Guttiferone E Displays Antineoplastic Activity Against Melanoma Cells.

Guttiferone E (GE) is a benzophenone found in Brazilian red propolis. In the present study, the effect of GE on human (A-375) and murine (B16-F10) melanoma cells was investigated. GE significantly reduced the cellular viability of melanoma cells in a time-dependent manner. In addition, GE demonstrated antiproliferative effect, with IC50 values equivalent to 9.0 and 6.6 µM for A-375 and B16-F10 cells, respectively. The treatment of A-375 cells with GE significantly increased cell populations in G0/G1 phase and decreased those in G2/M phase. Conversely, on B16-F10 cells, GE led to a significant decrease in the populations of cells in G0/G1 phase and concomitantly an increase in the population of cells in phase S. A significantly higher percentage of apoptotic cells was observed in A-375 (43.5%) and B16-F10 (49.9%) cultures after treatment with GE. Treatments with GE caused morphological changes and significant decrease to the melanoma cells' density. GE (10 µM) inhibited the migration of melanoma cells, with a higher rate of inhibition in B16-F10 cells (73.4%) observed. In addition, GE significantly reduced the adhesion of A375 cells, but showed no effect on B16-F10. Treatment with GE did not induce changes in P53 levels in A375 cultures. Molecular docking calculations showed that GE is stable in the active sites of the tubulin dimer with a similar energy to taxol chemotherapy. Taken together, the data suggest that GE has promising antineoplastic potential against melanoma.

Guttiferone K Exerts the Anti-inflammatory Effect on Mycobacterium Tuberculosis- (H37Ra-) Infected Macrophages by Targeting the TLR/IRAK-1 Mediated Akt and NF-κB Pathway.

Mycobacterium tuberculosis (Mtb) remains a great threat to global health, killing more people than any other single infectious agent and causing uncontrollable inflammation in the host. Poorly controlled inflammatory processes can be deleterious and result in immune exhaustion. The current tuberculosis (TB) control is facing the challenge of drugs deficiency, especially in the context of increasingly multidrug resistant (MDR) TB. Under this circumstance, alternative host-directed therapy (HDT) emerges timely which can be exploited to improve the efficacy of TB treatment and disease prognosis by targeting the host. Here, we established the in vitro infection model of Mtb macrophages with H37Ra strain to seek effective anti-TB active agent. The present study showed that Guttiferone K, isolated from Garcinia yunnanensis, could significantly inhibit Mtb-induced inflammation in RAW264.7 and primary peritoneal macrophages. It was evidenced by the decreased production of inflammatory mediators, including interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Further studies with immunoblotting and immunofluorescence revealed that Guttiferone K obviously inhibits the nuclear factor-kappa B (NF-κB) both in RAW264.7 and primary peritoneal macrophages relying on the TLR/IRAK-1 pathway. Guttiferone K could also suppress the NLRP3 inflammasome activity and induce autophagy by inhibiting the protein kinase B (p-Akt) and mammalian target of rapamycin (mTOR) phosphorylation at Ser473 and Ser2448 in both cell lines. Thus, Guttiferone K possesses significant anti-inflammatory effect, alleviating Mtb-induced inflammation with an underlying mechanism that targeting on the TLR/IRAK-1 pathway and inhibiting the downstream NF-κB and Akt/mTOR signaling pathways. Together, Guttiferone K can be an anti-inflammatory agent candidate for the design of new adjunct HDT drugs fighting against tuberculosis.

Therapeutic effects of 5,2'-dibromo-2,4',5'-trihydroxydiphenylmethanone (LM49) in an experimental rat model of acute pyelonephritis by immunomodulation and anti-inflammation.

Antibiotics are still the primary therapy for acute pyelonephritis (APN); rarely, natural polyphenols are also used. LM49 is a novel marine bromophenol derivative displaying strong anti-inflammatory effects. We investigated the therapeutic efficacy of LM49 in an experimental rat model of APN. The model was established by injecting 0.5 mL Escherichia coli (ATCC 25922, 108 CFU/mL) into the urinary bladders of Sprague Dawley rats. This model showed increased kidney viscera indices and renal bacterial growth scores, as well as pathological changes in kidneys. We also performed a broth microdilution antimicrobial susceptibility test of the E. coli strain. Both norfloxacin and LM49 treatment reduced kidney viscera indices and decreased microbial counts in urine cultures and kidney homogenates in APN rats. However, in vitro experiments showed that LM49 did not directly inhibit bacteria. Rather, LM49 treatment inhibited inflammatory cell infiltration or abscess and improved tissue lesions in the renal medullary junction, renal pelvis, and calyx, and high-dose LM49 treatment inhibited the production of inflammatory interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) in serum. CD4+ T cells were higher in the LM49 groups treated with high, medium, and low doses than in the model group, whereas only high-dose LM49 treatment increased the number of CD8+ T cells, as compared with that in the model group. However, LM49 treatment did not influence hematological parameters. Our results show that LM49 therapeutic effects in an APN animal model may be achieved by regulating immune responses and inhibiting inflammatory mediators, suggesting it as a candidate APN treatment.

Phenolics from Garcinia mangostana Inhibit Advanced Glycation Endproducts Formation: Effect on Amadori Products, Cross-Linked Structures and Protein Thiols.

Accumulation of Advanced Glycation Endproducts (AGEs) in body tissues plays a major role in the development of diabetic complications. Here, the inhibitory effect of bioactive metabolites isolated from fruit hulls of Garcinia mangostana on AGE formation was investigated through bio-guided approach using aminoguanidine (AG) as a positive control. Including G. mangostana total methanol extract (GMT) in the reaction mixture of bovine serum albumin (BSA) and glucose or ribose inhibited the fluorescent and non-fluorescent AGEs formation in a dose dependent manner. The bioassay guided fractionation of GMT revealed isolation of four bioactive constituents from the bioactive fraction; which were identified as: garcimangosone D (1), aromadendrin-8-C-glucopyranoside (2), epicatechin (3), and 2,3',4,5',6-pentahydroxybenzophenone (4). All the tested compounds significantly inhibited fluorescent and non-fluorescent AGEs formation in a dose dependent manner whereas compound 3 (epicatechin) was found to be the most potent. In search for the level of action, addition of GMT, and compounds 2-4 inhibited fructosamine (Amadori product) and protein aggregation formation in both glucose and ribose. To explore the mechanism of action, it was found that addition of GMT and only compound (3) to reaction mixture increased protein thiol in both glucose and ribose while compounds 1, 2 and 4 only increased thiol in case of ribose. In conclusion, phenolic compounds 1-4 inhibited AGEs formation at the levels of Amadori product and protein aggregation formation through saving protein thiol.

The potential health benefit of polyisoprenylated benzophenones from Garcinia and related genera: ethnobotanical and therapeutic importance.

The diversity present in biological activities and the medicinal significance of natural products provide a renewed interest in the use of natural compounds and, more importantly, their role as a basis for drug development. Advancements in the field of natural product chemistry provide valuable information on Garcinia fruits which revealed the presence of biologically important secondary metabolites named as polyisoprenylated benzophenones (PIBs). They are mainly present in the genus Garcinia (Guttiferae) which occupies a prominent position in the history of natural products. Compared to the long history of medicinal uses and widespread research on Garcinia, the study of polyisoprenylated benzophenones was relatively limited. During recent years, these PIBs have been recognized as interesting and valuable biologically active secondary metabolites as many of the isolated polyisoprenylated benzophenones exhibited significant cytotoxic activity in in vitro and in vivo assay. During past decades, some promising advances had been achieved in understanding the chemistry and pharmacology of polyisoprenylated benzophenones. However, there has been not any systematic review on the ethnobotanical importance, chemistry, isolation techniques, structure activity relationships and the biological activities of polyisoprenylated benzophenones. In this review, the biological activity of different structures of polyisoprenylated benzophenones isolated from genus Clusia, Garcinia, Vismia, Allanblackia, Moronobea, Symphonia, Hypericum, Tovomita, Tovomiptosis and Ochrocarpus have been described. Therefore, the goal of this review article would be a valuable reference for the natural product chemists and biologists working on these PIBs. Furthermore, the review article on polyisoprenylated benzophenones would also be useful from the drug discovery point of view as cytotoxic agents in near future. This review focuses our understanding about the specific biological effects of Garcinia fruits, which may be useful for predicting other medicinal uses, potential drug or food interactions and may benefit people where the fruits are prevalent and healthcare resources are scarce.

Cytotoxicity and modes of action of four naturally occuring benzophenones: 2,2',5,6'-tetrahydroxybenzophenone, guttiferone E, isogarcinol and isoxanthochymol.

INTRODUCTION: The emergence of drug-resistant cancer cells drastically reduces the efficacy of many antineoplasic agents and, consequently, increases the frequency of therapeutic failure. Benzophenones are known to display many pharmacological properties including cytotoxic activities. The present study was aimed at investigating the cytotoxicity and the modes of action of four naturally occurring benzophenones 2,2',5,6'-tetrahydroxybenzophenone (1), isogarcinol (2), isoxanthochymol (3) and guttiferone E (4) on a panel of eleven cancer cell lines including various sensitive and drug-resistant phenotypes. METHODS: The cytotoxicity of the compounds was determined using a resazurin reduction assay, whereas the caspase-Glo assay was used to detect the activation of caspases 3/7, caspase 8 and caspase 9 in cells treated with compounds 2-4. Flow cytometry was used for cell cycle analysis and detection of apoptotic cells, analysis of mitochondrial membrane potential (MMP) as well as measurement of reactive oxygen species (ROS). RESULTS: The four tested benzophenones inhibited the proliferation of all tested cancer cell lines including sensitive and drug-resistant phenotypes. Collateral sensitivity of cancer cells to compounds 1-4 was generally better than to doxorubicin. Compound 2 showed the best activity with IC50 values below or around 1 µM against HCT116 colon carcinoma cells (p53+/+) (0.86 µM) and leukemia CCRF-CEM (1.38 µM) cell lines. Compounds 2-4 strongly induced apoptosis in CCRF-CEM cells via caspases 3/7, caspase 8 and caspase 9 activation and disruption of MMP. CONCLUSIONS: The studied benzophenones are cytotoxic compounds that deserve more detailed exploration in the future, to develop novel anticancer drugs against sensitive and otherwise drug-resistant phenotypes.

Antimicrobial and antiproliferative activities of stingless bee Melipona scutellaris geopropolis.

BACKGROUND: Geopropolis is a type of propolis containing resin, wax, and soil, collected by threatened stingless bee species native to tropical countries and used in folk medicine. However, studies concerning the biological activity and chemical composition of geopropolis are scarce. In this study, we evaluated the antimicrobial and antiproliferative activity of the ethanolic extract of geopropolis (EEGP) collected by Melipona scutellaris and its bioactive fraction against important clinical microorganisms as well as their in vitro cytotoxicity and chemical profile. METHODS: The antimicrobial activity of EEGP and fractions was examined by determining their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against six bacteria strains as well as their ability to inhibit Streptococcus mutans biofilm adherence. Total growth inhibition (TGI) was chosen to assay the antiproliferative activity of EEGP and its bioactive fraction against normal and cancer cell lines. The chemical composition of M. scutellaris geopropolis was identified by reversed-phase high-performance liquid chromatography and gas chromatography-mass spectrometry. RESULTS: EEGP significantly inhibited the growth of Staphylococcus aureus strains and S. mutans at low concentrations, and its hexane fraction (HF) presented the highest antibacterial activity. Also, both EEGP and HF inhibited S. mutans biofilm adherence (p < 0.05) and showed selectivity against human cancer cell lines, although only HF demonstrated selectivity at low concentrations. The chemical analyses performed suggest the absence of flavonoids and the presence of benzophenones as geopropolis major compounds. CONCLUSIONS: The empirical use of this unique type of geopropolis by folk medicine practitioners was confirmed in the present study, since it showed antimicrobial and antiproliferative potential against the cancer cell lines studied. It is possible that the major compounds found in this type of geopropolis are responsible for its properties.

Chemosensitivity of conjunctival melanoma cell lines to target-specific chemotherapeutic agents.

OBJECTIVE: In conjunctival melanoma, local chemotherapy has been based so far on clinical evidence and limited to the therapy of melanoma in situ. Our aim was to define substances that may have the potential to add to therapeutic options in extended local growth and metastatic disease. Two conjunctival cell lines (CRMM-1 and CRMM-2) have been established from recurrent conjunctival melanoma. In this study, we examined the chemosensitivity of these cell lines to different cytotoxic substances. MATERIALS AND METHODS: The cell lines CRMM-1 and CRMM-2 were exposed to chemotherapeutics for 24 h and the IC50 was generated. Sulforhodamin-B assays were used for quantification of in vitro efficacy. Time of exposure and escalating concentrations of the substances were adapted to the experimental setting. RESULTS: Bortezomib, clusianone 502 (nemorosone), ranpirnase, and sorafenib were efficient in inhibiting the growth of conjunctival melanoma cell lines. The IC50 achieved concentrations below or around 10 µM for these substances. CONCLUSIONS: Bortezomib, clusianone 502, ranpirnase, and sorafenib inhibited growth in conjunctival melanoma cell lines efficiently. The new substances may be a suitable alternative for local therapy. New therapeutic options with highly specific targeted agents for metastatic disease have to be evaluated in further experiments.

7-epi-nemorosone from Clusia rosea induces apoptosis, androgen receptor down-regulation and dysregulation of PSA levels in LNCaP prostate carcinoma cells.

The aim of this work was to characterize the antitumoral activity of the plant compound 7-epi-nemorosone in prostate carcinoma cell lines. Prostate cancer is the most frequently diagnosed malignancy and the second-leading cause of cancer death in men. In spite of the current therapeutic options for this cancer entity, many patients die due to metastases in distant organs and acquired chemotherapy resistance. Thus, approaches to provide improvements in outcome and quality of life for such patients are urgently needed. Recently, the polyisoprenylated benzophenone 7-epi-nemorosone, originally collected by honeybees from Clusia rosea and Clusia grandiflora (Clusiaceae), has been described to be a potent antitumoral agent. Here, its activity in prostate carcinoma is reported. 7-epi-nemorosone was isolated from Caribbean propolis employing RP-HPLC techniques. Its cytotoxicity was assessed using the MTT proliferation assay in human androgen-dependent prostate carcinoma LNCaP cells including an MDR1(+) sub-line. No cross-resistance was detected. FACS-based cell cycle analysis revealed a significant increase in the sub-G0/G1, G1, and depletion in the S phase populations. A concomitant down-regulation of cyclins D1/D3 and CDK 4/6 in LNCaP cells was detected by Western blot. Annexin-V-FITC labeling and caspase-3 cleavage assays showed that 7-epi-nemorosone induced apoptotic events. Major signal transduction elements such as p38 MAPK and Akt/PKB as well as androgen receptor AR and PSA production were found to be down-regulated after exposure to the drug. ERK1/2 protein levels and phosphorylation status were down-regulated accompanied by up-regulation but inhibition of the activity of their immediate upstream kinases MEK1/2. Additionally, Akt/PKB enzymatic activity was effectively inhibited at a similar concentration as for MEK1/2. Here, we demonstrate for the first time that 7-epi-nemorosone exerts cytotoxicity in an androgen-dependent prostate carcinoma entity by targeting the MEK1/2 signal transducer.

Phytochemical analysis and antinociceptive properties of the seeds of Garcinia achachairu.

In a search for new and effective analgesic substances from the Brazilian biodiversity, the present study evaluates the chemical composition and antinociceptive potential of the methanol extract and a pure compound obtained from the seeds of Garcinia achachairu Rusby (Clusiaceae). The methanolic seed extract was directly subjected to purification by column chromatography and the purification was monitored by thin-layer chromatography. The main isolated compound was identified as Guttiferone A by comparison of conventional spectroscopic data (IR, NMR-(1)H and (13)C) to the literature data which was isolated for the first time from this plant. When evaluated in the acetic acid-induced nociception model in mice, the methanolic seed extract had an ID(50) (Inhibitory dose) of 13.1 (11.23-14.91) mg/kg and a maximal inhibition of 72 ± 4%. In the same model, Guttiferone A had an ID(50) of 4.54 (3.29-6.24) mg/kg and a maximal inhibition of 73 ± 5%. The methanolic seed extract and Guttiferone A were also active in pain models induced by formalin, capsaicin, glutamate and carrageenan. These data suggest that the antinociceptive effect of Guttiferone A partly depends on its interference with the synthesis or activity of the cytokine TNF-α, the keratinocyte-derived chemokine KC, and/or PGE(2). These data support, at least in part, the use of G. achachairu in folk medicine and suggest that this plant is an important source of compounds with a suitable profile for development as new and effective medicinal agents to treat pain processes.

Antinociceptive activity of Hypericum grandifolium Choisy in mice.

The present study investigated the antinociceptive activity of different extracts prepared from the aerial parts of blossom of Hypericum grandifolium Choisy-a species native to the Macaronesian Region-using the acetic acid-induced writhing, formalin and tail flick test in mice. Oral administration of methanol extract (500 and 1,000 mg/kg p.o.), the aqueous, butanol and chloroform fractions (500 mg/kg p.o.) as well as subfractions F2 and F3 (45 mg/kg p.o.) from the chloroform fraction significantly inhibited acetic acid-induced writhing, with values ranging from 28 to 50% of inhibition. The methanol extract (1,000 mg/kg p.o.) and chloroform fraction (500 mg/kg p.o.) significantly reduced both phases of formalin-induced pain (with inhibition values ranging from 18 to 53%), whereas subfraction F2 (45 mg/kg p.o.) significantly inhibited the late phase (30%). In the tail flick assay, only the chloroform fraction (500 mg/kg p.o.) significantly prolonged the tail flick response. Different constituents, such as flavonoids and benzophenone derivatives, could account for the effects observed. Taking together, the results indicate that Hypericum grandifolium Choisy possesses both peripheral and central antinociceptive activities in mice, suggesting an interesting therapeutic potential for this species in pain diseases.

Cytotoxic activity of nemorosone in human MCF-7 breast cancer cells.

Estrogen receptor (ER) antagonists have been widely used for breast cancer treatment; however, patients have increasingly shown resistance and sensitivity to the high toxicity of these drugs, and identification of novel targeted therapies is therefore required. To determine whether nemorosone, a polycyclic polyisoprenylated benzophenone isolated from floral resins of Clusia rosea Jacq. and Cuban propolis samples, exerts anticancer effects on human breast cancer cells, estrogen receptor positive (ERα+) MCF-7 and estrogen receptor negative (ERα-) MDA-MB-231 and LNCaP cells were used. Cells were treated with nemorosone alone or in association with 17ß-estradiol (E2) or an ER antagonist, ICI 182,780, a selective ER downregulator that completely abrogates estrogen-sensitive gene transcription. Nemorosone inhibited the cell viability of ERα+ but not of ERα- cells. In MCF-7, nemorosone induced inhibition of cell growth by blocking the cell cycle in the G0/G1 phase. Moreover, the expression of pERK1/2 and pAkt, considered to be hallmarks of the nongenomic estrogen signalling pathway, were reduced in MCF-7 cells treated with nemorosone. All these effects were enhanced by ICI 182,780. However, nemorosone was not able to interfere with E2-induced Ca²(+) release. These findings suggest that nemorosone may have therapeutic application in the treatment of breast cancer because of its activity on ERα.

Leishmanicidal activity of benzophenones and extracts from Garcinia brasiliensis Mart. fruits.

Infections by protozoans of the genus Leishmania are the major worldwide health problem, with high endemicity in developing countries. The drugs of choice for the treatment of leishmaniasis are the pentavalent antimonials, which exert renal and cardiac toxicity. Thus, there is a strong need for safer and more effective treatments against leishmaniasis. The present study was designated to evaluate, by a bioguided assay, the leishmanicidal activity of extracts (hexane, ethyl-acetate and ethanolic) and molecules both obtained by means of extraction from pericarps of Garcinia brasiliensis fruits. The hexane extract presented the best activity on the extracellular (promastigotes) and intracellular (amastigotes) forms of Leishmania (L.) amazonensis, when compared to the other extracts. Based on these findings, this extract was fractionated by silica gel column chromatography, affording nine fractions then resulting in three purified prenylated benzophenones - 7-epi-clusianone (1), garciniaphenone (2) and guttiferone-a (3). They showed significant activity on Leishmania (L.) amazonensis, and little toxicity for mammalian cells. Structure-activity relationships were evaluated showing that the IC(50) value displayed is dependent of prenyl groups and phenolic hydroxyls number, and inversely proportional to the hydrophobicity. Our results are promising, showing that these compounds are biologically active on Leishmania (L.) amazonensis.

Polyisoprenylated benzophenones from Clusiaceae: potential drugs and lead compounds.

Many new polyisoprenylated benzophenones with a bicyclo[3.3.1]-nonane-2,4,9-trione core structure have been isolated from plants in the Clusiaceae family, and their potent biological properties have been the subject of several studies. This review summarizes the biological activities reported for these secondary metabolites including cytotoxic, antimicrobial, antioxidant, and anti-inflammatory activities. Our efforts during the past years have foremost been directed towards isolating new polyisoprenylated benzophenones, as well as understanding the possible target and mechanism of action through which these compounds arrest cancer cells and inhibit the progression of the cell-cycle. The transcription of genes is affected in cancer cells treated with polyisoprenylated benzophenones; the oncogene c-Myb is down-regulated and endoplasmatic stress genes XBP1, ATF4, and DDIT3/CHOP are turned on. Consequently, the expression of iNOS and cell cycle regulators such as cyclin D and E are reduced. Evidence presented by independent investigators suggests that polyisoprenylated benzophenones affect the mediators in the Akt/mTOR stress pathway, although the specific target remains to be discovered. In addition, benzophenones isolated from plants display high antioxidant capacity and protect cells from oxidative stress and the formation of ROS involved during the inflammatory process. Since antiviral activity was initially reported for guttiferone A, potent synthetic analogues have been developed as effective new non-nucleoside reverse transcriptase inhibitors (NNRTI) to treat drug resistant HIV-1. In addition, benzophenones exert antimicrobial effects particularly against MRSA. The structure-activity relationships of polyisoprenylated benzophenones from natural sources and those of synthetic analogues are included in this review. Absorption, metabolism, and elimination of benzophenones are also discussed.

Antianaphylactic properties of 7-epiclusianone, a tetraprenylated benzophenone isolated from Garcinia brasiliensis.

Prior studies have emphasized the anti-inflammatory and antioxidant properties of polyisoprenylated benzophenone derivatives, but their putative effect on allergic conditions has not yet been addressed. In the current study, the naturally occurring 7-epiclusianone, isolated from Garcinia brasiliensis, was investigated to check its effectiveness on allergen-evoked intestinal spasm. The standard antiallergic azelastine was used for comparison. We found that 7-epiclusianone and azelastine inhibited antigen-induced contractions of guinea pig ileum with similar IC (50) values (2.3 +/- 1.1 microM and 3.3 +/- 1.2 microM, respectively). A similar blockade of anaphylactic histamine release from the ileum was also noted. In contrast, azelastine was more potent than 7-epiclusianone to prevent spasms induced by histamine (IC (50) = 6.3 +/- 0.2 nM and 3.7 +/- 0.1 microM, respectively). These findings reveal that 7-epiclusianone is clearly active against the anaphylactic response and should be considered as a molecular template in drug discovery for allergic syndromes.

Tolcapone decreases plasma levels of S-adenosyl-L-homocysteine and homocysteine in treated Parkinson's disease patients.

BACKGROUND: Elevated plasma total homocysteine (tHcy) appeared in levodopa/dopadecarcoxylase inhibitor (DDI) treated patients with Parkinson's disease (PD). One therapeutic approach for tHcy reduction is vitamine supplementation, since folic acid and cobalamine catalyse and enhance metabolism of tHcy to methionine. A further therapeutic alternative is inhibition of catechol-O-methyltransfrase (COMT) on a regular basis, when levodopa/DDI treatment is performed. METHODS: We measured the concentrations of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), tHcy, levodopa and 3-O-methyldopa in plasma of 13 levodopa treated PD patients before first drug intake at 0600 hours. Blood samples were taken before and after 2 days of additional application of the centrally acting catechol-O-methyltransferase inhibitor tolcapone 100 mg t.i.d. RESULTS: Plasma levels of SAH [day 1: 48.32+/-22.52, 23.92-98.25 (mean+/-SD, range; micromol/l); day 3: 37.72+/-15.84, 23.4-61.89; p = 0.01] and tHcy (day 1: 13.88+/-5.62, 7.63-24.81; day 3: 11.38+/-4.44, 5.98-20.45; p = 0.04) significantly reduced. Plasma levels of levodopa did not significantly (p = 0.17) increase, whereas 3-OMD concentrations significantly (p = 0.0002) reduced after additional tolcapone intake. There was no significant change of SAM plasma levels (p = 0.22). CONCLUSION: Our prospective trial shows, that COMT inhibition with tolcapone lowers tHcy synthesis. Tolcapone may also possess beside its proven, occasional, hepatotoxic potency also beneficial effects via decrease of SAH and tHcy. This may hypothetically reduce homocysteine mediated progress of neuronal degeneration and the risk for onset of dementia, vascular disease and polyneuropathy in levodopa treated PD patients in the long term.

New polyisoprenylated benzophenones from Venezuelan propolis.

Two new polyisoprenylated benzophenones, 18-ethyloxy-17-hydroxy-17,18-dihydroscrobiculatone A and 18-ethyloxy-17-hydroxy-17,18-dihydroscrobiculatone B, together with the known scrobiculatones A and B, were isolated from Venezuelan propolis. The scrobiculatones A and B showed significant antibacterial activity and moderate toxicity to Artemia salina nauplii.

Effect of oxybenzone on PGE2-production in vitro and on plaque and gingivitis in vivo.

OBJECTIVES: To study the effect of oxybenzone on prostaglandin E2 (PGE2) production in cell culture and to evaluate the effect of an oxybenzone-containing dentifrice on plaque and gingivitis in a 6-week clinical trial. MATERIAL AND METHODS: Human embryo palatal mesenchyme (HEPM) cells were used for testing the inhibition of IL-1beta-stimulated PGE2-production in vitro by different concentrations of oxybenzone. For the in vivo study, a total of 66 individuals with a Quigley & Hein plaque index of at least 1.5 and an Ainamo & Bay gingival index of at least 0.2 were included in a double-blind clinical trial with two cells and a parallel design. Two compositions of fluoride dentifrice were used, one with the addition of 0.5% oxybenzone, and one without. Plaque and gingival index were obtained at three time points: (1) at baseline, (2) after 3 weeks, and (3) after 6 weeks. RESULTS: A dose-dependent inhibition of PGE2-production was found in the HEPM cell culture following oxybenzone exposure. In the clinical trial, a 25% reduction of gingival index was observed in the oxybenzone group (p<0.001) after 6 weeks as compared with 2% for the placebo group. CONCLUSIONS: These findings indicate that PGE2-production is reduced by oxybenzone in vitro and that the use of oxybenzone in a dentifrice reduces gingivitis in vivo.

A novel cytotoxic guttiferone analogue from Garcinia macrophylla from the Suriname rainforest.

Bioassay-guided fractionation of the EtOAc extract of the twigs of Garcinia macrophylla from Suriname produced the known benzophenone, guttiferone A (1), and a new guttiferone analogue, guttiferone G (2). Friedelin was also isolated. The structures of compounds 1 and 2 were elucidated using 1D and 2D NMR spectroscopy. Compounds 1 and 2 were weakly cytotoxic in the A2780 human ovarian cell line, with IC (50) values of 6.8 and 8.0 microg/mL, respectively.