Cudrania Tricuspidata Extract and Its Major Constituents Inhibit Oxidative Stress-Induced Liver Injury.

The fruits, leaves, and roots of Cudrania tricuspidata have been reported to contain large amounts of vitamin B, vitamin C, and flavonoids. They exhibit various physiological activities such as antitumor and anti-inflammatory effects. However, the hepatoprotective effects of C. tricuspidata extracts against oxidative stress-mediated liver injury have not yet been investigated. We thus examined whether C. tricuspidata leaf extracts (CTEs) protect against oxidative stress-mediated liver injury in vitro and in vivo and elucidated the underlying mechanism. The cytoprotective effects of CTE through the NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE) activation were presented and measured by biochemical analysis in HepG2 cells. To assess the protective effects of CTE in vivo, mice were administered with CTE (250 and 500 mg/kg; 5 days; p.o.) before a single dose of acetaminophen (APAP) (300 mg/kg; 24 h; i.p.). CTE increased ARE luciferase activity when compared with extracts of other parts of C. tricuspidata. CTE upregulated nuclear translocation of Nrf2 and its target gene expression. In addition, CTE inhibited the generation of reactive oxygen species (ROS) and cell death induced by arachidonic acid (AA) and iron (Fe) treatment in primary hepatocytes or HepG2 cells. The cytoprotective effects of CTE against oxidative stress might be due to kaempferol, the major flavonoid present in CTE. Kaempferol pretreatment blocked AA+Fe-induced ROS production and reversed glutathione depletion, which in turn led to decreased cell death. Furthermore, the protective effects of CTE against liver injury induced by excess APAP in mice or primary hepatocytes were observed. CTE could be a promising therapeutic candidate against oxidative stress-induced liver injury.

Topical film prepared with Rhus verniciflua extract-loaded pullulan hydrogel for atopic dermatitis treatment.

Atopic dermatitis (AD) is characterized by relapsing pruritus and skin dryness. Due to the pathogenic multiplicity and the adverse effects associated with the current therapeutics, development of transdermal drug delivery system is becoming an area of interest. Here, a novel topical film prepared with Rhus verniciflua extract (RVE)-loaded pullulan hydrogel (RVE@PH) was synthesized and tested its therapeutic efficacy on the AD rats modeled by neonatal capsaicin injection method. The RVE@PH was characterized by a Fourier-transform infrared spectroscopy and an in vitro release assay. Rat pups were randomly divided into two groups: vehicle-treated (VEH; n = 5) and capsaicin-treated (n = 15). The latter were given capsaicin subcutaneously at 24 h after birth for AD induction and further divided into three groups (n = 5 per each): not treated (CAP), pullulan hydrogel-applied (PH), and RVE@PH-applied (RVE-PH). The pullulan hydrogel and RVE@PH were topically applied on shoulder lesions for 14 days (from 42 to 56 days after birth). Their phenotypes were compared based on the dermatitis score, epidermal thickness, mast cell infiltration, and serum myeloperoxidase (MPO) activities. The PH group showed significant attenuation in all the aforementioned values compared to the CAP group, suggesting that pullulan hydrogel itself has therapeutic activity against AD. Notably, the attenuations were more potent in the RVE-PH group than the PH group, indicating that the therapeutic efficacy against AD is augmented by the presence of RVE, a loaded pharmaceutic. Collectively, these results indicate that RVE@PH inhibits AD through exerting the dual roles, that is, the pullulan hydrogel-mediated physical and RVE-mediated pharmaceutical actions. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2325-2334, 2019.

Platycarya strobilacea leaf extract protects mice brain with focal cerebral ischemia by antioxidative property.

The leaf extract of Platycarya strobilacea (PSL) has long been recognized as possessing various health-promoting activities. However, information on its possible protective effects against ischemic stroke is currently lacking. Here, using a mouse model of focal cerebral ischemia (fCI), we studied the protective potential of an oral supplement of PSL. Mice were randomly divided into four groups: SO, a group subjected to a sham-operation; VEH, pretreated with distilled water and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R); PSL-L and PSL-H, pretreated with low (20 mg/kg) and high (100 mg/kg) doses of PSL, respectively, and subjected to the MCAO/R procedure. PSL was administered via an oral route daily for 8 days prior to surgery. We then measured the infarct volumes and sensorimotor deficits and studied the underlying antioxidant mechanisms by quantifying apoptosis, reactive oxygen species (ROS) generation, oxidative damages, and antioxidant enzymes in the ischemic cortex. The results showed a marked attenuation in infarct volume and sensorimotor deficits in both the PSL-L and PSL-H groups when compared with VEH. The terminal deoxynucleotidyl transferase dUTP nick end labeling and the immunohistochemical detection of the cleaved caspase-3 revealed that PSL could reduce cellular apoptosis in the ischemic lesion in a dose-dependent manner. The dihydroethidium-fluorescence, 4-hydroxynonenal, and 8-hydroxyl-2'-deoxyguanosine immunoreactivities in the ischemic lesion were markedly attenuated in the PSL-L group compared with the VEH group, indicating that PSL could attenuate ROS generation and the associated oxidative damage in the ischemic cortex. Finally, western blot results indicated that PSL can upregulate levels of heme oxygenase-1 (HO-1), an antioxidant enzyme, in the lesion area. Together, these results suggest that PSL can exert protective effects against fCI, and the mechanism may involve HO-1 upregulation.

Extract of Rhus verniciflua stokes protects against renal ischemia-reperfusion injury by enhancing Nrf2-mediated induction of antioxidant enzymes.

Ischemia-reperfusion injury (IRI) may cause acute kidney disease (AKD) by mediating the oxidative stress-induced apoptosis of parenchymal cells. The extract of Rhus verniciflua Stokes (RVS) is used as a traditional herbal medicine as it exhibits anti-oxidant, anti-apoptotic and anti-inflammatory properties. Therefore, the current study investigated the therapeutic effect and the underlying mechanism of RVS on IRI-induced AKD in vivo and in vitro. The current study assessed the effects of RVS on a mouse model of renal IRI and in hypoxic human renal tubular epithelial HK-2 cells. The results demonstrated that the IRI-induced elevation of blood urea nitrogen, serum creatinine and lactate dehydrogenase was significantly attenuated by the intraoral administration of RVS (20 mg/kg/day) for 14 days prior to surgery. It was demonstrated that IRI surgery induced histological damage and cellular apoptosis in renal parenchyma, which were attenuated by pretreatment with RVS. Furthermore, in HK-2 cells incubated with 300 µM CoCl2 to induce chemical hypoxia, it was demonstrated that RVS treatment significantly inhibited cell death and the production of reactive oxygen species (ROS). Furthermore, RVS treatment upregulated the levels of endogenous antioxidant enzymes, including heme oxygenase-1 and catalase, as well as their upstream regulator nuclear factor erythroid 2-related factor 2, in HK-2 cells. Taken together, these results suggested that the intraoral administration of RVS induces a therapeutic effect on IRI-induced AKD. These effects are at least partly due to the attenuation of ROS production via upregulation of the antioxidant defense system in renal tubular cells.

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.

Evaluation of Herb-Drug Interactions of Hovenia dulcis Fruit Extracts.

BACKGROUND: Hovenia dulcis (Rhamnaceae) fruits are popularly used as herbal medicines or dietary supplements in Asian countries due to functions such as liver protection and detoxification from alcohol poisoning. Accordingly, it is very likely for dietary supplemental products, including H. dulcis fruit extracts, to be taken with prescription drugs. OBJECTIVE: In this study, possible food-drug interactions involving H. dulcis fruit extracts were evaluated based on the inhibition of cytochrome P450 (CYP) enzyme activity. MATERIAL AND METHODS: The water extract of H. dulcis fruit extracts was incubated in human liver microsomes with CYP-specific substrates. The formation of the CYP-specific metabolites was measured using liquid chromatography-tandem mass spectrometry. RESULTS: H. dulcis fruit extracts showed negligible effects on seven CYP isozyme activities at all concentrations tested. CONCLUSION: This result suggests that H. dulcis fruit extracts may have minimal pharmacokinetic interactions with coadministered drugs through the modulation of CYP enzymes. SUMMARY: Food-drug interactions involving H. dulcis fruit extracts were evaluated.The inhibition of CYPs by H. dulcis extracts was tested.H. dulcis extracts showed negligible effects on CYP activities.H. dulcis extracts may have minimal pharmacokinetic interactions with co-administered drugs. Abbreviations Used: CYP: cytochrome P450 enzymes, HPLC: High performance liquid chromatography, LC-MS/MS : liquid chromatography-tandem mass spectrometry, MRM: multiple-reaction monitoring.

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 ß (TGF-ß). Simultaneously, we also found that RVS reciprocally increased the expression of Smad7, a negative regulatory protein of the TGF-ß/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.

Anti-Helicobacter pylori activity of crude N-acetylneuraminic acid isolated from glycomacropeptide of whey.

Helicobacter pylori colonizes the gastric mucosa of about half of the world's population, causing chronic gastritis and gastric cancer. An increasing emergence of antibiotic-resistant H. pylori arouses demand on alternative non-antibiotic-based therapies. In this study, we freshly prepared crude N-acetylneuraminic acid obtained from glycomacropeptide (G-NANA) of whey through a neuraminidase-mediated reaction and evaluated its antibacterial ability against H. pylori and H. felis. Overnight cultures of the H. pylori were diluted with fresh media and different concentrations (1-150 mg/mL) of crude G-NANA were added directly to the culture tube. Bacterial growth was evaluated by measuring the optical density of the culture medium and the number of viable bacteria was determined by a direct count of the colony forming units (CFU) on agar plates. For the in vivo study, mice were orally infected with 100 µL (5×10(8) cfu/mL) of H. felis four times at a day's interval, accompanied by a daily administration of crude G-NANA or vehicle. A day after the last infection, the mice were daily administered the crude G-NANA (0, 75, and 300 mg/mL) for 10 days and euthanized. Their stomachs were collected and bacterial colonization was determined by quantitative real-time PCR. Crude G-NANA inhibited H. pylori's growth and reduced the number of viable bacteria in a dose-dependent manner. Furthermore, crude G-NANA inhibited bacterial colonization in the mice. These results showed that crude G-NANA has antibacterial activity against Helicobacter and demonstrated its therapeutic potential for the prevention of chronic gastritis and gastric carcinogenesis induced by Helicobacter infection in humans.

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 Ca(2+) signaling. RVS heartwood extract attenuated contraction of aortic rings induced by the vasoconstrictors serotonin and phenylephrine, and inhibited the Ca(2+) signaling evoked by serotonin in vascular smooth muscle cells. Subsequent activity-guided fractionation identified fisetin as an active constituent exerting a Ca(2+) inhibitory effect. Fisetin could inhibit major Ca(2+) mobilization pathways including extracellular Ca(2+) influx mediated by the L-type voltage-gated Ca(2+) channel, Ca(2+) release from the intracellular store and store-operated Ca(2+) entry. In accordance with Ca(2+) inhibitory effect, fisetin attenuated vasoconstriction by serotonin and phenylephrine. These results suggest that the anticontractile effect, which is presumably mediated by inhibition of Ca(2+) signaling, may contribute to the improvement of blood circulation by RVS.

A Liquid Chromatography-Tandem Mass Spectrometry Method for Simultaneous Quantitation of 10 Bioactive Components in Rhus verniciflua Extracts.

The purpose of this study was to develop a simultaneous method to quantify 10 bioactive compounds in Rhus verniciflua extracts using high-performance liquid chromatography-tandem mass spectrometry. The chromatographic separation was performed using a C18 column under gradient elution with 0.1% formic acid and acetonitrile as the mobile phase solvents. The analytes were detected in the negative-ion mode using multiple-reaction monitoring detection with an electrospray ionization interface. The calibration curves for all the analytes showed good linearity (r(2) >0.997) over the concentration range of 1-1,000 ng/mL. The recovery values were within 89.53-110.14%, and the intra- and interday coefficients of variation were <4.86% for all the tested compounds. The developed method was successfully applied to a quality assessment of the R. verniciflua extract samples.

HPLC Determination of Bioactive Flavonoids in Hovenia dulcis Fruit Extracts.

A simple, accurate and reproducible reversed-phase liquid chromatographic method was developed for qualitative and quantitative determination of four bioactive flavonoids (ampelopsin, taxifolin, myricetin and quercetin) from the fruit-stalk extract of Hovenia dulcis Thunb. Chromatographic separation was performed on a C18 column (4.6 × 150 mm, 3.5 µm) with mobile phase consisting of 0.1% acetic acid and 100% acetonitrile at a flow rate of 1.0 mL/min. The analysis was performed using a diode array detector at 365 nm. The method was validated in terms of selectivity, linearity, accuracy, precision and recovery. Good linearity was observed over the investigated concentration range (10-500 µg/mL), with correlation coefficient values greater than 0.99. The intra- and inter-day precisions over the concentration range were <3.91% (relative standard deviation), and the accuracy was between 91.57 and 106.66%. The mean recovery for all the analytes was 100.87%. This method was successfully applied in the quality assessment of bioactive flavonoids in the fruit-stalk extract of H. dulcis.

Pharmacokinetic Profile of Eight Phenolic Compounds and Their Conjugated Metabolites after Oral Administration of Rhus verniciflua Extracts in Rats.

Rhus verniciflua (Toxicodendron vernicifluum) is a medicinal tree popularly used in Asian countries such as China, Japan, and Korea as a food additive or herbal medicine because of its beneficial effects. R. verniciflua extract (RVE) contains diverse phenolic compounds, such as flavonoids, as its major biological active constituents. In this study, the pharmacokinetic profiles of eight phenolic compounds were investigated following oral administration of RVE to rats. The eight phenolic compounds were 2,4-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid, fisetin, fustin, butin, sulfuretin, taxifolin, and garbanzol. The plasma concentrations of the eight compounds were determined by using a liquid chromatography-triple-quadrupole mass spectrometer before and after treatment with ß-glucuronidase. When 1.5 g/kg RVE was administered, the eight compounds were all detected in plasma, mainly as conjugated forms. These pharmacokinetic data would be useful for understanding the pharmacological effects of RVE.

Extract of Rhus verniciflua stokes protects the diet-induced hyperlipidemia in mice.

Rhus verniciflua stokes (RVS) is a popular medicinal plant in oriental medicines which is commonly used to resolve extravasated blood. To elucidate the molecular mechanism of the role of RVS extracts on the regulation of lipid and cholesterol biosynthesis, we investigated whether RVS extract protect the hyperlipidemia in western diet-induced C57BL6/J mice. Mice fed a western diet and additionally RVS extracts was administered orally at a dose of 0.1 or 1 g/kg/day for 2 weeks respectively. Group with higher dose of RVS extract showed a significantly decreased body weight compared with western diet fed mice groups. And total cholesterol, LDL-cholesterol levels and fatty liver formation were also improved especially in group of mice fed western diet supplemented high dose RVS extracts. Next, synthesis of hepatic bile acids were significantly increased in RVS extract fed groups. Furthermore, RVS extracts significantly increase promoter activity of Cyp7a1 via up-regulate the transcriptional expression level of LXRα. Our data suggest that RVS extracts could be a potent therapeutic ingredient for prevent a hyperlipidemia via increase of bile acids biosynthesis.

Antiplatelet effects of Rhus verniciflua stokes heartwood and its active constituents--fisetin, butein, and sulfuretin--in rats.

Rhus verniciflua stokes (RVS) is known to promote blood circulation by preventing blood stasis, although the active ingredients and the underlying mechanism are unclear. Platelets are the primary cells that regulate circulation and contribute to the development of diverse cardiovascular diseases by aggregation and thrombosis. The study assessed the antiplatelet activity of RVS and sought to identify the active constituents. Pretreatment of washed platelets with RVS heartwood extract blunted the aggregatory response of platelets to collagen. In the subfractions, fisetin, butein, and sulfuretin were identified as effective inhibitors of platelet aggregation by collagen, thrombin, and adenosine-5'-diphosphate. Antiplatelet activities of all three compounds were concentration dependent, and fisetin had longer in vitro duration of action compared with butein or sulfuretin. Extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase activation by collagen was prevented by fisetin, whereas butein and sulfuretin failed to inhibit ERK and p38 activation was not affected by any of the compounds. Rats orally administered 100 mg/(kg·day(-1)) fisetin for 7 days were resistant to arterial thrombosis, although total extract of RVS heartwood exhibited little effect at a dose of 1000 mg/(kg·day(-1)). RVS heartwood may have cardiovascular protective activity by inhibiting platelet aggregation. The active constituents are fisetin, butein, and sulfuretin, and fisetin is orally effective against thrombosis.

Inhibitory effect of Rhus verniciflua Stokes extract on human aromatase activity; butin is its major bioactive component.

Rhus verniciflua Stokes has been used as a traditional herbal medicine in Asia. In this study, the effect of R. verniciflua extract on human aromatase (cytochrome P450 19, CYP19) activity was investigated to elucidate the mechanism for the effect of R. verniciflua extract on androgen hormone levels. Androstenedione was used as a substrate and incubated with R. verniciflua extract in cDNA-expressed CYP19 supersomes in the presence of NADPH, and estrone formation was measured using liquid chromatography-tandem mass spectrometry. R. verniciflua extract was assessed at concentrations of 10-1000 µg/mL. The resulting data showed that R. verniciflua extract inhibited CYP19-mediated estrone formation in a concentration-dependent manner with an IC50 value of 136 µg/mL. Subsequently, polyphenolic compounds from R. verniciflua extract were tested to identify the ingredients responsible for the aromatase inhibitory effects by R. verniciflua extract. As a result, butin showed aromatase inhibitory effect in a concentration-dependent manner with an IC50 value of 9.6 µM, whereas the inhibition by other compounds was negligible. These results suggest that R. verniciflua extract could modulate androgen hormone levels via the inhibition of CYP19 activity and butin is a major ingredient responsible for this activity.

Simultaneous determination of bioactive phenolic compounds in the stem extract of Rhus verniciflua stokes by high performance liquid chromatography.

A simple, sensitive, and precise reversed-phase liquid chromatographic method was developed for the quantitative determination of 4 bioactive phenolic compounds (gallic acid, fustin, fisetin, and sulfuretin) from the stem extract of Rhus verniciflua stokes. Chromatographic analysis was performed on a Capcell Pak C18 column (150 × 4.6 mm, 3 µm) with a mobile phase consisting of 0.1% formic acid and 90% acetonitrile at a flow rate of 1 mL/min. Quantitation was performed using a UV-vis detector at 260 nm. The method was validated in terms of selectivity, linearity, accuracy, precision, and recovery. Excellent linear behavior was observed over the investigated concentration range (10-500 µg/mL for gallic acid, fustin, and fisetin; 0.5-100 µg/mL for sulfuretin) with correlation coefficient (r(2)) values >0.99. The intra- and inter-day precision over the concentration range of compounds was less than 6.65% (relative standard deviation) and the accuracy was between 92.42% and 103.62%. The mean recoveries for all the analytes were more than 92.18%. This method was successfully applied for the analysis of bioactive phenolic compounds in the R. verniciflua extracts.

Anti-fatigue activity of Hovenia dulcis on a swimming mouse model through the inhibition of stress hormone expression and antioxidation.

Hovenia dulcis (H. dulcis) Thunb., which is distributed in Korea, China, and Japan, has been known to show hepatoprotective and free radical scavenging effects and enhance physical activity. Therefore, the objectives of this present study were to determine the anti-fatigue activity of hot-water extract from H. dulcis peduncle, and to find the reason why H. dulcis extract (HDE)-ingested mice had enhanced physical activity against swimming performance. The mice orally administrated with HDE (HDE-mice) dramatically enhanced their swimming time compared to the control mice. HDE significantly decreased serum levels of stress hormones, such as cortisol and adrenocorticotropic hormone (ACTH) in mice. The levels of thiobarbituric acid reactive substances (TBARS) were dramatically decreased in gastrocnemius muscle from both 100 mg/kg of HDE (LHDE) and 200 mg/kg of HDE (HHDE)-ingested mice compared to the control mice. The liver activities of superoxide dismutase (SOD) were significantly increased in HHDE-mice with increasing tendency in LHDE-mice. In addition, HHDE-mice significantly decreased the levels of blood glucose, total cholesterol (T-Chol), and triglyceride (TG). These results suggest that HDE had a significant anti-fatigue effect via its anti-stress and antioxidant activities, and thereby enhanced physical activity in swimming performance.

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.