Anti-inflammatory and analgesic activities with gastroprotective effect of semi-purified fractions and isolation of pure compounds from Mediterranean gorgonian Eunicella singularis

Molecular Docking of the Terpenes in Gorgonian Corals to COX-2 and iNOS Enzymes as Anti-Inflammatory

Background:

Because the inflammatory pathway is triggered by the enzymes cyclooxygenase- 2 (COX-2) and inducible nitric oxide synthase (iNOS), inhibitors, such as nonsteroidal anti-inflammatory drugs (NSAIDs), are needed, although these have side effects. Therefore, the discovery and development of natural medicine as a lead compound are needed. The gorgonian corals have been reported to contain cyclic diterpenes with anti-inflammatory activities. The specific anti-inflammatory inhibitor potential has not been reported regarding these secondary metabolites, whether in COX-2 or iNOS. Thus, the in silico method is the right alternative.

Objective:

This study aimed to determine the potency of fifteen terpenes of the various gorgonian corals to COX-2 and iNOS enzymes as an anti-inflammatory.

Methods:

Molecular docking was performed using ChemDraw Ultra 12.0, Chem3D Pro 12.0, Biovia Discovery Studio 2016 Client®, Autodock Tools 4.2, prediction pharmacokinetics (Pre-ADMET), and oral administration (Lipinski rule of five).

Results:

Potential terpenes based on ΔG (kcal/mol) and Ki (nM) to COX-2 were gyrosanol B (-10,32; 27,15), gyrosanol A (-10,20; 33,57), echinolabdane A (-9,81; 64,76). Only nine terpenes were specific to COX-2 active sites, while for iNOS were palmonine F (-7.76; 2070), briarenol C (-7.55; 2910), and all test compounds binding to the iNOS active sites. Pre-ADMET prediction obtained that HIA was very excellent (70–100%), Caco-2 had moderate permeability (4–70 nm sec-1), and PPB had strong binding (> 90%). Eight terpenes qualified for the Lipinski rule of five.

Conclusion:

iNOS was a specific target for terpenes based on the free energy of binding (ΔG).

Chemical Evaluation, Antioxidant, Antiproliferative, Anti-Inflammatory and Antibacterial Activities of Organic Extract and Semi-Purified Fractions of the Adriatic Sea Fan, Eunicella cavolini

Due to sedentary lifestyle and harsh environmental conditions, gorgonian coral extracts are recognized as a rich source of novel compounds with various biological activities, of interest to the pharmaceutical and cosmetic industries. The presented study aimed to perform chemical screening of organic extracts and semi-purified fractions obtained from the common Adriatic gorgonian, sea fan, Eunicella cavolini (Koch, 1887) and explore its abilities to exert different biological effects in vitro. Qualitative chemical evaluation revealed the presence of several classes of secondary metabolites extended with mass spectrometry analysis and tentative dereplication by using Global Natural Product Social Molecular Networking online platform (GNPS). Furthermore, fractions F4 and F3 showed the highest phenolic (3.28 ± 0.04 mg GAE/g sample) and carotene (23.11 ± 2.48 mg β-CA/g sample) content, respectively. The fraction F3 inhibited 50% of DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) and ABTS (2,2′-azino-bis (3-ethylbenzthiazolin-6-yl) sulfonic acid) radicals at the concentrations of 767.09 ± 11.57 and 157.16 ± 10.83 µg/mL, respectively. The highest anti-inflammatory potential was exhibited by F2 (IC₅₀ = 198.70 ± 28.77 µg/mL) regarding the inhibition of albumin denaturation and F1 (IC₅₀ = 254.49 ± 49.17 µg/mL) in terms of soybean lipoxygenase inhibition. In addition, the most pronounced antiproliferative effects were observed for all samples (IC₅₀ ranging from 0.82 ± 0.14–231.18 ± 46.13 µg/mL) against several carcinoma cell lines, but also towards non-transformed human fibroblasts pointing to a generally cytotoxic effect. In addition, the antibacterial activity was tested by broth microdilution assay against three human pathogenic bacteria: Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The latter was the most affected by fractions F2 and F3. Finally, further purification, isolation and characterization of pure compounds from the most active fractions are under investigation.

Secondary Metabolites from Gorgonian Corals of the Genus Eunicella: Structural Characterizations, Biological Activities, and Synthetic Approaches

Gorgonian corals, which belong to the genus Eunicella, are known as natural sources of diverse compounds with unique structural characteristics and interesting bioactivities both in vitro and in vivo. This review is focused primarily on the secondary metabolites isolated from various Eunicella species. The chemical structures of 64 compounds were divided into three main groups and comprehensively presented: a) terpenoids, b) sterols, and c) alkaloids and nucleosides. The observed biological activities of depicted metabolites with an impact on cytotoxic, anti-inflammatory, and antimicrobial activities were reviewed. The most promising biological activities of certain metabolites point to potential candidates for further development in pharmaceutical, cosmetic, and other industries, and are highlighted. Total synthesis or the synthetic approaches towards the desired skeletons or natural products are also summarized.

Marine Pharmacology in 2014-2015: Marine Compounds with Antibacterial, Antidiabetic, Antifungal, Anti-Inflammatory, Antiprotozoal, Antituberculosis, Antiviral, and Anthelmintic Activities; Affecting the Immune and Nervous Systems, and Other Miscellaneous Mechanisms of Action

The systematic review of the marine pharmacology literature from 2014 to 2015 was completed in a manner consistent with the 1998-2013 reviews of this series. Research in marine pharmacology during 2014-2015, which was reported by investigators in 43 countries, described novel findings on the preclinical pharmacology of 301 marine compounds. These observations included antibacterial, antifungal, antiprotozoal, antituberculosis, antiviral, and anthelmintic pharmacological activities for 133 marine natural products, 85 marine compounds with antidiabetic, and anti-inflammatory activities, as well as those that affected the immune and nervous system, and 83 marine compounds that displayed miscellaneous mechanisms of action, and may probably contribute to novel pharmacological classes upon further research. Thus, in 2014-2015, the preclinical marine natural product pharmacology pipeline provided novel pharmacology as well as new lead compounds for the clinical marine pharmaceutical pipeline, and thus continued to contribute to ongoing global research for alternative therapeutic approaches to many disease categories.

Oxysterols from a Marine Sponge Inflatella sp. and Their Action in 6-Hydroxydopamine-Induced Cell Model of Parkinson's Disease

Four new oxysterols 1⁻4 along with previously known oxygenated sterols 5⁻14 were isolated from the sponge Inflatella sp., collected from the Sea of Okhotsk. Structures of 1⁻4 were elucidated by the detailed NMR spectroscopic and mass-spectrometric analyses as well as by comparison of the corresponding experimental data with those reported in literature. The influence of compounds 1⁻14 on the viability of neuronal Neuro2a cells treated by 6-hydroxydopamine and reactive oxygen species (ROS) formation in these cells was investigated.

Analgesic Effect of 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one in Experimental Animal Models of Nociception

Curcuminoids derived from turmeric rhizome have been reported to exhibit antinociceptive, antioxidant and anti-inflammatory activities. We evaluated the peripheral and central antinociceptive activities of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a novel synthetic curcuminoid analogue at 0.1, 0.3, 1 and 3 mg/kg (intraperitoneal), through chemical and thermal models of nociception. The effects of DHHPD on the vanilloid and glutamatergic systems were evaluated through the capsaicin- and glutamate-induced paw licking tests. Results showed that DHHPD significantly (p < 0.05) attenuated the writhing response produced by the 0.8% acetic acid injection. In addition, 1 and 3 mg/kg of DHHPD significantly (p < 0.05) reduced the licking time spent by each mouse in both phases of the 2.5% formalin test and increased the response latency of mice on the hot-plate. However, the effect produced in the latter was not reversed by naloxone, a non-selective opioid receptor antagonist. Despite this, DHHPD decreased the licking latency of mice in the capsaicin- and glutamate-induced paw licking tests in a dose response manner. In conclusion, DHHPD showed excellent peripheral and central antinociceptive activities possibly by attenuation of the synthesis and/or release of pro-inflammatory mediators in addition to modulation of the vanilloid and glutamatergic systems without an apparent effect on the opioidergic system.