Search

Resveratrol and its derivatives are the most important phytoalexins with a crucial role in plant defense mechanisms. These compounds can occur either naturally or in response to abiotic stresses. Among them, salinity is one of the major threats to the sustainability and productivity of agro-economically important species, particularly those involved in the vini-viticulture sector. Understating salinity tolerance mechanisms in plants is required for the development of novel engineering tools. This study aimed to investigate the potential role of resveratrol derivatives in salinity tolerance of wild grapevines. Our data revealed that the tolerant Tunisian wild grapevine genotype "Ouchtata" exhibited an increased accumulation of resveratrol derivatives (glycosylated and non-glycosylated resveratrol and t-ɛ-viniferin and hydroxylated t-piceatannol) in both stems and roots, along with an increased total antioxidant activity (TAA) compared to the sensitive genotype "Djebba" under stress conditions, suggesting an involvement of these stilbenes in redox homeostasis, thereby, protecting cells from salt-induced oxidative damage. Overall, our study revealed, for the first time, an active role for resveratrol derivatives in salt stress tolerance in wild grapevine, highlighting their potential use as metabolic markers in future grapevine breeding programs for a sustainable vini-viticulture in salt-affected regions. [ABSTRACT FROM AUTHOR]

Resveratrol is a typical plant phenolic compound whose derivatives are synthesized through hydroxylation, O-methylation, prenylation, and oligomerization. Resveratrol and its derivatives exhibit anti-neurodegenerative, anti-rheumatoid, and anti-inflammatory effects. Owing to the diverse biological activities of these compounds and their importance in human health, this study attempted to synthesize five resveratrol derivatives (isorhapontigenin, pterostilbene, 4-methoxyresveratrol, piceatannol, and rhapontigenin) using Escherichia coli. Two-culture system was used to improve the final yield of resveratrol derivatives. Resveratrol was synthesized in the first E. coli cell that harbored genes for resveratrol biosynthesis including TAL (tyrosine ammonia lyase), 4CL (4-coumaroyl CoA ligase), STS (stilbene synthase) and genes for tyrosine biosynthesis such as aroG (deoxyphosphoheptonate aldolase) and tyrA (prephenate dehydrogenase). Thereafter, culture filtrate from the first cell was used for the modification reaction carried out using the second E. coli harboring hydroxylase and/or O-methyltransferase. Approximately, 89.8 mg/L of resveratrol was synthesized and using the same, five derivatives were prepared with a conversion rate of 88.2% to 22.9%. Using these synthesized resveratrol derivatives, we evaluated their anti-inflammatory activity. 4-Methoxyresveratrol, pterostilbene and isorhapontigenin showed the anti-inflammatory effects without any toxicity. In addition, pterostilbene exhibited the enhanced anti-inflammatory effects for macrophages compared to resveratrol. [ABSTRACT FROM AUTHOR]

Stilbenes, including trans-resveratrol (3,4′,5-trihydroxy- trans-stilbene), are known to exert beneficial health effects and contribute to plant biotic stress resistance. Much remains to be discovered about the cell signaling pathways regulating stilbene biosynthesis. It has recently been shown that overexpression of the calcium-dependent protein kinase VaCPK20 gene considerably increased t-resveratrol accumulation in cell cultures of Vitis amurensis. In this study, we analyzed the involvement of other CDPK family members, VaCPK1 and VaCPK26, on stilbene synthesis and biomass production by cell cultures of V. amurensis. We showed that overexpression of the VaCPK1 and 26 genes induced production of stilbenes by 1.7-4.6-fold (for VaCPK1) and by 2.5-6.2-fold (for VaCPK26) in several independently established cell lines compared to the empty vector-transformed control. Using HPLC-UV-MS, we detected five stilbenes in the grape cells: t-resveratrol diglucoside, t-piceid, t-resveratrol, ε- and δ-viniferin. The VaCPK1- and VaCPK26-transformed calli were capable of producing 1.4-3.1 and 1.8-4.9 mg/l of t-resveratrol, respectively (up to 0.4 for and 0.6 mg/g of dry weight for VaCPK26 and VaCPK1, respectively), while the control line synthesized only 0.5 mg/l of t-resveratrol (0.07 mg/g DW). The up-regulation of t-resveratrol production in the VaCPK1- and VaCPK26-overexpressing grape calli correlated with a significant up-regulation of stilbene synthase ( STS) gene expression, especially VaSTS7. The data indicate that VaCPK1 and 26 genes, which are close homologues of VaCPK20, are positive regulators of stilbene biosynthesis in grapevine. [ABSTRACT FROM AUTHOR]

Using 2-thiophenecarbonyl chloride and 2-furoyl chloride to modify the structure of the natural product resveratrol, we synthesized five novel resveratrol derivatives. The target compounds were evaluated for their antitumor activities against cervical cancer HeLa cells by the MTT method. The results indicated that the compound 3a displayed the best antitumor activities, which is higher than the value of resveratrol, and its inhibition ratio was 95.1% against HeLa cells at the concentration of 75 μmol/L. [ABSTRACT FROM AUTHOR]

Resveratrol (3,5,4′-trihydroxystilbene), a naturally occurring stilbene that occurs in a variety of foods and beverages, has attracted increasing attention over the past decade because of its beneficial bioactivity, including chemopreventive and antitumor activity. Because several resveratrol derivatives are structurally similar to resveratrol, a set of 26 methoxylated trans-stilbene resveratrol derivatives were synthesized and evaluated for their in-vitro antitumor activity against three cancer cell lines (K562, HT29, and HePG2). Pharmacological data indicated that several of the derivatives had marked antiproliferative activity compared with resveratrol, as reference, especially the most promising compound (IC values 1.28, 0.59 and 0.98 μM against K562, HT29, and HePG2 cell lines, respectively). Substitution of the stilbene structure with methoxy at the C-4′ position had the greatest effect on activity. The anti-tumor potential of these compounds could serve as a basis for development of novel antitumor agents. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease is associated with inhibited AMP-activated kinase (AMPK) and activation of sterol regulatory element binding protein 1 (SREBP-1). AMPK phosphorylation inhibits SREBP-1, a major transcription factor of de novo lipogenesis, by inhibiting the liver X receptor (LXR) or by direct phosphorylation. Resveratrol, a polyphenol, has regulatory effects on hepatic lipid metabolism as a potent AMPK activator. In this study, we evaluated the anti-steatogenic effects of resveratrol and its derivatives and identified the molecular mechanism in vitro and in vivo. Resveratrol and its derivatives decreased lipid accumulation by free fatty acids (FFA mixture; 0.5 mM, oleic acid:palmitic acid = 2: 1) in H4IIEC3 cells. Synthesized derivatives of resveratrol had lower cytotoxicity than the parental molecule with similar potency. SY-102 suppressed SREBP-1 maturation by T0901317, an LXR agonist, and decreased SRE luciferase activity and the mRNA levels of lipogenic genes. Inhibition of AMPK by pre-treatment with compound C completely blocked the effects of SY-102. To evaluate their efficacy in vivo, mice were fed a high-fat diet for 5 days, and resveratrol or SY-102 was administered orally for the last 2 days. Oral administration of the SY-102 increased AMPK phosphorylation, followed by reduced hepatic triglyceride accumulation to a similar extent as resveratrol. These data demonstrate that SY-102, a synthesized derivative of resveratrol, might provide a promising therapeutic effect against fatty liver disease. [ABSTRACT FROM AUTHOR]

Quantitative structure-activity relationships (QSARs) were developed for the aryl hydrocarbon receptor (AhR) binding affinity of non-fluorinated and fluorinated cis and trans 3,4′,5-substituted resveratrol derivatives. Lower quality QSAR fits were found when all compounds were modeled together, in contrast to strong correlations with Hammett substituent constants and atomic charges for separate non-fluorinated/fluorinated and cis/ trans groupings. The collective findings suggest little promise in developing new resveratrol derivatives with significantly higher AhR binding affinity beyond the range already mapped by the available experimental data sets. The results also suggest that future QSAR searches for AhR binding affinity among resveratrol derivatives will likely need to proceed in a more constrained class-by-class fashion owing to the potentially different mechanistic implications from changes in the types/positions of aromatic substitution and the cis/ trans geometrical isomerism. The antioxidant activity of hydroxystilbenes can be accurately modeled using high-quality empirical univariate relationships with various molecular descriptors. In comparison, correlations between theoretical bond dissociation enthalpies and ionization energies of the molecular and dissociated forms yielded lower quality QSAR fits with the antioxidant behavior. [ABSTRACT FROM AUTHOR]