1.
The effect of grape products containing polyphenols on C-reactive protein levels: a systematic review and meta-analysis of randomised controlled trials.
Sarkhosh-Khorasani, S, Hosseinzadeh, M
The British journal of nutrition. 2021;(11):1230-1245
Abstract
Although grape polyphenols can decrease chronic inflammations, their effect on C-reactive protein (CRP) levels is still controversial. So, this meta-analysis was conducted to investigate the effect of grape products containing polyphenols on CRP concentrations. In order to collect the relevant randomised controlled trials (RCT), the databases of PubMed, Scopus, Web of Science and Google Scholar were searched up to 30 March 2020. The random effects model, standardised mean difference (SMD) and 95 % CI were applied in data analysis. Meta-analysis was conducted over seventeen eligible RCT containing a total of 668 participants. The study registration number is CRD42018110169. Based on the results, grape products containing polyphenols decreased CRP levels significantly (SMD = −0·229; 95 % CI −0·41, −0·05; P = 0·013). Sensitivity analysis was performed by removing each individual study and the results did not change. According to the subgroup analysis, higher doses of grape polyphenols (>500 mg/d) and longer intervention periods (≥12 weeks) had significant effects on CRP levels. Furthermore, grape polyphenols significantly reduced the CRP levels in patients with a clinical condition. In the same vein, grape seed extract and other grape products, such as grape extract, juice and raisins, decreased CRP levels significantly. According to the meta-regression results, the CRP level depends on the dose and duration of the grape polyphenol supplementation. Based on the findings, grape products containing polyphenols had a significant effect on CRP levels. Further well-designed and long-term clinical trials are highly recommended to achieve more comprehensive and accurate results.
2.
Water status and must composition in grapevine cv. Chardonnay with different soils and topography and a mini meta-analysis of the δ13 C/water potentials correlation.
Brillante, L, Mathieu, O, Lévêque, J, van Leeuwen, C, Bois, B
Journal of the science of food and agriculture. 2018;(2):691-697
Abstract
BACKGROUND The measurement of carbon isotopic discrimination in grape sugars at harvest (δ13 C) is an integrated assessment of water status during ripening. It is an efficient alternative to assess variability in the field and discriminate between management zones in precision viticulture, but further work is needed to completely understand the signal. RESULTS This work, spanning over 3 years, performed in a hillslope toposequence in Burgundy, delineates the relationships between main soil properties (gravel amount, slope, texture) and the grapevine water status assessed by δ13 C. The highest δ13 C, indicating most severe water deficit, was recorded in gravelly soils on steep slopes. The amount of sugars and malic and tartaric acids was also related to δ13 C. The relationship between δ13 C and predawn leaf water potentials (Ψpd ) was also investigated, because the absolute values of measured δ13 C were lower than the values currently found in the literature. CONCLUSIONS A mini-meta-analysis was performed, which showed that the slope of the relationships between minimum Ψpd and δ13 C was stable across studies (a change of 1‰ in δ13 C corresponded to a change of -0.2 MPa in the minimum Ψpd ), while the intercept of the comparison δ13 C/Ψpd changed, probably because of genetic variations between varieties, or environmental differences. © 2017 Society of Chemical Industry.
3.
Factors influencing stomatal conductance in response to water availability in grapevine: a meta-analysis.
Lavoie-Lamoureux, A, Sacco, D, Risse, PA, Lovisolo, C
Physiologia plantarum. 2017;(4):468-482
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Abstract
The main factors regulating grapevine response to decreasing water availability were assessed under statistical support using published data related to leaf water relations in an extensive range of scion and rootstock genotypes. Matching leaf water potential (Ψleaf ) and stomatal conductance (gs ) data were collected from peer-reviewed literature with associated information. The resulting database contained 718 data points from 26 different Vitis vinifera varieties investigated as scions, 15 non-V. vinifera rootstock genotypes and 11 own-rooted V. vinifera varieties. Linearised data were analysed using the univariate general linear model (GLM) with factorial design including biological (scion and rootstock genotypes), methodological and environmental (soil) fixed factors. The first GLM performed on the whole database explained 82.4% of the variability in data distribution having the rootstock genotype the greatest contribution to variability (19.1%) followed by the scion genotype (16.2%). A classification of scions and rootstocks according to their mean predicted gs in response to moderate water stress was generated. This model also revealed that gs data obtained using a porometer were in average 2.1 times higher than using an infra-red gas analyser. The effect of soil water-holding properties was evaluated in a second analysis on a restricted database and showed a scion-dependant effect, which was dominant over rootstock effect, in predicting gs values. Overall the results suggest that a continuum exists in the range of stomatal sensitivities to water stress in V. vinifera, rather than an isohydric-anisohydric dichotomy, that is further enriched by the diversity of scion-rootstock combinations and their interaction with different soils.