Aging is an oxidative stress-associated process that progresses with age. Our aim is to delay or attenuate these oxidative alterations and to keep individuals healthy as they age using natural compounds supplementation. Therefore, we conducted the present study to investigate the protective potentials of quercetin against D-galactose (D-gal)-associated oxidative alterations that were induced experimentally in male Wistar rats. Forty-five rats were randomly allocated into five groups of nine rats each. The groups were a control group that was reared on a basal diet and injected subcutaneously with 120 mg D-gal dissolved in physiological saline solution (0.9% NaCl) per kg body weight daily and quercetin-treated groups that received the same basal diet and subcutaneous daily D-gal injections were supplemented orally with 25, 50, and 100 mg of quercetin per kg body weight for 42 days. Pancreatic and renal samples were subjected to histopathological, immunohistochemical, and relative mRNA expression assessments. Aging (p53, p21, IL-6, and IL-8), apoptotic (Bax, CASP-3, and caspase-3 protein), proliferative (Ki67 protein), antiapoptotic (Bcl2 and Bcl2 protein), inflammatory (NF-κB, IL-1β, and TNF-α), antioxidant (SOD1), and functional markers (GCLC and GCLM genes and insulin, glucagon, and podocin proteins) were determined to evaluate the oxidative alterations induced by D-gal and the protective role of quercetin. D-gal caused oxidative alterations of the pancreas and kidneys observed via upregulations of aging, apoptotic, and inflammatory markers and downregulated the antiapoptotic, proliferative, antioxidant, and functional markers. Quercetin potentially attenuated these aging-related oxidative alterations in a dose-dependent manner. Finally, we can conclude that quercetin supplementation is considered as a promising natural protective compound that could be used to delay the aging process and to maintain human health.

Gastric ulcers are among the most broadly perceived illnesses affecting individuals. Alcohol consumption is the main cause of gastric ulceration. This study assessed the protective effects of Salvadora persica (SP) extract against ethanol‐induced gastric ulcer and elucidated the conceivable underlying mechanisms involved. For this purpose, 40 rats were allotted into 4 equal groups (control, ethanol‐ (EtOH‐) treated, and SP‐treated “SP200 and SP400” groups). The control and EtOH‐treated groups were given phosphate buffer saline (PBS), and both the SP200 and SP400 groups were given SP extract dissolved in PBS at doses of 200 and 400 mg/kg b.w., respectively. All treatments were given orally for 7 constitutive days. On the 8th day, all rats were fasted for 24 h followed by oral gavage of PBS in the control group and chilled absolute ethanol solution (5 ml/kg b.w.) in the EtOH‐ and SP‐treated groups to induce gastric lesions. One hour later, the rats were sacrificed and the stomachs were harvested. Gross and microscopic examinations of the EtOH‐treated group showed severe gastric hemorrhagic necrosis, submucosal edema, destruction of epithelial cells, and reduced glycoprotein content at the mucus surface. These pathological lesions were defeated by SP extract treatment. Administration of SP extract modulated the oxidative stress and augmented the antioxidant defenses. The elevated ethanol‐expressed tumor necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) genes, as well as bcl‐2‐like protein 4 (Bax) and inducible nitric oxide synthase (iNOS), were diminished in the SP‐treated group. Curiously, SP extract upregulated endothelial nitric oxide synthase (eNOS) and transforming growth factor‐β1 (TGF‐β1) gene expression comparable to that of the EtOH‐treated rats. Aggregately, SP exerted antiulcer activities in ethanol‐induced gastric ulcer rat models via modulation of oxidant/antioxidant status, mitigation of proinflammatory cytokines, and apoptosis, as well as remodeling of both NOS isoforms.

Iron oxide nanoparticle (IONP) therapy has diverse health benefits but high doses or prolonged therapy might induce oxidative cellular injuries especially in the brain. Therefore, we conducted the current study to investigate the protective role of quercetin supplementation against the oxidative alterations induced in the brains of rats due to IONPs. Forty adult male albino rats were allocated into equal five groups; the control received a normal basal diet, the IONP group was intraperitoneally injected with IONPs of 50 mg/kg body weight (B.W.) and quercetin-treated groups had IONPs + Q25, IONPs + Q50 and IONPs + Q100 that were orally supplanted with quercetin by doses of 25, 50 and 100 mg quercetin/kg B.W. daily, respectively, administrated with the same dose of IONPs for 30 days. IONPs induced significant increases in malondialdehyde (MDA) and significantly decreased reduced glutathione (GSH) and oxidized glutathione (GSSG). Consequently, IONPs significantly induced severe brain tissue injuries due to the iron deposition leading to oxidative alterations with significant increases in brain creatine phosphokinase (CPK) and acetylcholinesterase (AChE). Furthermore, IONPs induced significant reductions in brain epinephrine, serotonin and melatonin with the downregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) and mitochondrial transcription factor A (mtTFA) mRNA expressions. IONPs induced apoptosis in the brain monitored by increases in caspase 3 and decreases in B-cell lymphoma 2 (Bcl2) expression levels. Quercetin supplementation notably defeated brain oxidative damages and in a dose-dependent manner. Therefore, quercetin supplementation during IONPs is highly recommended to gain the benefits of IONPs with fewer health hazards.