Cytotoxicity of urushiols isolated from sap of Korean lacquer tree (Rhus vernicifera Stokes)

Vortex-blending matrix solid-phase dispersion and UPLC-Q-TOF/MS were proposed to extract and examine the urushiols from Toxicodendron vernicifluum bark

Toxicodendron vernicifluum bark has been used for many years as a component in foods and as a traditional herbal medication. Unfortunately, the presence of urushiols, which induce allergies, limits its application. This study used a vortex-blending matrix solid-phase dispersion microextraction technique to extract urushiols from Toxicodendron vernicifluum bark. HPLC was used to evaluate the amounts of the extracted urushiols (15:0, 15:1, 15:2, and 15:3). The modified magnetic adsorbent was prepared through an in situ coprecipitation method and characterized using a variety of techniques. The optimized extraction conditions are as follows: using magnetic Zeolite Socony Mobil-Five as an adsorbent, a 1:2 sample/adsorbent ratio, 2.5 min of vortex-blending time, 4 mL of 0.1% (V/V) trifluoroacetic acid-methanol as the elution solvent and 8 min of ultrasound time. There was good linearity and high repeatability in the method. Furthermore, the limits of detection for the urushiols ranged from 0.20 to 0.50 μg/mL. Under the optimized conditions, 50 compounds were identified by ultra high performance liquid chromatography and quadrupole time-of-flight mass spectrometry. These compounds included 8 phenolic acids, 9 monomeric urushiols, 11 urushiol dimers, 10 other components, and 11 flavonoids. The suggested approach, which has the advantages of few stages and high extraction efficiency over existing extraction procedures, is a potentially useful method for obtaining and evaluating urushiols in raw materials or extracts.

Design, Synthesis, and Biological Evaluation of New Urushiol Derivatives as Potent Class I Histone Deacetylase Inhibitors

In the present study, a novel series of 11 urushiol-based hydroxamic acid histone deacetylase (HDAC) inhibitors was designed, synthesized, and biologically evaluated. Compounds 1-11 exhibited good to excellent inhibitory activities against HDAC1/2/3 (IC50 : 42.09-240.17 nM) and HDAC8 (IC50 : 16.11-41.15 nM) in vitro, with negligible activity against HDAC6 (>1409.59 nM). Considering HDAC8, docking experiments revealed some important features contributing to inhibitory activity. According to Western blot analysis, select compounds could notably enhance the acetylation of histone H3 and SMC3 but not-tubulin, indicating their privileged structure is appropriate for targeting class I HDACs. Furthermore, antiproliferation assays revealed that six compounds exerted greater in vitro antiproliferative activity against four human cancer cell lines (A2780, HT-29, MDA-MB-231, and HepG2, with IC50 values ranging from 2.31-5.13 μM) than suberoylanilide hydroxamic acid; administration of these compounds induced marked apoptosis in MDA-MB-231 cells, with cell cycle arrest in the G2/M phase. Collectively, specific synthesized compounds could be further optimized and biologically explored as antitumor agents.

Urushiol V Suppresses Cell Proliferation and Enhances Antitumor Activity of 5-FU in Human Colon Cancer Cells by Downregulating FoxM1

Colorectal cancer (CRC) is one of the most common malignant tumor. 5-FU is commonly used for the treatment of CRC. However, the development of drug resistance in tumor chemotherapy can seriously reduce therapeutic efficacy of 5-FU. Recent data show that FoxM1 is associated with 5-FU resistance in CRC. FoxM1 plays a critical role in the carcinogenesis and drug resistance of several malignancies. It has been reported that urushiol V isolated from the cortex of Rhus verniciflua Stokes is cytotoxic to several types of cancer cells. However, the underlying molecular mechanisms for its antitumor activity and its potential to attenuate the chemotherapeutic resistance in CRC cells remain unknown. Here, we found that urushiol V could inhibit the cell proliferation and induced S-phase arrest of SW480 colon cancer cells. It inhibited protein expression level of FoxM1 through activation of AMPK. We also investigated the combined effect of urushiol V and 5-FU. The combination treatment reduced FoxM1 expression and consequently reduced cell growth and colony formation in 5-FU resistant colon cancer cells (SW480/5-FUR). Taken together, these result suggest that urushiol V from Rhus verniciflua Stokes can suppress cell proliferation by inhibiting FoxM1 and enhance the antitumor capacity of 5-FU. Therefore, urushiol V may be a potential bioactive compound for CRC therapy.

HEXA-018, a Novel Inducer of Autophagy, Rescues TDP-43 Toxicity in Neuronal Cells

The autophagy-lysosomal pathway is an essential cellular mechanism that degrades aggregated proteins and damaged cellular components to maintain cellular homeostasis. Here, we identified HEXA-018, a novel compound containing a catechol derivative structure, as a novel inducer of autophagy. HEXA-018 increased the LC3-I/II ratio, which indicates activation of autophagy. Consistent with this result, HEXA-018 effectively increased the numbers of autophagosomes and autolysosomes in neuronal cells. We also found that the activation of autophagy by HEXA-018 is mediated by the AMPK-ULK1 pathway in an mTOR-independent manner. We further showed that ubiquitin proteasome system impairment- or oxidative stress-induced neurotoxicity was significantly reduced by HEXA-018 treatment. Moreover, oxidative stress-induced mitochondrial dysfunction was strongly ameliorated by HEXA-018 treatment. In addition, we investigated the efficacy of HEXA-018 in models of TDP-43 proteinopathy. HEXA-018 treatment mitigated TDP-43 toxicity in cultured neuronal cell lines and Drosophila. Our data indicate that HEXA-018 could be a new drug candidate for TDP-43-associated 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.

Novel pH-Sensitive Urushiol-Loaded Polymeric Micelles for Enhanced Anticancer Activity

Purpose

The aim of this study was to develop a means of improving the bioavailability and anticancer activity of urushiol by developing an urushiol-loaded novel tumor-targeted micelle delivery system based on amphiphilic block copolymer poly(ethylene glycol)-b-poly-(β-amino ester) (mPEG-PBAE).

Materials and Methods

We synthesized four different mPEG-PBAE copolymers using mPEG-NH₂ with different molecular weights or hydrophobicity levels. Of these, we selected the mPEG₅₀₀₀-PBAE-C₁₂ polymer and used it to develop an optimized means of preparing urushiol-loaded micelles. Response surface methodology was used to optimize this formulation process. The micellar properties, including particle size, pH sensitivity, drug release dynamics, and critical micelle concentrations, were characterized. We further used the MCF-7 human breast cancer cell line to explore the cytotoxicity of these micelles in vitro and assessed their pharmacokinetics, tissue distribution, and antitumor activity in vivo.

Results

The resulting micelles had a mean particle size of 160.1 nm, a DL value of 23.45%, and an EE value of 80.68%. These micelles were found to release their contents in a pH-sensitive manner in vitro, with drug release being significantly accelerated at pH 5.0 (98.74% in 72 h) without any associated burst release. We found that urushiol-loaded micelles were significantly better at inducing MCF-7 cell cytotoxicity compared with free urushiol, with an IC₅₀ of 1.21 mg/L. When these micelles were administered to tumor model animals in vivo, pharmacokinetic analysis revealed that the total AUC and MRT of these micelles were 2.28- and 2.53-fold higher than that of free urushiol, respectively. Tissue distribution analyses further revealed these micelles to mediate significantly enhanced tumor urushiol accumulation.

Conclusion

The pH-responsive urushiol-loaded micelles described in this study may be ideally suited for clinical use for the treatment of breast cancer.

Complete Chloroplast Genome Sequence of Chinese Lacquer Tree (Toxicodendron vernicifluum, Anacardiaceae) and Its Phylogenetic Significance

Chinese lacquer tree (Toxicodendron vernicifluum) is an important commercial arbor species widely cultivated in East Asia for producing highly durable lacquer. Here, we sequenced and analyzed the complete chloroplast (cp) genome of T. vernicifluum and reconstructed the phylogeny of Sapindales based on 52 cp genomes of six families. The plastome of T. vernicifluum is 159,571 bp in length, including a pair of inverted repeats (IRs) of 26,511 bp, separated by a large single-copy (LSC) region of 87,475 bp and a small single-copy (SSC) region of 19,074 bp. A total of 126 genes were identified, of which 81 are protein-coding genes, 37 are transfer RNA genes, and eight are ribosomal RNA genes. Forty-nine mononucleotide microsatellites, one dinucleotide microsatellite, two complex microsatellites, and 49 long repeats were determined. Structural differences such as inversion variation in LSC and gene loss in IR were detected across cp genomes of the six genera in Anacardiaceae. Phylogenetic analyses revealed that the genus Toxicodendron is closely related to Pistacia and Rhus. The phylogenetic relationships of the six families in Sapindales were well resolved. Overall, this study providing complete cp genome resources will be beneficial for determining potential molecular markers and evolutionary patterns of T. vernicifluum and its closely related species.

Rhus verniciflua leaf extract suppresses obesity in high-fat diet-induced obese mice

Background

Obesity is a serious health problem in the world. We thought that the activity and safety of natural plants and/or foods are very important in the management of therapy for obesity. Rhus verniciflua (R. verniciflua) is also known as lacquer tree in Japan and Korea, and it is consumed as food ingredients and/or traditional herbal medicine. We prepared an extract from R. verniciflua leaves (Rv-PEM01-99) to develop a new functional food material and/or nutritional supplements.

Objective

This study evaluated the anti-obesity effects of the Rv-PEM01-99 in high-fat diet (HFD)-induced obese mice.

Design

Six-week-old male C57BL/6J mice were divided into three groups: group I (HFD group), group II (HFD + 1% Rv-PEM01-99 group), and group III (HFD + 2% Rv-PEM01-99 group). Throughout the 56-day treatment period, body weights of these mice were checked twice a week. After 56 days, blood biochemical analyses were performed.

Results

In animal studies, no death or abnormalities in food consumption were observed between groups I, II, and III. Body weight gain in the groups administered Rv-PEM01-99 was less than that in group I. In particular, body weight gain in group III was significantly less than that in group I after 52 days of Rv-PEM01-99 administration. In addition, intra-abdominal fat and leptin levels in group III were significantly lower than those in group I. HPLC and LC/MS analysis showed a quercetin derivative as an active compound in Rv-PEM01-99.

Conclusion

Rv-PEM01-99, containing a quercetin derivative, showed anti-obesity effect in HFD-fed mice. It could therefore be useful as food material and/or nutritional supplement for management of obesity.

Protective effect of Rhus verniciflua Stokes extract in an experimental model of post-menopausal osteoporosis

Post-menopausal osteoporosis (PMO) is a major global human health concern. Owing to the need for therapeutic drugs without side effects, natural extracts containing various polyphenolic compounds that may exert estrogenic effects have been studied in depth. Rhus verniciflua Stokes (RVS), which has been used as a traditional herbal medicine for centuries in Korea, was recently revealed to exert estrogenic effects attributable to its bioactive ingredients sulfuretin and butein, which have strong estrogen receptor–binding affinities. In this study, the protective potential of RVS in PMO was evaluated by using an experimental animal model of PMO, which was established by ovariectomy (OVX) of female Sprague Dawley rats. The oral administration of RVS at 20 mg/kg or 100 mg/kg for 8 weeks markedly protected against OVX-induced atrophy of the uterine tube and reversed the elevation in the ratio of serum receptor activator of nuclear factor-κB ligand to osteoprotegerin, which is a marker of disease severity. In addition, RVS inhibited OVX-induced tibia bone loss, activated osteogenic activity, and suppressed osteoclastic activity in the tibial epiphyseal plate, a region of bone remodeling. Collectively, these factors indicated that the oral intake of RVS might be beneficial for the prevention of PMO.

Design, virtual screening, molecular docking and molecular dynamics studies of novel urushiol derivatives as potential HDAC2 selective inhibitors

Three series of novel urushiol derivatives were designed by introducing a hydroxamic acid moiety into the tail of an alkyl side chain and substituents with differing electronic properties or steric bulk onto the benzene ring and alkyl side chain. The binding affinity toward HDAC2 of the compounds was screened by Glide docking. The best scoring compounds were processed further with molecular docking, MD simulations and binding free energy studies to analyze the binding modes and mechanisms. Six compounds, 21, 23, 10, 19, 9 and 30, gave Glide scores of -7.9 to -8.5, which revealed that introducing F, Cl, triazole, benzamido, formamido, hydroxyl or nitro substituents onto the benzene ring could increase binding affinity significantly. Molecular docking studies revealed that zinc ion coordination, hydrogen bonding and hydrophobic interactions contributed to the high calculated binding affinities of these compounds toward HDAC2 and that His145, His146, Gly154, Glu103, His183, Asp104, Tyr308 and Phe155 contributed favorably to the binding. MD simulations and binding free energy studies showed that all complexes possessed good stability as characterized by low RMSDs; low RMSFs of residues, moderate hydrogen bonding and zinc ion coordination; and low values of binding free energies. van der Waals and electrostatic interactions provided major contributions to the stability of these complexes. These results show the promising potential of urushiol derivatives as potent HDAC2 binding lead compounds.

3-Decylcatechol induces autophagy-mediated cell death through the IRE1α/JNK/p62 in hepatocellular carcinoma cells

The natural, phenolic lipid urushiol exhibits both antioxidant and anticancer activities; however, its biological activity on hepatocellular carcinoma (HCC) has not been previously investigated. Here, we demonstrate that an urushiol derivative, 3-decylcatechol (DC), induces human HCC Huh7 cell death by induction of autophagy. DC initiates the autophagic process by activation of the mammalian target of rapamycin signaling pathway via Unc-51-like autophagy activating kinase 1, leading to autophagosome formation. The autophagy inhibitor, chloroquine, suppressed autolysosome formation and cell death induction by DC, indicating an autophagic cell death. Interestingly, DC also activated the endoplasmic reticulum (ER) stress response that promotes autophagy via p62 transcriptional activation involving the inositol-requiring enzyme 1α/c-Jun N-terminal kinase/c-jun pathway. We also show that cytosolic calcium mobilization is necessary for the ER stress response and autophagy induction by DC. These findings reveal a novel mechanism by which this urushiol derivative induces autophagic cell death in HCC.

Rhus verniciflua Stokes attenuates cholestatic liver cirrhosis-induced interstitial fibrosis via Smad3 down-regulation and Smad7 up-regulation

Cholestatic liver cirrhosis (CLC) eventually proceeds to end-stage liver failure by mediating overwhelming deposition of collagen, which is produced by activated interstitial myofibroblasts. Although the beneficial effects of Rhus verniciflua Stokes (RVS) on various diseases are well-known, its therapeutic effect and possible underlying mechanism on interstitial fibrosis associated with CLC are not elucidated. This study was designed to assess the protective effects of RVS and its possible underlying mechanisms in rat models of CLC established by bile duct ligation (BDL). We demonstrated that BDL markedly elevated the serological parameters such as aspartate aminotransferase, alanine transaminase, total bilirubin, and direct bilirubin, all of which were significantly attenuated by the daily uptake of RVS (2 mg/kg/day) for 28 days (14 days before and after operation) via intragastric route. We observed that BDL drastically induced the deterioration of liver histoarchitecture and excessive deposition of extracellular matrix (ECM), both of which were significantly attenuated by RVS. In addition, we revealed that RVS inhibited BDL-induced proliferation and activation of interstitial myofibroblasts, a highly suggestive cell type for ECM production, as shown by immunohistochemical and semi-quantitative detection of α-smooth muscle actin and vimentin. Finally, we demonstrated that the anti-fibrotic effect of RVS was associated with the inactivation of Smad3, the key downstream target of a major fibrogenic cytokine, i.e., transforming growth factor β (TGF-β). Simultaneously, we also found that RVS reciprocally increased the expression of Smad7, a negative regulatory protein of the TGF-β/Smad3 pathway. Taken together, these results suggested that RVS has a therapeutic effect on CLC, and these effects are, at least partly, due to the inhibition of liver fibrosis by the downregulation of Smad3 and upregulation of Smad7.

Growth inhibitory and apoptosis-inducing effects of allergen-free Rhus verniciflua Stokes extract on A549 human lung cancer cells

Evidence suggests that Rhus verniciflua Stokes (RVS) or its extract has the potential to be used for the treatment of inflammatory and neoplastic diseases. However, direct use of RVS or its extract as a herbal medicine has been limited due to the presence of urushiol, an allergenic toxin. In the present study, we prepared an extract of the allergen‑removed RVS (aRVS) based on a traditional method and investigated its inhibitory effect on the growth of various types of human cancer cells, including lung (A549), breast (MCF-7) and prostate (DU-145) cancer cell lines. Notably, among the cell lines tested, treatment with the aRVS extract strongly inhibited proliferation of the A549 cells at a 0.5 mg/ml concentration for 24 h that was not cytotoxic to normal human dermal fibroblasts. Furthermore, aRVS extract treatment largely reduced the survival and induced apoptosis of the A549 cells. At the mechanistic levels, treatment with the aRVS extract led to the downregulation of Bcl-2 and Mcl-1 proteins, the activation of caspase-9/-3 proteins, an increase in cytosolic cytochrome c levels, the upregulation of Bax protein, an increase in phosphorylated p53 protein but a decrease in phosphorylated S6 protein in the A549 cells. Importantly, treatment with z-VAD‑fmk, a pan-caspase inhibitor attenuated aRVS extract-induced apoptosis in the A549 cells. These results demonstrate firstly that aRVS extract has growth inhibitory and apoptosis-inducing effects on A549 human lung cancer cells through modulation of the expression levels and/or activities of caspases, Bcl-2, Mcl-1, Bax, p53 and S6.

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.

Heartwood extract of Rhus verniciflua Stokes and its active constituent fisetin attenuate vasoconstriction through calcium-dependent mechanism in rat aorta

Rhus verniciflua Stokes (RVS) exert cardiovascular protective activity by promoting blood circulation, but its active ingredients and underlying mechanism have yet to be identified. This study investigated the vascular effects of RVS, focusing on vasoconstriction and smooth muscle Ca2+ signaling. RVS heartwood extract attenuated contraction of aortic rings induced by the vasoconstrictors serotonin and phenylephrine, and inhibited the Ca2+ signaling evoked by serotonin in vascular smooth muscle cells. Subsequent activity-guided fractionation identified fisetin as an active constituent exerting a Ca2+ inhibitory effect. Fisetin could inhibit major Ca2+ mobilization pathways including extracellular Ca2+ influx mediated by the L-type voltage-gated Ca2+ channel, Ca2+ release from the intracellular store and store-operated Ca2+ entry. In accordance with Ca2+ inhibitory effect, fisetin attenuated vasoconstriction by serotonin and phenylephrine. These results suggest that the anticontractile effect, which is presumably mediated by inhibition of Ca2+ signaling, may contribute to the improvement of blood circulation by RVS.

Urushiol Induces Apoptosis via a p53-dependent Pathway in Human Gastric Cancer Cells

BACKGROUND

Urushiols are mixtures of olefinic catechols which is isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes). The aim of this study was to determine the anticancer effects of urushiol in human gastric adenocarcinoma cell lines.

METHODS

The cytotoxicity of urushiols was assessed by MTT assays on the two gastric adenocarcinoma cell lines, MKN-45 (wild type of p53) and MKN-28 (mutant type of p53). We also examined the action mechanisms of urushiol by analyzing its effects on cell cycle progression and apoptosis induction.

RESULTS

The cytotoxic results from MTT assays indicated that urushiol inhibited human gastric cancer cell growth in a dose-dependent manner, with IC50 values of approximately 15 and 20 μg/ml on MKN-45 and MKN-28 cells, respectively. Urushiol mediated cell death on these two cancer cell lines through different pathways. Urushiol induced apoptosis on MKN-45 cells, concomitant with apoptotic nuclear change, DNA fragmentation, poly (ADP-ribose) polymerase cleavage and apoptotic body formation via extrinsic pathway of apoptosis. However, no apoptotic features were induced by urushiol treatment on MKN-28 cells. Urushiol induced cytostatic cell growth inhibition via upregulation of the cyclin-dependent kinase inhibitors, p21 (WAF1/CIP1) and p27 (KIP1) proteins and down-regulation of cyclin-dependent kinase 2 and 4 proteins in a p53-independent manner.

CONCLUSIONS

These data provide evidence that urushiol has the potential to be used as a chemotherapeutic agent in human gastric cancer.

Single and 90-day repeated oral dose toxicity studies of fermented Rhus verniciflua stem bark extract in Sprague-Dawley rats

Fermented Rhus verniciflua stem bark (FRVSB) extract, an urushiol-free extract of Rhus verniciflua Stokes (RVS) fermented with Fomitella fraxinea, has various biological activities. The present study was carried out to investigate the potential toxicity of the FRVSB extract following single and repeated oral administration to Sprague-Dawley rats. In the single dose toxicity study, the FRVSB extract was administered orally to male and female rats at single doses of 0, 2500, 5000, and 10,000mg/kg. No animals died and no toxic changes were observed in clinical signs, body weight, and necropsy findings during the 15-day period following administration. In the repeated dose toxicity study, the FRVSB extract was administered orally to male and female rats for 90days at doses of 0, 556, 1667, and 5000mg/kg/day. There were no treatment-related adverse effects in clinical signs, body weight, food and water consumption, ophthalmic examination, urinalysis, hematology, serum biochemistry, necropsy findings, organ weight, and histopathology at any dose tested. The approximate lethal dose of the FRVSB extract was >10,000mg/kg in both genders, the oral no-observed-adverse-effect level of the FRVSB extract was >5000mg/kg/day in both genders, and no target organs were identified.

Effects of Anti-diarrhoeal Herbs on Growth Performance, Nutrient Digestibility, and Meat Quality in Pigs

Two studies were conducted to investigate the effects of anti-diarrhoeal herbs on growth performance, nutrient digestibility, and meat quality in pigs. In Exp 1, 150 weanling-growing piglets (average BW = 7.5±0.24 kg, average age = 27±1 d) were allotted into one of the five dietary treatments, including: i) CON, basal diet, ii) DP, basal diet+1 g/kg date pits, iii) JH, basal diet+0.5 g/kg Japanese-honeysuckle, iv) HCT, basal diet+1 g/kg houttuynia cordata thunb, and v) LE, basal diet+1 g/kg laquer tree extract. From wk 0 to 5, the JH, HCT and LE groups presented higher (p<0.05) ADFI, ADG and gain/feed ratio (G/F) than CON and DP groups. During wk 5 to 10, Pigs fed JH, HCT and LE diets indicated higher (p<0.05) ADG and ADFI than the pigs fed CON and DP diets. During the entire experimental period, a significant increase of ADG appeared in JH, HCT and LE (p<0.05). Pigs fed JH, HCT and LE diets got a higher (p<0.05) ADFI than the pigs fed CON and DP diets. Pigs fed diets with supplementations of herb additives revealled lower (p<0.05) score of diarrhea pigs during d 2 to d 6 compared with pigs fed CON diet. In Exp 2, 60 growing-finishing barrows and gilts (average BW = 54.10±1.20 kg, average age = 54±3 d) were allotted to three treatments: i) CON, basal diet; ii) YG, basal diet+1 g/kg yellow ginger and iii) HR, basal dietary+1 g/kg hoantchy root, respectively. From wk 0 to 5, Dietary supplementation of YG and HR enhanced (p<0.05) ADG. No difference was found between YG and HR treatments. During, wk 5 to 10, ADG also was observed higher in YG and HR treatments than CON group (p<0.05). Additional, YG had the highest ADG (p<0.05) among treatments. There was always an increase of ADG in YG and HR (p<0.05) through all periods. HR treatment showed a lower (p<0.05) score of diarrhoeal pigs on d 1and d 2 compared with CON treatment. Pigs fed YG and HR diets had a higher (p<0.05) longissimus muscle area (LMA) than pigs fed CON diet. In conclusion, anti-diarrhoeal herbs can improve growth performance, and prevent diarrhea incidence in pigs, it can also increase LMA in finishing pigs.

Sulfuretin isolated from heartwood of Rhus verniciflua inhibits LPS-induced inducible nitric oxide synthase, cyclooxygenase-2, and pro-inflammatory cytokines expression via the down-regulation of NF-kappaB in RAW 264.7 murine macrophage cells

It has been reported that Rhusverniciflua exhibits anti-inflammatory, anti-oxidant and anti-cancer activities. However, little is known about biological activity of sulfuretin, a flavonoid isolated from R.verniciflua. In the present study, we investigated the anti-inflammatory effect and the underlying molecular mechanisms of sulfuretin in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Sulfuretin dose-dependently reduced the productions of nitric oxide (NO), prostaglandin E(2) (PGE(2)), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta) induced by LPS. Consistent with these findings, sulfuretin significantly suppressed the LPS-induced expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-alpha, and IL-1 beta. In addition, sulfuretin attenuated LPS-induced DNA binding and the transcriptional activities of nuclear factor-kappa B (NF-kappaB), which was accompanied by a parallel reduction of degradation and phosphorylation of inhibitory kappa B-alpha (I kappaB-alpha) and consequently by decreased nuclear translocation of p65 subunit of NF-kappaB. Furthermore, pretreatment with sulfuretin significantly inhibited the LPS-stimulated activation of I kappaB kinase beta (IKK beta). Taken together, these results suggest that the anti-inflammatory effect of sulfuretin in LPS-treated RAW 264.7 macrophages is associated with the suppression of NF-kappaB transcriptional activity via the inhibitory regulation of IKKbeta phosphorylation.

Evaluation of Genotoxicity of Water and Ethanol Extracts from Rhus verniciflua Stokes (RVS)

Rhus verniciflua Stokes (RVS), one of traditional medicinal plants in Asia, was found to have pharmacological activities such as antioxidative and antiapoptotic effects, raising the possibility for the development of a novel class of anti-cancer drugs. Thus, potential genotoxic effects of RVS in three short-term mutagenicity assays were investigated, which included the Ames assay, in vitro Chromosomal aberration test, and the in vivo Micronucleus assay. In Ames test, the addition of RVS water extracts at doses from 313 up to 5000 mg/plate induced an increase more than 2-fold over vehicle control in the number of revertant colonies in TA98 and TA1537 strains for detecting the frame-shift mutagens. The similar increase in reversion frequency was observed after the addition of RVS ethanol extracts. To assess clastogenic effect, in vitro chromosomal aberration test and in vivo micronucleus assay were performed using Chinese hamster lung cells and male ICR mice, respectively. Both water and ethanol extracts from RVS induced significant increases in the number of metaphases with structural aberrations mostly at concentrations showing the cell survival less than 60% as assessed by in vitro CA test. Also, there was a weak but statistically significant increase in number of micronucleated polychromatic erythrocytes (MNPCEs) in mice treated with water extract at 2000 mg/kg while ethanol extracts of RVS at doses of up to 2000 mg/kg did not induce any statistically significant changes in the incidence of MNPCEs. Therefore, our results lead to conclusion that RVS acts as a genotoxic material based on the available in vitro and in vivo results.

Selective antiproliferative and apoptotic effects of flavonoids purified from Rhus verniciflua Stokes on normal versus transformed hepatic cell lines

Considerable attention is being concentrated on dietary flavonoids in developing novel cancer-preventive approaches due to their potential ability to induce selective apoptosis of cancer cells. In this study, we prepared a flavonoid-containing fraction from a crude acetone extract of Rhus verniciflua Stokes (RVS), traditionally used as a food additive and as an herbal medicine, and named RVS chloroform-methanol fraction (RCMF). We evaluated the effects of RCMF on proliferation and apoptosis using mouse embryonic primary hepatic cells (MPHC), embryonic normal hepatic cell line (BNL CL.2), and its SV40-mediated transformed cell line (BNL SV A.8). We also investigated the effects of RCMF on the antioxidant defense system in those cells. This study demonstrated that RCMF exhibited a selective growth inhibition and apoptosis induction on transformed cells. BNL SV A.8 cells were more sensitive to RCMF-mediated cytotoxicity than were MPHC or BNL CL.2. RCMF-mediated reduction of MnSOD activity and glutathione (GSH) content in BNL SV A.8 cells is thought to be associated with RCMF-induced apoptosis. Our findings suggest that RCMF is an agent which may be capable of inducing growth inhibition and apoptosis of hepatic tumor cells.

Extract from Rhus verniciflua Stokes is capable of inhibiting the growth of human lymphoma cells

Rhus verniciflua Stokes (RVS), used as a food additive and a traditional herbal medicine, has both antioxidant and antitumor activities which are known to be closely associated with the polyphenolic compounds that it contains. In the present study, we purified a fraction from a crude acetone extract of RVS, named RCMF (RVS chloroform-methanol fraction), and evaluated its ability to scavenge free radicals and inhibit cell growth. In addition, the active compounds responsible for the activities were identified. Results showed that RCMF contained an antioxidant potential and strongly suppressed the proliferative capability of B lymphoma cells. RCMF-mediated suppression of cell growth was verified to be apoptotic, based on the increased DNA fragmentation and low fluorescence intensity in the nuclei after propidium iodide staining, and also on the appearance of DNA laddering. Finally, EI-MS, 1H-NMR, and 13C-NMR spectra confirmed that RCMF contained flavonoid derivatives, including protocatechuic acid, fustin, fisetin, sulfuretin, and butein, suggesting that these flavonoid derivatives are the main active compounds responsible for the antioxidant and antiproliferative activities of RCMF.

Ethanol-eluted extract of Rhus verniciflua stokes inhibits cell growth and induces apoptosis in human lymphoma cells

Rhus verniciflua Stokes (RVS) has been used as a traditional herbal medicine. Several earlier studies indicated that an ethanol extract of RVS has both anti-oxidant and anti-tumor properties, although the mechanism for the activity remains to be elucidated. In this report, we prepared a highly purified ethanol extract from RVS, named REEE-1 (Rhus ethanol eluted extract-1), and investigated the mechanism involved in its growthinhibitory effect on the human B and T lymphoma cell lines, BJAB and Jurkat, respectively. Results from tritium uptake proliferation assays showed that the proliferative capacities of both BJAB and Jurkat cells were strongly suppressed in the presence of REEE-1. This was further confirmed through trypan blue exclusion experiments that revealed a dose-dependent decrease in viable cell numbers after REEE-1 treatment. REEE-1-mediated suppression of cell growth was verified to be apoptotic, based on the increase in DNA fragmentation, low fluorescence intensity in nuclei after propidium iodide staining, and the appearance of DNA laddering. In particular, REEE-1 exerted its anti-oxidant activity through the inhibition of hydroxyl radical-mediated degradation by iron ion chelation rather than direct scavenging of hydroxyl radicals. Furthermore, REEE-1 was revealed to be a potential scavenger of superoxide anions. Collectively, our findings suggest that REEE-1 is a natural anti-oxidant that could be used as a cancer chemo-preventive and therapeutic agent.

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.

Identification of Rhus verniciflua Stokes compounds that exhibit free radical scavenging and anti-apoptotic properties

Rhus verniciflua Stokes (RVS) is a widely used herbal plant with various biological properties. Our previous study using cultured neuronal cells showed that an ethanol extract of RVS had strong antioxidant properties. In this study, we characterized the antioxidant activity of the RVS ethanol extract and identified the active compounds responsible for this activity. From the RVS ethanol extract, we derived three water-eluted fractions and another three fractions eluted by organic solvents, and determined that the water-eluted fractions are what protect against reactive oxygen species (ROS) generated by iron and enzymes. Water-eluted fraction F(2) was the most efficient antioxidant. Moreover, DNA fragmentation and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining experiments revealed that F(2) also protects against thymocyte apoptosis mediated by hydroxyl radicals. Finally, EI-MS, (1)H-NMR, and (13)C-NMR spectra signals confirmed that the fraction contained flavonoid derivatives, including fustin, quercetin, butein, and sulfuretin. These results suggest that the flavonoid derivatives in F(2) are the compounds in the RVS ethanol extract that act as antioxidants.