Resveratrol and other Stilbenes: Effects on Dysregulated Gene Expression in Cancers and Novel Delivery Systems

Phytocompounds and their molecular targets in immunomodulation: a review

Immune cells are important for the healthy function of every organ. The homeostasis of the immune system is selfregulated by T-cells, B-cells, and natural killer cells. The immunomodulation process of immune cells is part of the immunotherapy. According to therapeutic methods of immune responses are categorized as inducing (immunostimulant), amplification (immune booster), attenuation (immunomodulation), and prevention (immunosuppressive) actions. The prevalence of chronic immunological diseases like viral infections, allergies, and cancer is mainly due to the over-activation of the immune system. Further, immunomodulators are reported to manage the severity of chronic immunological disorders. Moreover, these immunomodulator-acting proteins are identified as potential molecular targets for the regulation of the immune system. Moreover, natural compound like phytocompounds are known to bind these targets and modulates the immune system. The specialized phytocompounds like curcumin, quercetin, stilbenes, flavonoids, and lignans are shown the immunomodulatory actions and ameliorate the immunological disorders. The present scenario of a COVID-19 pandemic situation has taught us the need to focus on strengthening the immune system and the development of the most promising immunotherapeutics. This review is focused on an overview of various phytocompounds and their molecular targets for the management of immunological disorders via immunosuppressants and immunostimulants actions.

Resveratrol Analogues as Dual Inhibitors of Monoamine Oxidase B and Carbonic Anhydrase VII: A New Multi-Target Combination for Neurodegenerative Diseases?

Neurodegenerative diseases (NDs) are described as multifactorial and progressive syndromes with compromised cognitive and behavioral functions. The multi-target-directed ligand (MTDL) strategy is a promising paradigm in drug discovery, potentially leading to new opportunities to manage such complex diseases. Here, we studied the dual ability of a set of resveratrol (RSV) analogs to inhibit two important targets involved in neurodegeneration. The stilbenols 1−9 were tested as inhibitors of the human monoamine oxidases (MAOs) and carbonic anhydrases (CAs). The studied compounds displayed moderate to excellent in vitro enzyme inhibitory activity against both enzymes at micromolar/nanomolar concentrations. Among them, the best compound 4 displayed potent and selective inhibition against the MAO-B isoform (IC50 MAO-A 0.43 µM vs. IC50 MAO-B 0.01 µM) with respect to the parent compound resveratrol (IC50 MAO-A 13.5 µM vs. IC50 MAO-B > 100 µM). It also demonstrated a selective inhibition activity against hCA VII (KI 0.7 µM vs. KI 4.3 µM for RSV). To evaluate the plausible binding mode of 1−9 within the two enzymes, molecular docking and dynamics studies were performed, revealing specific and significant interactions in the active sites of both targets. The new compounds are of pharmacological interest in view of their considerably reduced toxicity previously observed, their physicochemical and pharmacokinetic profiles, and their dual inhibitory ability. Compound 4 is noteworthy as a promising lead in the development of MAO and CA inhibitors with therapeutic potential in neuroprotection.

Substitution of a triazole for the central olefin in biologically active stilbenes

The stilbene moiety is commonly found in natural products and these compounds display an extraordinary range of biological activity. Efforts to derive useful drugs from stilbenes must address the potential liabilities of this structure, including a propensity for cis/trans isomerization. To identify olefin replacements that address this limitation while preserving biological activity we have prepared analogues of two bioactive stilbenes, a pawhuskin and a schweinfurthin, where a 1,2,3-triazole ring formally replaces the stilbene double bond. The new schweinfurthin analogue (23) has been tested for anti-proliferative activity against 60 cell lines, and shows a strong correlation of bioactivity when compared to the compound that inspired its synthesis (22).

Identification and Expression Analysis of Stilbene Synthase Genes in Arachis hypogaea in Response to Methyl Jasmonate and Salicylic Acid Induction

Stilbene synthase is an important enzyme of the phenylpropanoid pathway, regulating the production of several biologically active stilbenoids. These compounds have antioxidant, anti-inflammatory, and anti-cancer properties. However, the detailed characterization of stilbene synthase genes in Arachis hypogaea has not yet been performed. In this study, the comprehensive characterization of stilbene synthase genes in A. hypogaea was conducted, commencing with identification, phylogenetic analysis, and study of their expression in response to exogenous hormonal treatment. We identified and isolated five AhSTSs genes and recorded their expression pattern in peanut (BARD-479) in response to methyl jasmonate (MeJA) and salicylic acid (SA) treatment. The presence of Chal_sti_synt, ACP_syn_III, and FAE1_CUT1_rppA domains in all AhSTSs indicated their role in the biosynthesis of stilbene and lipid metabolism. Cis-regulatory element analysis indicated their role in light responsiveness, defense responses, regulation of seed development, plant growth, and development. Despite close structural and functional similarities, expression and correlational analysis suggested that these genes may have a specific role in peanut, as individual AhSTS exhibited differential expression upon hormonal treatment in a genotype dependent manner. Further studies on functional characterization involving the transcriptional regulation of AhSTSs can clearly explain the differential expression of stilbene synthase genes to hormonal treatment.

Phenolic Compound Profile by UPLC-MS/MS and Encapsulation with Chitosan of Spondias mombin L. Fruit Peel Extract from Cerrado Hotspot-Brazil

Taperebá (Spondias mombin L.) is a native species of the Brazilian Cerrado that has shown important characteristics such as a significant phenolic compound content and biological activities. The present study aimed to characterize the phenolic compound profile and antioxidant activity in taperebá peel extract, as well as microencapsulating the extract with chitosan and evaluating the stability of the microparticles. The evaluation of the profile of phenolic compounds was carried out by UPLC-MS/MS. The in vitro antioxidant activity was evaluated by DPPH and ABTS methods. The microparticles were obtained by spray drying and were submitted to a stability study under different temperatures. In general, the results showed a significant content of polyphenols and antioxidant activity. The results of UPLC-MS/MS demonstrated a significant content of polyphenols in taperebá peel, highlighting the high content of ellagic acid and quercetin compounds. There was significant retention of phenolic compounds when microencapsulated, demonstrating high retention at all evaluated temperatures. This study is the first to microencapsulate the extract of taperebá peel, in addition to identifying and quantifying some compounds in this fruit.

Lemongrass Essential Oil Components with Antimicrobial and Anticancer Activities

The prominent cultivation of lemongrass (Cymbopogon spp.) relies on the pharmacological incentives of its essential oil. Lemongrass essential oil (LEO) carries a significant amount of numerous bioactive compounds, such as citral (mixture of geranial and neral), isoneral, isogeranial, geraniol, geranyl acetate, citronellal, citronellol, germacrene-D, and elemol, in addition to other bioactive compounds. These components confer various pharmacological actions to LEO, including antifungal, antibacterial, antiviral, anticancer, and antioxidant properties. These LEO attributes are commercially exploited in the pharmaceutical, cosmetics, and food preservations industries. Furthermore, the application of LEO in the treatment of cancer opens a new vista in the field of therapeutics. Although different LEO components have shown promising anticancer activities in vitro, their effects have not yet been assessed in the human system. Hence, further studies on the anticancer mechanisms conferred by LEO components are required. The present review intends to provide a timely discussion on the relevance of LEO in combating cancer and sustaining human healthcare, as well as in food industry applications.

Synthesis of a Coumarin-Based Analogue of Schweinfurthin F

The natural schweinfurthins are stilbenes with significant antiproliferative activity and an uncertain mechanism of action. To obtain a fluorescent analogue with minimal deviation from the natural structure, a coumarin ring system was annulated to the D-ring, creating a new analogue of schweinfurthin F. This stilbene was prepared through a convergent synthesis, with a Horner-Wadsworth-Emmons condensation employed to form the central stilbene olefin. After preparation of a tricyclic phosphonate via a recent and more efficient modification of the classic Arbuzov reaction, condensation was attempted with an appropriately substituted bicyclic aldehyde but the coumarin system did not survive the reaction conditions. When olefin formation preceded generation of the coumarin, the stilbene formation proceeded smoothly and ultimately allowed access to the targeted coumarin-based schweinfurthin analogue. This analogue displayed the desired fluorescence properties along with significant biological activity in the National Cancer Institute's 60-cell line bioassay, and the pattern of this biological activity mirrored that of the natural product schweinfurthin F. This approach gives facile access to new fluorescent analogues of the natural schweinfurthins and should be applicable to other natural stilbenes as well.

Curcumin, Quercetin, Catechins and Metabolic Diseases: The Role of Gut Microbiota

Polyphenols (PPs) are the naturally occurring bioactive components in fruits and vegetables, and they are the most abundant antioxidant in the human diet. Studies are suggesting that ingestion of PPs might be helpful to ameliorate metabolic syndromes that may contribute in the prevention of several chronic disorders like diabetes, obesity, hypertension, and colon cancer. PPs have structural diversity which impacts their bioavailability as they accumulate in the large intestine and are extensively metabolized through gut microbiota (GM). Intestinal microbiota transforms PPs into their metabolites to make them bioactive. Interestingly, not only GM act on PPs to metabolize them but PPs also modulate the composition of GM. Thus, change in GM from pathogenic to beneficial ones may be helpful to ameliorate gut health and associated diseases. However, to overcome the low bioavailability of PPs, various approaches have been developed to improve their solubility and transportation through the gut. In this review, we present evidence supporting the structural changes that occur after metabolic reactions in PPs (curcumin, quercetin, and catechins) and their effect on GM composition that leads to improving overall gut health and helping to ameliorate metabolic disorders.