What Is New for an Old Molecule? Systematic Review and Recommendations on the Use of Resveratrol

Background

Resveratrol is a natural compound suggested to have beneficial health effects. However, people are consuming resveratrol for this reason without having the adequate scientific evidence for its effects in humans. Therefore, scientific valid recommendations concerning the human intake of resveratrol based on available published scientific data are necessary. Such recommendations were formulated after the Resveratrol 2010 conference, held in September 2010 in Helsingør, Denmark.

Methodology

Literature search in databases as PubMed and ISI Web of Science in combination with manual search was used to answer the following five questions: ¹Can resveratrol be recommended in the prevention or treatment of human diseases?; ²Are there observed “side effects” caused by the intake of resveratrol in humans?; ³What is the relevant dose of resveratrol?; ⁴What valid data are available regarding an effect in various species of experimental animals?; ⁵Which relevant (overall) mechanisms of action of resveratrol have been documented?

Conclusions/Significance

The overall conclusion is that the published evidence is not sufficiently strong to justify a recommendation for the administration of resveratrol to humans, beyond the dose which can be obtained from dietary sources. On the other hand, animal data are promising in prevention of various cancer types, coronary heart diseases and diabetes which strongly indicate the need for human clinical trials. Finally, we suggest directions for future research in resveratrol regarding its mechanism of action and its safety and toxicology in human subjects.     

The impact of foliar boron sprays on reproductive biology and seed quality of black gram

An experiment was conducted under glass house condition to study the effect of foliar application of boron (B) on reproductive biology and seed quality of black gram (Vigna mungo). Black gram (V. mungo L. var. DPU-88-31) was grown under controlled sand culture condition at deficient and sufficient B levels. After 32 days of sowing B deficient plants were sprayed with three concentrations of B (0.05%, 0.1% and 0.2% borax) at three different stages of reproductive development, i.e. prior to flowering, initiation of bud formation and after bud formation. Deficient B supply decreased the anther and pollen size, pollen tube growth, pollen viability as well as stigmatic receptivity which were increased by foliar B application. Foliar spray at all the three concentrations and at all stages increased the yield parameters like number of pods, pod size and number of seeds formed per plant. Foliar B application also improved the seed yield and seed quality in terms of storage seed proteins (albumin, globulin, glutenin and prolamin) and carbohydrates (sugars and starch) in black gram. The foliar application of B in appropriate doses (particularly 0.1%) after bud formation made quantitative and qualitative improvement in seed yield of black gram by supplementing additional/critical B requirements for reproductive development.     

The cytosolic chaperone Hsc70 promotes traffic to the cell surface of intracellular retained melanocortin-4 receptor mutants

Inherited modifications in protein structure frequently cause a loss-of-function by interfering with protein synthesis, transport, or stability. For the obesity-linked melanocortin-4 receptor (MC4R) and other G protein-coupled receptors, many mutants are intracellular retained. The biogenesis and trafficking of G protein-coupled receptors are regulated by multiple factors, including molecular chaperone networks. Here, we have investigated the ability of the cytosolic cognate 70-kDa heat-shock protein (Hsc70) chaperone system to modulate cell surface expression of MC4R. Clinically occurring MC4R mutants S58C, P78L, and D90N were demonstrated to have reduced trafficking to the plasma membrane and to be retained at the endoplasmic reticulum (ER). Analyses by fluorescence recovery after photobleaching revealed that the mobility of MC4R mutant protein at the ER was reduced, implying protein misfolding. In cells expressing MC4R, overexpression of Hsc70 resulted in increased levels of wild-type and mutant receptors at the cell surface. MC4R and Hsc70 coimmunoprecipitated, and fluorescence recovery after photobleaching analyses showed that increasing cellular levels of Hsc70 promoted the mobility of ER retained MC4R. Moreover, expression of HSJ1b, a cochaperone that enhances degradation of Hsc70 clients, reduced cellular levels of MC4R. Hsp70 and Hsp90 chaperone systems collaborate in the cellular processing of clients. For MC4R, inhibition of endogenous Hsp90 by geldanamycin reduced receptor levels. By contrast, expression of the Hsp90 cochaperone Aha1 (activator of Hsp90 ATPase) increased cellular levels of MC4R. Finally, we demonstrate that signaling of intracellular retained MC4R mutants is increased in cells overexpressing Hsc70. These data indicate that cytosolic chaperone systems can facilitate rescue of intracellular retained MC4R by improving folding. They also support proteostasis networks as a potential target for MC4R-linked obesity.     

Deoxycytidine glyoxal: lesion induction and evidence of repair following vitamin C supplementation in vivo

Oxidative DNA damage is postulated to be involved in carcinogenesis, and as a consequence, dietary antioxidants have received much interest. A recent report indicates that vitamin C facilitates the decomposition of hydroperoxides in vitro, generating reactive aldehydes. We present evidence for the in vivo generation of glyoxal, an established product of lipid peroxidation, glucose/ascorbate autoxidation, or free radical attack of deoxyribose, following supplementation of volunteers with 400 mg/d vitamin C. Utilizing a monoclonal antibody to a deoxycytidine-glyoxal adduct (gdC), we measured DNA lesion levels in peripheral blood mononuclear cells. Supplementation resulted in significant (p =.001) increases in gdC levels at weeks 11, 16, and 21, with corresponding increases in plasma malondialdehyde levels and, coupled with previous findings, is strongly suggestive of a pro-oxidative effect. However, continued supplementation revealed a highly significant (p =.0001) reduction in gdC levels. Simultaneous analysis of cyclobutane thymine dimers revealed no increase upon supplementation but, as with gdC, levels decreased. Although no single mechanism is identified, our data demonstrate a pro-oxidant event in the generation of reactive aldehydes following vitamin C supplementation in vivo. These results are also consistent with our hypothesis for a role of vitamin C in an adaptive/repair response and indicate that nucleotide excision repair specifically may be affected.     

Yeast functional screen to identify genetic determinants capable of conferring abiotic stress tolerance in <Emphasis Type="Italic">Jatropha curcas</Emphasis>

Background  

Environmentally inflicted stresses such as salinity and drought limit the plant productivity both in natural and agricultural system. Increasing emphasis has been directed to molecular breeding strategies to enhance the intrinsic ability of plant to survive stress conditions. Functional screens in microorganisms with heterologous genes are a rapid, effective and powerful tool to identify stress tolerant genes in plants. Jatropha curcas (Physic nut) has been identified as a potential source of biodiesel plant. In order to improve its productivity under stress conditions to benefit commercial plantations, we initiated prospecting of novel genes expressed during stress in J. curcas that can be utilized to enhance stress tolerance ability of plant.