Evaluating the Antioxidant Properties of the Leaves and Stems of Alpinia oxyphylla In Vitro and Its Growth-Promoting, Muscle Composition Change, and Antioxidative Stress Function on Juvenile Litopenaeus vannamei

Alpinia oxyphylla is a homology of medicine and food. This study aims to investigate the dominant chemical composition and explore the antioxidant properties of the ethanol extract of the leaves and stems of A. oxyphylla (AOE) on juvenile shrimp, Litopenaeus vannamei. An in vitro test showed that AOE and its dominant chemical composition procyanidin B-2 (1) and epicatechin (2) presented DPPH and ABTS radical scavenging activities. A shrimp feeding supplement experiment revealed that shrimp growth parameters and muscle composition were improved significantly when fed with a 200 mg/Kg AOE additive. Meanwhile, the activities of antioxidant enzymes (CAT, GSH-Px, SOD, and T-AOC) in serum and the liver and the expression of related genes (LvMn-SOD, LvCAT, LvproPo, and LvGSH-Px) were enhanced with various degrees in different AOE additive groups while the content of MDA was significantly decreased. Moreover, the antioxidative effect of AOE additive groups on shrimp was also observed in an acute ammonia nitrogen stress test.

Orientin Attenuated d-GalN/LPS-Induced Liver Injury through the Inhibition of Oxidative Stress via Nrf2/Keap1 Pathway

Oxidative stress is involved in the pathogenesis of liver diseases, including liver injury, a serious health problem worldwide. Natural polyphenols have attracted increasing attention as potential agents for the prevention and treatment of liver diseases. Orientin, a flavonoid component with antioxidant capacity, has been regarded as a promising nutraceutical for patients with liver damage. This study aimed to investigate the amelioration effect of orientin on d-galactosamine and lipopolysaccharides (d-GalN/LPS) induced liver injury in mice, with a focus on its underlying mechanisms by using the H₂O₂-induced oxidative damage model of HepG2 cells. Results indicated that orientin alleviated d-GalN/LPS-induced liver damage by improving the hepatic histological changes and reducing the levels of hepatic and serum alanine aminotransferase and aspartic acid aminotransferase. Additionally, supplementation of orientin improved the antioxidant ability in mice by decreasing the levels of hepatic malondialdehyde, protein carbonyl, myeloperoxidase, nitric oxide, glutathione, glutathione peroxidase, gluathione reductase, and superoxide dismutase. Orientin treatment significantly elevated both the protein and mRNA expressions of nuclear factor erythroid 2-related factor 2, Kelch-like ECH-associated protein-1, heme oxygenase-1, and nicotinamide quinone oxidoreductase 1 in liver and HepG2 cells. The management of orientin also elevated the protein expression of glutathione S-transferase and Maf in HepG2 cells. Taken together, it suggested that orientin played an amelioration effect on liver injury by suppressing oxidative stress, which might be strongly related to the activation of Nrf2/ARE through PI3K/Akt and P38/MAPK signal pathways.

Photoprotective effects of sweet potato leaf polyphenols and caffeic acid against UV-induced skin-damage in BALB/C nude mice

This study aimed at clarifying the mechanism by which sweet potato leaf polyphenols (SPLPs) ameliorate ultraviolet (UV) radiation damage, using the BALB/c hairless female mouse model. The moisture and hydroxyproline (HYP) contents of the model mouse skin and the thickness of the epidermis and dermis were determined by staining and histological examination. Anti-oxidative enzyme activities, malondialdehyde (MDA) content, and protein carbonyl content in skin tissue and serum were investigated. Expression of inflammatory markers and mitogen-activated protein kinase signaling pathways were evaluated. Topical caffeic acid at 30 mg kg^-1 most strongly inhibited the decrease in skin moisture, HYP content, and the thickening of the epidermis. Topical SPLP at 100 mg kg^-1 most significantly inhibited the dermal thickening, increased the activities of the superoxide dismutase, catalase as well as glutathione peroxidase, and decreased the content of serum MDA and protein carbonyls markedly. Furthermore, the topical SPLP suppressed the UV-induced rise in the inflammatory markers MMP-1, TNF-α, and NF-κB, and alleviated phosphorylation levels of the stress-signaling proteins JNK and p38. Thus, topical SPLP provided the best overall protection for mouse skin from UV-induced damage.

Differences in the Functional Activity and Redox Homeostasis Between the Left and Right Adrenal Gland of Rats Exposed to Chronic Isolation Stress

The aim of this study was to examine whether there are differences in adrenomedullary function in respect to the left and right sides in chronic stress conditions. We investigated how chronic stress isolation (CSI 12 weeks) affected the protein levels of key enzymes involved in adrenaline (A) synthesis (phenyl ethanolamine N-methyltransferase -PNMT), storage (vesicular monoamine transporters 2 - VMAT2) and degradation (catechol-O-methyltransferase - COMT), as well as the concentrations of A as an index for adrenomedullary function in the left and right adrenal medulla. Also, we examined the concentrations of malondialdehyde (MDA), protein levels of nuclear factor κB (NF-κB), and activity of catalase (CAT) in the left and right adrenal medulla. The investigated parameters were quantified by Western blot analysis, assay of enzymatic activity, and CAT Research ELISA kits. We found that CSI pro duced significantly increased levels of PNMT protein, and VMAT2 protein, as well as increased concentrations of A in the right adrenal medulla. However, we recorded that CSI increased protein levels of COMT and NF-κB, as well as the concentrations of MDA in the left adrenal medulla. Also, CSI decreased the activity of CAT only in the left adrenal medulla. Based on these results, it may be concluded that adrenomedullary function is different in respect to the left and right sides in chronic stress conditions.

Modulation of Hippocampal Antioxidant Defense System in Chronically Stressed Rats by Lithium

This study examined the effects of lithium on gene expression and activity of the antioxidant enzymes copper zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in the hippocampus of chronically stressed rats. In addition, we examined the effects of lithium on anxiety behaviors, hippocampal concentrations of dopamine (DA) and malondialdehyde (MDA), protein levels of brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT), as well as activity of monoamine oxidase (MAO) in chronically stressed rats. The investigated parameters were quantified by real-time RT-PCR, Western blot analyses, and assays of enzyme activities. We found that lithium did not change gene expression of SOD1, CAT, GPx, and GR but decreased gene expression of SOD2 in chronically stressed rats. A very important result in this study was that lithium treatment decreased the enzyme activities of SOD1 and SOD2 but increased the enzyme activities of GPx and GR in stress condition, which indicates the control of redox balance. The reduced concentration of MDA confirms this. In addition, we found that lithium treatment decreased high protein levels of BDNF and DAT in chronically stressed rats to the level found in unstressed animals. Also, lithium treatment increased the expression of TH but decreased the enzyme activity of MAO B, which contributed to the increase of hippocampal concentration of DA in chronically stressed rats to the level of unstressed animals. Finally, lithium treatment in animals exposed to chronic stress increased the time spent in open arms. Lithium-induced modulation of hippocampal antioxidant status and attenuation of oxidative stress stabilized behavior in animals with high anxiety index. In addition, reduced oxidative stress was followed by the changes of both turnover of DA and levels of BDNF protein in chronically stressed rats treated with lithium. These findings may be important in preclinical research of the effects of lithium on oxidative stress level in pathological conditions.

Hydrogen peroxide-induced oxidative stress, acetylcholinesterase inhibition, and mediated brain injury attenuated by Thymus algeriensis

The aim of the current study was to evaluate acetylcholinesterase (AChE) inhibition, antioxidant enzyme activities, and malondialdehyde (MDA) levels induced by hydrophobic fractions of Thymus algeriensis (HFTS) growing in Tunisia. The results showed that hydrogen peroxide (H₂O₂), an oxidative stress inducer, acts by decreasing the body mass and brain mass of rats. Moreover, we found higher MDA levels in the group treated with H₂O₂ (P < 0.05) and a significantly lower activity of catalase, glutathione peroxidase, glutathione S-transferase, and superoxide dismutase, as well as a reduction in reduced glutathione activity in the brain tissues of H₂O₂-treated rats when compared with those of the control group (P < 0.05); however, rats that received HFTS with H₂O₂ experienced a decrease in MDA levels in the brain. In contrast, HFTS demonstrated neuroprotective effects in rat brain. Overall, exposure to HFTS prior to H₂O₂ induced a marked dose-dependent increase in reactive oxygen species scavenger levels (P < 0.05) accompanied by a statistically significant decrease in MDA levels (P < 0.05) when compared with no exposure. Notably, the activity of AChE was affected by exposure to natural compounds; levels were significantly lower in HFTS-treated rats and in those treated with the combination of HFTS and a low or high dose of H₂O₂. Furthermore, histopathological analysis showed that brain injuries occurred with high doses of H₂O₂ administered alone or with a low dose of HFTS, whereas a high dose of essential oil markedly alleviated neurone degeneration. The results suggest that HFTS alleviates neuroinflammation by acting as an AChE inhibitor and attenuates H₂O₂-induced brain toxicity.