Comparative Analysis of the Developmental Toxicity in Xenopus laevis and Danio rerio Induced by Al2 O3 Nanoparticle Exposure.

Engineered aluminum oxide nanoparticles (Al2 O3 NPs) having high-grade thermal stability and water-dispersion properties are extensively used in different industries and personal care products. Toxicological response evaluation of these NPs is indispensable in assessing the health risks and exposure limits because of their industrial disposal into the aquatic environment. We assessed and compared the developmental toxicity of Al2 O3 NPs in Xenopus laevis and Danio rerio over a period of 96 h using the frog embryo teratogenic assay Xenopus and a fish embryo toxicity assay. Engineered Al2 O3 NP exposure produced dose-dependent embryonic mortality and decreased the embryo length, indicating a negative effect on growth. Moreover, Al2 O3 NPs induced various malformations, such as small head size, a bent/deformed axis, edema, and gut malformation, dose-dependently and altered the expression of heart- and liver-specific genes in both X. laevis and D. rerio, as revealed by whole-mount in-situ hybridization and reverse transcriptase polymerase chain reaction. In conclusion, the toxicological data suggest that Al2 O3 NPs are developmentally toxic and teratogenic and negatively affect the embryonic development of X. laevis and D. rerio. Our study can serve as a model for the toxicological evaluation of nanomaterial exposure on vertebrate development that is critical to ensure human and environmental safety. Environ Toxicol Chem 2019;38:2672-2681. © 2019 SETAC.

Induction of apoptosis by obovatol as a novel therapeutic strategy for acute myeloid leukemia.

Obovatol, a compound isolated from the bark cortex of Magnolia officinalis (cortex Magnoliae officinalis; M. officinalis), has been studied for use in the treatment of solid cancers. However, the mechanisms of action and the effects of obovatol against acute myeloid leukemia (AML) remain unclear and require further investigation. Therefore, this study was conducted using a human AML cell line (MM6). Obovatol increased pro-apoptotic (Bax) and decreased anti-apoptotic (Bcl-2) protein expression, resulting in caspase-3 and caspase-9 activation measured by caspase-Glo 3/7 assay. Furthermore, obovatol activated the mitogen-activated protein kinase (MAPK) signaling pathway [c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38] and inhibited the activation of the nuclear factor-κB (NF-κB) signaling pathway analyzed by western blot analysis. Taken together, these findings provide evidence that obovatol inhibits cell proliferation in AML and induces apoptosis through the activation of the MAPK pathway in addition to the intrinsic apoptotic pathway. In addition, obovatol suppressed the expression of mixed-lineage leukemia (MLL) target genes by inhibiting the activation of the NF-κB pathway. Therefore, these results suggest that obovatol may have potential for use in the treatment of leukemia.

Antiobesity effect of Gynostemma pentaphyllum extract (actiponin): a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: The effects of actiponin was investigated, a heat-processed Gynostemma pentaphyllum extract, on body weight, fat loss, and metabolic markers of Korean participants in a 12-week, randomized, double-blind, placebo-controlled clinical trial. DESIGN AND METHODS: Obese participants (BMI ≥ 25 kg m(-2) and WHR ≥ 0.90 for male or WHR ≥ 0.85 for female) who had not been diagnosed with any disease and met the inclusion criteria were recruited for this study. The 80 subjects were randomly divided into actiponin (n = 40, 450 mg day(-1) ) and placebo (n = 40) groups. Outcomes included measurement of efficacy (abdominal fat distribution, anthropometric parameters, and blood lipid profiles) and safety (adverse events, laboratory test results, electrocardiogram data, and vital signs). RESULTS: During 12-week of actiponin supplementation, total abdominal fat area, body weight, body fat mass, percent body fat, and BMI were significantly decreased (P = 0.044, P < 0.05, P < 0.0001, P < 0.0001, and P < 0.05, respectively) in the actiponin group compared to the placebo group. No clinically significant changes in any safety parameter were observed. CONCLUSION: Our study revealed that actiponin is a potent antiobesity reagent that does not produce any significant adverse effects. These results suggest that actiponin supplementation may be effective for treating obese individuals.

Heat-processed Gynostemma pentaphyllum extract improves obesity in ob/ob mice by activating AMP-activated protein kinase.

Gynostemma pentaphyllum is widely used in Asian countries as a herbal medicine to treat dyslipidemia, type 2 diabetes and inflammation. An ethanol extract of G. pentaphyllum lessened obesity by activating AMP-activated protein kinase (AMPK). The levels of damulins A and B, components responsible for AMPK activation in the extract, were increased by autoclaving in a time-dependent manner. Heat-processed G. pentaphyllum extract, actiponin containing damulins A (0.93 %, w/w) and B (0.68 %, w/w), significantly stimulated fat oxidation and glucose uptake via AMPK activation in L6 myotube cells. Oral administration of actiponin to ob/ob mice for 8 weeks decreased body weight gain, liver weight, and blood cholesterol levels with AMPK activation in the soleus muscle. Our results demonstrate the beneficial effect of G. pentaphyllum on improving obesity and have elucidated the underlying molecular mechanisms.

The essential oil from Angelica gigas NAKAI suppresses nicotine sensitization.

Behavioral sensitization, as evidenced by the progressive enhanced locomotor response to a subsequent injection of the drug, is the major behavioral outcome produced by repeated injections of nicotine, and a model for studying drug addiction. It is putatively regarded that the alteration of extracellular dopamine release in the nucleus accumbens is closely associated with nicotine-induced behavioral sensitization. The present study was performed to evaluate the effects of the essential oil from Angelica gigas NAKAI (on fragrance inhalation) on repeated nicotine-induced locomotor activity and extracellular dopamine levels in the nucleus accumbens of rats using in vivo microdialysis. Rats were given repeated injections of saline or nicotine (0.4 mg/kg s.c., twice a day for 7 d), followed by one challenge injection on the 4th day after the last daily injection. Systemic challenge with nicotine (0.4 mg/kg s.c.) produced a larger increase in locomotor activity in nicotine-pretreated rats than in saline-pretreated rats. A direct local challenge of 3 mM nicotine via a microdialysis probe also induced a larger increase in dopamine release in nicotine-pretreated rats than in saline-pretreated rats. Most importantly, our results showed that inhalation of the essential oils from Angelica gigas NAKAI significantly decreased both dopamine release in the nucleus accumbens and locomotor activity induced by a nicotine challenge. These results suggest that the essential oils from Angelica gigas NAKAI inhibit nicotine-induced behavioral and neurochemical sensitization, and imply that the essential oil from Angelica gigas NAKAI may be effective in treating nicotine addiction, possibly by modulating dopamine release in the nucleus accumbens.

Vitamin E supplementation alters HDL-cholesterol concentration and paraoxonase activity in rabbits fed high-cholesterol diet: comparison with probucol.

Vitamin E and probucol are well-known antioxidants that prevent cells from the oxidative stress, which is a risk factor of atherosclerosis. Male rabbits were fed either 0.03% vitamin E or 0.05% probucol in a 0.5% high-cholesterol (HC) diet for 8 weeks. Vitamin E and probucol significantly suppressed an increase in plasma total-cholesterol (total-C) and low-density lipoprotein cholesterol compared to HC-control group. However, plasma high-density lipoprotein-cholesterol (HDL-C) and HDL-C/total-C ratio levels and plasma paraoxonase activity were only significantly higher in vitamin E group after 8 weeks. Hepatic ACAT activity was significantly lower in both vitamin E and probucol groups than in HC-control group, while HMG-CoA reductase activity was the highest only in the probucol group. Total fecal sterol content was significantly higher in probucol and vitamin E groups than in the two control groups. Some atherogenic signs were discovered in the aortic fatty streak of HC-control group, yet not in other groups. Hepatic mRNA expressions of apo B-100 and apo C-III were significantly lower in probucol group than in other groups. Vitamin E supplementation was found to alter the plasma HDL-C-related factors; meanwhile, probucol supplementation was very effective in enhancing cholesterol metabolism, except for a negative effect that reduced plasma HDL-C concentration.

Anti-diabetic effects of DA-11004, a synthetic IDPc inhibitor in high fat high sucrose diet-fed C57BL/6J mice.

DA-11004 is a synthetic, potent NADP-dependent isocitrate dehydrogenase (IDPc) inhibitor where IC50 for IDPc is 1.49 microM. The purpose of this study was to evaluate the effects of DA-11004 on the high fat high sucrose (HF)-induced obesity in male C57BL/6J mice. After completing a 8-week period of experimentation, the mice were sacrificed 1 hr after the last DA-11004 treatment and their blood, liver, and adipose tissues (epididymal and retroperitoneal fat) were collected. There was a significant difference in the pattern of increasing body weight between the HF control and the DA-11004 group. In the DA-11004 (100 mg/kg) treated group the increase in body weight significantly declined and a content of epididymal fat and retroperitoneal fat was also significantly decreased as opposed to the HF control. DA-11004 (100 mg/ kg) inhibited the IDPc activity, and thus, NADPH levels in plasma and the levels of free fatty acid (FFA) or glucose in plasma were less than the levels of the HF control group. In conclusion, DA-11004 inhibited the fatty acid synthesis in adipose tissues via IDPc inhibition, and it decreased the plasma glucose levels and FFA in HF diet-induced obesity of C57BL/6J mice.

Two cinnamate derivatives produce similar alteration in mRNA expression and activity of antioxidant enzymes in rats.

Cinnamate is a widespread secondary metabolite of phenolic compound synthesized by plants for defensive purposes. The current study was designed to investigate the effect of two structurally related cinnamate derivatives, 4-hydroxycinnamate and 3-(4-hydroxyphenyl)propionic acid (HPP), on the mRNA expression and activity of antioxidant enzymes in high-cholesterol-fed rats. Male rats were fed a 1 g/100 g high-cholesterol diet with supplements of either 4-hydroxycinnamate or HPP (0.135 mmol/100 g diet) for 6 weeks. The plasma paraoxonase activity was found to be higher in the cinnamate-derivative-supplemented groups than in the control group. The erythrocyte superoxide dismutase (SOD) and catalase (CAT) activities, plus glutathione (GSH) level, were all significantly higher in the 4-hydroxycinnamate- and HPP-supplemented groups than in the control group. However, both 4-hydroxycinnamate and HPP supplementation significantly lowered the hepatic activities and mRNA expression of CAT and glutathione peroxidase (GSH-Px) compared to the control group. The hepatic mRNA expression and activity of SOD did not differ between the groups. The hepatic thiobarbituric acid reactive substances (TBARS) level was significantly lowered by the 4-hydroxycinnamate and HPP supplementation. Accordingly, these results indicate that supplementation by 4-hydroxycinnamate and HPP would seem to enhance the antioxidative defense of erythrocyte. Both HPP and 4-hydroxycinnamate would appear to be beneficial in improving the function of antioxidative enzymes on a molecular level in high-cholesterol-fed rats.

Cinnamate supplementation enhances hepatic lipid metabolism and antioxidant defense systems in high cholesterol-fed rats.

This study investigated the effect of cinnamate, a phenolic compound found in cinnamon bark and other plant materials, on lipid metabolism and antioxidant enzyme activities in rats fed a high cholesterol diet. Three groups of rats were given a diet containing 1 g of cholesterol/kg for 6 weeks. The control group only received the high cholesterol diet, whereas the other two groups received a diet supplemented with lovastatin or cinnamate (0.1 g/100 g of diet). The plasma high-density lipoprotein-cholesterol levels were significantly higher in the cinnamate group than in either the control or lovastatin groups, and the atherogenic index was significantly lower in rats with cinnamate supplementation. Supplementation with cinnamate resulted in significantly lower hepatic cholesterol and triglyceride levels. Accumulation of hepatic lipid droplets was higher in the control group than in the rats supplemented with either cinnamate or lovastatin. Hepatic 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase activity was significantly lower in the cinnamate group compared with the other groups, whereas only acyl-CoA:cholesterol acyltransferase activity was significantly lower in the lovastatin group compared with the control group. Cinnamate supplementation resulted in higher catalase and glutathione peroxidase activities, while hepatic thiobarbituric acid-reactive substances were significantly lower in both the cinnamate and lovastatin groups. The fecal acidic sterol was higher in the lovastatin group than in the control or cinnamate groups. These results suggest that dietary cinnamate inhibits hepatic HMG-CoA reductase activity, resulting in lower hepatic cholesterol content, and suppresses lipid peroxidation via enhancement of hepatic antioxidant enzyme activities.

Evaluation by mutagenesis of the importance of 3 arginines in alpha, beta, and gamma subunits of human NAD-dependent isocitrate dehydrogenase.

Mammalian NAD-dependent isocitrate dehydrogenase is an allosteric enzyme, activated by ADP and composed of 3 distinct subunits in the ratio 2alpha:1beta:1gamma. Based on the crystal structure of NADP-dependent isocitrate dehydrogenases from Escherichia coli, Bacillus subtilis, and pig heart, and a comparison of their amino acid sequences, alpha-Arg88, beta-Arg99, and gamma-Arg97 of human NAD-dependent isocitrate dehydrogenase were chosen as candidates for mutagenesis to test their roles in catalytic activity and ADP activation. A plasmid harboring cDNA that encodes alpha, beta, and gamma subunits of the human isocitrate dehydrogenase (Kim, Y. O., Koh, H. J., Kim, S. H., Jo, S. H., Huh, J. W., Jeong, K. S., Lee, I. J., Song, B. J., and Huh, T. L. (1999) J. Biol. Chem. 274, 36866-36875) was used to express the enzyme in isocitrate dehydrogenase-deficient E. coli. Wild type (WT) and mutant enzymes (each containing 2 normal subunits plus a mutant subunit with alpha-R88Q, beta-R99Q, or gamma-R97Q) were purified to homogeneity yielding enzymes with 2alpha:1beta:1gamma subunit composition and a native molecular mass of 315 kDa. Specific activities of 22, 14, and 2 micromol of NADH/min/mg were measured, respectively, for WT, beta-R99Q, and gamma-R97Q enzymes. In contrast, mutant enzymes with normal beta and gamma subunits and alpha-R88Q mutant subunit has no detectable activity, demonstrating that, although beta-Arg99 and gamma-Arg97 contribute to activity, alpha-Arg88 is essential for catalysis. For WT enzyme, the Km for isocitrate is 2.2 mm, decreasing to 0.3 mm with added ADP. In contrast, for beta-R99Q and gamma-R97Q enzymes, the Km for isocitrate is the same in the absence or presence of ADP, although all the enzymes bind ADP. These results suggest that beta-Arg99 and gamma-Arg97 are needed for normal ADP activation. In addition, the gamma-R97Q enzyme has a Km for NAD 10 times that of WT enzyme. This study indicates that a normal alpha subunit is required for catalytic activity and alpha-Arg88 likely participates in the isocitrate site, whereas the beta and gamma subunits have roles in the nucleotide functions of this allosteric enzyme.