Synthesis of eugenol derivatives and its anti-inflammatory activity against skin inflammation

Design and Synthesis of Eugenol Derivatives Bearing a 1,2,3-Triazole Moiety for Papaya Protection against Colletotrichum gloeosporioides

A series of 19 novel eugenol derivatives containing a 1,2,3-triazole moiety was synthesized via a two-step process, with the key step being a copper(I)-catalyzed azide-alkyne cycloaddition reaction. The compounds were assessed for their antifungal activities against Colletotrichum gloeosporioides, the causative agent of papaya anthracnose. Triazoles 2k, 2m, 2l, and 2n, at 100 ppm, were the most effective, reducing mycelial growth by 88.3, 85.5, 82.4, and 81.4%, respectively. Molecular docking calculations allowed us to elucidate the binding mode of these derivatives in the catalytic pocket of C. gloeosporioides CYP51. The best-docked compounds bind closely to the heme cofactor and within the channel access of the lanosterol (LAN) substrate, with crucial interactions involving residues Tyr102, Ile355, Met485, and Phe486. From such studies, the antifungal activity is likely attributed to the prevention of substrate LAN entry by the 1,2,3-triazole derivatives. The triazoles derived from natural eugenol represent a novel lead in the search for environmentally safe agents for controlling C. gloeosporioides.

Eugenol Possesses Colitis Protective Effects: Impacts on the TLR4/MyD88/NF-[Formula: see text]B Pathway, Intestinal Epithelial Barrier, and Macrophage Polarization

Eugenol (EU) has been shown to ameliorate experimental colitis due to its anti-oxidant and anti-inflammatory bioactivities. In this study, DSS-induced acute colitis was established and applied to clarify the regulation efficacy of EU on intestinal barrier impairment and macrophage polarization imbalance along with the inflammatory response. Besides, the adjusting effect of EU on macrophages was further investigated in vitro. The results confirmed that EU intervention alleviated DSS-induced colitis through methods such as restraining weight loss and colonic shortening and decreasing DAI scores. Microscopic observation manifested that EU maintained the intestinal barrier integrity in line with the mucus barrier and tight junction protection. Furthermore, EU intervention significantly suppressed the activation of TLR4/MyD88/NF-[Formula: see text]B signaling pathways and pro-inflammatory cytokines gene expressions, while enhancing the expressions of anti-inflammatory cytokines. Simultaneously, WB and FCM analyses of the CD86 and CD206 showed that EU could regulate the DSS-induced macrophage polarization imbalance. Overall, our data further elucidated the mechanism of EU's defensive effect on experimental colitis, which is relevant to the protective efficacy of intestinal barriers, inhibition of oxidative stress and excessive inflammatory response, and reprogramming of macrophage polarization. Hence, this study may facilitate a better understanding of the protective action of the EU against UC.

Synthesis, anti-amoebic activity and molecular docking simulation of eugenol derivatives against Acanthamoeba sp

Amoebae of the genus Acanthamoeba can cause diseases such as amoebic keratitis and granulomatous amoebic encephalitis. Until now, treatment options for these diseases have not been fully effective and have several drawbacks. Therefore, research into new drugs is needed for more effective treatment of Acanthamoeba infections. Eugenol, a phenolic aromatic compound mainly derived from cloves, has a variety of pharmaceutical properties. In this study, nine eugenol derivatives (K1-K9), consisting of five new and four known compounds, were synthesized and screened for their antiamoebic properties against Acanthamoeba sp. The structure of these compounds was characterized spectroscopically by Fourier transform infrared (FTIR), Ultraviolet-Visible (UV-Vis), 1H and 13C Nuclear Magnetic Resonance (NMR) and mass spectrometer (MS). The derived molecules were screened for antiamoebic activity by determining IC50 values based on 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and observation of amoeba morphological changes by light and fluorescence microscopy. Most of the tested compounds possessed strong to moderate cytotoxic effects against trophozoite cells with IC50 values ranging from 0.61 to 24.83 μg/mL. Observation of amoebae morphology by light microscopy showed that the compounds caused the transformed cells to be roundish and reduced in size. Furthermore, fluorescence microscopy observation using acridine orange (AO) and propidium iodide (PI) (AO/PI) staining showed that the cells have damaged membranes by displaying a green cytoplasm with orange-stained lysosomes. Acidification of the lysosomal structure indicated disruption of the internal structure of Acanthamoeba cells when treated with eugenol derivatives. The observed biological results were also confirmed by interaction simulations based on molecular docking between eugenol derivatives and Acanthamoeba profilin. These interactions could affect the actin-binding ability of the protein, disrupting the shape and mobility of Acanthamoeba. The overall results of this study demonstrate that eugenol derivatives can be considered as potential drugs against infections caused by Acanthamoeba.

Synthesis and anticancer activity of novel Eugenol derivatives against breast cancer cells

Eugenol chemically known as 4-allyl-2-methoxyphenol is a major phenolic component of Syzigium aromaticum and associated with significant biological activities. In the present work, new eugenol 1,2,3-triazole derivatives have been synthesized, characterized using NMR, mass spectrometry, IR, and elemental analysis and screened for their anticancer activity against breast cancer cells. Compound 9, namely 3-(4-((4-allyl-2-methoxyphenoxy)methyl)-1H-1,2,3-triazol-1-yl)-N'-(4-methylbenzoyl) benzohydrazide was found to be the most potent candidate and better than eugenol in exhibiting cytotoxicity with IC₅₀ 6.91 and 3.15 μM, comparable to Doxorubicin with IC₅₀ 6.58 and 3.21 μM against MDA-MB-231 and MCF-7 cells, respectively. Furthermore, compound 9 treated MCF-7 cells as observed by propidium iodide staining significantly increased cell population of S phase and G2 phase to 43.64% and 35.19%, respectively therefore arresting cell cycle at G2 and S phase. These results indicate that eugenol linked 1,2,3-triazole ring could be used as anticancer leads for the treatment of this deadly diseases.

Dissecting dietary and semisynthetic volatile phenylpropenes: A compile of their distribution, food properties, health effects, metabolism and toxicities

Phenylpropenes represent a major subclass of plant volatiles, including eugenol, and (E)-anethole. They contribute to the flavor and aroma of many chief herbs and spices, to exert distinct notes in food, i.e., spicy anise- and clove-like to fruit. Asides from their culinary use, they appear to exert general health effects, whereas some effects are specific, e.g., eugenol being a natural local anesthetic. This review represents the most comprehensive overview of phenylpropenes with respect to their chemical structures, different health effects, and their food applications as flavor and food preservatives. Side effects and toxicities of these compounds represent the second main part of this review, as some were reported for certain metabolites generated inside the body. Several metabolic reactions mediating for phenylpropenes metabolism in rodents via cytochrome P450 (CYP450) and sulfotransferase (SULT) enzymes are presented being involved in their toxicities. Such effects can be lessened by influencing their pharmacokinetics through a matrix-derived combination effect via administration of herbal extracts containing SULT inhibitors, i.e., nevadensin in sweet basil. Moreover, structural modification of phenylpropanes appears to improve their effects and broaden their applications. Hence, such review capitalizing on phenylpropenes can help optimize their applications in nutraceuticals, cosmeceuticals, and food applications.

Tailored Functionalization of Natural Phenols to Improve Biological Activity

Phenols are widespread in nature, being the major components of several plants and essential oils. Natural phenols' anti-microbial, anti-bacterial, anti-oxidant, pharmacological and nutritional properties are, nowadays, well established. Hence, given their peculiar biological role, numerous studies are currently ongoing to overcome their limitations, as well as to enhance their activity. In this review, the functionalization of selected natural phenols is critically examined, mainly highlighting their improved bioactivity after the proper chemical transformations. In particular, functionalization of the most abundant naturally occurring monophenols, diphenols, lipidic phenols, phenolic acids, polyphenols and curcumin derivatives is explored.

4-chloro eugenol interacts synergistically with artesunate against drug resistant P. falciparum inducing oxidative stress

4-chloro eugenol (4CE), a semisynthetic analog of phytomolecule eugenol exhibited potent antiplasmodial activity with IC₅₀ in the range of 1.5-5 μM against sensitive as well as drug resistant strain of P. falciparum. This analog also showed synergy with a clinically used antimalarial drug artesunate and was able to curtail the IC₅₀ of artesunate up to 4-5 folds. Although, 4CE did not show any effect on heme polymerization, the most common drug target in the malaria parasite, it could increase the level of reactive oxygen species (ROS) and reactive nitrogen species (RNS) alone as well as in combination with artesunate. Further, 4CE induced oxidative stress was observed to affect the macromolecules in terms of DNA damage, protein carbonylation and lipid peroxidation. At the physiological level, cellular organelles like mitochondria and endoplasmic reticulum were observed to be get affected by 4CE in terms of membrane depolarization and calcium ion leakage respectively. These observations could be validated by expression analysis of oxidative stress responsive genes and proteins. Further, in in vivo assay, 4CE showed significant chemo-suppression of parasitemia as well as an increase in mean survival time in the murine malaria model. Interestingly, in combination with artesunate, 4CE showed higher chemo-suppression as well as enhanced mean survival time at a much lower concentrations of both the partners as compared to an individual dose of artesunate and 4CE. A combination of 4CE and artesunate was also observed to attenuate cerebral malaria pathogenesis.