A new substance (Yoshixol) with an interesting antibiotic mechanism from wood oil of Japanese traditional tree (Kiso-Hinoki), Chamaecyparis obtusa

The Precious Potential of the Sacred Tree Chamaecyparis obtusa (Siebold & Zucc.) Endl. as a Source of Secondary Metabolites with Broad Biological Applications

Chamaecyparis obtusa (Siebold & Zucc.) Endl., which belongs to the Cupressaceae family, occurs naturally in North America and Asia, especially in Korea, Taiwan and Japan, where it is an evergreen, coniferous, sacred, ethnic tree. It has many useful varieties that are widespread throughout the world and grown for decorative purposes. It is most commonly used as an ornamental plant in homes, gardens or parks. It is also widely used in many areas of the economy; for example, its wood is used in architecture as well as furniture production. In addition, oil extracted from Chamaecyparis obtusa is increasingly used in cosmetology for skin care. Due to its wide economic demand, mainly in Japan, it represents the largest area of plantation forest. Despite this, it is on the red list of endangered species. Its use in ethnopharmacology has led to more and more research in recent years in an attempt to elucidate the potential mechanisms of its various biological activities, such as antimicrobial, antioxidant, anticancer, antidiabetic, antiasthmatic, anti-inflammatory, antiallergic, analgesic and central nervous system effects. It has also been shown that Chamaecyparis obtusa can be used as an insect repellent and an ingredient in plant disease treatment. This thesis provides a comprehensive review of the biological studies to date, looking at different areas of the economic fields of potential use of Chamaecyparis obtusa.

Essential Oils Composition and Biological Activity of Chamaecyparis obtusa, Chrysopogon nigritanus and Lavandula coronopifolia Grown Wild in Sudan

Generally, there are scant data about the constituents and eventually the biological activity of essential oils (EOs) from aromatic plants that grow naturally in Sudan. The present study aimed to determine the chemical composition, and antioxidant and enzyme inhibitory activities of EO extracted from the fruit of Chamaecyparis obtusa (Siebold and Zucc.) Endl. (family Cupressaceae), root of Chrysopogon nigritanus (Benth.) Veldkampis (family Poaceae) and aerial part of Lavandula coronopifolia Poir (family Lamiaceae). The fruit of C. obtusa contained only monoterpenes, mainly hydrogenated ones, with α-pinene (69.07%) as the major component. Oxygenated sesquiterpenes comprised the highest content of the C. nigritanus root EO with cedr-8-en-15-ol (28.69%) as the major constituent while aerial parts of L. coronopifolia contained both monoterpenes and sesquiterpenes and the oxygenated monoterpene lavandulol (26.56%) as dominant compounds. The EO of the root of C. nigritanus significantly displayed (p < 0.05) the highest anti-DPPH radical, Fe³⁺- and Cu²⁺-reducing and metal-chelating activities, while that of C. obtusa fruit significantly exerted (p < 0.05) the best anti-ABTS radical and total antioxidant activity. The two EOs significantly exhibited (p < 0.05) the highest anti-acetylcholinesterase and -butyrylcholinesterase activities, respectively, while EO of L. coronopifolia was the only oil to show a considerable inhibitory effect against the tyrosinase and α-glucosidase enzymes. In conclusion, EOs from these three plants could be natural agents with promising functional properties for food, cosmetics, and pharmaceutical applications.

Antimicrobial activity of gaseous Citrus limon var pompia leaf essential oil against Listeria monocytogenes on ricotta salata cheese

Contamination by Listeria monocytogenes is a particularly challenging problem in the food industry due to the ability of the bacterium to develop under conditions normally used for food preservation. Here, we show that the gaseous phase of Citrus limon var pompia leaf essential oil (hereafter PLEO) exerts specific anti-Listeria activity on ricotta salata cheese stored at 5 °C. The synergic effect of gaseous PLEO treatment and refrigeration was first confirmed in vitro on L. monocytogenes strains treated for 3 h with gaseous PLEO and then stored at 5 °C. Ricotta cheese was then inoculated with L. monocytogenes strains and subjected to hurdle technology with different concentrations of gaseous PLEO. Cell counts revealed gaseous PLEO to exert a bactericidal effect on L. monocytogenes 20600 DSMZ and a bacteriostatic effect on a mix of L. monocytogenes strains. Scanning and transmission electron microscopy analyses of L. monocytogenes cells suggested that gaseous PLEO targets the bacterial cell wall and plasma membrane. Chemical analyses of the liquid and vapor phases of PLEO indicated linalyl acetate to be the predominant compound, followed by limonene and the two isomers of citral, whereas EO composition analysis, although generally in line with previous findings, showed the presence of linalyl acetate for the first time. Solid-phase microextraction coupled with gas chromatography confirmed the presence of all crude oil components in the headspace of the box.

A facile one pot synthesis of novel pyrimidine derivatives of 1,5-benzodiazepines via domino reaction and their antibacterial evaluation

A new series of pyrimidine (8, 14, 18 and 23) embellished analogues of 1,5-benzodiazepines were synthesized by the one-pot domino approach using the catalyst DABCO (1,4-diazabicyclo[2.2.2]octane). For each compound synthesized, anti-microbial efficacy was determined using broth microdilution assay and half maximal inhibitory concentration (IC₅₀). Furthermore, FESEM (Field emission scanning electron microscope) studies were also carried out to observe the effect of the structure of test compounds on the morphology of both Gram-positive (S. aureus) and Gram-negative (E. coli) cell walls. The leakage of nucleotides and their integral components from compromised bacterial cells was assessed by plotting the optical density (OD) with respect to time of exposure at 320 nm. Anti-bacterial studies revealed that compound 23 was most active against targeted bacterial species. Results of the antibacterial study indicated that all the test compounds possess significant antibacterial potential against targeted bacterial strains. Amongst all, in the FE-SEM study, compound 23 caused marked alteration in bacterial cell morphology and resulted in maximum leakage of cell nucleotides in bacterial strains as compared to controls. Further efforts are required to establish their efficacy as antibacterial agents in clinical management.

'Structural constraints in cyanobacteria-mediated whole-cell biotransformation of methoxylated and methylated derivatives of 2'-hydroxychalcone

Halophilic and freshwater strains of cyanobacteria representing the Oscillatoriales, Nostocales, Chroococcales, and Synechococcales orders of Cyanophyta were examined to determine (i) the resistance of their cultures when suppressed by the presence of exogenous methoxylated and methylated derivatives of 2'-hydroxychalcone, (ii) morphological changes in cells treated with the tested chalcones and, most importantly, (iii) whether these photoautotrophic microorganisms transform chalcone derivatives in a structure- or strain-dependent manner. The growth of cyanobacterial cultures depended on chalcone derivatives and the strain; nevertheless, trends for correlations between these parameters are difficult to determine. The exposure of cyanobacteria to the tested chalcones revealed severe membrane damage that was consistent with the disruption of membrane integrity. All examined blue-green algae transformed methoxy derivatives of 2'-hydroxychalcone via hydrogenative bio-reduction and formed the corresponding hydroxydihydro derivatives with various efficiencies (≤1 - 70%), depending more on the structure than on the strain. We observed dependency of the routes and efficiency of biohydrogenation of tested chalcones on the location of the methoxyl substituent and, to a lesser extent, on cyanobacterial strains. 2'-hydroxy-4″-methylchalcone was also converted by cyanobacteria to various products, amongst which the most interesting were 2'-ethoxy derivatives. The final products of biocatalytic transformation were extracted from the cyanobacterial media, separated by high performance thin-layer chromatography (HPTLC) and identified by a combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS technique) and one-dimensional (1D ¹H and ¹³C) and two-dimensional (2D HSQC and COSY) nuclear magnetic resonance (NMR) spectroscopy.

Essential Oils and Non-volatile Compounds Derived from Chamaecyparis obtusa: Broad Spectrum Antimicrobial Activity against Infectious Bacteria and MDR(multidrug resistant) Strains

The aim of this study was to evaluate the antibacterial activity of essential oil from Chamaecyparis obtusa against general infectious microbes and drug resistant strains of clinical origin. The results indicate that both essential oil and non-volatile residue have broad inhibitory activity against test strains. Essential oil and non-volatile residues showed antimicrobial activity not only against general infectious bacteria, but also against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) strains.

Chemical composition of essential oil from ripe fruit of Schinus terebinthifolius Raddi and evaluation of its activity against wild strains of hospital origin

The essential oil (EO) composition of ripe fruit of S. terebinthifolius Raddi was analyzed by GC-MS. The oil extraction yielded 6.54 ± 1.06% (w/w). Seventeen compounds were identified, accounting for 91.15% of the total oil, where monoterpenes constituted the main chemical class (85.81%), followed by sesquiterpenes (5.34%). The major monoterpene identified was δ-3-carene (30.37%), followed by limonene (17.44%), α-phellandrene (12.60%) and α-pinene (12.59%). Trans-caryophyllene (1.77%) was the major sesquiterpene identified. The antibacterial activity of the essential oil was evaluated against wild strains of hospital origin (Escherichia coli, Pseudomonas sp., Klebsiella oxytoca, Corynebacterium sp., Staphylococcus aureus, Enterobacter sp., Enterobacter agglomerans, Bacillus sp., Nocardia sp. and Streptococcus group D). The essential oil of the ripe fruit of S. terebinthifolius Raddi has shown to be active against all tested wild strains, with minimum inhibitory concentration ranging from 3.55 μg/mL to 56.86 μg/mL. However, it has revealed some differences in susceptibility: the general, Gram-positive species showed greater sensitivity to the action of EO, which is probably due to the lower structural complexity of their cell walls.

Comparison of clinical and histological effects between lactobacillus-fermented Chamaecyparis obtusa and tea tree oil for the treatment of acne: an eight-week double-blind randomized controlled split-face study

BACKGROUND

Screening of natural compounds for the development of anti-acne therapeutic agents has been steadily required considering various side effects of acne medications. However, previous studies have mainly focused on experimental tests without clinical trials and histopathological analysis.

OBJECTIVES

To compare the clinical efficacy, safety and histopathological changes between Lactobacillus-fermented Chamaecyparis obtusa (LFCO) and existing tea tree oil (TTO).

METHODS

A total of 34 patients were instructed to apply 5% LFCO to the involved areas of a randomly allocated side and 5% TTO extract to the other side for 8 weeks in a double-blind split-face clinical trial.

RESULTS

After 8 weeks, inflammatory acne lesions were reduced by 65.3% on the LFCO side and by 38.2% on the TTO side. LFCO was also superior to TTO in the onset time of efficacy (p < 0.05). The LFCO side further demonstrated improvement for non-inflammatory lesions (52.6%, p < 0.05), decreased size of sebaceous glands and sebum output reductions. Patients' subjective satisfaction was also higher without severe adverse reactions. Protein expressions of nuclear factor κB decreased earlier on the LFCO side, and those of interleukin-1α (IL-1α), IL-8, insulin-like growth factor 1 receptor and sterol regulatory element-binding protein 1 decreased subsequently. Ultra-performance liquid chromatography/high-resolution mass spectrometry further demonstrated that the contents of dihydroxybenzoic acid, taxifolin and quercetin were increased in LFCO after fermentation.

CONCLUSIONS

LFCO treatment was rapid and effective for treating acne lesions compared to TTO. Histopathological findings correlated well with the clinical acne grade and treatment response. This novel natural compound appears to be effective and safe for acne treatment.

Generation of Reactive Oxygen Species from Hinokitiol under Near-UV Irradiation

Near-UV irradiation caused the decomposition of hinokitiol in an aqueous solution. During the photochemical reaction, the distinct electron spin resonance signal characteristic of the adduct of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) with the hydroxyl radical was accompanied by small signals corresponding to the adduct of DMPO with the superoxide anion radical. More than 95% of Escherichia coli cells were killed by the incubation with hinokitiol under near-UV irradiation by BLB fluorescent lamps. These results indicated the generation of reactive oxygen species during photochemical reaction of hinokitiol under near-UV irradiation.

Antifungal and Antibacterial Activity of the Essential Oil of from Spain

The essential oils extracted from the young stems and leaves of Chamaecyparis lawsoniana(A.Murray) Parl. have been analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry. A total of 66 compounds were identified representing around the 99% of the total oil. The oil was richer in monoterpenes than in sesquiterpenes. The only main component was limonene with a percentage composition of 77.7%. The rest of compounds that contribute to the fragrance had percentage composition lower that the 3.0%: p-cymen-7-ol (3.0%), myrcene (2.4%), camphor (2.1%), δ-elemene (1.6%), oplopanonyl acetate (1.6%), methyl perillate (1.3%), terpinen-4-ol (1.0%) and β-oplopenone 1.0%. The antibacterial and antifungal activity of this oil was also tested against different microorganisms. The only fungus tested, Candida albicans,was very sensitive to the treatment with an inhibition halos of 20mm. The oil was more effective with the Gram (+) than with Gram (-) bacteria. The inhibition halos were 12mm, 12-13mm and 12-13mm for Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus respectively. We report new data of the antibacterial and antifungal activity of the essential oil of this species. The essential oil of C. lawsoniana could be considered as a good natural antibacterial and antifungal agent.

In Vitro and in Vivo Therapeutics of β-Thujaplicin on Lps-Induced Inflammation in Macrophages and Septic Shock in Mice

β-thujaplicin, an active constituent from Chamaecyparis obtusa, has been shown to have acaricidal and antimicrobial effects. Very few studies have focused on the potential of the anti-inflammatory effect of β-thujaplicin. Moreover, its capability of inhibiting inflammatory mediators e.g. TNF-α gene transcription, nitric oxide (NO) and prostaglandin E2, remains unknown. Besides those molecular mechanisms behind the anti-inflammatory effect of β-thujaplicin, solid proof of its effectiveness in vivo has not yet been studied. In our study, in vitro effects of β-thujaplicin were verified on RAW 264.7 macrophages which were stimulated by LPS. Indomethacin was used as a positive control. The inducible NO production after stimulation was measured by Griess reagent. PGE2, IL-6 and TNF-α were measured by ELISA methods. Protein expressions of iNOS, COX2, and NF-κB were evaluated by Western blotting. Septic ICR mice were administered 20 mg/kg of LPS and then the mortality rate was monitored. Within the concentration range which was devoid of cytotoxicty, β-thujaplicin exhibited a clear dose-dependent inhibition on LPS-induced NO production. Furthermore, β-thujaplicin inhibited LPS-induced PGE2, IL-6, and TNF-α production as well as iNOS, COX2, and NF-κB protein expression more substantially potent than indomethacin. In agreement with the in vitro study, β-thujaplicin was shown to be effective in vivo for inhibiting LPS-induced NO and TNF-α production and a significant decrease in mortality rate of mice suffering from septic shock was observed. This study demonstrates the potential of β-thujaplicin in treatment of inflammation and sepsis. These effects occur through an efficient blockage of TNF-α and iNOS production, β-thujaplicin efficacy is comparable to that of indomethacin thus it can be a substitution but bear less depletion of PGE2, making this compound very promising in clinical applications.

Antibacterial and Antioxidant Activities of Acid and Bile Resistant Strains of Lactobacillus fermentum Isolated from Miang

Miang is a kind of traditional fermented tea leaves, widely consumed in northern Thailand as a snack. It contains several kinds of Lactobacilli spp. The aim of this study was to isolate strains of Lactobacillus fermentum from miang and to investigate their antibacterial and antioxidant activities. The agar spot and well assays were used for determination of antibacterial power. The antibacterial mechanism was investigated by cell morphologic change under scanning electron microscope (SEM). Antioxidant activity was studied by means of free radical scavenging and ferric reducing power assays. The acid and bile screening tests indicated that L. fermentum FTL2311 and L. fermentum FTL10BR presented antibacterial activity against several pathogenic bacteria: Listeria monocytogenes DMST 17303, Salmonella Typhi DMST 5784, Shigella sonnei DMST 561 (ATCC 11060) and Staphylococcus aureus subsp. aureus DMST 6512 (ATCC 6538Ptm). The results from SEM suggested that the antibacterial action was due to the destruction of cell membrane which consequently caused the pathogenic cell shrinking or cracking. The antioxidant study suggested that both L. fermentum FTL2311 and L. fermentum FTL10BR strains could liberate certain substances that possessed antioxidant activity expressed as trolox equivalent antioxidant capacity (TEAC) and equivalent concentration (EC) values for free radical scavenging and reducing mechanisms, respectively. The supernatant of L. fermentum FTL2311 broth revealed TEAC and EC values of 22.54±0.12 and 20.63±0.17 >M.mg^-1 respectively, whereas that of L. fermentum FTL10BR yielded TEAC and EC values of 24.09±0.12 and 21.26±0.17 >M.mg^-1 respectively. These two strains isolated from miang present high potential as promising health-promoting probiotics.

Chemical Composition, Antifungal and Antibacterial Activity of the Essential Oil of Chamaecyparis Nootkatensis from Spain

The chemical composition of the oil of Chamaecyparis nootkatensis (D. Don) Spach. has been analysed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GCMS). A total of 34 compounds were identified representing more than 90% of the total oil. The oil was richer in monoterpenes than in sesquiterpenes, the major constituents being limonene (53.2%), δ-3-carene (21.0%) and α-pinene (12.2%). The antibacterial and antifungal activities of the oil were also tested against Candida albicans, Bacillus subtilis, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Salmonella sp. and Serratia marcescens. Only two of these, Bacillus subtilis and Candida albicans, were sensitive to the treatment, inhibition zones of 11 and 14 mm diameter being obtained, respectively. As far as we know, this is the first report of the antifungal and antibacterial activity of this species.

Chemical composition, antimicrobial and antioxidant activities of the essential oil and the ethanol extract of Cleistocalyx operculatus (Roxb.) Merr and Perry buds

In the present study, the essential oil isolated from the buds of Cleistocalyx operculatus by hydrodistillation was analyzed by GC and GC/MS. A total of 55 compounds representing 93.71% of the oil were identified. The oil significantly inhibited the growth of food spoilage (FS), food-borne (FB), skin pathogens (SP), methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE) and multiantibiotic-resistant bacteria (MARB). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the oil against the tested microorganisms were found in the range of 1-20muL/mL. Whereas the ethanol extract exhibited potential antibacterial activity against the entire tested Gram positive bacteria and one food spoilage Gram negative bacterium P. aeruginosa. The MIC and MBC values of ethanol extract against the tested bacteria were found in the range of 0.25-32mg/mL. The scanning electron microscopic (SEM) studies demonstrated potential detrimental effect of the essential oil on the morphology of MRSA-P249 and VRE-B2332 at the used MIC values, along with the potential effect on cell viabilities of the tested bacteria. Moreover, the total antioxidant capacity and the scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals of the essential oil and the ethanol extract were also evaluated.

Antibacterials and modulators of bacterial resistance from the immature cones of Chamaecyparis lawsoniana

As part of an on-going project to characterize compounds from immature conifer cones with antibacterial or modulatory activity against multidrug-resistant (MDR) strains of Staphylococcus aureus, eight compounds were isolated from the cones of Chamaecyparis lawsoniana. The active compounds were mainly diterpenes, with minimum inhibitory concentrations ranging from 4 to 128 microg/ml against MDR effluxing S. aureus strains and two epidemic methicillin-resistant (EMRSA) clinical isolates. The compounds extracted were the diterpenes ferruginol, pisiferol and its epimer 5-epipisiferol, formosanoxide, trans-communic acid and torulosal, the sesquiterpene oplopanonyl acetate and the germacrane 4beta-hydroxygermacra-1(10)-5-diene. Some of these compounds also exhibited modulatory activity in potentiating antibiotic activity against effluxing strains and ferruginol, used at a sub-inhibitory concentration, resulted in an 80-fold potentiation of oxacillin activity against strain EMRSA-15. An efflux inhibition assay using an S. aureus strain possessing the MDR NorA efflux pump resulted in 40% inhibition of ethidium bromide efflux at 10 microM ferruginol (2.86 microg/ml). We report the (1)H and (13)C NMR data for the cis A/B ring junction epimer of pisiferol which we have named 5-epipisiferol. We also unambiguously assign all (1)H and (13)C NMR resonances for trans-communic acid.

Chemical composition and antimicrobial activity of Chamaecyparis obtusa leaf essential oil

The essential oil obtained from the leaves of Chamaecyparis obtusa was analyzed by GC and GC-MS. alpha-Terpinyl acetate, sabinene, isobornyl acetate and limonene were found to be the major components. The oil showed relatively strong antibacterial activities against Gram (+) bacteria and some fungi.

Mosquito larvicidal activity of active constituent derived from Chamaecyparis obtusa leaves against 3 mosquito species

Mosqutio larvicidal activity of Chamaecyparis obtusa leaf-derived materials against the 4th-stage larvae of Aedes aegypti (L.), Ochlerotatus togoi (Theobald), and Culex pipiens pallens (Coquillett) was examined in the laboratory. A crude methanol extract of C. obtusa leaves was found to be active (percent mortality rough) against the 3 species larvae; the hexane fraction of the methanol extract showed a strong larvicidal activity (100% mortality) at 100 ppm. The bioactive component in the C. obtusa leaf extract was characterized as beta-thujaplicin by spectroscopic analyses. The LC50 value of beta-thujaplicin was 2.91, 2.60, and 1.33 ppm against Ae. aegypti, Oc. togoi, and Cx. pipiens pallens larvae. This naturally occurring C. obtusa leaves-derived compound merits further study as a potential mosquito larval control agent or lead compound.

Antimicrobial activity of essential oils against Helicobacter pylori

BACKGROUND

Helicobacter pylori is an important pathogen responsible for gastroduodenal diseases in humans. Although the eradication of H. pylori using antibiotics often improves gastroduodenal diseases, resistance to the antibiotics is emerging.

MATERIALS AND METHODS

The antimicrobial effect of essential oils and the development of resistance to the essential oils were evaluated in vitro and in vivo.

RESULTS

Thirteen essential oils used in this study completely inhibited the growth of H. pylori in vitro at a concentration of 0.1% (v/v). Cymbopogon citratus (lemongrass) and Lippia citriodora (lemon verbena) were bactericidal against H. pylori at 0.01% at pH 4.0 and 5.0. Resistance to lemongrass did not develop even after 10 sequential passages, whereas resistance to clarithromycin developed under the same conditions. In in vivo studies, the density of H. pylori in the stomach of mice treated with lemongrass was significantly reduced compared with untreated mice.

CONCLUSIONS

These results demonstrate that the essential oils are bactericidal against H. pylori without the development of acquired resistance, suggesting that essential oils may have potential as new and safe agents for inclusion in anti-H. pylori regimens.

YoshixolTR inhibits B16 melanoma cell growth in vivo and induces apoptosis-like (quantum thermodynamic) cell death

In this report, antitumor effects of YoshixolTR in vivo and in vitro were investigated in B16 melanoma cells. For in vivo experiments, the present study shows a dramatic inhibition of tumor growth of B16 melanoma transplanted on the leg or intraperitoneal cavity after treatment with YoshixolTR intraperitoneally. A proliferation of B16 cells in vitro was inhibited by YoshixolTR in a dose-and time-dependent manner. YoshixolTR induced apoptosis-like cell death in histological observations (phase-contrast, scanning and transmission electron microscopy), DNA fragmentation, and a smaller increase in lactate dehydrogenase (LDH) as a marker of cell leakage. Immunohistochemical investigation of cytoskeletal components, such as actin and tubulin, showed a cell wall disruption of B16 melanoma cells and a nuclear extrusion after the treatment with YoshixolTR. Treatment with YoshixolTR in vitro showed an arrest at the G0/G1 stage of the cell cycle, followed by a flow cytometric measurement. As a possible physiological mechanism of YoshixolTR on B16 melanoma cells, intracellular Ca++ was measured with Fura-2 technique. An adequate concentration of YoshixolTR, which induces apoptosis-like cell death, showed a decrease in intracellular free Ca++ concentration. In conclusion, YoshixolTR has an antitumor potency with a new biological mechanism of cell growth, proliferation, and differentiation, including cellular signalling pathways, and is a new candidate for an ideal chemotherapeutic agent against malignant tumors.

In vitro and in vivo antitumor activity of YoshixolTR against murine L1210 leukemic cells

In this report, antiproliferative effects of YoshixolTR in vitro and in vivo were investigated in murine L1210 cells. A proliferation of L1210 cells in vitro was inhibited by YoshixolTR in a dose- and time-dependent manner. This inhibition showed an arrest at the G0/G1 stage of the cell cycle, followed by a flow cytometric measurement. YoshixolTR induced apoptosis-like cell death identified by histological observations (scanning electron and transmission electron microscopy), DNA fragmentation, and a smaller increase in lactate dehydrogenase (LDH). In the in vivo experiments, YoshixolTR (5 microl/kg of body weight, on days 1, 3, and 5) was injected intraperitoneally in mice inoculated with L1210 cells. No marked prolongation of survival occurred between the control group and treated group. However, a survival curve in the treated group showed a shift toward a possible longer survival time. Additionally, on the basis of apoptosis-like cell death due to YoshixolTR as indicated above, a possibility of immunotherapy as a tumor vaccine has been examined. A vaccination of rabbit anti-serum, which consisted of components from the L1210 cells killed by YoshixolTR, produced a dramatic improvement of viability in the leukemic mice. In conclusion, YoshixolTR has an anti-leukemic potency with a new biological mechanism and an inductive potency of super-antigens as immunotherapeutic agents against malignant tumors.

Mechanism of mitochondrial dysfunction and cytotoxicity induced by tropolones in isolated rat hepatocytes

The mechanism of mitochondrial dysfunction and toxicity induced by the tropolones, beta-thujaplicin (4-isopropyl tropolone), tropolone and tropone, has been studied in freshly isolated rat hepatocytes. Incubation of hepatocytes with beta-thujaplicin (1-4 mM) elicited a concentration and time-dependent cell killing. The toxicity was accompanied by losses of cellular ATP, total adenine nucleotides and glutathione, independently of lipid peroxidation and protein thiol oxidation. The beta-thujaplicin-induced cytotoxicity was enhanced by the pretreatment of hepatocyte suspensions with EDTA (4 mM), a hydrophilic chelator, or by incubation in Ca2+ and Mg2+-deficient Krebs-Henseleit buffer. The partition coefficient of beta-thujaplicin, which formed complex with the divalent cations in Krebs-Henseleit buffer, in n-octanol/buffer was increased either in the presence of EDTA or absence of divalent cations. Comparison of toxic effects based on cell viability and adenine nucleotide levels showed that beta-thujaplicin was more toxic than tropolone or tropone in Krebs-Henseleit buffer containing EDTA (4 mM). The addition of beta-thujaplicin to isolated hepatic mitochondria reduced state 3 respiration with NAD+-linked substrate (pyruvate plus malate) and/or with an FAD-linked substrate (succinate plus rotenone), whereas state 3 respiration of ascorbate plus tetramethyl-p-phenylenediamine (cytochrome oxidase-linked respiration) was not significantly affected by beta-thujaplicin. Further, the addition of these tropolones caused a concentration-dependent increase in the rate of state 4 oxygen consumption, indicating an uncoupling effect. These results indicate that beta-thujaplicin- and tropolone-induced cytotoxicity are associated with an acute ATP depletion via mitochondrial dysfunction related to oxidative phosphorylation and that the induction of cytotoxicity is affected by EDTA or divalent cations.