Combined Treatment of 6-Gingerol Analog and Tobramycin for Inhibiting Pseudomonas aeruginosa Infections.

Pseudomonas aeruginosa is a ubiquitous human pathogen that causes severe infections. Although antibiotics, such as tobramycin, are currently used for infection therapy, their antibacterial activity has resulted in the emergence of multiple antibiotic-resistant bacteria. The 6-gingerol analog, a structural derivative of the main component of ginger, is a quorum sensing (QS) inhibitor. However, it has a lower biofilm inhibitory activity than antibiotics and the possibility to cause toxicity in humans. Therefore, novel and more effective approaches for decreasing dosing concentration and increasing biofilm inhibitory activity are required to alleviate P. aeruginosa infections. In this study, a 6-gingerol analog was combined with tobramycin to treat P. aeruginosa infections. The combined treatment of 6-gingerol analog and tobramycin showed strong inhibitory activities on biofilm formation and the production of QS-related virulence factors of P. aeruginosa compared to single treatments. Furthermore, the combined treatment alleviated the infectivity of P. aeruginosa in an insect model using Tenebrio molitor larvae without inducing any cytotoxic effects in human lung epithelial cells. The 6-gingerol analog showed these inhibitory activities at much lower concentrations when used in combination with tobramycin. Adjuvant effects were observed through increased QS-disrupting processes rather than through antibacterial action. In particular, improved RhlR inactivation by this combination is a possible target for therapeutic development in LasR-independent chronic infections. Therefore, the combined treatment of 6-gingerol analog and tobramycin may be considered an effective method for treating P. aeruginosa infections. IMPORTANCE Pseudomonas aeruginosa is a pathogen that causes various infectious diseases through quorum-sensing regulation. Although antibiotics are mainly used to treat P. aeruginosa infections, they cause the emergence of resistant bacteria in humans. To compensate for the disadvantages of antibiotics and increase their effectiveness, natural products were used in combination with antibiotics in this study. We discovered that combined treatment with 6-gingerol analog from naturally-derived ginger substances and tobramycin resulted in more effective reductions of biofilm formation and virulence factor production in P. aeruginosa than single treatments. Our findings support the notion that when 6-gingerol analog is combined with tobramycin, the effects of the analog can be exerted at much lower concentrations. Furthermore, its improved LasR-independent RhlR inactivation may serve as a key target for therapeutic development in chronic infections. Therefore, the combined treatment of 6-gingerol analog and tobramycin is suggested as a novel alternative for treating P. aeruginosa infections.

Urushiol Compounds Detected in Toxicodendron-Labeled Consumer Products Using Mass Spectrometry.

BACKGROUND: Urushiol, the culprit allergen in Toxicodendron plants such as poison ivy, is an oily mixture of 15 and 17 carbon side chain alk-(en)-yl catechols. Recently, consumer products have been identified that contain Toxicodendron as an ingredient on their label; however, no studies have assessed whether urushiol is indeed present within these products. OBJECTIVE: The aim of the study was to determine whether urushiol compounds are present in consumer products labeled as containing Toxicodendron species. METHODS: Gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were performed on 9 consumer products labeled as containing Toxicodendron species, including topical homeopathic remedies. Single ion monitoring gas chromatography-mass spectrometry was programmed in selective ion mode to detect 3-methylcatechol characteristic fragment ions of alk-(en)-yl catechols after silanization. Similarly, single ion monitoring liquid chromatography-tandem mass spectrometry was programmed to detect 4 urushiol pentadecylcatechols and 5 urushiol heptadecylcatechols using previously reported mass-to-charge ratios. RESULTS: Gas chromatography-mass spectrometry detected alk-(en)-yl catechols in 67% (6/9) of the products tested. Liquid chromatography-tandem mass spectrometry detected multiple urushiol pentadecylcatechols and heptadecylcatechols in 44% (4/9) of the products tested. CONCLUSIONS: Alk-(en)-yl catechols and multiple urushiols were detected in consumer products listing Toxicodendron species as an ingredient. Clinicians should be aware of these known allergenic ingredients in consumer products.

Antioxidant activities of novel resveratrol analogs in breast cancer.

The objective of the present study was to characterize the role of novel resveratrol (Res) analogs: 4-(E)-{(4-hydroxyphenylimino)-methylbenzene, 1, 2-diol} (HPIMBD) and 4-(E)-{(p-tolylimino)-methylbenzene-1,2-diol} (TIMBD) as potent antioxidants against breast cancer. Non-neoplastic breast epithelial cell lines MCF-10A and MCF-10F were treated with 17ß-estradiol (E2), Res, HPIMBD, and TIMBD for up to 72 h. mRNA and protein levels of antioxidant genes, superoxide dismutase 3 (SOD3) and N-quinoneoxidoreductase-1 (NQO1) and transcription factors, nuclear factor erythroid 2-related factor (Nrf) 1, 2 and 3 were quantified after the above treatments. Generation of reactive oxygen species (ROS) was measured by CM-H2-DCFDA and oxidative-DNA damage was determined by measuring 8-hydroxy-2-deoxyguanosine (8-OHdG). HPIMBD and TIMBD scavenged cellular ROS production, attenuated oxidative DNA damage, increased mRNA and protein expression levels of SOD3 and NQO1 and activated Nrf signaling pathway. Our studies demonstrate that HPIMBD and TIMBD have the potential as novel antioxidants to prevent development of breast cancer.

[6]-Gingerol induces bone loss in ovary intact adult mice and augments osteoclast function via the transient receptor potential vanilloid 1 channel.

SCOPE: [6]-Gingerol, a major constituent of ginger, is considered to have several health beneficial effects. The effect of 6-gingerol on bone cells and skeleton of mice was investigated. METHODS AND RESULTS: The effects of 6-gingerol on mouse bone marrow macrophages and osteoblasts were studied. 6-Gingerol-stimulated osteoclast differentiation of bone marrow macrophages but had no effect on osteoblasts. Capsazepine, an inhibitor of TRPV1 (transient receptor potential vanilloid 1) channel, attenuated the pro-osteoclastogenic effect of 6-gingerol or capsaicin (an agonist of TRPV1). Similar to capsaicin, 6-gingerol stimulated Ca(2) + influx in osteoclasts. The effect of daily feeding of 6-gingerol for 5 wk on the skeleton of adult female Balb/cByJ mice was investigated. Mice treated with capsaicin and ovariectomized (OVx) mice served as controls for osteopenia. 6-Gingerol caused increase in trabecular osteoclast number, microarchitectural erosion at all trabecular sites and loss of vertebral stiffness, and these effects were comparable to capsaicin or OVx group. Osteoclast-specific serum and gene markers of 6-gingerol-treated mice were higher than the OVx group. Bone formation was unaffected by 6-gingerol. CONCLUSION: Daily feeding of 6-gingerol to skeletally mature female mice caused trabecular osteopenia, and the mechanism appeared to be activation of osteoclast formation via the TRPV1 channel.

Antibacterial effects of the urushiol component in the sap of the lacquer tree (Rhus verniciflua Stokes) on Helicobacter pylori.

BACKGROUND: Urushiol is a major component of the lacquer tree which has been used as a folk remedy for the relief of abdominal discomfort in Korea. The aim of this study was to evaluate the antibacterial effects of the urushiol on Helicobacter pylori. MATERIALS AND METHODS: Monomer and 2-4 polymer urushiol were used. In the in vitro study, pH- and concentration-dependent antibacterial activity of the urushiol against H. pylori were investigated. In addition, the serial morphological effects of urushiol on H. pylori were examined by electron microscopy. In vivo animal study was performed for the safety, eradication rate, and the effect on gastritis of urushiol. The expression of pro-inflammatory cytokines was checked. RESULTS: All strains survived within a pH 6.0-9.0. The minimal inhibitory concentrations of the extract against strains ranged 0.064-0.256 mg/mL. Urushiol caused separation of the membrane and lysis of H. pylori within 10 minutes. Urushiol (0.128 mg/mL × 7 days) did not cause complications on mice. The eradication rates were 33% in the urushiol monotherapy, 75% in the triple therapy (omeprazole + clarithromycin + metronidazole), and 100% in the urushiol + triple therapy, respectively. H. pylori-induced gastritis was not changed by urushiol but reduced by eradication. Only the expression of interleukin-1ß in the gastric tissue was significantly increased by H. pylori infection and reduced by the urushiol and H. pylori eradication (p = .014). CONCLUSIONS: The urushiol has an antibacterial effect against H. pylori infection and can be used safely for H. pylori eradication in a mouse model.

Avoidance of dyskinesia: preclinical evidence for continuous dopaminergic stimulation.

Current concepts suggest that avoidance of pulsatile stimulation of dopamine receptors in Parkinson's disease (PD) can prevent the onset of dyskinesia. In MPTP-treated primates, repeated administration of levodopa or other short-acting dopamine agonist drugs leads to the onset of marked involuntary movements. In contrast, treatment with long-acting dopamine agonists leads to a much lower level of dyskinesia. Similar results have been obtained in PD patients, although the introduction of levodopa is a requirement in virtually all patients and this leads to further increases in motor complications. The concept of continuous dopaminergic stimulation should also apply to levodopa, such that reduced dyskinesia would be expected if it could be administered in a manner that avoids pulsatile receptor stimulation. In MPTP monkeys, administration of multiple small doses of levodopa in conjunction with the peripheral COMT inhibitor entacapone removes much of the pulsatility of motor function seen with standard levodopa treatment regimens and, at the same time, results in a lower incidence and intensity of dyskinesia. Furthermore, the addition of multiple small doses of levodopa plus entacapone to dopamine agonist treatment also avoids dyskinesia induction in MPTP-treated primates. These results suggest that administering of levodopa with entacapone as either initial or supplemental therapy for PD patients might reduce the risk for motor complications. Clinical trials to assess this hypothesis and determine if the results in MPTP monkeys can be duplicated in PD patients are warranted.

Allergic contact dermatitis caused by Lithraea molleoides and Lithraea brasiliensis: identification and characterization of the responsible allergens.

BACKGROUND: Allergic contact dermatitis caused by species of Lithraea genus (Anacardiaceae) is frequent in South America. Nevertheless, it has been scarcely reported in the literature, hitherto the responsible allergens have not been studied in some species. OBJECTIVE: The purpose of this study was to identify and characterize the allergenic compounds of Lithraea molleoides and brasiliensis, and to investigate the existence of cross-reactions with Toxicodendron allergens. METHODS: Twenty-seven South American subjects (17 with previous Lithraea dermatitis and 10 controls without any plant dermatitis) and four North American subjects who are highly sensitive to poison oak were tested with both purified Lithraea molleoides and brasiliensis extracts and poison oak urushiol. Lithraea extracts were analyzed by gas liquid chromatography (GLC) and gas chromatography-mass spectrometry (GC-MS). RESULTS: All 17 Lithraea-sensitive subjects reacted to poison oak urushiol and 13 of them also reacted to Lithraea molleoides and/or brasiliensis extracts. All 4 poison oak sensitive subjects reacted to poison oak urushiol and to Lithraea extracts. In both groups of sensitive subjects, the responses to poison oak urushiol were stronger and occurred at lower concentration than those to Lithraea extracts. The allergenic fraction in both Lithraea species consisted of: 3-pentadecylcatechol, 3-pentadecenylcatechol, 3-heptadecenylcatechol and 3-hepta-dec-dienilcatechol. CONCLUSION: We concluded that Lithraea molleoides and brasiliensis allergens are closely related to urushiol, although their eliciting potential seems to be lower in comparison with poison oak urushiol, even for Lithraea-sensitive subjects.

Treatment of poison ivy/oak allergic contact dermatitis with an extract of jewelweed.

BACKGROUND: Jewelweed (Impatiens biflora) is a plant which has been used for centuries for the treatment of poison ivy/oak allergic contact dermatitis. Numerous claims for its effectiveness exist in the lay press, and over-the-counter medicaments containing jewelweed are reputed to be an effective remedy for poison ivy/oak dermatitis. Despite these claims, few scientific studies testing the effectiveness of jewelweed have been performed. OBJECTIVE: Our objective in this pilot study was to test the efficacy of an extract of jewelweed in the treatment of experimentally induced allergic contact dermatitis to poison ivy/oak. METHODS: A randomized, double-blinded, paired comparison investigation was performed. Ten adult volunteers were patch tested to urushiol, the allergenic resin in poison ivy/oak. For each volunteer, one patch test site was treated with an extract prepared from the fresh stems of jewelweed; the remaining site was treated with distilled water to serve as a control. Sites were examined on days 2, 3, 7, and 9 with reactions graded on a numerical scale. RESULTS: All subjects developed dermatitis at each patch test site. There was no statistically significant difference in the objective scores at the sites treated with jewelweed extract versus the distilled water control sites. CONCLUSION: This study demonstrated that an extract of jewelweed was not effective in the treatment of poison ivy/oak allergic contact dermatitis.

Effect of one month's treatment with peripherally acting catechol-O-methyltransferase inhibitor, entacapone, on pharmacokinetics and motor response to levodopa in advanced parkinsonian patients.

Twelve parkinsonian patients with levodopa-related end-of-dose fluctuations in disability were studied in an open-label trial to examine the effects of peripheral catechol-O-methyltransferase (COMT) inhibition with entacapone on pharmacokinetics and metabolism of levodopa and on clinical response to levodopa after a single dose and after 4 weeks' medication with entacapone. The clinical response was assessed with continuous monitoring using the motor part of Unified Parkinson's Disease Rating Scale. Entacapone increased statistically significantly the mean area under the plasma concentration-time curve (AUC) of levodopa by 29% after a single dose and by 21% after 4 weeks' administration, without affecting other pharmacokinetic parameters of levodopa. The AUC of 3-O-methyldopa decreased by 45% and AUC of homovanillic acid by 21% after 4 weeks' dosing with entacapone. The duration of motor response to levodopa increased significantly from 2.3 h to 3.2 h (i.e., by 39%) after a single dose and to 3.4 h (i.e., by 48%) after 4 weeks' medication with entacapone. The magnitude of clinical response remained unchanged, but peak latency of motor response was prolonged after 4 weeks' medication. The duration and magnitude of dyskinesias also increased. Peripheral COMT inhibition with entacapone increased significantly the bioavailability of levodopa and prolonged its antiparkinsonian effect after a single dose and after repeated dosing for 4 weeks. Thus entacapone seems to be a valuable adjuvant to levodopa treatment in parkinsonian patients with end-of-dose failure.

Heat treatment of Japanese lacquerware renders it hypoallergenic.

Japanese lacquer is made from the sap of the Japanese lacquer tree (Toxicodendron vernicifluum), a member of the Anacardiacae plant family. Objects painted with this material are described collectively as lacquerware. Both fresh lacquer and lacquerware may evoke allergic contact reactions ascribable to the urushiols contained therein. In this study, we have examined the effects of heating on the ability of lacquerware to elicit an allergic contact reaction. Lacquer films prepared with and without heat treatment were tested on urushiol-sensitive subjects. Patch test reactions were strongest to untreated film and decreased with increasing level of heat treatment. Assays for free urushiol in the lacquer films demonstrated that free urushiol content decreased with increasing heat treatment and that urushiols with saturated and monounsaturated alk(en)yl chains predominated.

Hyposensitization to poison ivy after working in a cashew nut shell oil processing factory.

19 adults were patch tested to urushiol, the allergen in poison ivy/oak, to determine their sensitivity to this allergen after working in a cashew nut shell oil (CNSO) processing plant. The cashew nut tree and poison ivy/oak are in the same botanical family. Anacardiaceae, and they share similar chemicals which cause allergic contact dermatitis. 13 of the 19 workers had a preemployment history of poison ivy sensitivity, with 10 developing CNSO dermatitis. After working in this factory for several months, 9 of the 13 noticed a decreased sensitivity or no sensitivity to poison ivy/oak. When tested to urushiol extract, only 3 reacted positively, 2 minimally. These results imply that hyposensitization to poison ivy/oak occurred in these employees after development of hardening to cashew nut shell oil.