Host-guest complexation of eugenol in cyclodextrins for enhancing bioavailability

Cyclodextrin Inclusion Complexes for Improved Drug Bioavailability and Activity: Synthetic and Analytical Aspects

Many active pharmaceutical ingredients show low oral bioavailability due to factors such as poor solubility and physical and chemical instability. The formation of inclusion complexes with cyclodextrins, as well as cyclodextrin-based polymers, nanosponges, and nanofibers, is a valuable tool to improve the oral bioavailability of many drugs. The microencapsulation process modifies key properties of the included drugs including volatility, dissolution rate, bioavailability, and bioactivity. In this context, we present relevant examples of the stabilization of labile drugs through the encapsulation in cyclodextrins. The formation of inclusion complexes with drugs belonging to class IV in the biopharmaceutical classification system as an effective solution to increase their bioavailability is also discussed. The stabilization and improvement in nutraceuticals used as food supplements, which often have low intestinal absorption due to their poor solubility, is also considered. Cyclodextrin-based nanofibers, which are polymer-free and can be generated using environmentally friendly technologies, lead to dramatic bioavailability enhancements. The synthesis of chemically modified cyclodextrins, polymers, and nanosponges based on cyclodextrins is discussed. Analytical techniques that allow the characterization and verification of the formation of true inclusion complexes are also considered, taking into account the differences in the procedures for the formation of inclusion complexes in solution and in the solid state.

Assessment of host-guest molecular encapsulation of eugenol using β-cyclodextrin

Eugenol is a natural compound with well-known repellent activity. However, its pharmaceutical and cosmetic applications are limited, since this compound is highly volatile and thermolabile. Nanoencapsulation provides protection, stability, conservation, and controlled release for several compounds. Here, eugenol was included in β-cyclodextrin, and the complex was characterized through X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Additionally, we used molecular dynamics simulations to explore the eugenol-β-cyclodextrin complex stability with temperature increases. Our computational result demonstrates details of the molecular interactions and conformational changes of the eugenol-β-cyclodextrin complex and explains its stability between temperatures 27°C and 48°C, allowing its use in formulations that are subjected to varied temperatures.

Tumor Targeting and pH-Sensitive Inclusion Complex Based on HP-β-CD as a Potential Carrier for Paclitaxel: Fabrication, Molecular Docking, and Characterization

In this study, a tumor-targeting and pH-sensitive inclusion complex based on the host-guest recognition between the chitosan and folic acid grafted HP-β-CD (FA-CS-CD) and stearic acid modified 2-benzimidazolemethanol (BM-SA) was designed and fabricated for the controlled delivery of paclitaxel (PTX). Through the combination of computational simulations and experiments, the interaction between FA-CS-CD, BM-SA, and PTX was investigated, and the optimized preparation method was obtained. For the optimized PTX-loaded FA-CS-CD/BM-SA inclusion complex, the particle size and zeta potential were 146 nm and +15.4 mV, respectively. In vitro drug release study revealed the pH-triggered drug release behavior of the inclusion complex. Both in vitro and in vivo evaluations demonstrated that the PTX-loaded FA-CS-CD/BM-SA inclusion complex exhibited enhanced antitumor efficiency and minimized systemic toxicity. This system might be a promising carrier for PTX.

Mannosylated Systems for Targeted Delivery of Antibacterial Drugs to Activated Macrophages

Macrophages are a promising target for drug delivery to influence macrophage-associated processes in the body, namely due to the presence of resistant microorganisms in macrophages. In this work, a series of mannosylated carriers based on mannan, polyethylenimine (PEI) and cyclodextrin (CD) was synthesized. The molecular architecture was studied using FTIR and ¹H NMR spectroscopy. The particle size, from small 10-50 nm to large 500 nm, depending on the type of carrier, is potentially applicable for the creation of various medicinal forms: intravenous, oral and inhalation. Non-specific capture by cells with a simultaneous increase in selectivity to CD206+ macrophages was achieved. ConA was used as a model mannose receptor, binding galactosylated (CD206 non-specific) carriers with constants of the order of 10⁴ M^-1 and mannosylated conjugates of 10⁶-10⁷ M^-1. The results of such primary "ConA-screening" of ligands are in a good agreement in terms of the comparative effectiveness of the interaction of ligands with the CD206+ macrophages: non-specific (up to 10%) absorption of highly charged and small particles; weakly specific uptake of galactosylated polymers (up to 50%); and high affine capture (more than 70-80%) of the ligands with grafted trimannoside was demonstrated using the cytometry method. Double and multi-complexes of antibacterials (moxifloxacin with its adjuvants from the class of terpenoids) were proposed as enhanced forms against resistant pathogens. In vivo pharmacokinetic experiments have shown that polymeric carriers significantly improve the efficiency of the antibiotic: the half-life of moxifloxacin is increased by 2-3 times in conjugate-loaded forms, bio-distribution to the lungs in the first hours after administration of the drug is noticeably greater, and, after 4 h of observation, free moxifloxacin was practically removed from the lungs of rats. Although, in polymer systems, its content is significant-1.2 µg/g. Moreover, the importance of the covalent crosslinking carrier with mannose label was demonstrated. Thus, this paper describes experimental, scientifically based methods of targeted drug delivery to macrophages to create enhanced medicinal forms.

A comprehensive and systematic review on potential anticancer activities of eugenol: From pre-clinical evidence to molecular mechanisms of action

BACKGROUND

Eugenol (1-allyl-4-hydroxy-3-methoxybenzene) is an important simple phenolic compound mainly derived from Syzygium aromaticum and many other plants. It is traditionally used in ayurveda and aromatherapy for the healing of many health problems. It also has significant applications in dentistry, agriculture, and flavour industry. This simple phenol has an eclectic range of pharmacological properties, such as antioxidant, anti-inflammatory, and anticancer activities. It is regarded as safe by the Food and Agricultural Organization of the United Nations due to its non-carcinogenic and non-mutagenic properties.

PURPOSE

The aim of this comprehensive review is to present a critical and systematic assessment of the antitumor ability of eugenol and its associated molecular targets in various cancers.

METHODS

It was carried out following the preferred reporting items for systematic reviews and meta-analysis guidelines. Risk of bias assessment was performed using the SYstematic review centre for laboratory animal experimentation guidelines. The literature search was performed in standard databases such as Science Direct, PubMed, Google Scholar, Scopus, and Web of Science using the keywords 'eugenol' or 'eugenol essential oil' and 'anti-cancer properties of eugenol'.

RESULTS

The scientific information from fifty-three studies was encompassed in the present review work. Eugenol exhibits significant anticancer effects in a variety of biological pathways, namely apoptosis, autophagy, cell cycle progression, inflammation, invasion, and metastasis. Eugenol-induced apoptosis has been noticed in osteosarcoma, skin tumors, melanoma, leukemia, gastric and mast cells. It decreases the expression of cyclin D1, cyclin B, proliferating cell nuclear antigen, nuclear factor-ƙB, inhibitor of nuclear factor ƙB, and B-cell lymphoma-2. Eugenol increases the expression of B-cell lymphoma-2 (BCL-2) associated X, BH3-interacting domain death agonist, BCL-2 associated agonist of cell death, apoptotic protease activating factor 1, cytochrome c, p21, and p53.

CONCLUSION

The anticancer potential exhibited by eugenol is mainly attributed to its anti-metastatic, anti-proliferative, anti-angiogenic, anti-inflammatory, cell cycle arrest, apoptotic, and autophagic effects. Hence, the use of eugenol alone or along with other chemotherapeutic anticancer agents is found to be very effective in cancer therapy.

Antibacterial Mechanism of Eugenol Against Shigella sonnei and Its Antibacterial Application in Lettuce Juice

Shigella sonnei is a species of Shigella, and the infection rate of S. sonnei is increasing year by year. Eugenol is an active ingredient in clove essential oil and is a generally recognized as safe (GRAS)-certified food ingredient. The mechanism of inhibition of S. sonnei by eugenol has been investigated in this study. The minimum inhibitory concentration of eugenol against both S. sonnei ATCC 25931 and S. sonnei CMCC 51592 was 0.5 mg/mL and minimum bactericidal concentration (MBC) for both strains was 0.8 mg/mL. The inhibition effect of eugenol against S. sonnei was due to increased levels of reactive oxygen species in cells, changed cell membrane permeability, and induced cell membrane dysfunction, for instance, cell membrane hyperpolarization and intracellular ATP concentration drops. The results of confocal laser scanning microscope and field emission scanning electron microscopy showed that eugenol leads to decreased cell membrane integrity, resulting in changed cell morphology. Moreover, eugenol inactivated S. sonnei in Luria-Bertani (LB) broth and lettuce juice. These results indicated that eugenol could inactivate S. sonnei and has the potential to control S. sonnei in the food industry.

Mannosylated Polymeric Ligands for Targeted Delivery of Antibacterials and Their Adjuvants to Macrophages for the Enhancement of the Drug Efficiency

Bacterial infections and especially resistant strains of pathogens localized in macrophages and granulomas are intractable diseases that pose a threat to millions of people. In this paper, the theoretical and experimental foundations for solving this problem are proposed due to two key aspects. The first is the use of a three-component polymer system for delivering fluoroquinolones to macrophages due to high-affinity interaction with mannose receptors (CD206). Cytometry assay determined that 95.5% macrophage-like cells were FITC-positive after adding high-affine to CD206 trimannoside conjugate HPCD-PEI1.8-triMan, and 61.7% were FITC-positive after adding medium-affine ligand with linear mannose label HPCD-PEI1.8-Man. The second aspect is the use of adjuvants, which are synergists for antibiotics. Using FTIR and NMR spectroscopy, it was shown that molecular containers, namely mannosylated polyethyleneimines (PEIs) and cyclodextrins (CDs), load moxifloxacin (MF) with dissociation constants of the order of 10⁻⁴–10⁻⁶ M; moreover, due to prolonged release and adsorption on the cell membrane, they enhance the effect of MF. Using CLSM, it was shown that eugenol (EG) increases the penetration of doxorubicin (Dox) into cells by an order of magnitude due to the creation of defects in the bacterial wall and the inhibition of efflux proteins. Fluorescence spectroscopy showed that 0.5% EG penetrates into bacteria and inhibits efflux proteins, which makes it possible to increase the maximum concentration of the antibiotic by 60% and maintain it for several hours until the pathogens are completely neutralized. Regulation of efflux is a possible way to overcome multiple drug resistance of both pathogens and cancer cells.

Encapsulated hydroxychloroquine and chloroquine into cyclic oligosaccharides are the potential therapeutics for COVID-19: insights from first-principles calculations

Novel-Coronavirus (COVID-19) outburst has become a worldwide pandemic which threaten the scientific community to design and discover efficient and effective treatment strategies against this deadly virus (SARS-CoV-2). Still now, there is no antiviral therapy or drug available in the market which can efficiently combat the infection caused by this virus. In this respect, using available drugs by screening with molecular docking and molecular dynamics studies not only minimizes lengthy chemical trials but also reduces discovery cost for the pharmaceutical industry. During the COVID-19 pandemic situations hydroxychloroquine, chloroquine known as HCQ and CQ tablets have gained popularity as for the treatment coronavirus (COVID-19) but the main threatening effect of HCQ, CQ use lies on their side effects like blistering, peeling, loosening of the skin, blurred vision stomach pain, diarrhea, chest discomfort, pain, or tightness, cough or hoarseness which require immediate medical attention. Encapsulation of HCQ and CQ drugs by the cyclic macromolecules such as α and β-Cyclodextrin, to form host-guest complexes is very effective strategy to mask the cytotoxicity of certain drugs and alleviating and modulating side effects of drug applications. In the present work, we have encapsulated the HCQ and CQ drugs α and β-Cyclodextrin and made a comprehensive analysis of stability, optical properties. Details analysis verified that between QC and HCQ, HQC showed stronger affinity towards β-Cyclodextrin. This strategy can reduce the side effect of HCQ and CQ thereby offers a new way to use these drugs. We hope the present study should help the researchers to develop potential therapeutics against the novel coronavirus.

Cinnamaldehyde and eugenol protect against LPS-stimulated oxidative stress and inflammation in Raw 264.7 cells

Macrophages are leukocytes that play a strategic role in immune response and can be associated with various diseases due to their effects on the inflammation process and oxidative events. The current study was evaluated the anti-inflammatory and antioxidant properties of cinnamaldehyde and eugenol, which are phyto-compounds with numerous bioactive properties, on lipopolysaccharide (LPS)-induced macrophage cells. For this purpose, Raw 264.7 cells were incubated with cinnamaldehyde or eugenol (15, 25, and 50 μM) then stimulated with LPS. After 24 hr, tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and IL-6 levels (as inflammatory mediators), and malondialdehyde (MDA) and nitric oxide (NOx) levels as well as superoxide dismutase (SOD) and catalase (CAT) activities (as oxidative status markers) were determined in cell cultures. Cinnamaldehyde and eugenol pre-treatments decreased TNF-α, IL-1β, and IL-6 levels as compared to LPS group at all concentrations. Furthermore, these pre-treatments increased SOD activity while decreased MDA and NOx levels as well as CAT activity at different concentrations. Our results demonstrated that these phyto-compounds have potential for the treatment of various diseases as protective agents against chronic inflammation and oxidative stress. PRACTICAL APPLICATIONS: Chronic inflammation and oxidative stress are complications that play a detrimental role in the pathophysiology of many diseases. Alternative treatment methods have been investigated to prevent them. Cinnamaldehyde and eugenol are phyto-compounds with high bioactivity that can be obtained from foods and spices. In this study, the protective effects of cinnamaldehyde and eugenol on lipopolysaccharide-induced oxidative stress and inflammation in macrophage cells were investigated. According to the obtained results, cinnamaldehyde and eugenol pre-treatments decreased inflammation and also reduced oxidative stress. Cinnamaldehyde and eugenol may be a better natural alternative protective agent for the chronic inflammation- and oxidative stress-related diseases.

Self-assembly behavior of oligo(ethylene glycol) substituted polycaprolactone homopolymers

In this work, non-ionic amphiphilic oligo(ethylene glycol)-substituted polycaprolactone homopolymers readily self-assembled to form micelles in a polar environment, which allowed the encapsulation of a hydrophobic molecule.