Inclusion of vitexin in β-cyclodextrin: preparation, characterization and expectorant/antitussive activities

Examination of the effects of vitexin and vitexin-loaded solid lipid nanoparticles on neuropathic pain and possible mechanisms of action

This research aims to investigate the possible antiallodynic and antihyperalgesic effects of pure vitexin and vitexin-loaded solid lipid nanoparticles (SLN) on neuropathic pain and the pathways mediating these effects. Chronic constriction nerve injury was induced in female rats, and the effects of vitexin at the doses of 5, 10, 20, 40 mg/kg were evaluated. Ketanserin, ondansetron, WAY-100635, yohimbine and bicuculin, which are antagonists of receptors on pain pathways. were used to examine the mechanisms of the effects of vitexin. Pure vitexin exhibited antiallodynic activity at all administered doses, whereas antihyperalgesic activity was not observed at 5 mg/kg vitexin dose. SLN formulation was prepared with 5 mg/kg vitexin, the lowest dose. Vitexin-loaded formulation significantly increased antiallodynic and antihyperalgesic effects. Ondansetron, WAY-100635, yohimbine, and bicuculine antagonized the antiallodynic and antihyperalgesic effects of vitexin. So, it was concluded that serotonin (5-hydroxtryptamine, 5-HT) receptor subtypes 5-HT3 and 5-HT1A, alpha-2 adrenergic, and γ-Aminobutyric acid type A (GABA-A) receptors are involved in the antiallodynic and antihyperalgesic activity of vitexin. In conclusion, vitexin and vitexin-loaded formulation have the potential for clinical use in neuropathic pain management, and different pain pathways contributed to this effect. And also, it is thought that vitexin-loaded SLN formulation is more effective than pure vitexin, which will provide an advantage in treatment.

Vitexin-loaded poly(ethylene glycol) methyl ether-grafted chitosan/alginate nanoparticles: preparation, physicochemical properties and in vitro release behaviors

BACKGROUND

Vitexin, a flavonoid in various foods and medicinal plants, has potential clinical, therapeutic and food applications due to its bioactive properties and beneficial health effects. However, its poor water solubility causes low oral bioavailability and poor absorption in the gastrointestinal tract, limiting its practical applications. Encapsulation is an efficient approach to overcome these limitations. This study demonstrates the encapsulation of vitexin into poly(ethylene glycol) methyl ether-grafted chitosan (mPEG-g-CTS)/alginate (ALG) polyelectrolyte complex nanoparticles.

RESULTS

The vitexin-loaded mPEG-g-CTS/ALG nanoparticles were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy and X-ray diffraction. The vitexin-loaded mPEG-g-CTS/ALG nanoparticles had a spherical shape, 50-200 nm in diameter, and negatively charged surface (-27 to -38 mV). They possessed a loading capacity of 4-60%, encapsulation efficiency of 50-100% and antioxidant activity (30-52% 2,2-diphenyl-1-picrylhydrazyl decoloration) when their initial vitexin content was 0.02-0.64 g g-1 polymers. Successful vitexin loading into mPEG-g-CTS/ALG nanoparticles was also indirectly confirmed by the enhanced thermal stability of both polymers and the residual soybean oil used in the emulsion preparation step and delayed oxidative degradation of the residual soybean oil. Vitexin's in vitro release from the mPEG-g-CTS/ALG nanoparticles was very fast in phosphate buffer at pH 11, followed by pH 7, and very slow in acetate buffer at pH 3. The gastrointestinal digestion of vitexin increased by encapsulating into mPEG-g-CTS/ALG nanoparticles.

CONCLUSIONS

Vitexin-loaded mPEG-g-CTS/ALG nanoparticles were successfully fabricated using a two-step process of oil-in-water emulsion and ionic gelation without the use of pungent odor acids and other crosslinkers. The obtained nanoparticles are suitable for oral intestinal-specific delivery systems. © 2023 Society of Chemical Industry.

Flavonoids in the Spotlight: Bridging the Gap between Physicochemical Properties and Formulation Strategies

Flavonoids are hydroxylated polyphenols that are widely distributed in plants with diverse health benefits. Despite their popularity, the bioavailability of flavonoids is often overlooked, impacting their efficacy and the comparison of products. The study discusses the bioavailability-related physicochemical properties of flavonoids, with a focus on the poorly soluble compounds commonly found in dietary supplements and herbal products. This review sums up the values of pKa, log P, solubility, permeability, and melting temperature of flavonoids. Experimental and calculated data were compiled for various flavonoid subclasses, revealing variations in their physicochemical properties. The investigation highlights the challenges posed by poorly soluble flavonoids and underscores the need for enabling formulation approaches to enhance their bioavailability and therapeutic potential. Compared to aglycones, flavonoid glycosides (with sugar moieties) tend to be more hydrophilic. Most of the reviewed aglycones and glycosides exhibit relatively low log P and high melting points, making them "brick dust" candidates. To improve solubility and absorption, strategies like size reduction, the potential use of solid dispersions and carriers, as well as lipid-based formulations have been discussed.

Pachira macrocarpa Schltdl. & Cham., HPLC Profile, and Neuroprotective Potential via Regulation of JNK, miRNA132, and miRNA-125b

In this study, we investigated the polyphenolic profile of Pachira macrocarpa Schltdl. & Cham. by HPLC analysis and we also isolated three compounds from the ethyl acetate leaf extract, which were identified by different spectral data as vitexin 1, luteolin 2, and ferulic acid 3. Moreover, we investigated the three isolated compounds and the plant extract for their therapeutic potential against AlCl3 exposure-induced neurotoxicity in rats. This investigation aims to determine whether vitexin, luteolin, and ferulic acid in Pachira macrocarpa Schltdl. & Cham. extract (P. macrocarpa) have the ability to treat AlCl3-induced brain toxicity in rats. Six groups of rats were created: group 1 (normal group), group 2 treated with AlCl3, and groups 3, 4, 5, and 6 treated with AlCl3 with vitexin, luteolin, ferulic acid, and P. macrocarpa extract, respectively, for 28 days. Neurotoxicity was assessed by measuring plasma IL-8 and IL-33 as well as brain superoxide dismutase (SOD), glutathione reductase (GSR), B-cell lymphoma-2 (BcL-2), B-cell lymphoma-2 associated-x (Bax), and neurogranin using the ELISA technique and c-Jun N-terminal kinase (JNK), miRNA-125b, and miRNA-132 levels using western blot and PCR. HPLC analysis identified major phenolics and flavonoids. Among the phenolics identified, chlorogenic acid was prevalent (2159.14 μg/g), and regarding flavonoids, rutin was prevalent (204.69 μg/g). A significant elevation of IL-8 and IL-33 as well as brain Bax, neurogranin, and JNK levels and of miRNA-125b gene expression levels was observed following AlCl3 exposure. However, significant depletion of SOD, GSR, BcL-2, total protein, and miRNA-132 gene expression was observed in AlCl3-treated rats. Administration of the P. macrocarpa extract and its isolated compounds significantly increased SOD, GSR, BcL-2, total protein, and miRNA132 gene expression and decreased IL-8 and IL-33 as well as brain Bax, neurogranin, and JNK levels and brain miRNA-125b gene expression compared to AlCl3-treated rats. P. macrocarpa extract and its isolated compounds ameliorated AlCl3-induced oxidative stress and neurotoxicity in rats.

Fabrication and characterization of nanoemulsions for encapsulation and delivery of vitexin: antioxidant activity, storage stability and in vitro digestibility

BACKGROUND

Nanoemulsions were prepared as an encapsulation and delivery system for vitexin, a poorly water-soluble antioxidant. This study evaluated how the type and concentration of the dispersed oil phase and vitexin loading impacted droplet characteristics and nanoemulsion stability. The influences of storage temperature on antioxidant activity and in vitro gastrointestinal digestion on nanoemulsion stability were also investigated.

RESULTS

Nanoemulsions prepared at different dispersed oil concentrations showed diverse characteristics and stability. Highest stability against droplet aggregation and phase separation with small oil droplets (< 150 nm) was observed for nanoemulsions prepared using 300 g kg^-1 medium-chain triglyceride oil. These nanoemulsions are able to entrap and deliver vitexin with high encapsulation efficiency (88-90%) with no significant effect on emulsion stability. Vitexin-loaded nanoemulsions were stable during storage when refrigerated (4 °C) and at room temperature (25 °C) for up to 45 days with no effect on their antioxidant activity. Significantly delayed lipolysis rate and decreased extent of lipid digestion were observed in vitexin-loaded nanoemulsions.

CONCLUSIONS

Stable vitexin-loaded nanoemulsions were successfully produced by high-pressure homogenization using a mixture of Tween 80 and lecithin as emulsifiers. Vitexin-loaded nanoemulsions stabilized with a mixture of these two emulsifiers were effective in retaining antioxidant activity during storage and protecting vitexin from changes during gastrointestinal digestion. Our results suggested that nanoemulsions were effective vitexin delivery systems for food applications. © 2022 Society of Chemical Industry.

Dermal Drug Delivery of Phytochemicals with Phenolic Structure via Lipid-Based Nanotechnologies

Phenolic compounds are a large, heterogeneous group of secondary metabolites found in various plants and herbal substances. From the perspective of dermatology, the most important benefits for human health are their pharmacological effects on oxidation processes, inflammation, vascular pathology, immune response, precancerous and oncological lesions or formations, and microbial growth. Because the nature of phenolic compounds is designed to fit the phytochemical needs of plants and not the biopharmaceutical requirements for a specific route of delivery (dermal or other), their utilization in cutaneous formulations sets challenges to drug development. These are encountered often due to insufficient water solubility, high molecular weight and low permeation and/or high reactivity (inherent for the set of representatives) and subsequent chemical/photochemical instability and ionizability. The inclusion of phenolic phytochemicals in lipid-based nanocarriers (such as nanoemulsions, liposomes and solid lipid nanoparticles) is so far recognized as a strategic physico-chemical approach to improve their in situ stability and introduction to the skin barriers, with a view to enhance bioavailability and therapeutic potency. This current review is focused on recent advances and achievements in this area.

Cyclodextrin Monomers and Polymers for Drug Activity Enhancement

Cyclodextrins (CDs) and cyclodextrin (CD)-based polymers are well-known complexing agents. One of their distinctive features is to increase the quantity of a drug in a solution or improve its delivery. However, in certain instances, the activity of the solutions is increased not only due to the increase of the drug dose but also due to the drug complexation. Based on numerous studies reviewed, the drug appeared more active in a complex form. This review aims to summarize the performance of CDs and CD-based polymers as activity enhancers. Accordingly, the review is divided into two parts, i.e., the effect of CDs as active drugs and as enhancers in antimicrobials, antivirals, cardiovascular diseases, cancer, neuroprotective agents, and antioxidants.