RESUMEN

Preliminary antibacterial metabolite production screening unveiled that B. amyloliquefaciens MTCC 12,713 associated with the intertidal red alga Kappaphycus alverezii exhibited potential inhibitory effects against drug-resistant pathogens methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Four homologous siderophore types of bacillibactins were isolated from a heterotrophic marine bacterium through bioactivity-guided purification. All detectable natural product gene clusters in B. amyloliquefaciens MTCC 12,713 were analyzed by sequencing the complete genome of the bacterium. The studied compounds displayed broad spectrum bactericidal activity against multidrug-resistant strains with a range of minimum inhibitory concentration values from 1.56 to 6.25 µg/mL, whereas standard antibiotic chloramphenicol was active at 6.25 to 12.5 µg/mL. Structure-bioactivity relationship assessment showed that higher electronic values were responsible for antibacterial properties against the nosocomial pathogens. The 2, 3-dihydroxybenzoate (dhb)-assisted biosynthetic pathway of catecholate-enclosed bacillibactins was proposed through the bacillibactin synthase multienzyme complex catalysis followed by dimerization of dhbACEBF operons with 16 genes (~ 12 kb bacterial genome). The present findings recognized an undescribed 4-methoxy-11'-pentanoyloxy-bacillibactin C as a source of potential antibacterial agent for use against drug-resistant pathogens for pharmaceutical applications. KEY POINTS: • Bacillus amyloliquefaciens in association with Kappaphycus alverezii was isolated • Four antibacterial bacillibactin analogs were identified from symbiotic bacterium • 4-Methoxy-11'-pentanoyloxy-bacillibactin C showed potential antibacterial activity.

Asunto(s)

Bacillus , Staphylococcus aureus Resistente a Meticilina , Antibacterianos/farmacología , Oligopéptidos , Sideróforos

RESUMEN

Marine heterotrophs are treasured bio-resources of antimicrobial metabolites, and herein we report the biosynthetic potential of Bacillus amyloliquefaciens (ex. Fukumoto) Priest et al. (Bacillaceae) strain MTCC 12713 isolated from an intertidal macroalga Kappaphycus alvarezii (Doty) L.M.Liao (Rhodophyta: Solieriaceae). The bacterium showed promising biological activities against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. Genome mining of B. amyloliquefaciens MTCC 12713 predicted the gene clusters coding for biosynthesis of antibacterial metabolites. Bioactivity-guided purification was directed to isolate four homologous members of trans-acyltransferase polyketide synthase-derived antibiotics, which were classified as macrobrevin analogues. The compounds exhibited antibacterial activities against nosocomial pathogens, for example, methicillin-resistant S. aureus, vancomycin-resistant E. faecalis, Klebsiella pneumoniae and Pseudomonas aeruginosa with a range of MIC values from 1.56 to 6.25 µg/mL, although standard antibiotic chloramphenicol was active at 6.25-12.5 µg/mL. Conspicuously, the macrobrevin compound encompassing hexahydro-41-hydroxy-macrobrevin-31-acetate functionality, displayed considerably greater antagonistic activities against methicillin-resistant S. aureus, vancomycin-resistant E. faecalis, Vibrio parahaemolyticus, P. aeruginosa, K. pneumoniae, and Streptococcus pyogenes (MIC 1.56 µg/mL) compared to the positive controls and other macrobrevin analogues. Trans-AT polyketide synthase-stimulated biosynthetic pathway of macrobrevin compounds, through repetitive decarboxylative Claisen condensation between acetyl-S-KS domain and malonate-S-ACP units could corroborate the structural elucidation. In the genome mining study, among the 34 biosynthetic gene clusters, a hybrid trans-acyltransferase (trans-AT) pks/nrps gene cluster, which extends up to ∼81 Kb, was recognized in the genome of B. amyloliquefaciens MTCC 12713. The pks/nrps cluster revealed 46% similarity to trans-AT PKS-derived macrobrevin isolated from a mesophilic bacterium Brevibacillus sp. Leaf182 associated with the phyllosphere of the wild-type genotype of Arabidopsis thaliana. The binding positions for macrobrevins with S. aureus peptide deformylase showed docking score of larger than 14 kcal/mol, which was considerably greater than macrolactin N and actinonin (<10 kcal/mol). These present findings documented that the marine heterotrophic B. amyloliquefaciens MTCC 12713 could be used to develop prospective antibacterial agents belonging to macrobrevin analogues for biotechnological and pharmaceutical applications.

Asunto(s)

Bacillus amyloliquefaciens , Infección Hospitalaria , Staphylococcus aureus Resistente a Meticilina , Policétidos , Algas Marinas , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana , Policétidos/farmacología , Estudios Prospectivos , Staphylococcus aureus

RESUMEN

The rise in antibiotic-resistant bacterial strains prompting nosocomial infections drives the search for new bioactive substances of promising antibacterial properties. The surfaces of seaweeds are rich in heterotrophic bacteria with prospective antimicrobial substances. This study aimed to isolate antibacterial leads from a seaweed-associated bacterium. Heterotrophic Bacillus amyloliquefaciens MTCC 12716 associated with the seaweed Hypnea valentiae, was isolated and screened for antimicrobial properties against drug-resistant pathogens. The bacterial crude extract was purified and three novel amicoumacin-class of isocoumarin analogues, 11'-butyl acetate amicoumacin C (amylomacin A), 4'-hydroxy-11'-methoxyethyl carboxylate amicoumacin C (amylomacin B) and 11'-butyl amicoumacin C (amylomacin C) were isolated to homogeneity. The studied amylomacins possessed potential activities against Pseudomonas aeruginosa, vancomycin-resistant Enterococcus faecalis, Klebsiella pneumoniae, methicillin-resistant Staphylococcus aureus, and Shigella flexneri with a range of minimum inhibitory concentration values from 0.78 to 3.12 µg/mL, although standard antibiotics ampicillin and chloramphenicol were active at 6.25-25 µg/mL. Noticeably, the amylomacin compound encompassing 4'-hydroxy-11'-methoxyethyl carboxylate amicoumacin C functionality (amylomacin B), displayed considerably greater antagonistic activities against methicillin-resistant S. aureus, vancomycin-resistant E. faecalis, Vibrio parahaemolyticus, Escherichia coli, and K. pneumoniae (minimum inhibitory concentration 0.78 µg/mL) compared to the positive controls and other amylomacin analogues. Antimicrobial properties of the amylomacins, coupled with the presence of polyketide synthase-I/non-ribosomal peptide synthetase hybrid gene attributed the bacterium as a promising source of antimicrobial compounds with pharmaceutical and biotechnological applications.

Asunto(s)

Antibacterianos/metabolismo , Antiinfecciosos/metabolismo , Bacillus amyloliquefaciens/fisiología , Bacterias/efectos de los fármacos , Algas Marinas/microbiología , Algas Marinas/fisiología , Antibacterianos/química , Antibacterianos/aislamiento & purificación , Antibacterianos/farmacología , Antiinfecciosos/química , Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/farmacología , Bacillus amyloliquefaciens/genética , Bacillus amyloliquefaciens/aislamiento & purificación , Infección Hospitalaria , Farmacorresistencia Bacteriana/efectos de los fármacos , Enterococcus faecalis/efectos de los fármacos , Escherichia coli , Procesos Heterotróficos , Klebsiella pneumoniae/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Péptido Sintasas , Sintasas Poliquetidas , Policétidos , Pseudomonas aeruginosa/efectos de los fármacos , Rhodophyta , Shigella flexneri/efectos de los fármacos

RESUMEN

During the previous decade, genome-built researches on marine heterotrophic microorganisms displayed the chemical heterogeneity of natural product resources coupled with the efficacies of harnessing the genetic divergence in various strains. Herein, we describe the whole genome data of heterotrophic Bacillus amyloliquefaciens MB6 (MTCC 12,716), isolated from a marine macroalga Hypnea valentiae, a 4,107,511-bp circular chromosome comprising 186 contigs, with 4154 protein-coding DNA sequences and a coding ratio of 86%. Simultaneously, bioactivity-guided purification of the bacterial extract resulted in six polyketide classes of compounds with promising antibacterial activity. Draft genome sequence of B. amyloliquefaciens MB6 unveiled biosynthetic gene clusters (BGCs) engaged in the biosynthesis of polyketide-originated macrolactones with prospective antagonistic activity (MIC ≤ 5 µg/mL) against nosocomial pathogens. Genome analysis manifested 34 putative BGCs necessitated to synthesize biologically active polyketide-originated frameworks or their derivatives. These results provide insights into the genetic basis of heterotrophic B. amyloliquefaciens MTCC 12,716 as a prospective lead for biotechnological and pharmaceutical applications.

Asunto(s)

Antibacterianos/aislamiento & purificación , Bacillus/genética , Policétidos/farmacología , Bacillus/química , Bacterias/efectos de los fármacos , Genoma Bacteriano , Pruebas de Sensibilidad Microbiana , Policétidos/química , Rhodophyta/microbiología

RESUMEN

A heterotrophoic Bacillus amyloliquefaciens MTCC12713 isolated from an intertidal macroalga Kappaphycus alverezii displayed promising antibacterial activities against multidrug-resistant bacteria. Genome mining of the bacterium predicted biosynthetic gene clusters coding for antibacterial secondary metabolites. Twenty-one membered macrocyclic lactones, identified as difficidin analogues bearing 6-hydroxy-8-propyl carboxylate, 9-methyl-19-propyl dicarboxylate, 6-methyl-9-propyl dicarboxylate-19-propanone, and (20-acetyl)-6-methyl-9-isopentyl dicarboxylate (compounds 1 through 4) functionalities were purified through bioassay-guided fractionation. The difficidin analogues exhibited bactericidal activities against vancomycin-resistant Enterococcus faecalis, methicillin-resistant Staphylococcus aureus, and other drug-resistant strains, such of Klebsiella pneumonia and Pseudomonas aeruginosa with the minimum inhibitory concentration of about 2-9 × 10-3 µM. A plausible enzyme-catalyzed biosynthetic pathway that is generated through addition of acrylyl initiator unit by repetitive decarboxylative Claisen condensation modules with malonate units was recognized, and their structures were corroborated with gene organization of the dif operon, which could comprehend dif A-O (~ 70 kb). Drug-likeness score for 5-ethoxy-28-methyl-(9-methyl-19-propyl dicarboxylate) difficidin (compound 2, 0.35) was greater than those of other difficidin analogues, which corroborated the potential in vitro antibacterial properties of the former. The present study demonstrated the potential of difficidin analogues for pharmaceutical and biotechnological uses against the bottleneck of emergent drug-resistant pathogens. KEY POINTS: • Difficidins were isolated from marine alga associated Bacillus amyloliquefaciens. • Whole-genome mining of bacterial genome predicted biosynthetic gene clusters. • Greater drug-likeness for difficidin 2 confirmed its potent antibacterial activity.

Asunto(s)

Bacillus , Staphylococcus aureus Resistente a Meticilina , Policétidos , Algas Marinas , Antibacterianos/farmacología , Lactonas , Pruebas de Sensibilidad Microbiana

RESUMEN

Nuclear factor-kappa B is an inducible transcription element, which was considered as an important regulator of immune functions, and plays a critical role to induce inflammatory reactions. In this study, we have demonstrated the anti-inflammatory potentials of previously undescribed (4 â†’ 13)-abeo-euryfuranyls (1-2) from the spineless cuttlefish Sepiella inermis in lipopolysaccharide-stimulated macrophages. The euryfuranyl bearing (4 â†’ 13)-abeo-euryfuranyl-2-ene-6-hydroxymethyl-propanoate framework (compound 1) displayed prominent inhibitory effects against pro-inflammatory cyclooxygenase-2 (IC50 0.36 mM) and 5-lipoxygenase (IC50 0.70 mM). Additionally, it suppressed the generation of inducible nitric oxide synthase along with cyclooxygenase-2 and 5-lipoxygenase in lipopolysaccharide-stimulated macrophages. The euryfuranyl analogue (1) down-regulated the mRNA expression of cyclooxygenase-2 and nuclear factor-κB signaling pathway in lipopolysaccharide-activated macrophage cells by hindering the degradation of inhibitor-κB proteins, and transfer of the subunit NF-κB p65 to the nucleus from the cytosol. These results demonstrated that the euryfuranyl analogue could be explored as a promising anti-inflammatory therapeutic lead attenuating nuclear factor-κB signaling cascade.

Asunto(s)

Antiinflamatorios/farmacología , Furanos/farmacología , Macrófagos/efectos de los fármacos , FN-kappa B/antagonistas & inhibidores , Animales , Antiinflamatorios/química , Antiinflamatorios/aislamiento & purificación , Decapodiformes , Relación Dosis-Respuesta a Droga , Furanos/química , Furanos/aislamiento & purificación , Lipopolisacáridos/antagonistas & inhibidores , Lipopolisacáridos/farmacología , Macrófagos/metabolismo , Ratones , Estructura Molecular , FN-kappa B/metabolismo , Células RAW 264.7 , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad

RESUMEN

Four biogenic ß-sitosterol analogues were identified from methanolic extract of the leaves of loop-root mangrove Rhizophora mucronata. These were characterized as 4, 14, 23-trimethyl-3ß-sitosterol (1), 7-ethyl-3ß-sitosterol (2), sitosteryl-3ß-(33E)-pent-33-enoate (3) and 12α-hydroxy-3ß-sitosterol (4) based on comprehensive spectroscopic techniques. Anti-inflammatory activities of ß-sitosterol 4 against pro-inflammatory enzymes 5-lipoxygenase and cyclooxygenase-2 were found to be significantly higher (IC50 1.85 and 1.92 mM, respectively) compared to those demonstrated by compounds of 1-3 (p < 0.05). These ß-sitosterol analogues disclosed superior selectivity indices (1.43-2.07) with regard to inducible cyclooxygenase-2 than its constitutive isoform cyclooxygenase-1, when compared to the standard, ibuprofen (0.44). Antioxidant properties of 12α-hydroxy-ß-sitosterol (4) were found to be significantly greater (IC50 1.43-1.67 mM) than those of other sitosterol analogues. Structure-activity correlation analyses put forward that the bioactive potencies of the titled ß-sitosterols were positively correlated to their electronic parameters. Molecular docking simulations were carried out in the active sites of 5-lipoxygenase/cyclooxygenase-2, and the docking scores and binding energies of the studied ß-sitosterol analogues were positively correlated with their attenuation properties against 5-lipoxygenase and cyclooxygenase-2.

Asunto(s)

Antiinflamatorios/farmacología , Antioxidantes/farmacología , Inhibidores de la Ciclooxigenasa 2/farmacología , Inhibidores de la Lipooxigenasa/farmacología , Extractos Vegetales/farmacología , Rhizophoraceae/química , Sitoesteroles/farmacología , Araquidonato 5-Lipooxigenasa/química , Ciclooxigenasa 2/química , Raíces de Plantas/química

RESUMEN

New dolabellanes {6-methoxy-dolabella-8(17),12-diene-10ß,18-diol (1), 3-methoxy-dolabella-12(18)-ene-4ß-ol (2), 3-methoxy-dolabella-10,18(19)-diene-5α,8ß-diol (3)} and dolastanes {2,7-dimethoxy-14α-hydroxy-dolasta-1(15),9-diene (4) and 4,7-dimethoxy-9ß,14α-dihydroxy-dolasta-1-ene (5)} were identified from brown seaweed Padina tetrastromatica (family Dictyotaceae), collected from the southeast coast of India. Compounds 1-3 were found to possess dolabellane skeleton with [9.3.0] cyclotetradecane framework whereas, 4-5 were composed of tricyclic diterpenes with linear arrangement of six-seven-five fused alicyclic rings. Compounds 3 and 5 registered greater antioxidative activities (IC50 ≤0.63 mg/mL) than other analogues (IC50 ≥0.65 mg/mL), whereas their attenuating potentials against carbolytics α-amylase and α-glucosidase (IC50 ∼0.12-0.14 mg/mL) were comparable with those displayed by acarbose (IC50 0.14-0.12 mg/mL). Bioactive potentials of titled compounds were assessed by electronic and lipophilic parameters. The lesser binding energies of 3 (-9.71 kcal/mol) and 5 (-8.59 kcal/mol) through molecular docking demonstrated their effective hydrogen bonding interactions with α-amylase. Thus, dolabellanes and dolastanes might be used as anti-diabetic and antioxidant leads to reduce the risk of hyperglycaemia.

Asunto(s)

Antioxidantes/farmacología , Diterpenos/farmacología , Inhibidores Enzimáticos/farmacología , Phaeophyceae/química , Algas Marinas/química , Almidón/metabolismo , Antioxidantes/química , Fraccionamiento Químico , Cromatografía , Diterpenos/química , Inhibidores de Glicósido Hidrolasas/farmacología , Simulación del Acoplamiento Molecular , Extractos Vegetales/química , Metabolismo Secundario/efectos de los fármacos , Análisis Espectral , alfa-Amilasas/antagonistas & inhibidores , alfa-Glucosidasas/metabolismo

RESUMEN

Cephalopod squid, Uroteuthis (Photololigo) duvaucelii is consumed as culinary delicacy along the southwest part of Asian continent. Ethyl acetate:methanol extract of U. duvaucelii was chromatographically fractionated to yield C19 furano-norditerpenoid (1) along with irregular C15 sesquiterpenoid (2) and C20 diterpenoid compounds (3). In vitro anti-inflammatory and antioxidant analyses were utilised to evaluate their bio-potentials. The C19 furano-norditerpenoid was reported for significantly effective 2,2-diphenyl-1-picrylhydrazyl radical inhibition (IC50 0.60 mg/mL) than other compounds and α-tocopherol (IC50 ≥ 0.64 mg/mL). The 2,2'-azino-bis-3-ethylbenzothiozoline-6-sulfonic acid inhibition and ferrous ion chelating potentials were higher for compounds 1 and 2 (IC50 ∼ 0.69 and ∼0.84 mg/mL, respectively) compared to α-tocopherol (IC50 0.76-0.95 mg/mL). The studied compounds displayed comparable inhibitory activities with synthetic ibuprofen against pro-inflammatory inducible 5-lipoxygenase (IC50 ∼ 0.92 mg/mL). The lower hydrophobicity and steric variables were directly correlated with their antioxidative and anti-inflammatory properties. The studied compounds could be utilised as natural antioxidants and anti-inflammatory functional food ingredients.

Asunto(s)

Antiinflamatorios/farmacología , Antioxidantes/farmacología , Decapodiformes/química , Inflamación/patología , Terpenos/farmacología , Animales , Antiinflamatorios/química , Depuradores de Radicales Libres/farmacología , Inhibidores de la Lipooxigenasa/farmacología , Metabolismo Secundario/efectos de los fármacos , Terpenos/química , Terpenos/aislamiento & purificación

RESUMEN

Heterotrophic Gamma-proteobacterium Shewanella algae MTCC 12715, associated with an intertidal red algae Hypnea valentiae, presented broad-spectra of antibacterial activities against pathogenic bacteria bringing about nosocomial infection. Bioassay-guided fractionation of the bacterial crude extract resulted in two undescribed macrocyclic polyketide analogs, with anti-infective activities against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis (MIC 3.1-5.0 µg/mL). In order to identify the polyketide biosynthetic machinery termed type-I polyketide synthase (pks-I) encoding biologically active secondary metabolites in this strain, the ketosynthase-coding regions of DNA with ≈700 bp size, were amplified, and the partial sequence was submitted in the GenBank (accession number MH157093). The titled compounds were classified under macrocyclic polyketides bearing dodecahydropyrano-trioxacyclooctadecine-dione and trioxo-octadecahydro-1H-benzo[o]tetraoxacyclopentacosine-carboxylate functionalities. Structure-activity correlation analysis displayed that hydrophobic descriptor of the studied compounds could play a prominent role in its anti-infective property against the opportunistic pathogens. Further, in silico molecular docking studies were performed in the allosteric sites of penicillin-binding protein (PBP2a) coded by mecA genes of MRSA, and the best binding pose for each compound (docking score -8.47 kcal/mol and -9.58 kcal/mol, respectively) could be correlated with their in vitro antibacterial activities. The pks-I assisted biosynthetic pathway of macrocyclic polyketides through step-wise decarboxylative condensation initiated by malonate-acyl carrier protein corroborated their structural attributes. Chemical mining of the studied macroalgae-associated heterotrophic bacterium thus revealed the promising antagonistic properties of macrocyclic polyketides isolated from Shewanella algae MTCC 12715 against multidrug-resistant pathogens.

Asunto(s)

Antibacterianos/farmacología , Compuestos Macrocíclicos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Policétidos/farmacología , Shewanella/química , Enterococos Resistentes a la Vancomicina/efectos de los fármacos , Antibacterianos/química , Relación Dosis-Respuesta a Droga , Compuestos Macrocíclicos/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Policétidos/química , Relación Estructura-Actividad

RESUMEN

Extensive biodiversity and availability of marine and estuarine molluscs, along with their their wide-range of utilities as food and nutraceutical resources developed keen attention of the food technologists and dieticians, particularly during the recent years. The current review comprehensively summarized the nutritional qualities, functional food attributes, and bioactive properties of these organisms. Among the phylum mollusca, Cephalopoda, Bivalvia, and Gastropoda were mostly reported for their nutraceutical applications and bioactive properties. The online search tools, like Scifinder/Science Direct/PubMed/Google Scholar/MarinLit database and marine natural product reports (1984-2019) were used to comprehend the information about the molluscs. More than 1334 secondary metabolites were reported from marine molluscs between the periods from 1984 to 2019. Among various classes of specialized metabolites, terpenes were occupied by 55% in gastropods, whereas sterols occupied 41% in bivalves. The marketed nutraceuticals, such as CadalminTM green mussel extract (Perna viridis) and Lyprinol® (Perna canaliculus) were endowed with potential anti-inflammatory activities, and were used against arthritis. Molluscan-derived therapeutics, for example, ziconotide was used as an analgesic, and elisidepsin was used in the treatment of cancer. Greater numbers of granted patents (30%) during 2016-2019 recognized the increasing importance of bioactive compounds from molluscs. Consumption of molluscs as daily diets could be helpful in the enhancement of immunity, and reduce the risk of several ailments. The present review comprehended the high value compounds and functional food ingredients from marine and estuarine molluscs.

Asunto(s)

Bivalvos , Ingredientes Alimentarios , Animales , Antiinflamatorios , Ecosistema , Estudios Prospectivos

RESUMEN

A polygalactosamino-glucopyranosyl fucopyranose →4)-ß-GlcAp{(3→1)-α-Fucp}-ß-GalNAcp-(4,6-SO3-)-(1→ isolated from the bivalve Crassostrea madrasensis exhibited prospective anti-inflammatory activity against cyclooxygenase-2 and 5-lipoxygenase (IC50 < 50 µg mL-1) on lipopolysaccharide-induced macrophages. The polygalactan attenuated inducible nitric oxide synthase (IC50 65.7 µg mL-1) in lipopolysaccharide-prompted inflammation leading to the reduction of pro-inflammatory cytokine nitric oxide (236.2 µg mL-1 lysate), nuclear factor-κB, tumor necrosis factor-α, and interleukins (0.19-0.22 units mg-1 protein at 100 µg mL-1) by inhibiting cyclooxygenase-2. The polygalacatan suppressed the mRNA of nuclear factor-κB and cyclooxygenase-2 in lipopolysaccharide-induced macrophages. Western blot experiment revealed that the polygalactan attenuated the migration of nuclear factor-κB-p65 to the nucleus from cytoplasm, and suppressed the phosphorylation of α-subunit of κB inhibitor. Greater selectivity index of sulfated polygalactan (3.93) towards inducible cyclooxygenase-2 as compared with the anti-inflammatory agent ibuprofen (1.11), and the potential to inhibit nuclear factor-κB cascade to generate chemokine production manifested its utilization in the development of functional food attenuating inflammation-related disorders.

Asunto(s)

Antiinflamatorios/farmacología , Crassostrea/química , Galactanos/farmacología , Inflamación/tratamiento farmacológico , Lipopolisacáridos/toxicidad , Macrófagos/efectos de los fármacos , FN-kappa B/metabolismo , Animales , Ciclooxigenasa 2/química , Citocinas/metabolismo , Galactanos/aislamiento & purificación , Inflamación/inducido químicamente , Inflamación/metabolismo , Inflamación/patología , Macrófagos/metabolismo , Macrófagos/patología , Ratones , FN-kappa B/genética , Fosforilación , Transducción de Señal

RESUMEN

Angiotensin converting enzyme (ACE) is a multifunctional enzyme involved in translation of angiotensin-I (AngI) to vasoconstrictor angiotensin-II (AngII). A sulfated N-acetylglucosamino-glucuronopyranosyl-arabinopyranan characterized as poly-[(2-methoxy-ß-arabinopyranosyl)-(1 â†’ 3)-(ß-glucurono)-(1 â†’ 4)-(2-acetamido-2-deoxy-3,6-di-O-sulfonato-ß-glucopyranose)] was purified and reported first time from the edible portion of Amphioctopus neglectus and evaluated for various pharmacological properties. The polysaccharide exhibited potential ACE attenuation property (IC50 0.11 mg mL-1), whereas molecular docking simulations displayed its efficient binding at the ACE active site with lesser inhibitory constant (Ki) of 17.36 nM and binding energy (-10.59 kcal mol-1). The in-vitro analysis showed that the studied polysacharide attenuated AngII prompted cardiac hypertrophy at 50 µg mL-1 in the cardiomyoblast cells, whereas 48% reduction in cellular surface area with extended viability could be correlated with anti-hypertrophic properties of the studied polysaccharide. The sulfated N-acetylglucosamino-glucuronopyranosyl-arabinopyranan purified from A. neglectus could function as a prospective functional lead against the pathophysiological conditions leading to hypertension.

Asunto(s)

Acetilglucosamina/química , Acetilglucosamina/farmacología , Alimentos Marinos/análisis , Sulfatos/química , Acetilglucosamina/aislamiento & purificación , Angiotensina II/efectos adversos , Angiotensina II/metabolismo , Animales , Antihipertensivos/química , Antihipertensivos/aislamiento & purificación , Antihipertensivos/farmacología , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Antioxidantes/farmacología , Cardiomegalia/tratamiento farmacológico , Cardiomegalia/etiología , Cardiomegalia/metabolismo , Cefalópodos/química , Susceptibilidad a Enfermedades , Humanos , Espectroscopía de Resonancia Magnética , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Monosacáridos/química , Peptidil-Dipeptidasa A/metabolismo , Polisacáridos/química , Polisacáridos/aislamiento & purificación , Relación Estructura-Actividad

RESUMEN

Intertidal red algae Hypnea valentiae associated Bacillus amyloliquefaciens MTCC 12716 revealed potential inhibitory effects on the growth of drug-resistant pathogens. In the genome of B. amyloliquefaciens MTCC 12716, biosynthetic gene clusters encoding antibacterial metabolites were predicted, which might be expressed and contributed to the broad-spectrum anti-infective activity. Three homologue members of the 24-membered macrocyclic lactone family, named as bacvalactones 1-3 bearing 13-O-ethyl (1); 15-O-furanyl-13-O-isobutyl-7-O-propyl-propanoate (2); and 15-O-furanyl-13-O-isobutyl-7-O-propyl-propanoate-7,24-dimethyl (3) functionalities, were acquired through bioactivity-guided purification. The macrocyclic lactones displayed bactericidal activity against opportunistic pathogens causing nosocomial infections, for instance, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecalis (VREfs), and multidrug-resistant strains of Pseudomonas aeruginosa and Klebsiella pneumonia with MIC ≤ 3.0 µg/mL, whereas standard antibiotics ampicillin and chloramphenicol were active only at concentrations of ≥ 6.25 mg/mL. The biosynthetic pathway of macrocyclic lactones that are generated by trans-AT polyketide synthases through stepwise extension of an acetyl starter unit by eleven sequential Claisen condensations with malonyl-CoA was established, and the structures were correlated with the gene organization of the mln operon, which encompasses nine genes mln A-I (approximately 47 kb in size). The best binding poses for each compounds (1-3) with Staphylococcus aureus peptide deformylase (SaPDF) unveiled docking scores (≥ 9.70 kcal/mol) greater than that of natural peptide deformylase inhibitors, macrolactin N and actinonin (9.14 and 6.96 kcal/mol, respectively), which supported their potential in vitro bioactivities. Thus, the present work demonstrated the potential of macrocyclic lactone for biotechnological and pharmaceutical applications against emerging multidrug-resistant pathogens. Key Points •Three antibacterial bacvalactones were identified from the symbiotic bacterium. •The symbiotic bacterial genome was explored to identify the biosynthetic gene clusters. •Trans-AT pks-assisted mln biosynthetic pathway of the macrocyclic lactone was proposed. •In silicomolecular interactions of the bacvalactones with S. aureus PDF were analyzed.

Asunto(s)

Bacillus amyloliquefaciens/química , Bacterias/efectos de los fármacos , Lactonas/farmacología , Compuestos Macrocíclicos/farmacología , Rhodophyta/microbiología , Antibacterianos/farmacología , Organismos Acuáticos/microbiología , Bacillus amyloliquefaciens/genética , Vías Biosintéticas/genética , Simulación por Computador , Farmacorresistencia Bacteriana Múltiple , Klebsiella pneumoniae/efectos de los fármacos , Lactonas/química , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Familia de Multigenes , Pseudomonas aeruginosa/efectos de los fármacos , Metabolismo Secundario , Simbiosis

RESUMEN

Three homologous oxygenated elansolid-type of polyketide spanned macrolides were isolated from a heterotrophic marine bacterium, Bacillus amyloliquefaciens MTCC 12716, associated with an intertidal red alga Hypnea valentiae. The complete genome of the bacterium was sequenced and all detectable natural product gene clusters were analysed. The B. amyloliquefaciens MTCC 12716 genome features polyketide synthase (pks) systems of every known formally classified family, nonribosomal peptide synthetases and hybrid clusters. Comprehensive spectroscopic studies revealed the compounds to possess isobenzofuranyl benzoate and 1H-furopyrano[2,3-c]oxacyclononadecine-6-carboxylate moieties. The identified compounds displayed broad-spectrum bactericidal activity against methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecalis, and drug-resistant strains of Pseudomonas aeruginosa and Klebsiella pneumoniae with minimum inhibitory concentrations (MICs) of ≤1.0 µg/mL, whereas the standard antibiotics ampicillin and chloramphenicol were active only at concentrations of ≥6.25 µg/mL. The plausible mechanism of elansolid-type macrolide biosynthesis by trans-AT polyketide synthases through the pks starter unit para-hydroxybenzoic acid was hypothesised, and the structures were correlated with the gene organisation, with the predicted gene cluster comprising 16 genes (~81 kb in size). The best binding poses for each compound with the peptide deformylase (PDF) protein of S. aureus revealed docking scores (>11.30 kcal/mol) greater than actinonin (6.96 kcal/mol), a natural PDF inhibitor. The higher electronic values along with optimum lipophilic parameters support the potential anti-infective properties of the studied macrolides. These antibacterial elansolid-type of polyketide spanned macrolides in marine symbiotic B. amyloliquefaciens could be potential leads for biotechnological and pharmaceutical applications against emerging multidrug-resistant pathogens.

Asunto(s)

Antiinfecciosos/farmacología , Bacillus amyloliquefaciens/química , Macrólidos/farmacología , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Antiinfecciosos/aislamiento & purificación , Bacillus amyloliquefaciens/genética , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Productos Biológicos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Humanos , Macrólidos/química , Macrólidos/aislamiento & purificación , Oxígeno

RESUMEN

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 < 0.40 mg/mL) related to α-tocopherol (IC50 > 0.60 mg/mL). The pro-inflammatory anti-5-lipoxygenase potential of studied cembrane was higher (IC50 < 0.80 mg/mL) related to those demonstrated by ibuprofen and sodium salicylate (IC50 > 0.90 mg/mL).

Asunto(s)

Antiinflamatorios/aislamiento & purificación , Antioxidantes/aislamiento & purificación , Diterpenos/aislamiento & purificación , Gastrópodos/química , Inhibidores de la Lipooxigenasa/aislamiento & purificación , Moluscos/química , Animales , Antiinflamatorios/química , Antiinflamatorios/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Compuestos de Bifenilo , Diterpenos/farmacología , Inhibidores de la Lipooxigenasa/química , Inhibidores de la Lipooxigenasa/farmacología , Ácidos Sulfónicos/química

RESUMEN

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 < 0.45 mg mL-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.

Asunto(s)

Antiinflamatorios/aislamiento & purificación , Benzopiranos/aislamiento & purificación , Decapodiformes/química , Inhibidores de la Lipooxigenasa/aislamiento & purificación , Animales , Antiinflamatorios/farmacología , Antioxidantes/farmacología , Benzopiranos/farmacología , Inhibidores de la Ciclooxigenasa 2/aislamiento & purificación , Inhibidores de la Ciclooxigenasa 2/farmacología , Inhibidores de la Ciclooxigenasa/aislamiento & purificación , Inhibidores de la Ciclooxigenasa/farmacología , Depuradores de Radicales Libres/aislamiento & purificación , Depuradores de Radicales Libres/farmacología , Inhibidores de la Lipooxigenasa/farmacología

RESUMEN

Spineless marine cuttlefish Sepiella inermis has been considered as a popular dietary cephalopod species in Asian and Mediterranean coasts. Bioassay-directed purification of organic extract of S. inermis ensued in the characterization of two chromenyl derivatives. The studied compounds exhibited significantly greater antioxidant potencies (IC50  ≤ 0.5 mg/ml) when compared with α-tocopherol. The substituted 1H-isochromenyloxy-11-hydroxyethyl pentanoate isoform (compound 1) efficiently inhibited the carbolytic enzymes along with key regulator of insulin secretion dipeptidyl peptidase-IV (IC50 0.16 mg/ml). The molecular docking simulations displayed optimum binding affinity of the compound 1 (-10.01 kcal/mol) with dipeptidyl peptidase-IV and lesser inhibition constant (Ki 46.41 nM), which along with its permissible hydrophobic-hydrophilic balance (log Pow  ~ 2) appeared to play significant roles in its greater antihyperglycemic activity compared to other studied chromenyl isoform. The greater antioxidant and antidiabetic properties of compound 1 could be utilized as an important natural lead against hyperglycemic-related disorders. PRACTICAL APPLICATIONS: The edible spineless marine cuttlefish Sepiella inermis are ubiquitously available in Asian and Mediterranean coasts. The sequential chromatographic purification of the organic extract of S. inermis led to the identification of two pure chromenyl chemotypes. The metabolites with substituted 1H-isochromenyloxy-11-hydroxyethyl pentanoate isoform (compound 1) displayed potential antioxidative and antihyperglycemic activities compared to the chemotype (2) bearing 3H-isochromen-5-yl moiety. The attenuating potential of chromenyl chemotype 1 against carbohydrate hydrolyzing enzymes and insulin secretion regulator attributed towards its efficiency as an important natural lead against postprandial hyperglycemia and incretin hormone regulation to maintain glucose homeostasis in the biological system. The chromenyl metabolites isolated from S. inermis could be utilized as a functional food ingredient in the nutraceutical formulations against hyperglycemic-related disorders.

Asunto(s)

Antioxidantes/farmacología , Decapodiformes/química , Dipeptidil Peptidasa 4/efectos de los fármacos , Inhibidores de la Dipeptidil-Peptidasa IV/farmacología , Hipoglucemiantes/farmacología , Animales , Antioxidantes/aislamiento & purificación , Benzopiranos/aislamiento & purificación , Benzopiranos/farmacología , Inhibidores de la Dipeptidil-Peptidasa IV/aislamiento & purificación , Hipoglucemiantes/aislamiento & purificación , Simulación del Acoplamiento Molecular

RESUMEN

The Asian green mussel, Perna viridis is a nutritious health food in the estuarine and coastal sea beds of the Arabian Sea along the west coast of India. In the present study, bioactivity-guided purification of the chloroform fraction of the methanolic extract of P. viridis was carried out. The isolated secondary metabolites were characterized by spectroscopic experiments, and their antioxidative/antiinflammatory properties were evaluated. The titled compounds were characterized as 3-hydroxy-13-vinyl-dodecahydro-11-phenanthrenone (1), 4,4,9-trimethyl-13-vinyl-dodecahydro-2-phenanthrenone (2), 11,20-dihydroxy-6,6-dimethyl-decahydro-5H-benzo[h]naphtho[1,2-c]chromene-16-carbaldehyde (3), 16-acetyl-20-hydroxy-6,6-dimethyl-dodecahydro-5H-benzo[h]naphtho[1,2-c]chromen-12-one (4), cholest-5-en-3ß-3-yl-(30-hydroxy-3-methyl-36-methyleneundeca-30E,34E-dienoate) (5), and cholest-5-en-3ß-3-yl-((E)-33-oxooct-31-enoate) (6). No significant differences in the antioxidant activities of the compounds with chromene-16-carbaldehyde (3) and chromen-12-one (4) functionalities (IC50 0.52-0.68 mg/ml) vis-à-vis the positive control, α-tocopherol (IC50 0.65-0.76 mg/ml) were registered. The studied compounds, 1-4, displayed potential antiinflammatory activities against pro-inflammatory 5-lipoxygenase (5-LOX) (IC50  < 1 mg/ml). The balanced hydrophilic-lipophilic properties and lower steric values of the studied compounds, 1-4, were correlated with their bioactive potentials. PRACTICAL APPLICATIONS: The edible bivalve green mussels, P. viridis, are broadly available in the estuarine and coastal regions of the Indian Peninsula. The sequential chromatographic purification of the chloroform fraction of the methanolic extract of P. viridis led to the identification of six pure secondary metabolites. The metabolites with substituted chromene-16-carbaldehyde and chromen-12-one functionalities displayed potential antioxidative and antiinflammatory activities compared to other studied compounds. These bioactive metabolites could be used in functional food formulations and as antioxidant leads in medicinal food applications.

Asunto(s)

Antiinflamatorios/química , Antioxidantes/química , Perna/química , Mariscos/análisis , Animales , Antiinflamatorios/metabolismo , Antiinflamatorios/farmacología , Antioxidantes/metabolismo , Antioxidantes/farmacología , Alimentos Funcionales/análisis , Perna/metabolismo , Metabolismo Secundario

RESUMEN

Amphioctopus neglectus (Family: Octopodidae) is recognised as culinary delicacy in many cultures and a common sea food item on the Mediterranean and Asian coasts. Bioassay-directed fractionation of ethyl acetate/methanol extract of A. neglectus ensued in the characterisation of four previously undescribed macrocyclic lactones (1-4). These compounds exhibited potential radical-scavenging capacities (IC50 0.95-1.73 mM) along with anti-hypertensive activities (IC50 1.12-2.34 mM) against angiotensin converting enzyme (ACE). The optimum binding affinity of compound 2 (-9.84 kcal mol-1) bearing furo[1,4,8]trioxacyclohexadecine-12,19-dione moiety with ACE, along with its permissible hydrophobic-hydrophilic balance, manifested towards its greater anti-hypertensive activity compared to other analogues. The compound 2, with lesser values of the inhibitory constant (Ki = 1.0 mM) towards ACE, was found to bind more effectively to the enzyme in a non-competitive manner, and could describe the greater inhibitory ramifications than those displayed by other compounds (Ki >1.1 mM). The ex-vivo studies revealed that compound 2 imparted protective effects against angiotensin-II induced cardiac hypertrophy at 25 µg mL-1 on H9C2 cell lines, wherein about 34 percent decrease in cell area with increase in viability could be attributed to anti-hypertrophic effects of the compound administrated. These results confirmed that the protective effect of the isolated macrocyclic lactones is mediated by enhancement of anti-oxidant defense systems, which subsequently attenuates the hypertensive related disorders.

Asunto(s)

Angiotensina II/toxicidad , Productos Biológicos/uso terapéutico , Cardiomegalia/inducido químicamente , Cardiomegalia/prevención & control , Lactonas/uso terapéutico , Simulación del Acoplamiento Molecular/métodos , Animales , Antioxidantes/química , Antioxidantes/aislamiento & purificación , Antioxidantes/uso terapéutico , Productos Biológicos/química , Productos Biológicos/aislamiento & purificación , Cardiomegalia/metabolismo , Línea Celular , Lactonas/química , Lactonas/aislamiento & purificación , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Octopodiformes , Relación Estructura-Actividad