Bioactive abietane diterpenes and benzofuran neolignans from the resins of Toxicodendron vernicifluum.

Six new compounds (1-6), including two abietane diterpenes (1,2) and four benzofuran neolignans (3-6), along with five known compounds (7-11) were isolated and identified through phytochemical investigation on the resins of Toxicodendron vernicifluum (Toxicodendri Resina). The structures of the new compounds were fully elucidated by their 1D and 2D NMR, HRESIMS, UV, and IR spectroscopic data analyses. The absolute configurations of 1-4 were deduced by comparison of the experimental and calculated electronic circular dichroism (ECD) data. The inhibitory effects of the isolates on myocardial fibrosis induced by TGF-ß were examined, and compounds 1, 5, and 7-10 showed the anti-proliferation of myocardial fibroblasts at the concentrations of 10-40 µM in a dose-dependent manner.

Novel Flavan-3,4-diol vernicidin B from Toxicodendron Vernicifluum (Anacardiaceae) as potent antioxidant via IL-6/Nrf2 cross-talks pathways.

BACKGROUND: Oxidative stress is considered to be a pathological factor of various neurodegenerative diseases. Studies have confirmed the antioxidant activity of T. vernicifluum. However, the main active components responsible for antioxidant activity remain unknown. OBJECTIVE: The aim of this study is to explore the activities of vernicidin B on oxidative stress injury induced by H2O2 in SH-SY5Y cells, and the underlying mechanism of vernicidin B in oxidative stress-related neurological diseases is further discussed. METHODS: Various separation methods were used to isolate and identify the compounds in an EtOAc extract of T. vernicifluum. The structures of the isolates were clarified by HR-TOF-MS and 1D/2D NMR data and compared with findings in previous literature. The MTT assay was used to evaluate the potential antioxidant activity of the isolated flavonoids. The apoptosis rate, mitochondrial reactive oxygen species (ROS) level and mitochondrial potential were measured by flow cytometry and fluorescence microscope. The levels of related proteins were detected by Western blotting. RESULTS: Four new flavan-3,4-diols (1-4, vernicidins A-D) and 11 known flavonoids (5-15) were purified from the EtOAc extract of T. vernicifluum. Among these compounds, vernicidin B showed the most promising potential for protecting SH-SY5Y cells from H2O2-induced oxidative stress. Moreover, pretreatment with vernicidin B decreased ROS production and mitochondrial membrane potential and significantly attenuated H2O2-induced apoptosis in a dose-dependent manner. Mechanistically, the antioxidant stress activities of vernicidin B were confirmed to be related to the IL-6/Nrf2 cross-talks pathway and its downstream pathways, including PI3K/Akt/mToR-Gsk3ß, JAK2/STAT3 and MAPKs. CONCLUSIONS: Our findings suggested that vernicidin B can improve the oxidative stress injury induced by H2O2 through IL-6/Nrf2 cross-talks pathway, indicating that it may be a potential candidate drug for the treatment of oxidative stress-related neurodegenerative diseases.

Traditional uses, phytochemistry, and pharmacology of Toxicodendron vernicifluum (Stokes) F.A. Barkley - A review.

ETHNOPHARMACOLOGICAL RELEVANCE: Toxicodendron vernicifluum (Stokes) F.A. Barkley (syn. Rhus verniciflua or vernicifera Stokes, Anacardiaceae) (RVS), the lacquer tree, also known as sumac, has been used in China, Japan and South Korea for thousands of years as a highly durable coating material and a traditional herbal medicine, which contains medicinal ingredients with anti-tumor, anti-inflammatory, antiviral, and anti-rheumatic activities. AIM OF THIS REVIEW: This review intends to provide a comprehensive and critical appraisal of RVS, including its phytochemical data, botanical and pharmacological literature that support its therapeutic potential in treatment on human diseases, with emphasis on the isolation of natural occurring compounds and detailed pharmacological investigations. MATERIALS AND METHODS: Specific information of RVS was collected by using the key words "Toxicodendron vernicifluum", "Rhus verniciflua Stokes", "Rhus vernicifera Stokes" and "Lacquer tree" through published scientific materials (including PubMed, ScienceDirect, Wiley, ACS, CNKI, Scifinder, Springer, Web of Science, Google Scholar, and Baidu Scholar) and other literature sources. RESULTS: The major phytoconstituents, 175 of which are presented in this review, including flavonoids, urushiols, terpenes, phenolic acids and other types of compounds, of which flavonoids and urushiols are main components. The extracts and isolates purified from RVS showed a wide range of in vitro and in vivo pharmacological effects, such as anti-cancer, anti-oxidation, anti-inflammatory, antimicrobial, tyrosinase inhibition and so on. CONCLUSION: The modern pharmacological research of RVS mainly focus on the pharmacological effects of crude extract or active constituents, of which the flavonoids are widely studied. However, there are few reports on the relationship between pharmacological effects and their structures. And at present, there is still a lack of researches that are of both effective and in-depth. Meanwhile, there is little research on quality control. Apart from the wood and lacquer, other botanical parts also need to be explored further. In addition to phenolic compounds, the study on other types of components in T. vernicifluum would start more sparks for the discovery of new bioactive principles.

Toxicodendron vernicifluum Stokes extract inhibits solid tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells in BALB/c mice.

Toxicodendron vernicifluum Stokes has long been used as a food supplement and traditional herbal medicine in East Asia. We applied a new extraction method to produce Toxicodendron vernicifluum Stokes extract (TVSE), that doesn't contain urushiol (an allergenic toxin) but dose have higher levels of some flavonoids such as fustin and fisetin. This study was conducted to investigate the anticancer effects of TVSE in an in vivo system. Fifty BALB/c mice were acclimated for one week and then injected with 4T1 murine mammary carcinoma cells in mammary fat pads. After 7 days, the mice were randomly divided into 5 groups, and orally administered with 0, 50, 100, 200 or 400 mg of TVSE/kg body weight (BW)/day for 20 days. TVSE reduced tumor volume and weight dose-dependently. The expression of Ki67 was significantly reduced and the number of TUNEL-positive apoptotic cells was significantly increased in the TVSE-treated group over 100 mg/kg BW/day. While tumor nodules were not found in the liver, but only in lungs, the number of tumor nodules was reduced in a dose-dependent manner in the TVSE treated groups compared to the control group. In breast tumors, expression of platelet endothelial cell adhesion molecule (PECAM-1) and vascular endothelial growth factor (VEGF) was reduced by TVSE treatment. TVSE treatment significantly suppressed mRNA expression in tumors of matrix metalloproteinase (MMP)-2, tissue inhibitor of metalloproteinase (TIMP)-1, urokinase-type plasminogen activator (uPA), intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 while increasing plasminogen activator inhibitor (PAI)-1. These results suggest that TVSE is potentially beneficial for the suppression of breast cancer growth and its-associated lung metastasis.

Accession-Level Differentiation of Urushiol Levels, and Identification of Cardanols in Nascent Emerged Poison Ivy Seedlings.

Poison ivy (Toxicodendron radicans (L.) Kuntze) shows accession-level differentiation in a variety of morphometric traits, suggesting local adaptation. To investigate whether the presumed defense compound urushiol also demonstrates accession-level accumulation differences, in vitro nascent germinated poison ivy seedlings from geographically isolated populations were germinated in vitro and then assayed for known urushiol congener accumulation levels. Significant accession-level differences in the accumulation levels of total C15- and C17-, total C15-, total C17-, specific C15 congeners, and specific C17 congeners of urushiol were identified. In addition, hereto novel C15- and C17-urushiol isomers were identified as well. Cardanols are assumed to be the penultimate metabolites giving rise to urushiols, but this assumption was not previously empirically validated. C15-cardanol congeners and isomers corresponding to expected substrates needed to produce the observed C15-urushiol congeners and isomers were identified in the same poison ivy seedling extracts. Total C15-cardanol and C15-cardanol congeners also showed significant accession-level differences. Based on the observed C15-cardanol congeners in poison ivy, the penultimate step in urushiol biosynthesis was proposed to be a cardanol-specific hydroxylase activity.

Unveiling the potentials of biocompatible silver nanoparticles on human lung carcinoma A549 cells and Helicobacter pylori.

Silver nanoparticles (AgNPs) are gaining importance in health and environment. This study synthesized AgNPs using the bark extract of a plant, Toxicodendron vernicifluum (Tv) as confirmed by a absorption peak at 420 nm corresponding to the Plasmon resonance of AgNPs. The AgNPs were spherical, oval-shaped with size range of 2-40 nm as evident by field emission transmission electron microscopy (FE-TEM) and particle size analysis (PSA). The particles formed were crystalline by the presence of (111), (220) and (200) planes, as revealed by X ray diffraction (XRD) and energy dispersive spectroscopy (EDS). The presence of amine, amide, phenolic, and alcoholic aromatics derived from Tv extract was found to be capping and or reducing agents as evident by Fourier-transform infrared spectroscopy (FTIR) spectra. The Tv-AgNPs were observed to be biocompatible to chick embryonic and NIH3T3 cells at various concentrations. Interestingly, Tv-AgNPs at the concentration of 320 µg. mL-1 induced 82.5% of cell death in human lung cancer, A549 cells and further 95% of cell death with annexin V FITC/PI based apoptosis. The Tv-AgNPs selectively targeted and damaged the cancer cells through ROS generation. The Tv-AgNPs displayed minimal inhibitory concentration (MIC) of 8.12 µg.mL-1 and 18.14 µg.mL-1 against STEC and H. pylori respectively. This multi-potent property of Tv-AgNPs was due to shape and size specific property that facilitated easy penetration into the bacterial and cancer cells for targeted therapy.

Changes of Phytochemical Components (Urushiols, Polyphenols, Gallotannins) and Antioxidant Capacity during Fomitella fraxinea⁻Mediated Fermentation of Toxicodendron vernicifluum Bark.

The stem bark of Toxicodendron vernicifluum (TVSB) has been widely used as a traditional herbal medicine and food ingredients in Korea. However, its application has been restricted due to its potential to cause allergies. Moreover, there is limited data available on the qualitative and quantitative changes in the composition of its phytochemicals during fermentation. Although the Formitella fraxinea-mediated fermentation method has been reported as an effective detoxification tool, changes to its bioactive components and the antioxidant activity that takes place during its fermentation process have not yet been fully elucidated. This study aimed to investigate the dynamic changes of urushiols, bioactive compounds, and antioxidant properties during the fermentation of TVSB by mushroom F. fraxinea. The contents of urushiols, total polyphenols, and individual flavonoids (fisetin, fustin, sulfuretin, and butein) and 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG) significantly decreased during the first 10 days of fermentation, with only a slight decrease thereafter until 22 days. Free radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) as an antioxidant function also decreased significantly during the first six to nine days of fermentation followed by a gentle decrease up until 22 days. These findings can be helpful in optimizing the F. fraxinea⁻mediated fermentation process of TVSB and developing functional foods with reduced allergy using fermented TVSB.

The protective effects of vernicilignan A, a new flavonolignan isolated from Toxicodendron vernicifluum on SH-SY5Y cells against oxidative stress-induced injury.

In this study, a new flavonolignan vernicilignan A was isolated from Toxicodendron vernicifluum. The neuroprotective effects of this compound against H2O2 induced cell injury in SH-SY5Y cells were evaluated by MTT assay and LDH release assay. Vernicilignan A dose-dependently attenuated the cell injury and LDH release induced by H2O2 in SH-SY5Y cells. Further study indicated that vernicilignan A reduced cell apoptosis caused by H2O2 treatment via regulation of some apoptotic related proteins including Bax, Bcl-2, caspase 3 and caspase 9. Also, vernicilignan A increase the cell viability of H2O2 treated cells via the activation of Akt and GSK3ß. Base on the findings, vernicilignan A exhibited neuroprotective effects through the activation of PI3K/Akt signaling and inhibition of mitochondria apoptosis pathway. Vernicilignan A might be a promising therapeutic agent for oxidative stress induced neurodegenerative diseases.

Sulfuretin has therapeutic activity against acquired lymphedema by reducing adipogenesis.

Acquired lymphedema is a pathological condition associated with lymphatic dysfunction caused by surgical treatments for cancer. Although global estimates of the prevalence of acquired lymphedema have been rising, there are currently no effective therapeutics available. Since adipose tissue accumulation is a clinical hallmark of lymphedema, we hypothesized that regulation of adipogenesis in lymphedematous tissue could be used as a therapeutic intervention against lymphedema. Toward this, we investigated the possibility of anti-adipogenic 30% ethanol Rhus verniciflua Stokes (RVS) extract as a potential lymphedema treatment. Oral administration of RVS extract ameliorated volumetric symptoms of lymphedema in a mouse model. RVS administration also reduced adipose tissue accumulation in lymphedematous tissue and downregulated expression of adipocyte markers, including Pparγ and Fabp4. Sulfuretin was identified as a major bioactive compound in the 30% ethanol RVS extract in liquid chromatography-mass spectrometry analysis. Similar to the activities of RVS, sulfuretin inhibited adipocyte differentiation in 3T3-L1 preadipocytes. Moreover, treatment with sulfuretin on lymphedema-induced mice reduced lymphedema volume, decreased the expression of adipogenic markers, but induced the expression of markers associated with lymphangiogenesis. Taken together, our data raise the possibility that sulfuretin might be used in therapeutic interventions against acquired lymphedema.

Treatment with Ruta graveolens 5CH and Rhus toxicodendron 9CH may reduce joint pain and stiffness linked to aromatase inhibitors in women with early breast cancer: results of a pilot observational study.

OBJECTIVE: To determine the possible effect of two homeopathic medicines, Ruta graveolens 5CH and Rhus toxicodendron 9CH, in the prevention of aromatase inhibitor (AI) associated joint pain and/or stiffness in women with early, hormone-receptor positive, breast cancer. METHODS: This prospective, unrandomized observational study was carried out between April and October 2014. Women were recruited in two groups, according to which of the two study centres they attended: one receiving homeopathy in addition to standard treatment (group H) and a control group, receiving standard treatment (group C). All women were treated with an AI. In addition, women in group H also took Ruta graveolens 5CH and Rhus toxicodendron 9CH (5 granules, twice a day) up to 7 days before starting AI treatment. The homeopathic medicines were continued for 3 months. Demographic and clinical data were recorded using a self-assessment questionnaire at inclusion (T0) and 3 months (T3). Primary evaluation criteria were the evolution of scores for joint pain and stiffness, the impact of pain on sleep and analgesic consumption in the two groups after 3 months of treatment. RESULTS: Forty patients (mean age 64.9±8.1 years) were recruited, 20 in each group. Two-thirds of the patients had joint pain before starting AI treatment. There was a significant difference in the evolution of mean composite pain score between T0 and T3 in the two groups (-1.3 in group H vs. +3.4 in group C; p=0.0001). The individual components of the pain score (frequency, intensity and number of sites of pain) also decreased significantly in group H. Nine patients in group C (45%) vs. 1 (5%) in group H increased their analgesic consumption between T0 and T3 (p=0.0076). After 3 months of treatment, joint pain had a worse impact on sleep in patients in group C (35% vs. 0% of patients; p=0.0083). The differences observed in the evolution of morning and daytime stiffness between the two groups were smaller (p=0.053 and p=0.33, respectively), with the exception of time necessary for the disappearance of morning stiffness which was greater in group C (37.7±23.0 vs. 17.9±20.1 min; p=0.0173). CONCLUSION: These preliminary results suggest that treatment with Ruta graveolens 5CH and Rhus toxicodendron 9CH may decrease joint pain/stiffness in breast cancer patients treated with AIs. A larger-scale randomized study is required to confirm these results.

Effect of Herbal Homeopathic Monopreparations on the Rate of Tissue Lymphatic Drainage in Healthy Mice.

We studied the effects of homeopathic monopreparations of plant origin Atropa Belladonna and Rhus toxicodendron in three dilutions (potencies) on interstitial humoral transport in healthy laboratory mice assessed by the rate of excretion of the lymphotropic label from the mesentery according to the Oyvin's method (vital biomicroscopy of intestinal mesentery in small animals). The homeopathic monopreparations exerted a dose-dependent inhibitory effect on the interstitial transport and lymphatic drainage in tissues of healthy mice.

New urushiols with platelet aggregation inhibitory activities from resin of Toxicodendron vernicifluum.

Eight new urushiol-type compounds (1-7b), along with seven known compounds were isolated from the resin of Toxicodendron vernicifluum Stokes. Their structures were determined by extensive spectroscopic methods, included (1)H NMR, (13)C NMR, HMQC, HMBC, HRESIMS, EI-MS in combination with CD methods. All the compounds except 7a and 7b were evaluated for their anti-platelet aggregation activities in vitro. Among them, compound 5 (IC50=5.12±0.85µmol/L), with a vic-diol moiety in the long alkyl chain showed the most potent inhibitory of platelet aggregation activity induced by ADP. In addition, compound 6 showed the effect of anti-platelet aggregation induced by AA with the IC50 value of 3.09±0.70µmol/L. Thus, these compounds might be the active components to the traditional use of Resina Toxicodendri for breaking up blood stasis, which could be related to the anti-platelet aggregation.

Identification of cytotoxic and anti-inflammatory constituents from the bark of Toxicodendron vernicifluum (Stokes) F.A. Barkley.

ETHNOPHARMACOLOGICAL RELEVANCE: Toxicodendron vernicifluum (Stokes) F.A. Barkley (Anacardiaceae) has traditionally been used as a food supplement and in traditional herbal medicine to treat inflammatory diseases and cancers for centuries in Korea. This study was designed to isolate the bioactive constituents from the ethanol extract of Toxicodendron vernicifluum bark and evaluate their cytotoxic and anti-inflammatory activities. MATERIAL AND METHODS: Bioassay-guided fractionation and chemical investigation of the ethanol extract of Toxicodendron vernicifluum bark resulted in the isolation and identification of three new polyphenols (1-3) and six flavonoids (4-9). The structures of the isolated compounds were elucidated by spectroscopic analysis, including 1D and 2D nuclear magnetic resonance (NMR) ((1)H, (13)C, COSY, HMQC and HMBC experiments), and high resolution (HR)-mass spectrometry, and their absolute configurations were further confirmed by chemical methods and circular dichroism (CD) data analysis. Compounds 1-9 were evaluated for their antiproliferative activities against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15), and anti-inflammatory activities by measuring nitric oxide (NO) levels in the medium of murine microglia BV-2 cells. RESULTS: The isolated compounds were characterized as in the following: three new polyphenols, rhusopolyphenols G-I (1-3) and six flavonoids including two aurones, 2-benzyl-2,3',4',6-tetrahydroxybenzo[b]furan-3(2H)-one (4), sulfuretin (5), two dihydroflavonols, (+)-(2S,3R)-fustin (6), (+)-epitaxifolin (7), one chalcone, butein (8), and one flavonol, fisetin (9). The published NMR assignments of 4 were corrected by the detailed analysis of spectroscopic data in this study. Among the tested compounds, compounds 4-9 showed antiproliferative activity against the tested cells, with IC50 values of 4.78-28.89 µM. Compounds 5 and 8 significantly inhibited NO production in lipopolysaccharide (LPS)-stimulated BV-2 cells with IC50 values of 23.37 and 11.68 µM, respectively. CONCLUSIONS: Polyphenols including flavonoids were one of the main constituents of Toxicodendron vernicifluum bark, and activities demonstrated by the isolated compounds support the ethnopharmacological use of Toxicodendron vernicifluum as anti-cancer and/or anti-inflammatory agents.

GQ5 Hinders Renal Fibrosis in Obstructive Nephropathy by Selectively Inhibiting TGF-ß-Induced Smad3 Phosphorylation.

TGF-ß1, via Smad-dependent or Smad-independent signaling, has a central role in the pathogenesis of renal fibrosis. This pathway has been recognized as a potential target for antifibrotic therapy. Here, we identified GQ5, a small molecular phenolic compound isolated from the dried resin of Toxicodendron vernicifluum, as a potent and selective inhibitor of TGF-ß1-induced Smad3 phosphorylation. In TGF-ß1-stimulated renal tubular epithelial cells and interstitial fibroblast cells, GQ5 inhibited the interaction of Smad3 with TGF-ß type I receptor (TßRI) by blocking binding of Smad3 to SARA, suppressed subsequent phosphorylation of Smad3, reduced nuclear translocation of Smad2, Smad3, and Smad4, and downregulated the transcription of major fibrotic genes such as α-smooth muscle actin (α-SMA), collagen I, and fibronectin. Notably, intraperitoneal administration of GQ5 in rats immediately after unilateral ureteral obstruction (UUO) selectively inhibited Smad3 phosphorylation in UUO kidneys, suppressed renal expression of α-SMA, collagen I, and fibronectin, and resulted in impressive renal protection after obstructive injury. Late administration of GQ5 also effectively attenuated fibrotic lesions in obstructive nephropathy. In conclusion, our results suggest that GQ5 hinders renal fibrosis in rats by selective inhibition of TGF-ß1-induced Smad3 phosphorylation.

Protective effect of detoxified Rhus verniciflua stokes on human keratinocytes and dermal fibroblasts against oxidative stress and identification of the bioactive phenolics.

Oxidative stress due to the over-production of reactive oxygen species (ROS) is associated with human skin aging. This study was designed to identify the bioactive phenolics in detoxified Rhus verniciflua Stokes (DRVS) that may protect human skin against oxidative stress. Under oxidative stress caused by H2O2, the 40% (v/v) aqueous methanol extract of DRVS protected human keratinocytes in a dose-dependent manner. The expression of matrix metalloproteinase-1 (MMP-1) was also inhibited by the DRVS extract in human dermal fibroblasts-neonatal cells exposed to ultraviolet A. The major bioactive phenolics of DRVS were tentatively identified by LC/Q-TOF-ESI-MS/MS, and included gallic acid, 2-(ethoxymethoxy)-3-hydroxyphenol, fustin, a fustin isomer, tetragalloyl glucose, pentagalloyl glucose, fisetin, sulfuretin, a sulfuretin isomer, and butein. The results suggest that a DRVS extract may be effective in slowing skin aging through its antioxidative properties and by down-regulating MMP-1 expression. Further studies are needed to examine whether this effect would be mediated by the phenolics identified in this study.

Urushiol detection using a profluorescent nitroxide.

A method to visually detect minute amounts of urushiol, the toxic catechol from poison oak, poison ivy, and poison sumac, has been developed utilizing the reaction of a profluorescent nitroxide with the B-n-butylcatecholboronate ester formed in situ from urushiol and B-n-butylboronic acid. The resulting N-alkoxyamine is strongly fluorescent upon illumination with a fluorescent lamp, allowing the location of the toxic urushiol contamination to be visualized. This methodology constitutes the groundwork for the future development of a spray to detect urushiol to avoid contact dermatitis, as well as to detect catecholamines for biomedical applications.

A synthesis of the phenolic lipid, 3-[(Z)-pentadec-8-enyl] catechol, (15:1)-urushiol.

A synthesis of (15:1)-urushiol, urushiol monoene, 3-[(Z)-pentadec-8-enyl] catechol, 1,2-dihydroxy-3-[(Z)-pentadec-8-enyl] benzene, one of the toxic principles of Rhus toxicodendron and of Rhus vernicifera is described. 6-Chlorohexan-1-ol protected at the OH group with ethyl vinyl ether reacted with 2,3-dimethoxybenzaldehyde in the presence of lithium to give, after removal of the protective group with methanolic 4-toluenesulphonic acid, 1-(2,3-dimethoxyphenyl) heptane-1,7-diol. Catalytic hydrogenolysis in ethanol with palladium-carbon selectively afforded 7-(2,3-dimethoxyphenyl)heptane-1-ol accompanied by a small proportion of the 7-(3-methoxyphenyl)heptane-1-diol, formed by demethoxylation. Reaction of the dimethoxy compound with boron tribromide resulted in both bromination and demethylation to give 7-(2,3-dihydroxyphenyl) heptylbromide. This bromide in tetrahydrofuran (THF) containing hexamethylphosphoric triamide reacted with excess lithium oct-1-yne to give 3-(pentadec-8-enyl)catechol which, by catalytic hydrogenation in ethyl acetate containing quinoline, selectively formed the required cis product, 3-[(Z)-pentadec-8-enyl]catechol which was identical chromatographically and spectroscopically with urushiol monoene separated from the natural product.

Atmospheric pressure ionization LC-MS-MS determination of urushiol congeners.

This paper describes atmospheric pressure ionization (API) LC-MS-MS determination of urushiols, 3-n-alkenyl- and -alkyl-substituted catechols responsible for poison oak dermatitis. Urushiol was isolated from Western poison oak according to the method of Elsohly et al. (1) (J. Nat. Prod. 1982, 45, 532-538)-the purified preparation contained C(17)- and C(15)-substituted urushiols with zero, one, two, and three double bonds as determined from GC-MS analysis of trimethylsilyl derivatives. Urushiol mixtures were separated on a C(18) reversed phase HPLC column with a methanol-water gradient with urushiols eluting in 100% methanol. Atmospheric pressure chemical ionization (APCI) produced primarily [M - H](-) and MH(+) molecule ions. Electrospray ionization (ESI) yielded [M - H](-) and adduct ions including [M + Cl](-). Daughter ions of [M - H](-) included quinoid radical anions ([M - H - H(2)](-) and m/z 122(-)) and a benzofuran phenate (m/z 135(-)). A suite of hydrocarbon fragments were produced by collision-induced dissociation of MH(+) directly or via an intermediate [MH - H(2)O](+) daughter ion. Six urushiol congeners, one not previously reported in poison oak, were determined by negative ion API-LC-MS-MS with detection limits of approximately 8 pg/microL (ESI) and approximately 800 pg/microL (APCI). API-LC-MS-MS was used to determine urushiol in surface wipes, air samples, and plant materials.

Antioxidant activity of a Rhus verniciflua Stokes ethanol extract.

A fractionated ethanol extract derived from Rhus Verniciflua Stokes (RVS) was assessed in both organic and aqueous media for the purpose of characterizing the mechanisms of antioxidant activity. RVS, an indigenous plant to Korea, was initially extracted with ethanol and characterized to contain a 90 KDa-ABTS reactive protein possessing 0.662 ng/mg copper. This characterization suggested that a primary component of RVS was Laccase, an oxidase enzyme complex. RVS exhibited a significant (P < 0.01) concentration-dependent inhibition of linoleic acid oxidation in an emulsion system up to 48 hours of incubation. Free radical scavenging activity of both a stable radical (e.g DPPH) and hydroxyl (e.g. *OH) radical followed a concentration-dependent pattern in different model systems. Using a liposome model with peroxyl radicals generated by AAPH, a significant extension of both the lag phase and a reduction of peak propagation of peroxyl radicals by RVS over a concentration range of 1 to 10 microg/ml was observed. RVS ethanol extract was also found to protect human low-density lipoprotein (LDL) from oxidative modification, mediated by cupric ion at 37 degrees C. Finally, RVS was found to be effective at protecting against plasmid DNA strand breakage induced by peroxyl free radicals in an aqueous medium. Our findings show that the ethanol fraction derived from RVS contained significant antioxidant activity in both polar and non-polar mediums.