Oxyresveratrol: Sources, Productions, Biological Activities, Pharmacokinetics, and Delivery Systems

Maclura cochinchinensis (Lour.) Corner Heartwood Extracts Containing Resveratrol and Oxyresveratrol Inhibit Melanogenesis in B16F10 Melanoma Cells

This study aimed to isolate and purify resveratrol and oxyresveratrol from the heartwoods of Maclura cochinchinensis, and to evaluate their inhibitory effects on melanogenesis in B16F10 murine melanoma cells. A methanol maceration process yielded a crude extract comprising 24.86% of the initial mass, which was subsequently analyzed through HPTLC, HPLC, and LC-MS/MS. These analyses revealed the presence of resveratrol and oxyresveratrol at concentrations of 4.32 mg/g and 33.6 mg/g in the extract, respectively. Initial purification employing food-grade silica gel column chromatography separated the extract into two fractions: FA, exhibiting potent inhibition of both tyrosinase activity and melanogenesis, and FM, showing no such inhibitory activity. Further purification processes led to the isolation of fractions Y11 and Gn12 with enhanced concentrations of resveratrol (94.9 and 110.21 mg/g, respectively) and fractions Gn15 and Gn16 with elevated levels of oxyresveratrol (321.93 and 274.59 mg/g, respectively), all of which significantly reduced melanin synthesis. These outcomes affirm the substantial presence of resveratrol and oxyresveratrol in the heartwood of M. cochinchinensis, indicating their promising role as natural agents for skin lightening.

Enhancing the Bioavailability of Resveratrol: Combine It, Derivatize It, or Encapsulate It?

Overcoming the limited bioavailability and extensive metabolism of effective in vitro drugs remains a challenge that limits the translation of promising drugs into clinical trials. Resveratrol, despite its well-reported therapeutic benefits, is not metabolically stable and thus has not been utilized as an effective clinical drug. This is because it needs to be consumed in large amounts to overcome the burdens of bioavailability and conversion into less effective metabolites. Herein, we summarize the more relevant approaches to modify resveratrol, aiming to increase its biological and therapeutic efficacy. We discuss combination therapies, derivatization, and the use of resveratrol nanoparticles. Interestingly, the combination of resveratrol with established chemotherapeutic drugs has shown promising therapeutic effects on colon cancer (with oxaliplatin), liver cancer (with cisplatin, 5-FU), and gastric cancer (with doxorubicin). On the other hand, derivatizing resveratrol, including hydroxylation, amination, amidation, imidation, methoxylation, prenylation, halogenation, glycosylation, and oligomerization, differentially modifies its bioavailability and could be used for preferential therapeutic outcomes. Moreover, the encapsulation of resveratrol allows its trapping within different forms of shells for targeted therapy. Depending on the nanoparticle used, it can enhance its solubility and absorption, increasing its bioavailability and efficacy. These include polymers, metals, solid lipids, and other nanoparticles that have shown promising preclinical results, adding more "hype" to the research on resveratrol. This review provides a platform to compare the different approaches to allow directed research into better treatment options with resveratrol.

Dietary Polyphenols: Review on Chemistry/Sources, Bioavailability/Metabolism, Antioxidant Effects, and Their Role in Disease Management

Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.

Hypoglycemic effects and associated mechanisms of resveratrol and related stilbenes in diet

Hyperglycemia has become a global health problem due to changes in diet and lifestyle. Most importantly, persistent hyperglycemia can eventually develop into type II diabetes. While the usage of current drugs is limited by their side effects, stilbenes derived from fruits and herbal/dietary plants are considered as important phytochemicals with potential hypoglycemic properties. Herein, the most common stilbenoids in consumed foods, i.e. resveratrol, pterostilbene, piceatannol, oxyresveratrol, and 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucopyranoside (THSG), are reviewed in this paper. These stilbenes are found to regulate glucose homeostasis via (a) modulation of feeding behaviour and nutrition absorption; (b) restoration of insulin signalling by enhancing insulin production/insulin sensitivity; (c) improvement of gut permeability, gut microbial profile and resulting metabolomes; and (d) amelioration of circadian rhythm disruption. In this review, we have summarized the underlying mechanisms for the hypoglycemic effects of the five most common dietary stilbenoids listed above, providing a comprehensive framework for future study and applications.

Phytochemicals as treatment for allergic asthma: Therapeutic effects and mechanisms of action

BACKGROUND

Allergic asthma is an inflammatory disease caused by the immune system's reaction to allergens, inflammation and narrowing of the airways, and the production of more than normal mucus. One of the main reasons is an increased production of inflammatory cytokines in the lungs that leads to the appearance of symptoms of asthma, including inflammation and shortness of breath. On the other hand, it has been proven that phytochemicals with their antioxidant and anti-inflammatory properties can be useful in improving allergic asthma.

PURPOSE

Common chemical treatments for allergic asthma include corticosteroids, which have many side effects and temporarily relieve symptoms but are not a cure. Therefore, taking the help of natural compounds to improve the quality of life of asthmatic patients can be a valuable issue that has been evaluated in the present review.

STUDY DESIGN AND METHODS

In this study, three databases (Scopus, PubMed, and Cochrane) with the keywords: allergic asthma, phytochemical, plant, and herb were evaluated. The primary result was 5307 articles. Non-English, repetitive, and review articles were deleted from the study.

RESULTS AND DISCUSSION

Finally, after carefully reading the articles, 102 were included in the study (2006-2022). The results of this review state that phytochemicals suppress the inflammatory pathways via inhibition of inflammatory cytokines production/secretion, genes, and proteins involved in the inflammation process, reducing oxidative stress indicators and symptoms of allergic asthma, such as cough and mucus production in the lungs.

CONCLUSION

With their antioxidant effects, this study concluded that phytochemicals suppress cytokines and other inflammatory indicators and thus can be considered an adjunctive treatment for improving allergic asthma.

Inhibitory actions of oxyresveratrol on the PI3K/AKT signaling cascade in cervical cancer cells

The phosphatidyl inositol 3-kinase (PI3K)/AKT signaling plays a critical role in cancer cell proliferation, migration, and invasion. This signal transduction axis in HPV-positive cervical cancer has been proved to be directly activated by E6/E7 proteins of the virus enhancing cervical cancer progression. Hence, the PI3K/AKT pathway is one of the key therapeutic targets for HPV-positive cervical cancer. Here we discovered that oxyresveratrol (Oxy) at noncytotoxic concentration specifically suppressed the phosphorylation of AKT but not ERK1/2. This potent inhibitory effect of Oxy was still observed even when cells were stimulated with fetal bovine serum. Inhibition of AKT phosphorylation at serine 473 by Oxy resulted in a significant decrease in serine 9 phosphorylation of GSK-3β, a downstream target of AKT. Dephosphorylation of GSK-3β at this serine residue activates its function in promoting the degradation of MCL-1, an anti-apoptotic protein. Results clearly demonstrated that in association with GSK-3β activation, Oxy preferentially downregulated the expression of anti-apoptotic protein MCL-1. Furthermore, results from the functional analyses revealed that Oxy inhibited cervical cancer cell proliferation, at least in part through suppressing nuclear expression of Ki-67. Besides, the compound retarded cervical cancer cell migration even the cells were exposed to a potent enhancer of epithelial-mesenchymal transition, TGF-β1. In consistent with these data, Oxy reduced the expression of β-catenin, N-cadherin, and vimentin. In conclusion, the study disclosed that Oxy specifically inhibits the AKT/GSK-3β/MCL-1 axis resulting in reduction in cervical cancer cell viability, proliferation, and migration.

Resveratrol Derivatives Inhibit Transthyretin Fibrillization: Structural Insights into the Interactions between Resveratrol Derivatives and Transthyretin

Hereditary ATTR amyloidosis is a disease caused by the deposition of amyloid fibrils formed by mutated transthyretin (TTR), a protein that binds to thyroid hormone in the serum, in the organs. The development of a small molecule that binds to and stabilizes TTR is a promising strategy for the treatment of ATTR amyloidosis. In the present study, we demonstrated that the resveratrol derivatives including pterostilbene available as a dietary supplement inhibit the fibrillization of V30M-TTR to the same extent as the approved drug tafamidis. Furthermore, based on a thermodynamic and X-ray crystallographic analysis, the binding of the resveratrol derivative to TTR was shown to be enthalpy-driven, with the binding enthalpy being acquired by hydrogen bonding to S117. Moreover, direct observation of hydrogen atoms by neutron crystallography provided details of the hydrogen bond network by S117 and emphasized the importance of the CH···π interaction by L110 in the ligand binding.

Untargeted metabolomics reveal pathways associated with neuroprotective effect of oxyresveratrol in SH-SY5Y cells

Oxyresveratrol has been documented benefits for neurodegenerative disease. However, the specific molecular mechanisms and pathways involved is currently limited. This study aimed to investigate the potential neuroprotective mechanisms of oxyresveratrol using rotenone-induced human neuroblastoma SH-SY5Y cytotoxicity. Cells were divided into the following groups: control, rotenone, and oxyresveratrol pre-treated before being exposed to rotenone. Cellular assays were performed to investigate neuroprotective effects of oxyresveratrol. The results showed that 20 μM oxyresveratrol was effective in preventing rotenone-induced cell death and decreasing ROS levels in the cells. The alteration of metabolites and pathways involved in the neuroprotective activities of oxyresveratrol were further investigated using LC-QTOF-MS/MS untargeted metabolomics approach. We hypothesized that oxyresveratrol's neuroprotective effects would be associated with neurodegenerative pathways. A total of 294 metabolites were identified. 7,8-dihydrobiopterin exhibited the highest VIP scores (VIP > 3.0; p < 0.05), thus considered a biomarker in this study. Our results demonstrated that pretreatment with oxyresveratrol upregulated the level of 7,8-dihydrobiopterin compared to the positive control. Pathway analysis verified that 7,8-dihydrobiopterin was primarily associated with phenylalanine, tyrosine, and tryptophan metabolism (impact = 1, p < 0.001), serving as essential cofactors for enzymatic function in the dopamine biosynthesis pathway. In conclusion, oxyresveratrol may be benefit for the prevention of neurodegenerative diseases by increasing 7,8-dihydrobiopterin concentration.

Ultrafast non-adiabatic dynamics of stilbene-based plant-derived sunscreens with cis-trans isomerization structures

In this work, we investigated the potential UV protection mechanism of the natural compounds hydroxy resveratrol and pterostilbene by combining theoretical calculations and femtosecond transient absorption spectra (FTAS). The UV absorption spectra showed that the two compounds exhibited strong absorption properties and high photostability. We found two molecules will reach the S₁ state or an even higher excited state after UV exposure and molecules in S₁ will cross a lower energy barrier to reach the conical intersection. The adiabatic trans-cis isomerization process happened and finally return to the ground. Meanwhile, FTAS clarified the time scale of trans-cis isomerization of two molecules was ∼ 10 ps, which also met the requirement of fast energy relaxation. This work also provides theoretical guidance for developing new sunscreen molecules from natural stilbene.

Antioxidant, Anti-Tyrosinase, and Anti-Skin Pathogenic Bacterial Activities and Phytochemical Compositions of Corn Silk Extracts, and Stability of Corn Silk Facial Cream Product

Zea mays L. Poaceae stigma (corn silk, CS) is a byproduct of agricultural waste and is used as a traditional herb in many countries. CS is rich in chemical compounds known to benefit human health and is also a remedy for infectious diseases and has anti-proliferative effects on human cancer cell lines. In the present study, CS extract has been evaluated for its antioxidant, antibacterial, and anti-tyrosinase activities and its phytochemical composition. The higher total phenolic and flavonoid contents were found in the ethanolic extract of corn silk (CSA), at 28.27 ± 0.86 mg gallic acid equivalent/g extract and 4.71 ± 0.79 mg quercetin equivalent/g extract, respectively. Moreover, the antioxidant content of CSA was found at 5.22 ± 0.87 and 13.20 ± 0.42 mg gallic acid equivalent/g extract using DPPH and reducing power assays. Furthermore, the ethanolic extract of corn silk showed tyrosinase inhibition with an IC50 value of 12.45 µg/mL. The bacterial growth inhibition of CSA was tested using agar disc diffusion and broth dilution assays against Cutibacterium acnes and Staphylococcus epidermidis. It was found that CSA inhibited C. acnes and S. epidermidis with an inhibition zone of 11.7 ± 1.2 and 9.3 ± 0.6 mm, respectively. Moreover, the CSA showed MIC/MBC of 15.625 mg/mL against C. acnes. The following phytochemical compounds were detected in CSA: cardiac glycosides; n-hexadecanoic acid; hexadecanoic acid, ethyl ester; oleic acid; and 9,12-octadecadienoic acid, ethyl ester. After the corn silk cream product was formulated, the product demonstrated stability without phase separation. This research is beneficial for promoting effective ways to use agricultural waste while utilizing the antioxidant, anti-tyrosinase, and antibacterial activities of corn silk. Moreover, the use of technology and innovation to obtain high-value CS extract will benefit the development of commercial cosmetic products by providing safe, natural, and quality ingredients to the consumer.

Non-ionic surfactant-assisted controlled release of oxyresveratrol on dendritic fibrous silica for topical applications

We present a simple and eco-friendly method for controlled drug release using a surfactant-assisted method. Oxyresveratrol (ORES) was co-loaded with a non-ionic surfactant onto KCC-1, a dendritic fibrous silica, using an ethanol evaporation technique. The carriers were characterized using FE-SEM, TEM, XRD, N₂ adsorption-desorption, FTIR, and Raman spectroscopy, and the loading and encapsulation efficiencies were assessed using TGA and DSC techniques. Contact angle and zeta potential were used to determine the surfactant arrangement and the particle charges. To investigate the effects of different surfactants (Tween 20, Tween 40, Tween 80, Tween 85, and Span 80) on ORES release, we conducted experiments under different pH and temperature conditions. Results showed that the types of surfactants, drug loading content, pH, and temperature significantly affected the drug release profile. The percentage of drug loading efficiency of the carriers was in the range of 80 %-100 %, and the release of ORES was in the order of M/KCC-1 > M/K/S80 > M/K/T40 > M/K/T20 > MK/T80 > M/K/T85 at 24 h. Furthermore, the carriers provided excellent protection for ORES against UVA and maintained its antioxidant activity. KCC-1 and Span 80 enhanced the cytotoxicity to HaCaT cells, while Tween 80 suppressed the cytotoxicity.

Collagenase and Tyrosinase Inhibitory Activities and Stability of Facial Cream Formulation Containing Cashew Leaf Extract

The cashew tree (Anacardium occidentale L.) is a tropical plant found widely in many Southeast Asian countries, including Thailand, and contains bioactive phenolic compounds with antioxidant activity. The natural antioxidants such as collagenase and tyrosinase inhibitors found in medicinal plants are promising agents in cosmetic products. This study evaluated the inhibitory activities of the collagenase and tyrosinase from cashew leaf extracts by developing and evaluating the stability of facial cream formulations. The ethanol (DEN), ethyl acetate (DEA) and distilled water (DDW) crude extracts of cashew leaves were investigated for their bioactive compound efficacy. The DDW extract had the highest yield (24.97%). All the extracts were investigated for their antioxidant activities. The DEN extract showed the highest DPPH radical-scavenging ability, ferric-reducing power and flavonoid compounds, which were 152.04 ± 2.40 mg gallic acid/g extract, 37.90 ± 1.07 mg gallic acid/g dry weight and 7.63 ± 0.07 mg quercetin/g dry weight, respectively. The DDW extract exhibited the highest potent activity, which was 111.00 ± 0.78 mg gallic acid/g dry weight in terms of phenolic content, while the DEN extract showed the highest tyrosinase inhibition at 0.100 mg/mL (46.97 ± 3.34%) and collagenase activity at 40 µg/mL. The results suggested that the ethanolic extracts from cashew leaves showed promise for use in skincare product development. Cosmeceutical formulations for skincare were prepared. The formula mixed with DEN extract and added to whitening and anti-aging skincare cream demonstrated good stability and physical properties.

Screening of Antioxidant, Antibacterial, Anti-Adipogenic, and Anti-Inflammatory Activities of Five Selected Medicinal Plants of Nepal

Introduction

Herbal products have been widely used for the treatment of diseases throughout the ages. In this research, we investigated antioxidant, antibacterial, anti-adipogenic, and anti-inflammatory activities of methanolic extracts of five ethnomedicinally important plants; namely, Alnus nepalensis, Dryopteris sparsa, Artocarpus lacucha, Litsea monopetala, and Lyonia ovalifolia.

Methods

We investigated the DPPH free radical scavenging potential, sensitivity of selected bacterial strains towards the extracts using a disc diffusion assay, anti-inflammatory activity in RAW-264.7 cells, and anti-adipogenic activity by the ORO assay in 3T3-L1 preadipocytes.

Results and discussion

The extract of A. nepalensis showed significant antioxidant activity (IC₅₀=4.838 µg/mL), followed by A. lacucha, L. monopetala, and L. ovalifolia, exhibiting comparable IC₅₀ values to that of ascorbic acid (IC₅₀=5.063 µg/mL). Alnus nepalensis also showed good antibacterial activity in disc diffusion methods, with remarkable zones of inhibition in A. baumannii (14.66 mm) and P. mirabilis (15.50 mm) bacterial species. In addition, A. nepalensis was found to increase adipogenesis in 3T3-L1 cells, evidenced by increased lipid deposition in differentiated 3T3-L1 cells. A similar pattern of increased adipogenesis was observed on treatment with L. ovalifolia extracts. On the other hand, A. lacucha effectively reduced lipid deposition in 3T3-L1 cells at 100 µg/mL (75.18±6.42%) by inhibiting adipogenesis, showing its potential use in the management of obesity. Furthermore, A. lacucha 100 µg/mL (15.91±0.277 µM) and L. monopetala 75 µg/mL (12.52±0.05 µM) and 100 µg/mL (11.77±0.33 µM) significantly inhibited LPS-induced nitric oxide production in RAW 264.7 cells. Also, A. nepalensis and L. ovalifolia inhibited NO production significantly, endorsing their anti-inflammatory potential.

Conclusion

The findings from these in-vitro studies suggest that the selected five plants possess remarkable antioxidant, antibacterial, anti-adipogenic, and anti-inflammatory activities. This study opens the door to conduct further advanced in-vivo experiments to find possible lead compounds for the development of valuable therapeutic agents for common health problems.

Main Determinants Affecting the Antiproliferative Activity of Stilbenes and Their Gut Microbiota Metabolites in Colon Cancer Cells: A Structure-Activity Relationship Study

trans-Resveratrol can be catabolized by the gut microbiota to dihydroresveratrol, 3,4'-dihydroxy-trans-stilbene, lunularin, and 4-hydroxydibenzyl. These metabolites can reach relevant concentrations in the colon. However, not all individuals metabolize RSV equally, as it depends on their RSV gut microbiota metabotype (i.e., lunularin producers vs. non-producers). However, how this microbial metabolism affects the cancer chemopreventive activity of stilbenes and their microbial metabolites is poorly known. We investigated the structure-antiproliferative activity relationship of dietary stilbenes, their gut microbial metabolites, and various analogs in human cancer (Caco-2 and HT-29) and non-tumorigenic (CCD18-Co) colon cells. The antiproliferative IC₅₀ values of pterostilbene, oxy-resveratrol, piceatannol, resveratrol, dihydroresveratrol, lunularin, 3,4'-dihydroxy-trans-stilbene, pinosylvin, dihydropinosylvin, 4-hydroxy-trans-stilbene, 4-hydroxydibenzyl, 3-hydroxydibenzyl, and 4-trans-stilbenemethanol were calculated. IC₅₀ values were correlated with 34 molecular characteristics by bi- and multivariate analysis. Little or no activity on CCD18-Co was observed, while Caco-2 was more sensitive than HT-29, which was explained by their different capacities to metabolize the compounds. Caco-2 IC₅₀ values ranged from 11.4 ± 10.1 μM (4-hydroxy-trans-stilbene) to 73.9 ± 13.8 μM (dihydropinosylvin). In HT-29, the values ranged from 24.4 ± 11.3 μM (4-hydroxy-trans-stilbene) to 96.7 ± 6.7 μM (4-hydroxydibenzyl). At their IC₅₀, most compounds induced apoptosis and arrested the cell cycle at the S phase, pterostilbene at G₂/M, while 4-hydroxy-trans-stilbene and 3,4'-dihydroxy-trans-stilbene arrested at both phases. Higher Connolly values (larger size) hindered the antiproliferative activity, while a lower pKa1 enhanced the activity in Caco-2, and higher LogP values (more hydrophobicity) increased the activity in HT-29. Reducing the styrene double bond in stilbenes was the most critical feature in decreasing the antiproliferative activity. These results (i) suggest that gut microbiota metabolism determines the antiproliferative effects of dietary stilbenes. Therefore, RSV consumption might exert different effects in individuals depending on their gut microbiota metabotypes associated with RSV metabolism, and (ii) could help design customized drugs with a stilbenoid and (or) dibenzyl core against colorectal cancer.

Nutritional and Phyto-Therapeutic Value of the Halophyte Cladium mariscus L. (Pohl.): A Special Focus on Seeds

This work searched for the phyto-therapeutic potential and nutritional value of seeds from the halophyte Cladium mariscus L. (Pohl.), aiming at its use as a source of bioactive ingredients for the food industry. Hence, the nutritional profile, including minerals, of seeds biomass was determined; food-grade samples were prepared, and their phytochemical fingerprinting assessed. Extracts were evaluated for in vitro antioxidant potential, inhibitory capacity towards enzymes related to neuroprotection, diabetes, and hyperpigmentation, and anti-inflammatory properties, along with a toxicological assessment. Sawgrass seeds can be considered a proper nutritional source with a good supply of minerals. All extracts had a high level of total phenolics (65.3−394.4 mg GAE/g DW) and showed a chemically rich and diverse profile of metabolites that have several biological properties described (e.g., antioxidant, anti-inflammatory). Extracts had no significant toxicity (cell viabilities > 80%) and were overall strong antioxidants (particularly at radical scavenging and reducing iron), effective tyrosinase inhibitors (55−71 mg KAE/g DW), showed anti-inflammatory properties (30−60% NO decrease), and had moderate capacity to inhibit enzymes related to neuroprotection (AChE 3.7−4.2, BChE 4.3−6.0 mg GALE/g DW) and diabetes (α-glucosidase 1.0−1.1, α-amylase 0.8−1.1 mmol ACAE/g). Altogether, results suggest that sawgrass seeds have the potential to be exploited as a new food product and are a reservoir of bioactive molecules with prospective applications as ingredients for value-added, functional, and/or preservative food products.

Oxyresveratrol and Gnetol Glucuronide Metabolites: Chemical Production, Structural Identification, Metabolism by Human and Rat Liver Fractions, and In Vitro Anti-inflammatory Properties

Stilbene metabolites are attracting great interest because many of them exhibit similar or even stronger biological effects than their parent compounds. Furthermore, the metabolized forms are predominant in biological fluids; therefore, their study is highly relevant. After hemisynthesis production, isolation, and structural elucidation, three glucuronide metabolites for oxyresveratrol (ORV) were formed: trans-ORV-4'-O-glucuronide, trans-ORV-3-O-glucuronide, and trans-ORV-2'-O-glucuronide. In addition, two glucuronide metabolites were obtained for gnetol (GN): trans-GN-2'-O-glucuronide and trans-GN-3-O-glucuronide. When the metabolism of ORV and GN is studied in vitro by human and rat hepatic enzymes, four of the five hemisynthesized compounds were identified and quantified. Human enzymes glucuronidated preferably at the C-2' position, whereas rat enzymes do so at the C-3 position. In view of these kinetic findings, rat enzymes have a stronger metabolic capacity than human enzymes. Finally, ORV, GN, and their glucuronide metabolites (mainly at the C-3 position) decreased nitric oxide, reactive oxygen species, interleukin 1β, and tumor necrosis factor α production in lipopolysaccharide-stimulated macrophages.

Recent Green Technologies in Natural Stilbenoids Production and Extraction: The Next Chapter in the Cosmetic Industry

Stilbenoids are well-known phytoalexins in the group of polyphenolic compounds. Because of their potent bioactivities, including antioxidant, antityrosinase, photoprotective, and antibacterial activities, stilbenoids are utilized as pharmaceutical active ingredient in cosmetic products. Thus, the demand for stilbenoids in the cosmetic industry is increasing. The main sources of stilbenoids are plants. Although plants are green and sustainable source materials, some of them do not allow a regular and constant supply due to seasonal and geographic reasons. Stilbenoids typically have been extracted by conventional organic solvent extraction, and then purified by separation techniques. This method is unfriendly to the environment and may deteriorate human health. Hence, the procedures called “green technologies” are focused on novel extraction methods and sustainable stilbenoids production by using biotechnology. In this review, the chemical structures together with the biosynthesis and current plant sources of resveratrol, oxyresveratrol, and piceatannol are described. Furthermore, recent natural deep eutectic solvents (NADES) for green extraction as well as plant cell cultures for the production of those stilbene compounds are updated.

Characterization, Stability, and Antibrowning Effects of Oxyresveratrol Cyclodextrin Complexes Combined Use of Hydroxypropyl Methylcellulose

Oxyresveratrol (Oxy) has attracted much attention by employing it as an antibrowning agent in fruits and vegetables. In this study, the formation of cyclodextrin (CD) inclusion exhibited a certain protective effect on Oxy oxidative degradation, while hydroxypropyl-β-cyclodextrin (HP–β-CD) inclusion complex showed stronger stabilizing effects than those of β-cyclodextrin (β-CD). The combined use of CD and hydroxypropyl methylcellulose (HPMC) greatly improved the stability of Oxy–CD inclusion complexes, with approximately 70% of the trans-Oxy retained after 30 days of storage under light conditions at 25 °C. The results of the interaction between CD and Oxy determined by phase solubility studies and fluorescence spectroscopic analysis showed that the binding strength of CD and Oxy increased in the presence of HPMC. Moreover, Oxy combined with ascorbic acid and HPMC showed an excellent antibrowning effect on fresh-cut apple slices during the 48 h test period, indicating that adding HPMC as the third component will not influence the antibrowning activity of Oxy.

Virtual screening reveals liquiritigenin as a broad-spectrum inhibitor of SARS-CoV-2 variants of concern: an in silico study

The SARS-CoV-2 has severely impacted the lives of people worldwide. Global concern is on the rise due to a large number of unexpected mutations in the viral genome, resulting in new variants. Nature-based bioactive phytochemicals hold great promise as inhibitors against pathogenic viruses. The current study was aimed at evaluating some bioactive antiviral phytochemicals against SARS-CoV-2 variants of concern. A total of 46 phytochemicals were screened against the pathogenic spike protein of Alpha, Beta, Delta, Gamma, and Omicron variants. In addition to molecular docking, screening for favorable pharmacokinetic and pharmacodynamic properties such as absorption, distribution, metabolism, excretion, and toxicity was undertaken. For each of the aforementioned five SARS-CoV-2 variants of concern, a 100 ns molecular dynamics simulation was run to assess the stability of the complexes between their respective spike protein receptor-binding domain and the best-selected compound. From our current investigation, the natural compound liquiritigenin turned out to be the most promising potential lead compound against almost all the variants. These findings could pave the way for the development of effective medications against SARS-CoV-2 variants. However, in vivo trials in future studies are necessary for further validation of our results.Communicated by Ramaswamy H. Sarma.

Anti-Inflammatory Activity of Oxyresveratrol Tetraacetate, an Ester Prodrug of Oxyresveratrol, on Lipopolysaccharide-Stimulated RAW264.7 Macrophage Cells

Oxyresveratrol (OXY) has been reported for its anti-inflammatory activity; however, the pharmaceutical applications of this compound are limited by its physicochemical properties and poor pharmacokinetic profiles. The use of an ester prodrug is a promising strategy to overcome these obstacles. In previous researches, several carboxylate esters of OXY were synthesized and oxyresveratrol tetraacetate (OXY-TAc) was reported to possess anti-melanogenic and anti-skin-aging properties. In this study, in addition to OXY-TAc, two novel ester prodrugs of OXY, oxyresveratrol tetrapropionate (OXY-TPr), and oxyresveratrol tetrabutyrate (OXY-TBu), were synthesized. Results from the Caco-2-permeation assay suggested that synthesized ester prodrugs can improve the membrane-permeation ability of OXY. The OXY-TAc exhibited the most significant profile, then this prodrug was chosen to observe anti-inflammatory activities with lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Our results showed that OXY-Tac significantly alleviated secretion of several pro-inflammatory mediators (nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α)), mitigated expression of enzyme-regulated inflammation (inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2)), and suppressed the MAPK cascades. Interestingly, the observed anti-inflammatory activities of OXY-TAc were more remarkable than those of its parent compound OXY. Taken together, we demonstrated that OXY-TAc improved physicochemical and pharmacokinetic profiles and enhanced the pharmacological effects of OXY. Hence, the results in the present study would strongly support the clinical utilities of OXY-TAc for the treatment of inflammation-related disorders.

Computational Analysis and Biological Activities of Oxyresveratrol Analogues, the Putative Cyclooxygenase-2 Inhibitors

Polyphenols are a large family of naturally occurring phytochemicals. Herein, oxyresveratrol was isolated from ethanolic crude extracts of Artocarpus lacucha Buch.-Ham., and chemically modified to derive its lipophilic analogues. Biological screening assays showed their inhibitory potency against cyclooxygenase-2 (COX-2) with very low cytotoxicity to the MRC-5 normal cell lines. At the catalytic site of COX-2, docking protocols with ChemPLP, GoldScore and AutoDock scoring functions were carried out to reveal hydrogen bonding interactions with key polar contacts and hydrophobic pi-interactions. For more accurate binding energetics, COX-2/ligand complexes at the binding region were computed in vacuo and implicit aqueous solvation using M06-2X density functional with 6-31G+(d,p) basis set. Our computational results confirmed that dihydrooxyresveratrol (4) is the putative inhibitor of human COX-2 with the highest inhibitory activity (IC₅₀ of 11.50 ± 1.54 µM) among studied non-fluorinated analogues for further lead optimization. Selective substitution of fluorine provides a stronger binding affinity; however, lowering the cytotoxicity of a fluorinated analogue to a normal cell is challenging. The consensus among biological activities, ChemPLP docking score and the binding energies computed at the quantum mechanical level is obviously helpful for identification of oxyresveratrol analogues as a putative anti-inflammatory agent.

Stilbenes: Characterization, bioactivity, encapsulation and structural modifications. A review of their current limitations and promising approaches

Stilbenes are phenolic compounds naturally synthesized as secondary metabolites by the shikimate pathway in plants. Research on them has increased in recent years due to their therapeutic potential as antioxidant, antimicrobial, anti-inflammatory, anticancer, cardioprotective and anti-obesity agents. Amongst them, resveratrol has attracted the most attention, although there are other natural and synthesized stilbenes with enhanced properties. However, stilbenes have some physicochemical and pharmacokinetic problems that need to be overcome before considering their applications. Human clinical evidence of their bioactivity is still controversial due to this fact and hence, exhaustive basis science on stilbenes is needed before applied science. This review gathers the main physicochemical and biological properties of natural stilbenes, establishes structure-activity relationships among them, emphasizing the current problems that limit their applications and presenting some promising approaches to overcome these issues: the encapsulation in different agents and the structural modification to obtain novel stilbenes with better features. The bioactivity of stilbenes should move from promising to evident.

Phytochemical Composition of Different Botanical Parts of Morus Species, Health Benefits and Application in Food Industry

In recent years, mulberry has acquired a special importance due to its phytochemical composition and its beneficial effects on human health, including antioxidant, anticancer, antidiabetic and immunomodulatory effects. Botanical parts of Morus sp. (fruits, leaves, twigs, roots) are considered a rich source of secondary metabolites. The aim of our study was to highlight the phytochemical profile of each of the botanical parts of Morus tree, their health benefits and applications in food industry with an updated review of literature. Black and white mulberries are characterized in terms of predominant phenolic compounds in correlation with their medical applications. In addition to anthocyanins (mainly cyanidin-3-O-glucoside), black mulberry fruits also contain flavonols and phenolic acids. The leaves are a rich source of flavonols, including quercetin and kaempferol in the glycosylated forms and chlorogenic acid as predominant phenolic acids. Mulberry bark roots and twigs are a source of prenylated flavonoids, predominantly morusin. In this context, the exploitation of mulberry in food industry is reviewed in this paper, in terms of developing novel, functional food with multiple health-promoting effects.

Oxyresveratrol Inhibits TNF-α-Stimulated Cell Proliferation in Human Immortalized Keratinocytes (HaCaT) by Suppressing AKT Activation

Psoriasis is a complex inflammatory disease characterized by hyperproliferative keratinocyte caused by active PI3K/AKT signaling. TNF-α concentrated in the psoriatic lesions stimulates AKT activation. We previously discovered that oxyresveratrol inhibited inflammation via suppressing AKT phosphorylation, therefore oxyresveratrol may possess a conserved property to block AKT activation and proliferation in keratinocyte in response to TNF-α. Our current study proved that oxyresveratrol exhibited potent anti-proliferative effects against TNF-α. These effects are explained by the findings that oxyresveratrol could potentially inhibit TNF-α-stimulated AKT and GSK3-β activation in a dose-dependent manner, and its inhibitory pattern was comparable to that of a specific PI3K inhibitor. Results from immunofluorescence supported that oxyresveratrol effectively inhibited AKT and GSK3-β activation in individual cells upon TNF-α stimulation. Furthermore, functional assay confirmed that oxyresveratrol repressed the expansion of the HaCaT colony over 3 days, and this was caused by the ability of oxyresveratrol to induce cell cycle arrest at S and G2/M phases and the reduction in the expression of a proliferative marker (Ki-67) and a survival marker (MCL-1). Given the importance of TNF-α and the PI3K/AKT pathway in the psoriatic phenotype, we anticipate that oxyresveratrol, which targets the TNF-α-stimulated PI3K/AKT pathway, would represent a promising psoriasis therapy in the near future.

UPLC-MS/MS Profiling, Antioxidant, α-Glucosidase Inhibitory, Cholinesterase Inhibitory, and Cardiovascular Protection Potentials of Jialing 20 (Morus multicaulis Perr.) Mulberry Branch Extract

As a by-product in the sericulture industry, mulberry branches are not currently utilized effectively. Jialing 20 is an artificial triploids mulberry that widely cultivated in southwest China. In this study, the chemical composition of the Jialing 20 mulberry branch extract (MBE) was first analyzed by UPLC-MS/MS, and 42 components, including alkaloids, flavonoids, and coumarins, were obtained. Then, the antioxidant activities, hypoglycemic effect, Alzheimer’s disease inhibition, and cardiovascular protection of MBE were also evaluated in vitro. The IC₅₀ values for the scavenging DPPH and ABTS radicals were, respectively, 31.23 ± 0.57 μg/mL and 8.88 ± 0.36 μg/mL (IC₅₀ values of positive Vc were, respectively, 4.41 ± 0.19 μg/mL and 8.79 ± 0.41 μg/mL). The IC₅₀ value for inhibiting α-glucosidase was 1.90 ± 0.05 μg/mL (IC₅₀ value of positive acarbose was 0.03 μg/mL). The IC₅₀ values for inhibiting acetylcholinesterase and butyrylcholinesterase were, respectively, 179.47 ± 0.38 μg/mL and 101.82 ± 3.37 μg/mL (IC₅₀ values of positive berberine were, respectively, 1.27 ± 0.03 μg/mL and 57.41 ± 0.21 μg/mL). MBE (10 μg/mL and 40 μg/mL) significantly increased the survival rate of oxidized low-density lipoprotein- (ox-LDL) induced human umbilical vein endothelial cells (HUVECs) and significantly decreased the intracellular reactive oxygen species. These results suggest that the extracts of Jialing 20 mulberry branches could be used as a functional food additive.

Synergistic Effects of Limosilactobacillus fermentum ASBT-2 with Oxyresveratrol Isolated from Coconut Shell Waste

Value-added phytochemicals from food by-products and waste materials have gained much interest and among them, dietary polyphenolic compounds with potential biological properties extend a promising sustainable approach. Oxyresveratrol (Oxy), a stilbenoid polyphenol, possesses great therapeutic potential, though its pharmacokinetic issues need attention. A good source of oxyresveratrol was found in underutilized coconut shells and the synbiotic applications of the compound in combination with a potential probiotic isolate Limosilactobacillus fermentum ASBT-2 was investigated. The compound showed lower inhibitory effects on the strain with minimum inhibitory concentration (MIC) of 1000 µg/mL. Oxyresveratrol at sub-MIC concentrations (500 µg/mL and 250 µg/mL) enhanced the probiotic properties without exerting any inhibitory effects on the strain. The combination at sub- MIC concentration of the compound inhibited Salmonella enterica and in silico approaches were employed to elucidate the possible mode of action of oxy on the pathogen. Thus, the combination could target pathogens in the gut without exerting negative impacts on growth of beneficial strains. This approach could be a novel perspective to address the poor pharmacokinetic properties of the compound.

Oxyresveratrol modulates the immune response in vitro

The naturally occurring stilbenoid oxyresveratrol was shown to influence inflammatory and metabolic processes. During cellular immune activation, tryptophan breakdown and neopterin formation via the enzymes indoleamine 2,3-dioxygenase-1 (IDO-1) and GTP-cyclohydrolase, respectively, are induced. Neopterin and the kynurenine to tryptophan ratio are reliable and pertinent biomarkers of Th1-type immune response and are also used in vitro to monitor effects of active plant ingredients on peripheral blood mononuclear cells (PBMCs). We investigated the effects of oxyresveratrol on the activity of the above-mentioned pathways in mitogen-stimulated human PBMC and in the myelomonocytic cell line THP-1. Oxyresveratrol exerted suppressive effects on tryptophan breakdown in both stimulated cell models. Of note, in PBMC, tryptophan breakdown was induced at lower concentrations (5–20 µM) and suppressed at higher treatment concentrations only. Neopterin formation was decreased dose-dependently in stimulated PBMC. In unstimulated PBMC similar, albeit lesser effects were observed. Data indicate that oxyresveratrol exerts distinct and concentration-dependent effects on different immune cell types. IDO-1 is targeted by oxyresveratrol and its activity can be modulated in both directions. Detailed investigations of the interactions would be interesting to fully explore the activity of this phytocompound.