial substitution of marine fish oil with suitable vegetable oils can reduce the feed cost considerably, in the context of rising fish oil prices. published