Previously undescribed antioxidative and anti-inflammatory chromenyls bearing 3H-isochromenone and furanyl-2H-chromenyl skeletons from the venerid clam, Paphia malabarica

Novel Furanyl-Substituted Isochromanyl Class of Anti-Inflammatory Turbinochromanone from Brown Seaweed Turbinaria conoides

Organic extract of the brown seaweed Turbinaria conoides (Sargassaceae) was chromatographically fractionated to yield an undescribed furanyl-substituted isochromanyl metabolite, named as turbinochromanone, which was characterized as methyl 4-[(3S)-8-{[(3R)-4-ethyl-2,3-dihydrofuran-3-yl]methyl}-1-oxo-3,4-dihydro-1H-2-benzopyran-3-yl]butanoate. The isochromanyl derivative possessed comparable attenuation potential against 5-lipoxygenase (IC₅₀ 3.70 μM) with standard 5-lipoxygenase inhibitor drug zileuton (IC₅₀ 2.41 μM). Noticeably, the index of anti-inflammatory selectivity of turbinochromanone (∼1.7) was considerably greater than that exhibited by the standard agent diclofenac (1.06). Antioxidant properties of turbinochromanone against oxidants (IC₅₀ ∼24 μM) further supported its potential anti-inflammatory property. Greater electronic properties (topological polar surface area of 61.8) along with comparatively lesser docking parameters of the studied compound with aminoacyl residues of targeted enzymes (cyclooxygenase-2 and 5-lipoxygenase) (binding energy of -11.05 and -9.40 kcal mol^-1 , respectively) recognized its prospective anti-inflammatory potential. In an aim to develop seaweed-based natural anti-inflammatory leads, the present study isolated turbinochromanone as promising 5-lipoxygenase and cyclooxygenase-2 inhibitor, which could be used for pharmaceutical and biotechnological applications.

High-value compounds from the molluscs of marine and estuarine ecosystems as prospective functional food ingredients: An overview

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.

Elemental Compositions and Fatty Acid Profiles of Bogue Fish (Boops boops) From Mediterranean Coast: A Comprehensive Evaluation of the Potential Effects on Human Health

Mersin Coast plays a quite important role in terms of biodiversity and productivity of the Mediterranean marine ecosystem. However, many effects such as industrial, urban, touristic, and agricultural factors cause pollution in this region as in many other coasts. Therefore, this study aims to discuss the potential risks and benefits of the consumption of bogue fish (Boops boops, Linnaeus, 1758) collected from the North-Eastern Mediterranean in terms of fatty acid and metal levels. The results showed that PUFA for winter and spring and SFA for summer and autumn as the predominant fractions were determined. ∑PUFA/∑SFA ratio was higher than the recommended value for each season. In addition, DHA was higher than EPA for all seasons. Nutritional and health values of lipids are maintained throughout a year, except for winter. The concentration of metal levels in the tested muscle was within the permissible limit of the world levels. Fortunately, the calculated estimated weekly intakes of metals (EWIs) were much lower than the provisional tolerable weekly intake (PTWI) for all seasons. Thus, human health risks resulting from the consumption of this fish species from Mersin Bay are unremarkable because fish muscles are not active tissues for metal accumulation. Besides, the target hazard quotient (THQ) and the total target hazard quotient (TTHQ) were < 1, indicating that there is no potential health risk for the consumers. Benefit/risk ratios for all seasons were calculated and found to be HQ_EFA < 1. It was determined that the cancer risk for consumers is quite low, except for heavy consumption cases. As a goal of the study, important information about the effects of seasons on the changes in lipid quality and metal properties of bogue fish was provided and discussed in detailed.

Antioxidative 2H-chromenyls attenuate pro-inflammatory 5-lipoxygenase and carbolytic enzymes: Prospective bioactive agents from Babylonidae gastropod mollusk Babylonia spirata

Oxygenated heterocycles are emerging as valuable pharmacophores involved in the prophylaxis and treatment of several diseases elicited by the reactive oxygen species. Bioassay-led chromatographic fractionation of the organic extract of the gastropod mollusk Babylonia spirata (family Babylonidae) yielded two unprecedented 2H-chromenyl derivatives characterized as 2-(butyryloxy)-5-hydroxy-hexahydro-2H-chromene-3-methyl carboxylate (1) and (3-hydroxy-hexahydro-2H-chromen-2-yl)methyl pentanoate (2). The chromenyl derivative (1) registered significantly greater attenuation potential against pro-inflammatory 5-lipoxygenase (IC₅₀  ~ 2.02 mM) than those exhibited by the compound (2) (IC₅₀ 2.76 mM) and the non-steroidal anti-inflammatory drug ibuprofen (IC₅₀ 4.36 mM, p < .05). The compound (1) exhibited comparable antioxidant activity (IC₅₀ 1.47-1.72 mM) with standard antioxidative agent α-tocopherol (IC₅₀ 1.4-1.7 mM). Inhibitory potential of chromenyl derivative (1) toward α-glucosidase (IC₅₀ 1.18 mM) and α-amylase (IC₅₀ 0.92 mM) was greater than those displayed by 2 (IC₅₀ 1.16-1.56 mM). Structure-activity relationships revealed that bioactivities of the compounds were determined by the electronic factors and hydrophilic-lipophilic balance. PRACTICAL APPLICATIONS: The marine gastropod Babylonia spirata is one of the prominent edible gastropod species harvested from the coastlines along the southwestern region of the Indian peninsula. Two 2H-chromenyl derivatives were isolated to homogeneity from the organic extract of the marine buccinid gastropod B. spirata by the bioactivity-guided chromatographic fractionation and were found to possess potential antioxidant and attenuation properties against pro-inflammatory 5-lipoxygenase and carbolytic enzymes. The attenuation properties of the 2H-chromenyls against pro-inflammatory 5-lipoxygenase showed that 2H-chromenyl analogs possessed significantly greater anti-inflammatory potential than the non-steroidal anti-inflammatory drug ibuprofen. In particular, the chromenyl derivative bearing 2H-chromene-3-methyl carboxylate framework might constitute a prospective biogenic constituent in functional food and pharmaceutical applications for use against oxidative agents, including inflammation and hyperglycemic pathologies.

Salicornolides A-C from Gracilaria salicornia attenuate pro-inflammatory 5-lipoxygense: Prospective natural anti-inflammatory leads

Three macrolides bearing the carbon framework of oxabicyclo[21.3.1]heptacosa-ene-diones (A and B) and oxabicyclo[19.3.1]pentacosa-ene-dione (C) were isolated and characterised from the organic extract of the intertidal red seaweed Gracilaria salicornia (family Gracilariaceae), which were named as salicornolides A-C. These natural macrolides were conformationally pre-organised ring structure providing diverse functionalities, and their potential bioactive properties led to the development of pharmacophores with anti-inflammatory properties. The 21-membered pyran-enclosed salicornolide B displayed greater cyclooxygenase-2 (IC₅₀ COX-2 1.13 mM) inhibitory activity than those exhibited by the 21-membered aryl salicornolide A and 19-membered salicornolide C (IC₅₀ COX-2-1.2 mM). The attenuating potential of the studied compounds against pro-inflammatory enzyme, 5-lipoxygenase (IC₅₀ LOX < 1.5 mM) was significantly greater than that displayed by the non-steroidal anti-inflammatory ibuprofen (IC₅₀ 4.5 mM), whereas the selectivity indices exhibited by salicornolides against cyclooxygenase-2 was significantly higher (1.18-1.41, P < 0.05) when compared to that of ibuprofen (SI 0.43) attributing the greater selectivity profile of the former towards inducible pro-inflammatory mediators than the latter. The minimal binding energy of salicornolide B (-9.64 kcal mol^-1), a greater number of hydrogen-bonds and lesser inhibitory constant (Ki 85.15 nM) might be responsible for effective binding towards 5-lipoxygenase, and that could attribute its greater anti-inflammation potential than those displayed by other compounds. The putative biosynthetic cascade initiated by malonate-acyl carrier protein unambiguously confirmed the structural attributions of the titled macrocyclic lactones. The undescribed salicornolides A-C from seaweed Gracilaria salicornia attenuating pro-inflammatory 5-lipoxygense might be considered as prospective natural anti-inflammatory leads for pharmaceutical applications.

Antioxidative oxygenated terpenoids with bioactivities against pro-inflammatory inducible enzymes from Indian squid, Uroteuthis (Photololigo) duvaucelii

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.

First report of chromenyl derivatives from spineless marine cuttlefish Sepiella inermis: Prospective antihyperglycemic agents attenuate serine protease dipeptidyl peptidase-IV

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 (K_i 46.41 nM), which along with its permissible hydrophobic-hydrophilic balance (log P_ow  ~ 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.

Previously undisclosed bioactive sterols from corbiculid bivalve clam Villorita cyprinoides with anti-inflammatory and antioxidant potentials

The estuarine Corbiculid bivalve black clam, Villorita cyprinoides collected from the Southwestern coastline regions of Arabian Sea are significant resources of nutritional and bioactive pluralities. The purification of ethyl acetate:methanol (EtOAc:MeOH) extract of V. cyprinoides characterized a previously undisclosed specialized abeo-pregnane-type sterol derivative 19 (10 → 5) abeo-20-methyl-pregn-10-en-3β-yl-hex-(3'E)-enoate (1) along with two cholestenols (22E),(24¹E)-24¹,24²-dihomocholesta-5,22,24¹-trien-3β-ol (2) and (22E)-24¹-homocholesta-5,22-dien-(3β,24¹β)-diol (3). These compounds were characterized by comprehensive spectroscopic investigations. The anti-inflammatory (anti-cyclooxygenase-1, 2/5-lipoxidase) activities of 1 were considerably higher (IC₅₀ < 1.10 mg/mL) than 2-3 (IC₅₀ > 1.10 mg/mL). These studied compounds registered greater selectivity indices (∼1.03) against cyclooxygenase-2 than cyclooxygenase-1. The antioxidant property of abeo-pregnane-type sterol as determined by in vitro 2,2'-azino-bis-(3-ethyl-benzthiazoline-6-sulfonic acid) quenching potential was significantly greater (IC₅₀ 0.94 mg/mL) than those of substituted dihomocholesta-trien-ol (2) and homocholesta-dien-diol (3) (IC₅₀ > 1.00 mg/mL). Structure-activity relationship studies demonstrated that bioactive potentials of the titled compounds were linearly related to their electronic factors along with optimum hydrophobic factors. In addition, molecular docking studies were performed in the active sites of COX-2 and their binding energies and docking scores were well correlated with in vitro anti-COX-2 potentials.

Antioxidative and anti-inflammatory pyranoids and isochromenyl analogues from Corbiculid bivalve clam, Villorita cyprinoides

Bivalve black clam, Villorita cyprinoides is traditional seafood in Southwestern coast of Arabian Sea. In this study, bioactivity-guided purification of ethyl acetate:methanol extract of black clam was carried out. Two irregular meroterpenoids {tetrahydro-3-methoxy-5-((E)-8,12-dimethyloct-8-enyl)-pyran-2-one (1) and dihydro-5-(8-(9,12-dihydro-8-methyl-11-propyl-2H-pyran-8-yl)-ethyl)-furan-2(3H)-one (2)} and two hexahydro-isochromenyl-meroterpenoids (3-4) were identified. The structures were characterized by detailed spectroscopy and their antioxidant/anti-inflammatory potentials were evaluated. Compound 2 registered significantly greater 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability (IC₅₀ <0.65 mg/mL) than other analogues (IC₅₀ ≥0.70 mg/mL). Ferrous ion (Fe²⁺) chelating ability was higher for 1-2 (IC₅₀ ∼0.84 mg/mL) than α-tocopherol (IC₅₀ 0.89 mg/mL). The 5-lipoxygenase inhibitory potential of furano-meroterpenoid analogue, 2 (IC₅₀ 0.76 mg/mL) was greater than other compounds (IC₅₀ >0.90 mg/mL). An optimum hydrophobic-hydrophilic balance of furano-meroterpenoid and lesser steric bulk manifested towards its greater bioactivities compared to other compounds. These anti-inflammatory and antioxidant leads could be used as potential functional food components.