1.Antioxidant and photoprotective effects of blanch water, a byproduct of the almond processing industry.
Mandalari G1, Arcoraci T, Martorana M, Bisignano C, Rizza L, Bonina FP, Trombetta D, Tomaino A. Molecules. 2013 Oct 9;18(10):12426-40. doi: 10.3390/molecules181012426.
The aim of the present work was to evaluate the antioxidant and photoprotective effect of blanch water (BW), a byproduct of the almond processing industry. The polyphenolic content of a BW extract, the level of proanthocyanidins and the vanillin index determination were determined. The antioxidant activity and the radical scavenging activity of the BW were evaluated by a range of in vitro tests. The in vivo photoprotective effect was investigated using a formulation containing 2% of the BW extract on skin erythema induced by acute UV-B exposure in twelve volunteers. Results confirmed the presence of added-value antioxidant compounds in the industrial BW extract, and the most representative compounds were naringenin-7-O-glucoside and kaempferol-7-O-rutinoside. The proanthocyanidin content was 71.84 ± 5.21 cyanidin equivalents/g of BW extract. The good antiradical activity of the BW extract was demonstrated in both the DPPH• test and in the Reducing Power test.
2.Substrate preference of citrus naringenin rhamnosyltransferases and their application to flavonoid glycoside production in fission yeast.
Ohashi T1, Hasegawa Y1, Misaki R1, Fujiyama K2. Appl Microbiol Biotechnol. 2016 Jan;100(2):687-96. doi: 10.1007/s00253-015-6982-6. Epub 2015 Oct 3.
Flavonoids, which comprise a large family of secondary plant metabolites, have received increased attention in recent years due to their wide range of features beneficial to human health. One of the most abundant flavonoid skeletons in citrus species is the flavanone naringenin, which is accumulated as glycosides containing terminal rhamnose (Rha) after serial glycosylation steps. The linkage type of Rha residues is a determining factor in the bitterness of the citrus fruit. Such Rha residues are attached by either an α1,2- or an α1,6-rhamnosyltransferase (1,2RhaT or 1,6RhaT). Although the genes encoding these RhaTs from pummelo (Citrus maxima) and orange (Citrus sinensis) have been functionally characterized, the details of the biochemical characterization, including the substrate preference, remain elusive due to the lack of availability of the UDP-Rha required as substrate. In this study, an efficient UDP-Rha in vivo production system using the engineered fission yeast expressing Arabidopsis thaliana rhamnose synthase 2 (AtRHM2) gene was constructed.
3.Vasorelaxant activity of 7-β-O-glycosides biosynthesized from flavonoids.
Penso J1, Cordeiro KC1, da Cunha CR1, da Silva Castro PF2, Martins DR2, Lião LM3, Rocha ML2, de Oliveira V4. Eur J Pharmacol. 2014 Jun 15;733:75-80. doi: 10.1016/j.ejphar.2014.03.014. Epub 2014 Apr 1.
In this work we report the vasorelaxant activity of 7-β-O-glycosides obtained with biosynthesis of naringenin-7-β-O-glycoside (3) and quercetin-7-β-O-glycoside (4). These compounds were obtained from naringenin (1) and quercetin (2) glycosylation catalyzed by Beauveria bassiana ATCC 7159. Screening of the best strain as a catalyst for glycosylation was carried out and the reaction conditions established. Cultures were grown in PDSM medium for 7 days at 27 °C. After purification by reverse-phase preparative HPLC, naringenin-7-β-O-glycoside (3) and quercetin-7-β-O-glycoside (4) were identified by (1)H and (13)C NMR. The right position and β-configuration of the glucose was determined through HSQC and HMBC experiments. The vasorelaxation potential of naringenin, quercetin and its glycosylated derivatives was evaluated using isolated aorta in vitro models. Interestingly, results suggest that vasorelaxation properties of naringenin, rutin and its glycosides are due to different pathways.
4.Protective effect of naringenin-7-O-glucoside against oxidative stress induced by doxorubicin in H9c2 cardiomyocytes.
Han XZ1, Gao S, Cheng YN, Sun YZ, Liu W, Tang LL, Ren DM. Biosci Trends. 2012 Feb;6(1):19-25. doi: 10.5582/bst.2012.v6.1.19.
Doxorubicin (DOX) is one of the most effective chemotherapeutic agents, but cardiotoxicity limits its clinical use. Although the mechanisms are not entirely understood, reactive oxygen species (ROS) and cardiomyocyte apoptosis appear to be involved in DOX cardiotoxicity. Protection or alleviation of DOX cardiotoxicity can be achieved by administration of natural phenolic compounds via activating endogenous defense systems and antiapoptosis. Naringenin-7-O-glucoside (NARG), isolated from Dracocephalum rupestre Hance, could protect from cardiomyocyte apoptosis and induce endogenous antioxidant enzymes against DOX toxicity, but the effects on intracellular ROS generation and cell membrane stability were not demonstrated. In the present study, we investigated the effects of NARG on H9c2 cell morphology, viability, lactate dehydrogenase (LDH) and creatine kinase (CK) leakage, glutathine peroxidase (GSH-Px) activity, intracellular Ca2+ concentration, and ROS generation.