Enhancement of TRP Gene Expression and UV Absorption by Bioconverted Chestnut Inner Shell Extracts Using Lactiplantibacillus plantarum

In this work, the suppression of tyrosinase-related genes, including an improvement in UV absorption effects of bioconverted CS extracts (BCS), was investigated to improve the skin-whitening effect. Total polyphenols and total flavonoids, which are bioactive components, increased 2.6- and 5.4-times in bioconversion using Lactiplantibacillus plantarum SM4, respectively, as compared to ultrasound-assisted extracts (UCS). The effect of BCS on radical scavenging activity, UV-A absorption, and tyrosinase activity inhibition, contributing to skin-whitening, were 1.3-, 1.2-, and 1.2-times higher than those of UCS, respectively. The main component identified in high-performance liquid chromatography (HPLC) was gallic acid in both UCS and BCS, which increased by 2.9-times following bioconversion. The gene expression of tyrosinase-related proteins, including TRP-1 and TRP-2 genes, was studied to confirm the suppression of melanin synthesis by BCS in order to identify the skin-whitening mechanism, and BCS decreased both genes’ expression by 1.7- and 1.6-times, demonstrating that BCS effectively suppressed melanin synthesis. These findings imply that the chestnut inner shell can be employed as a cosmetic material by simultaneously inhibiting melanogenesis and enhancing UV-A absorption through bioconversion using L. plantarum SM4.     

Bee venom stimulates human melanocyte proliferation, melanogenesis, dendricity and migration

Pigmentation may result from melanocyte proliferation, melanogenesis, migration or increases in dendricity. Recently, it has been reported that secreted phospholipase A(2)(sPLA(2)) known as a component of bee venom (BV), stimulates melanocyte dendricity and pigmentation. BV has been used clinically to control rheumatoid arthritis and to ameliorate pain via its anti-inflammatory and antinociceptive properties. Moreover, after treatment with BV, pigmentation around the injection sites was occasionally observed and the pigmentation lasted a few months. However, no study has been done about the effect of BV on melanocytes. Thus, in the present study, we examined the effect of BV on the proliferation, melanogenesis, dendricity and migration in normal human melanocytes and its signal transduction. BV increased the number of melanocytes dose and time dependently through PKA, ERK, and PI3K/Akt activation. The level of cAMP was also increased by BV treatment. Moreover, BV induced melanogenesis through increased tyrosinase expression. Furthermore, BV induced melanocyte dendricity and migration through PLA(2) activation. Overall, in this study, we demonstrated that BV may have an effect on the melanocyte proliferation, melanogenesis, dendricity and migration through complex signaling pathways in vitro, responsible for the pigmentation. Thus, our study suggests a possibility that BV may be developed as a therapeutic drug for inducing repigmentation in vitiligo skin.     

Melanocyte-stimulating Properties of Secretory Phospholipase A2

Abstract— Phospholipase A₂ (PLA₂) catalyzes the release of free fatty acids from membrane phospholipids, and its products derived from these fatty acids, such as prostaglandins and leukotrienes, significantly up-regulate the key mela-nogenic enzyme, tyrosinase, in melanocytes. This has led to suggestions that PLA₂ itself triggers melanin synthesis in melanogenesis following UV irradiation or inflammation.
We have examined the effect of secretory PLA₂ (sPLA₂) on melanogenesis in cultured human melanocytes. Secretory PLA₂ stimulated DNA synthesis and melanin synthesis, and these phenomena were completely inhibited by treatment with a phospholipase inhibitor, p- bromophenacyl bromide, demonstrating that the catalytic activity of sPLA₂ is required for melanogenesis. Secretory PLA₂ also stimulated tyrosinase activity, increased the amount of tyrosinase-related protein-1 and up-regulated the expression of both mRNA. These findings suggest that sPLA₂ is an important mediator of UV-induced or postinflammatory pigmentation.     

Cajanin Suppresses Melanin Synthesis through Modulating MITF in Human Melanin-Producing Cells

Despite its classification as a non-life-threatening disease, increased skin pigmentation adversely affects quality of life and leads to loss of self-confidence. Until now, there are no recommended remedies with high efficacy and human safety for hyperpigmentation. This study aimed to investigate anti-melanogenic activity and underlying mechanism of cajanin, an isoflavonoid extracted from Dalbergia parviflora Roxb. (Leguminosae) in human melanin-producing cells. Culture with 50 μM cajanin for 48–72 h significantly suppressed proliferation in human melanoma MNT1 cells assessed via MTT viability assay. Interestingly, cajanin also efficiently diminished melanin content in MNT1 cells with the half maximum inhibitory concentration (IC₅₀) at 77.47 ± 9.28 μM. Instead of direct inactivating enzymatic function of human tyrosinase, down-regulated mRNA and protein expression levels of MITF and downstream melanogenic enzymes, including tyrosinase, TRP-1 and Dct (TRP-2) were observed in MNT1 cells treated with 50 μM cajanin for 24–72 h. Correspondingly, treatment with cajanin modulated the signaling pathway of CREB and ERK which both regulate MITF expression level. Targeted suppression on MITF-related proteins in human melanin-producing cells strengthens the potential development of cajanin as an effective treatment for human hyperpigmented disorders.     

THE RATES OF PHOTOLYSIS OF THE FOUR INDIVIDUAL TRYPTOPHAN RESIDUES IN UV EXPOSED CALF γ-II CRYSTALLIN

Aqueous buffer solutions of the lens protein bovine gamma-II crystallin were irradiated at 295 nm in the presence of dithiothreitol to determine the individual photolysis susceptibilities of the four tryptophan residues. Reverse-phase high performance liquid chromatography was utilized to compare the tryptic peptide maps before and after irradiation. Sequence analysis of collected tryptic peptides showed that the four tryptophans in calf gamma-II crystallin. TRP-42, TRP-68, TRP-131, and TRP-157 appeared in four distinct tryptic peptides. Fluorescence and absorption (diode array) monitoring of the eluting peptides allowed assessment of the changes in peptide absorbance and fluorescence following irradiation. Tryptophan fluorescence losses of (40 +/- 15)%, (17 +/- 4)%, (35 +/- 5)% and (15 +/- 4)% were observed for the peptides containing TRP-42, TRP-68, TRP-131 and TRP-157, respectively. Thus the four tryptophans in calf gamma-II crystallin did not all photolyze at the same rate. The rate differences are presumably related to the microenvironments of the individual tryptophan residues, and this is discussed in terms of the known crystal structure of calf gamma-II crystallin.     

丙交酯-乙交酯共聚中的酯交换及共聚物结构和性质研究

以辛酸亚锡为催化剂 ,通过本体开环聚合合成了不同摩尔比的DL 丙交酯 乙交酯 (DL LA GA)共聚物 (PDL LGA) .1 H和1 3C NMR以及DSC结果表明 ,共聚物中GA结构单元的含量略高于按GA投料比计算的结果 ,聚合过程中存在二级酯交换反应 .当聚合温度为 16 0℃时 , GG 序列的平均长度 (lGG)随GA摩尔投料比增大而增长 ,而 LL 序列的平均长度 (lLL)则相反 .研究发现 ,随着GA摩尔投料比降低 , LL 单元的二级酯交换系数 (TⅡ[GLG])下降 ,至GA摩尔投料比达到为 5 0 %时最小 ,而后却逐渐增大 .L LA与GA在同样的条件下聚合 ,TⅡ[GLG]和lGG 都比DL LA与GA聚合的大 .聚合温度升高 ,TⅡ[GLG]增大 ,意味着二级酯交换反应加剧 ,但DL LA GA摩尔投料比较高 (75 2 5 )的共聚物的lGG 值有所下降 ,lLL值变化不大 ,而DL LA GA摩尔投料比较低 (5 0 5 0 )的共聚物的lGG值则变化不大 ,lLL值有所下降 ,说明聚合反应还受共聚单体的投料比和其它因素影响 .升高聚合温度比在较低温度下延长反应时间更有效改变共聚物的链结构 .在一定温度下聚合 ,共聚产物的Tg 随GA摩尔投料比增大而有规律降低和在氯仿中的溶解性下降 ;而DL LA GA摩尔投料比一定时 ,聚合温度对共聚物的Tg 的影响较为复杂 ,这与聚合温度对共聚物的链结构影响较大有关 .     

An important role for peroxiredoxin II in survival of A549 lung cancer cells resistant to gefitinib

Redox adaptation is an important concept that explains the mechanisms by which cancer cells survive under persistent endogenous oxidative stress and become resistant to certain anticancer agents. To investigate this concept, we determined the expression levels of peroxiredoxins (Prxs), antioxidant enzymes in drug-resistant non-small cell lung carcinoma cells. Prx II was remarkably increased only in A549/GR (gefitinib-resistant) cells compared with A549 cells, consistent with methylation/demethylation. Prx II was highly methylated in the A549 cells but was demethylated in the A549/GR cells. The elevated expression of Prx II resulted in the downregulation of reactive oxygen species (ROS) and cell death and upregulation of cell cycle progression in the A549/GR cells. When Prx II mRNA in the A549/GR cells was knocked down, the levels of ROS and apoptosis were significantly recovered to the levels of the controls. In addition, signaling molecules involved in apoptosis were increased in the A549/GR-shPrx II cells. There was no difference in the expression of MAPK/ERK between the A549/GR cells and A549/GR-shPrx II cells, but the phosphorylation of JNK was increased in the A549/GR cells and was markedly decreased in the A549/GR-shPrx II cells. Colony number and tumor growth were significantly decreased in the A549/GR-shPrx II cells compared with the A549/GR cells. Our findings suggest that Prx II has an important role in cancer cell survival via the modulation of signaling molecules involved in apoptosis and the phosphorylation of JNK by the downregulation of ROS levels in A549/GR cells.     

Gamma irradiation affects the total phenol,anthocyanin and antioxidant properties in three different persian pistachio nuts

The effects of gamma irradiation (GR) on total phenol, anthocyanin and antioxidant activity were investigated in three different Persian pistachio nuts at doses of 0, 1, 2 and 4 kGy. The antioxidant activity, as determined by FRAP and DPPH methods, revealed a significant increase in the 1–2 kGy dose range. Total phenol content (TPC) revealed a similar pattern or increase in this range. However, when radiation was increased to 4 kGy, TPC in all genotypes decreased. A radiation dose of 1 kGy had no significant effect on anthocyanin content of Kale-Ghouchi (K) and Akbari (A) genotypes, while it significantly increased the anthocyanin content in the Ghazvini (G) genotype. In addition, increasing the radiation to 4 kGy significantly increased the anthocyanin content of K and G genotypes. To conclude, irradiation could increase the phenolic content, anthocyanin and antioxidant activity of pistachio nuts.     

Microscopic analysis of ester hydrolysis reaction catalyzed by Candida rugosa lipase

The relationship between the kinetics of the lipase-catalyzed oil hydrolysis and the surface area distribution of oil droplets was investigated using ethyl decanoate and gum Arabic (GA) as a model oil and an emulsifier, respectively. Along an ethyl decanoate concentration gradient between 2 and 8 mM, the initial hydrolysis rate increased at 0.25% (w/v) GA but did not change at 1.0% (w/v) GA. At 0.25% GA, the surface area of droplets was narrowly distributed regardless of the ethyl decanoate concentration. However, at 1.0% GA and with ethyl decanoate concentrations higher than 2 mM, the fraction of relatively large droplets with a surface area larger than approximately 200 microm2, suddenly increased. The microscopy of ethyl decanoate emulsion during the hydrolysis reaction indicates that the large oil droplets were not hydrolyzed. At 20 mM ethyl decanoate where the hydrolysis rate remained the same between 0.25% and 1.0% GA, the surface area of droplets was narrowly distributed at 0.25% and 1.0% GA. Therefore, the constant hydrolysis rate observed in the emulsion of ethyl decanoate between 2 and 8 mM containing GA at 1.0%, is believed to be caused by the relatively large oil droplets with the interface quality differing from that of the small oil droplets.     

Glycyrrhizic Acid Inhibits SARS-CoV-2 Infection by Blocking Spike Protein-Mediated Cell Attachment

Glycyrrhizic acid (GA), also known as glycyrrhizin, is a triterpene glycoside isolated from plants of Glycyrrhiza species (licorice). GA possesses a wide range of pharmacological and antiviral activities against enveloped viruses including severe acute respiratory syndrome (SARS) virus. Since the S protein (S) mediates SARS coronavirus 2 (SARS-CoV-2) cell attachment and cell entry, we assayed the GA effect on SARS-CoV-2 infection using an S protein-pseudotyped lentivirus (Lenti-S). GA treatment dose-dependently blocked Lenti-S infection. We showed that incubation of Lenti-S virus, but not the host cells with GA prior to the infection, reduced Lenti-S infection, indicating that GA targeted the virus for infection. Surface plasmon resonance measurement showed that GA interacted with a recombinant S protein and blocked S protein binding to host cells. Autodocking analysis revealed that the S protein has several GA-binding pockets including one at the interaction interface to the receptor angiotensin-converting enzyme 2 (ACE2) and another at the inner side of the receptor-binding domain (RBD) which might impact the close-to-open conformation change of the S protein required for ACE2 interaction. In addition to identifying GA antiviral activity against SARS-CoV-2, the study linked GA antiviral activity to its effect on virus cell binding.     

Electrodeposited nanogold decorated graphene modified carbon ionic liquid electrode for the electrochemical myoglobin biosensor

In this paper, a carbon ionic liquid electrode (CILE) was fabricated using ionic liquid 1-hexylpyridinium hexafluorophosphate as modifier, which was further in situ electrodeposited with graphene (GR) and gold nanoparticles step by step to get an Au/GR nanocomposite modified CILE. Myoglobin (Mb) was further immobilized on the Au/GR/CILE surface with Nafion film to get the modified electrode denoted as Nafion/Mb/Au/GR/CILE. Cyclic voltammetric experiments indicated that a pair of well-defined quasi-reversible redox peaks appeared in pH 3.0 phosphate buffer solution with the formal potential (E ^0′) located at ?0.197 V (vs. saturated calomel electrode), which was the typical characteristics of Mb heme Fe(III)/Fe(II) redox couples. Thus, the direct electron transfer rate between Mb and the modified electrode was promoted due to the high conductivity and increased surface area of Au/GR nanocomposite present on electrode surface. Based on the cyclic voltammetric data, the electrochemical parameters of Mb on the modified electrode were calculated. The Mb-modified electrode showed excellent electrocatalytic activities towards the reduction of trichloroacetic acid and H₂O₂ with wider linear range and lower detection limit. Using GR and Au nanoparticles modified CILE, a new third-generation electrochemical Mb biosensor was constructed with good stability and reproducibility.     

Selenium methylselenocysteine protects human hepatoma HepG2 cells against oxidative stress induced by tert-butyl hydroperoxide

Selenium methylselenocysteine (Se-MeSeCys) is a common selenocompound in the diet with a tested chemopreventive effect. This study investigated the potential protective effect of Se-MeSeCys against a chemical oxidative stress induced by tert-butyl hydroperoxide (t-BOOH) on human hepatoma HepG2 cells. Speciation of selenium derivatives by liquid chromatography–inductively coupled plasma mass spectrometry depicts Se-MeSeCys as the only selenocompound in the cell culture. Cell viability (lactate dehydrogenase) and markers of oxidative status—concentration of reduced glutathione (GSH) and malondialdehyde (MDA), generation of reactive oxygen species (ROS) and activity of the antioxidant enzymes glutathione peroxidase (GPx) and glutathione reductase (GR)—were evaluated. Pretreatment of cells with Se-MeSeCys for 20 h completely prevented the enhanced cell damage, MDA concentration and GR and GPx activity and the decreased GSH induced by t-BOOH but did not prevent increased ROS generation. The results show that treatment of HepG2 cells with concentrations of Se-MeSeCys in the nanomolar to micromolar range confers a significant protection against an oxidative insult.     

Determination of thiamine HCl and pyridoxine HCl in pharmaceutical preparations using UV-visible spectrophotometry and genetic algorithm based multivariate calibration methods

Simultaneous determination of binary mixtures pyridoxine hydrochloride and thiamine hydrochloride in a vitamin combination using UV-visible spectrophotometry and classical least squares (CLS) and three newly developed genetic algorithm (GA) based multivariate calibration methods was demonstrated. The three genetic multivariate calibration methods are Genetic Classical Least Squares (GCLS), Genetic Inverse Least Squares (GILS) and Genetic Regression (GR). The sample data set contains the UV-visible spectra of 30 synthetic mixtures (8 to 40 microg/ml) of these vitamins and 10 tablets containing 250 mg from each vitamin. The spectra cover the range from 200 to 330 nm in 0.1 nm intervals. Several calibration models were built with the four methods for the two components. Overall, the standard error of calibration (SEC) and the standard error of prediction (SEP) for the synthetic data were in the range of <0.01 and 0.43 microg/ml for all the four methods. The SEP values for the tablets were in the range of 2.91 and 11.51 mg/tablets. A comparison of genetic algorithm selected wavelengths for each component using GR method was also included.     

基于石墨烯分子印迹电化学传感器测定芦丁

将石墨烯(GR)滴涂至裸Au电极表面,并以邻氨基酚为功能单体,芦丁为模板分子,制备了芦丁分子印迹膜电化学传感器,利用循环伏安法(CV)和差分脉冲伏安法(DPV)对制得的传感器进行了电化学性能研究,并且对制备条件和测定条件进行了优化。结果表明,与裸Au电极相比,该GR修饰的Au电极在[Fe(CN)_6]~(3-/4-)溶液中峰电流明显增大,显著提高了芦丁分子印迹传感器的灵敏度。在最优实验条件下,基于GR分子印迹电化学传感器在4.40×10~(-6)~2.80×10~(-4) mol/L范围内呈良好的线性关系,检测限为1.46×10~(-6) mol/L。用该传感器测定了黑茶中芦丁的含量,获得较好结果。