Synergistic Promotion on Tyrosinase Inhibition by Antioxidants.

When exposed to ultraviolet radiation, the human skin produces profuse reactive oxygen species (ROS), which in turn activate a variety of biological responses. Mounting ROS levels activate tyrosinase by mobilizing α-melanocyte-stimulating hormone in the epidermis and finally stimulates the melanocytes to produce melanin. Meanwhile, the Keap1-Nrf2/ARE pathway, which removes ROS, is activated at increased ROS levels, and antioxidant compounds facilitates the dissociation of Nrf2. In this study, we explored the possible suppressing effects of antioxidant compounds and tyrosine inhibitors on melanin formation and the promotory effects of these compounds on ROS scavenging. The antioxidant activity of glabridin (GLA), resveratrol (RES), oxyresveratrol (OXYR), and phenylethylresorcinol (PR) were investigated via the stable free radical 2,2-diphenyl-1-picrylhydrazyl method. The inhibitory effects of the four compounds and their mixtures on tyrosinase were evaluated. l-Tyrosine or 3-(3,4-dihydroxyphenyl)-l-alanine (l-DOPA) was used as a substrate. The results showed that all mixtures did not exhibit synergistic effects with the l-tyrosine as a substrate, suggesting that l-tyrosine is not suitable as a substrate. However, the mixtures of "GLA:RES," "GLA:OXYR," "OXYR:RES," and "PR:RES" demonstrated synergistic effects (CI < 0.9, p < 0.05), whereas "GLA:RES" and "PR:OXYR" indicated an additive effect (0.9 ditive1, p < 0.05). Furthermore, we used a molecular docking strategy to study the interactions of the four compounds with tyrosinase and l-DOPA. The molecular docking result is consistent with that of the experiment. Finally, we selected RES + OXYR and used PIG1 cells to verify whether OXYR synergistically promotes RES activity on tyrosinase. The two agents had a synergistic inhibitory effect on tyrosinase activity. These results provided a novel synergistic strategy for antioxidants and tyrosinase inhibitors, and this strategy is useful in skin injury treatment.

Heijiangdan ointment relieves oxidative stress from radiation dermatitis induced by (60)Co γ-ray in mice.

OBJECTIVE: To investigate the effects of Heijiangdan Ointment ( HJD) on oxidative stress in (60)Co γ-ray radiation-induced dermatitis in mice. METHODS: Female Wistar mice with grade 4 radiation dermatitis induced by (60)Co γ-rays were randomly divided into four groups (n=12 per group); the HJD-treated, recombinant human epidermal growth factor (rhEGF)-treated, Trolox-treated, and untreated groups, along with a negative control group. On the 11th and 21st days after treatment, 6 mice in each group were chosen for evaluation. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), and lactate dehydrogenase (LDH) were detected using spectrophotometric methods. The fibroblast mitochondria were observed by transmission electron microscopy (TEM). The expressions of fibroblast growth factor 2 (FGF-2) and transforming growth factor ß1 (TGF-ß1) were analyzed by western blot. RESULTS: Compared with the untreated group, the levels of SOD, MDA and LDH, on the 11th and 21st days after treatment showed significant difference (P<0.05). TEM analysis indicated that fibroblast mitochondria in the untreated group exhibited swelling and the cristae appeared fractured, while in the HJD group, the swelling of mitochondria was limited and the rough endoplasmic reticulum appeared more relaxed. The expressions of FGF-2 and TGF-ß1 increased in the untreated group compared with the negative control group (P<0.05). After treatment, the expression of FGF-2, rhEGF and Trolox in the HJD group were significantly increased compared with the untreated group (P<0.05), or compared with the negative control group (P<0.05). The expression of TGF-ß1 showed significant difference between untreated and negative control groups (P<0.05). HJD and Trolox increased the level of TGF-ß1 and the difference was marked as compared with the untreated and negative control groups (P<0.05). CONCLUSION: HJD relieves oxidative stress-induced injury, increases the antioxidant activity, mitigates the fibroblast mitochondrial damage, up-regulates the expression of growth factor, and promotes mitochondrial repair in mice.

[Study on pharmacokinetics and in vitro/in vivo correlation of menthol in Zhike Chuanbei Pipa dropping pills in rats].

To determine the concentration of menthol in rat plasma by GC. Rats were administered with single dose of Zhike Chuanbei Pipa dropping pills (ZCPDP) and different doses of menthol herbs. DAS 3. 1.6 software was used to calculate pharmacokinetic parameters, and the accumulative absorption percentage of menthol was calculated by Loo-Riegelman method. The linear regression analysis was made in vitro/in vivo accumulative absorption percentages to detect the in vitro/in vivo correlation. The results of the study showed that the pharmacokinetics behavior of menthol in ZCPDP was in conformity with two-compartment model characteristics. The main parameters were: tmax was 10 min, t1/2beta was (183. 93 52. 75) min, CL/F was (0. 426 +/- 0. 194) L . min-1 . kg-1, all of which were no difference between ZCPDP and menthol herbs with the same dosage. There were significant differences in tmax, t1/2beta, CL/F between menthol herbs with different dosages (P <0. 05) , with indirect proportion between AUC0-infinity and dosage. The regression equation of ZCPDP's accumulative absorption percentage and accumulative release percentage was Fa = 1. 160 3Q - 19. 968, r = 0. 981 3. These results suggested that the pharmacokinetics behavior was similar between ZCPDP and menthol herbs with the same dosage in rats, with good in vitro/in vivo correlation. There were significant differences in pharmacokinetics of menthol in the range of 19.2-570 mg . kg-1.

Effect of antiallergic herbal agents on chloride channel-3 and immune microenvironment in nasal mucosal epithelia of allergic rhinitis rabbits.

BACKGROUND: Allergic rhinitis (AR) is a Th2 dominant cytokine response. Chloride channel-3 (ClC-3) plays an important role in nasal mucosal edema and inflammatory pathologic changes in AR. Antiallergic herbal agents (AHA) are antiallergic herbal products. In the previous study, we have demonstrated that AHA clearly inhibited allergic medium and relieved allergic reaction of AR. The aim of this study was to evaluate the function of ClC-3 and discuss the possible therapeutic effects of AHA on immune microenvironment in AR. METHODS: AHA were produced and used to treat AR. An animal model of an AR rabbit was established by ovalbumin (OVA). The rhinitis rabbits were randomly divided into three groups: AHA treated group (AHATG), model group (MG) and healthy control group (HCG). The expressions of ClC-3 protein were examined by immunohistochemical method. The mucosal epithelial cells of all the rabbit groups were primarily cultured with tissue culture method in vitro with or without rhIL-4 or rhIL-2. Furthermore, the expressions of ClC-3 mRNA were detected by real-time PCR. The levels of monocyte chemotactic factor-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) protein in culture supernatants were measured by ELISA. RESULTS: The expressions of ClC-3 mRNA increased more in mucosal epithelial cells of MG than those in AHATG and HCG (P < 0.01). The levels of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of MG were significantly higher than those in the other two groups (P < 0.01). Those were significantly increased in MG untreated 12 hours later than those in other two groups (P < 0.01). The expressions of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of MG and HCG treated with rhIL-4 were significantly higher than those in the AHATG treated with rhIL-4 (P < 0.01). The levels of ClC-3 mRNA, MCP-1 and VCAM-1 protein in culture supernatants of all groups treated with rhIL-2 showed no significant changes (P > 0.05). CONCLUSIONS: AHA can inhibit the secretions of ClC-3, MCP-1 and VCAM-1 in mucosal epithelia and improve inflammatory reaction of AR. ClC-3 plays an important role in the secretion of cytokines and mucosal inflammatory response in AR. RhIL-4 can enhance the secretion of ClC-3, MCP-1 and VCAM-1 in mucosal epithelial cells, especially during the AR process. These enhanced effects of rhIL-4 were significantly suppressed by AHA. The secretions of ClC-3, MCP-1 and VCAM-1 can not be induced obviously by rhIL-2 in mucosal epithelial cells in AR.

Cranberry phytochemical extract inhibits SGC-7901 cell growth and human tumor xenografts in Balb/c nu/nu mice.

Cranberry extract possesses potent antioxidant capacity and antiproliferative activity against cancer in vitro and in vivo. The objectives of this study were to determine whether the cranberry extract inhibited proliferation of human gastric cancer SGC-7901 cells and human gastric tumor xenografts in the Balb/c nu/nu mouse. Cranberry extract at doses of 0, 5, 10, 20, and 40 mg/mL significantly inhibited proliferation of SGC-7901 cells, and this suppression was partly attributed to decreased PCNA expression and apoptosis induction. In a human tumor xenograft model, the time of human gastric tumor xenografts in the mouse was delayed in a dose-dependent manner. A dose-response inhibition was also observed in the averages of size, weight, and volume of tumor xenografts in the mouse between the control and cranberry-treated groups. These results demonstrate fresh cranberries to be a chemopreventive reagent.

[Inhibitory effect of oxaliplatin in combination with hyperthermia on angiogenesis].

OBJECTIVE: To study the effect of oxaliplatin in combination with hyperthermia on angiogenesis in vitro and in vivo. METHODS: MTT method was used to observe the influence of oxaliplatin on the proliferation of human umbilical vein endothelial cells (HUVEC) or human colon cancer cells (LOVO). The influence of oxaliplatin on HUVEC migration was evaluated by Transwell. Chick embryo chorioallantoic membrane (CAM) model was used to check whether the neovascularization of CAM could be suppressed in vivo. RESULTS: The survival rate of HUVEC was 80.1% - 42.5% within a range of 0.5 - 16 microg/ml and was negatively correlated with the concentration (correlation coefficient was - 0. 943, P = 0.005). The survival rate of LOVO cells within those doses was more than that of HUVEC. There was a synergistic antiangiogenic effect when a combination of oxaliplatin (0.5 microg/ml, 1 microg/ml and 16 microg/ml) with hyperthermia was used while additional effect was shown by the combinatioin of oxaliplatin (2 microg/ml, 4 microg/ml and 8 microg/ml) and hyperthermia in vitro. Oxaliplatin inhibited migration of HUVEC in vitro at low doses (0.25 - 2 microg/ml), and also suppressed angiogenesis of CAM in vivo at doses of 1 -4 microg/ml. CONCLUSION: The results of this experiment showed that low dose of oxaliplatin has anti-angiogenic effect in vitro, while in combination with hyperthermia has additional effect both in vivo and in vitro.