Genotoxicity studies on licorice flavonoid oil (LFO)

Licorice flavonoid oil (LFO) is a new functional food ingredient. In this study, the genotoxicity of LFO was investigated using a test battery of three different methods. In a reverse mutation assay using four Salmonella typhimurium strains and Escherichia coli, LFO did not increase the number of revertant colonies in any tester strain with or without metabolic activation by rat liver S9 mix. In a chromosomal aberration test using Chinese hamster lung (CHL/IU) cells, LFO did not induce any chromosomal aberrations either in the short period test without rat liver S9 mix or in the continuous treatment (24 h or 48 h) test. However, in the short-period test with rat liver S9 mix, LFO induced structural chromosomal aberrations at concentrations higher than 0.6 mg/mL. A bone marrow micronucleus test using male F344 rats was initially conducted. The animals were dosed by oral gavage at doses up to 5000 mg/kg/day. No significant or dose-dependent increases in the frequency of micronucleated polychromatic erythrocytes (MNPCE) were observed and the high dose suppressed the ratio of polychromatic erythrocytes (PCE) to total erythrocytes. Subsequently, a liver and peripheral blood micronucleus test using male F344 rats was conducted. No micronuclei induction either in hepatocytes or PCE was observed even at the highest dose of 5000 mg/kg/day. From the findings obtained from the genotoxicity assays performed in this study and the published pharmacokinetic studies of LFO, it appears unlikely that dietary consumption of LFO will present any genotoxic hazard to humans.

90-Day repeated-dose toxicity study of licorice flavonoid oil (LFO) in rats

Licorice flavonoid oil (LFO) is a new functional food ingredient consisting of licorice hydrophobic polyphenols in medium-chain triglycerides (MCT). As part of a safety evaluation, a 90-day oral toxicity study in rats was conducted using an LFO concentrate solution (2.90% glabridin). Male and female animals were assigned to one of 12 groups (10 males or females per group) and received corn oil (negative control), MCT (vehicle control), or 400, 600, 800 or 1600 mg/kg of the LFO concentrate solution. In conclusion, LFO concentrate solution induced an anticoagulation effect in both sexes, although there was a clear sex difference. Based on these findings, it is concluded that the no-observed-adverse-effect level (NOAEL) for the LFO concentrate solution is estimated to be 800 mg/kg/day for female rats, and approximately 400 mg/kg/day for male rats.

Evaluation of the mutagenic potential of ubidecarenone using three short-term assays

Addition of ubidecarenone, coenzyme Q(10) (CoQ(10)), to foods has been proposed for its nutritive value. Ubidecarenone is present naturally in a number of foods, including meats (e.g., beef, chicken) and fish (e.g., herring, rainbow trout), and on average, people are estimated to consume 2-20 mg/day of this metabolically important substance. Currently, relatively little formal evidence regarding the safety of ubidecarenone has been identified in the toxicology literature, despite its consumption by humans for centuries without reported notable adverse effects. As such, a series of toxicological studies, including mouse bone marrow micronucleus, chromosomal aberration, and bacterial reverse mutation tests, were conducted to evaluate the in vivo and in vitro mutagenic potential of CoQ(10). The test article, ubidecarenone, was devoid of clastogenic activity when administered orally to mice at doses up to 2000 mg/kg/day. In addition, the test article did not induce chromosomal aberration in CHL/IU cells exposed to concentrations as great as 5.0 mg/ml, nor did it induce reverse mutations in Salmonella typhimurium and Escherichia coli at concentrations as great as 5000 microg/plate.

28-Day repeated dose toxicity study of dried microorganism in rats

Ubidecarenone, also known as CoQ(10), is currently sold as a dietary supplement in the United States, with a majority of these products derived from the fermentation of carbohydrates or tobacco leaf extracts. In addition to its availability in dietary supplements, CoQ(10) is now being considered for use in foods. Accordingly, as part of the process for attaining "Generally Recognized as Safe" status, and to supplement information already available regarding the safety of CoQ(10) per se, a 28-day oral toxicity study in rats was conducted to evaluate the subacute safety of a microorganism biomass used as a new source in CoQ(10) production. Groups of Crj:CD(SD) rats (SPF) (6 males or females per group, 4 groups per sex) received dried microorganism at doses of 0, 500, 1000 or 2000 mg/kg/day via intragastric intubation. Clinical observations were recorded, and body weight, and food and water consumptions measured throughout the study. At the end of the study, aortic blood samples were collected from all animals for analysis of hematological and clinical chemistry parameters, and gross pathologic examination was performed. Histopathologic examination was performed on select tissues from the control and high-dose groups. There were no treatment-related changes that were considered to be of toxicological significance. Since rats treated with 2000 mg/kg of dried microorganism did not demonstrate any treatment-related changes, the no-observable-adverse-effect level (NOAEL) for dried microorganism was estimated to be greater than 2000 mg/kg/day under the present study conditions.

Combinatorial bio/chemical analysis of dioxin and dioxin-like compounds in waste recycling, feed/food, humans/wildlife and the environment

The present review describes international activities using bioassays/biomarkers in combination with chemical analysis to measure the effects of dioxin and dioxin-like compounds (DLCs) in the environment. The above authors reviewed already the state-of-art bioanalytical detection methods (BDMs) for dioxins and DLCs [Environ Int (2001)]. The aim of this study will be to review applications of these bioassays/biomarkers to evaluate potential dioxins and DLCs. The present literature study lists relative potencies (REPs) of polyhalogenated dibenzo-p-dioxins and -furans (PXDD/Fs; X = Cl, Br, F), their thio analogues polychlorinated dibenzothiophenes (PCDTs) and thianthrens (PCTAs), polyhalogenated biphenyls (PXBs), polychlorinated naphthalenes (PCNs) and other Ah receptor agonists measured by several biodetectors (Tier 3 screening). The authors will discuss some examples of the applications of some of these biodetectors in biomonitoring programmes and recently occurred dioxin crisis in feed/food. The diagnosis of the biopotency of these pollutants in technical processes like thermally treated waste, waste water treatment, landfill leachate treatment, commercial PCB-mixtures, the release into the environment (soil, air and water) and the final intake into wildlife and humans will be reviewed.

Bioanalytical screening methods for dioxins and dioxin-like compounds a review of bioassay/biomarker technology

Determination of environmental pollutants utilizing biodetectors such as bioassays, biomarkers, enzyme immunoassays (EIAs), or other bioanalytical tools is a continuously growing area. The present literature review describes the principles and advantages/limitations of several bioanalytical detection methods (BDMs) for the screening and diagnosis of dioxin and dioxin-like compounds. This study characterizes briefly the family of dioxin and dioxin-like compounds, discusses potential Ah receptor (AhR) ligands and cytochrome P-450 (CYP) 1A1-enzyme-inducing compounds. 'Milestones' in the development of BDMs are summarized and explained in detail for a number of bioanalytical tools that can be used to detect these classes of dioxin-like persistent bioaccumulative toxicants (PBTs). The design of a screening profile with a battery of bioassays/biomarkers coupled with the chemical analysis is evaluated. The relative potencies (REPs) to 2,3,7,8-TCDD for dioxin-like compounds are reviewed for various BDMs and the differences are noted.

Identification of enzymes responsible for rifalazil metabolism in human liver microsomes

1. The major metabolites of rifalazil in human are 25-deacetyl-rifalazil and 32-hydroxy-rifalazil. Biotransformation to these metabolites in pooled human liver microsomes, cytosol and supernatant 9000g (S9) fractions was studied, and the enzymes responsible for rifalazil metabolism were identified using inhibitors of esterases and cytochromes P450 (CYP). 2. The 25-deacetylation and 32-hydroxylation of rifalazil occurred in incubations with microsomes or S9 but not with cytosol, indicating that both the enzymes responsible for rifalazil metabolism were microsomal. Km and Vmax of the rifalazil-25-deacetylation in microsomes were 6.5 microM and 11.9 pmol/min/mg with NADPH, and 2.6 microM and 6.0 pmol/min/mg without NADPH, indicating that, although rifalazil-25-deacetylation did not require NADPH, NADPH activated it. Rifalazil-32-hydroxylation was NADPH dependent, and its Km and Vmax were 3.3 microM and 11.0 pmol/min/mg respectively. 3. Rifalazil-25-deacetylation in microsomes was completely inhibited by diisopropyl fluorophosphate, diethyl p-nitrophenyl phosphate and eserine, but not by p-chloromercuribenzoate or 5,5'-dithio-bis(2-nitrobenzoic acid), indicating that the enzyme responsible for the rifalazil-25-deacetylation is a B-esterase. 4. Rifalazil-32-hydroxylation in microsomes was completely inhibited by CYP3A4-specific inhibitors (fluconazole, ketoconazole, miconazole, troleandomycin) and drugs metabolized by CYP3A4 such as cyclosporin A and clarithromycin, indicating that the enzyme responsible for the rifalazil-32-hydroxylation is CYP3A4.

Isolation and identification of major metabolites of rifalazil in mouse and human

1. Three metabolites of rifalazil have been isolated from dog urine and identified as 25-deacetyl-rifalazil, 30-hydroxy-rifalazil and 25-deacetyl-30-hydroxy-rifalazil. In the current study major metabolites of rifalazil in mouse and human were isolated and identified, and their antimicrobial activities determined. 2. Urinary excretion of rifalazil and its metabolites in six mouse strains, CD-1 (ICR), BALB/c, C57BL/6, C3H/He, DBA/2 and CBA/J, was examined. Two major metabolites were detected in mouse urine obtained after several oral doses, and the proportion of rifalazil metabolites against total urinary excretion varied over a 2-fold range (4.8-8.7%) in the different mouse strains. 3. One of two major metabolites in mouse urine was 25-deacetyl-rifalazil and the other was unknown: it was isolated from mouse urine and identified by ms and 1H- and 13C-nmr as 32-hydroxy-rifalazil. 4. In human, two major metabolites of rifalazil were detected in urine obtained after administration of a single oral dose. These metabolites were also produced by incubation of rifalazil with pooled human liver microsomes, and identified by lc/ms and lc/ms/ms as 25-deacetyl-rifalazil and 32-hydroxy-rifalazil. 5. The antimicrobial activities of 32-hydroxy-rifalazil against gram-positive bacteria and mycobacteria were similar with those of the parent compound.

Effect of a new rifamycin derivative, rifalazil, on liver microsomal enzyme induction in rat and dog

1. The effect of a new rifamycin derivative, rifalazil (KRM-1648), on liver microsomal enzyme induction was studied in rat and dog with repeated oral administration of the compound. Relative liver weight, cytochrome b5 and P450 contents, enzyme activities of NADPH-cytochrome c reductase, aniline hydroxylase, p-nitroanisole O-demethylase, aminopyrine N-demethylase, and erythromycin N-demethylase were measured. 2. In rat, rifalazil treatment at 300 mg/kg/day for 10 days increased cytochrome b5 content but it did not affect liver weight, P450 content or enzyme activities. In contrast, rifampicin and rifabutin increased relative liver weights, cytochrome contents and enzyme activities under similar conditions. 3. In dog, rifalazil did not affect any parameters at 30 or 300 mg/kg/day for 13 weeks. 4. These findings indicate that rifalazil is not an enzyme inducer in rat and dog. This property differs from other rifamycin derivatives such as rifampicin and rifabutin.

Pharmacokinetics of KRM-1648, a new benzoxazinorifamycin, in rats and dogs

The pharmacokinetics of 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl) benzoxazinorifamycin (KRM-1648) in rats and dogs given a single oral dose of 3, 30, or 100 mg/kg of body weight were studied. In the rats, the concentrations of KRM-1648 in plasma, whole blood, and tissues peaked between 2.0 and 24.0 h, with elimination half-lives ranging from 6.2 to 19.5 h. The peak concentrations and the areas under the concentration-versus-time curves (AUC) for whole blood and tissues were 2 to 277 times higher than those for plasma. The high levels of KRM-1648 in tissues were consistent with its large volume of distribution (in excess of 10 liters/kg). A nonlinear increase in peak concentrations and AUCs for plasma, whole blood, and tissues occurred as the dose was increased and was consistent with the dose-dependent decrease in bioavailability. In the dogs, KRM-1648 levels in plasma and whole blood also exhibited a late time to the peak concentration (ranging from 4.0 to 11.2 h), a long elimination half-life (ranging from 15.2 to 24.0 h), and nonlinear kinetics. KRM-1648 exhibited high levels of plasma protein binding (more than 99%) and a high degree of affinity for lipoproteins in the plasma of both animals. After administration of KRM-1648, measurable levels of its metabolites, 25-deacetyl KRM-1648 in rats and 25-deacetyl KRM-1648 and 30-hydroxy KRM-1648 in dogs, were found in the biological samples tested. Thus, KRM-1648 is characterized by a high tissue affinity, a long elimination half-life, and nonlinear pharmacokinetics.

In vitro metabolism of a rifamycin derivative by animal and human liver microsomes, whole blood and expressed human CYP3A isoform

1. In vitro metabolism of a rifamycin derivative, benzoxazinorifamycin KRM-1648, was studied using mouse, rat, guinea pig, dog, monkey and human liver microsomes. 30-Hydroxy-KRM-1648 (M2) was produced in mouse, dog, monkey and human microsomes. 25-Deacetyl-KRM-1648 (M1) was produced in dog and human microsomes, but not in mouse or monkey microsomes. Neither M1 nor M2 was detected in rat or guinea pig microsomes. 2. In dog and human liver microsomes the formation of M2 was dependent on NADPH, but the formation of M1 was not. 3. In vitro metabolism of the parent compound was studied in whole blood in some species. Only M1 was detected in mouse and rat blood, and not in dog and human blood. 4. These findings demonstrated that the metabolite pattern in dog resembled that in man, and suggested that the 30-hydroxylation of KRM-1648 was mediated by cytochrome P450, but that the 25-deacetylation was not. 5. Among the ten recombinant human P450 isoforms used, only the cell lysates including CYP3A3 and CYP3A4 catalysed the M2 formation from KRM-1648.

Identification and antimicrobial activity of urinary metabolites of a rifamycin derivative in dog

1. Three metabolites of the antimicrobial agent 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin (KRM-1648) were isolated from dog urine obtained after administration of a single oral dose. These metabolites of KRM-1648 were identified by mass spectrometry and 1H and 13C-nmr spectrometry. 2. Three metabolites of KRM-1648 were identified as 25-deacetyl KRM-1648, 30-hydroxy KRM-1648 and 25-deacetyl-30-hydroxy KRM-1648. 3. The antimicrobial activities of 25-deacetyl KRM-1648 were comparable with those of the parent compound, whereas 30-hydroxy KRM-1648 was equipotent and 2-8-fold less active than the parent compound against bacteria and mycobacteria, respectively.

In vitro and in vivo activities of the benzoxazinorifamycin KRM-1648 against Mycobacterium tuberculosis

The in vitro and in vivo activities of a new benzoxazinorifamycin, KRM-1648 (KRM), against Mycobacterium tuberculosis were studied. The MIC at which 50% of the isolates are inhibited (MIC50) and the MIC90 of KRM for 30 fresh isolates of M. tuberculosis measured by the BACTEC 460 TB System were 0.016 and 2 micrograms/ml, respectively. These values were much lower than those for rifampin (RMP), which were 4 and >128 micrograms/ml, respectively, and considerably lower than those for rifabutin (RBT), which were 0.125 and 8 micrograms/ml, respectively. A correlational analysis of the MICs of these drugs for the clinical isolates revealed the presence of cross-resistance of the organisms to KRM and either RMP or RBT although the MICs of KRM were distributed over a much lower range than were those of the other two drugs. KRM and RMP at concentrations of 1 to 10 micrograms/ml almost completely inhibited the bacterial growth of RMP-sensitive strains (H37Rv, Kurono, and Fujii) of M. tuberculosis phagocytosed in macrophage-derived J774.1 cells. KRM was more active than RMP in inhibiting the growth of the RMP-resistant (MIC = 8 micrograms/ml) Kurata strain but failed to show such an effect against the RMP-resistant (MIC >128 micrograms/ml) Watanabe stain. When KRM was given to M. tuberculosis-infected mice at dosages of 5 to 20 mg/kg of body weight by gavage, one daily six times per week from day 1 after infection, it was much more efficacious than RMP against infections induced in mice by the RMP-sensitive Kurono strain, as measured by a reduction of rates of mortality, a reduction of the frequency and extent of gross lung lesions, histopathological changes in lung tissues, and a decrease in the bacterial loads in the lungs and spleens of infected mice. KRM also displayed significant therapeutic efficacy against infection induced by the RMP-resistant Kurata strain, while neither KRM nor RMP was efficacious against infection by the RMP-resistant Watanabe strain. In the case of infection with the Kurono strain, the efficacy of the drugs in prolonging the time of survival was in the order KRM, RBT, RMP. KRM was much more efficacious than RMP, when given at 1- to 4-week intervals. These findings suggest that KRM may be useful for the clinical treatment of tuberculosis contracted through RMP-sensitive strains, even when it is administered at long intervals.

Mechanism of action of antimycobacterial activity of the new benzoxazinorifamycin KRM-1648

The mechanism of antimicrobial activity of KRM-1648 (KRM), a new rifamycin derivative with potent antimycobacterial activity, was studied. Both KRM and rifampin (RMP) inhibited RNA polymerases from Escherichia coli and Mycobacterium avium at low concentrations: the 50% inhibitory concentrations (IC50s) of KRM and RMP for E. coli RNA polymerase were 0.13 and 0.10 micrograms/ml, respectively, while the IC50s for M. avium RNA polymerase were 0.20 and 0.07 microgram/ml. Both KRM and RMP exerted weak inhibitory activity against Mycobacterium fortuitum RNA polymerase, rabbit thymus RNA polymerases, E. coli DNA polymerase I, and two types of reverse transcriptases. Uptake of 14C-KRM by M. avium reached 18,000 dpm/mg (dry weight) 1.5 h after incubation, while uptake by E. coli cells was slight. KRM was much more effective in inhibiting uptake of 14C-uracil than was RMP (IC50 of KRM, 0.04 microgram/ml; IC50 of RMP, 0.12 microgram/ml). These findings suggest, first, that the potent antimycobacterial activity of KRM is due to inhibition of bacterial RNA polymerase and, second, that the activity of KRM against target organisms depends on target cell wall permeability.

High-performance liquid chromatographic determination of 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin (KRM-1648) and its deacetyl metabolite in plasma, whole blood, urine and tissue samples in rats

A reversed-phase high-performance liquid chromatographic method was developed for the determination of 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin (KRM-1648, I), a new rifamycin derivative, and its 25-deacetyl metabolite (KRM-1671, II) in plasma, whole blood, tissues and urine from rats. I and II were coextracted with an internal standard from each sample matrix by solid-phase extraction (Bond Elut). Plasma and urine were directly loaded onto Bond Elut, while whole blood and tissues were homogenized and extracted with methanol or dichloromethane-chloroform prior to Bond Elut extraction. The extracts were chromatographed on Shim-pack CLC-ODS(M) using acetonitrile-0.02 M citrate buffer containing 0.1 M sodium perchlorate (2:1, v/v), and peaks were detected at 643 nm. The validation data showed that the assays for I and II in plasma, whole blood, tissues and urine were selective, accurate and reproducible.

Synthesis and biological activity of 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives

As a part of our studies on the syntheses of benzoxazinorifamycin derivatives, 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives were synthesized, and tested for their antimicrobial activities. The antimicrobial activities of these compounds against gram-positive and gram-negative bacteria were almost identical to those of rifampicin (RFP) and rifabutain (RFB), however, antimicrobial activities against Mycobacterium tuberculosis were superior to RFP, while being similar to RFB. 3'-Hydroxy-5'-(4-alkyl-1-piperazinyl)benzoxazinorifamycin derivatives also had in vitro potent activities against Mycobacterium avium complex (MAC). Their minimal inhibitory concentration values against MAC were 2-256 times greater than RFP and RFB. Their in vivo efficacies against M. tuberculosis and MAC, after oral administration to mice, were superior to RFP and RFB, except for RFB against M. tuberculosis activity in vivo. Although they were absorbed from the gastrointestinal tract, their plasma levels were lower than that of RFP. Among these 5'-(4-alkyl-1-piperazinyl) derivatives, 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin, compound 19 (KRM-1648), was selected as the most promising and its preliminary pharmacokinetic characteristics in mice were investigated. Compound 19 was distributed much more in tissues, especially in spleen and lung, than in plasma and had a long elimination time from tissues.

Bactericidal action at low doses of a new rifamycin derivative, 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl) benzoxazinorifamycin (KRM-1648) on Mycobacterium leprae inoculated into footpads of nude mice

Among a series of newly-synthesized benzoxazinorifamycins, 2 of the 3'-hydroxy-5'-(4-alkyl-1-piperazinyl) derivatives, named KRM-1648 and KRM-2312, whose respective alkyl residues are isobutyl and isopropyl, were examined for efficacy against nude mouse-model leprosy. KRM-1648 completely inhibited the growth of leprosy bacilli inoculated into nude mouse footpads, even 6 months after the medication had been stopped, when given orally at a daily dose of 0.6 mg/kg, 5 or 6 times weekly, during 3-5 months postinoculation. In comparison, the growth inhibition by KRM-2312 was incomplete under the same conditions, though it was still stronger than that by rifampicin. Complete growth inhibition by KRM-1648 was also observed when it was given orally at a dose of 1 or 3 mg/kg twice weekly during the same period. In contrast, the growth inhibition by rifampicin was only slight at 1 mg/kg and partial at 3 mg/kg under the same condition.

Synthesis and biological activity of 5'-aminobenzoxazinorifamycin derivatives

Benzoxazinorifamycin reacted with various secondary amines to yield various 5'-substituted aminobenzoxazinorifamycin derivatives. The derivatives exhibited potent activities against gram-positive bacteria and mycobacteria. The antimicrobial activities of these compounds against Mycobacterium tuberculosis and Mycobacterium intracellulare were superior to those of rifampicin. Some of these compounds showed good plasma levels after oral administration in rats.

In vitro and in vivo activities of KRM-1648, a newly synthesized benzoxazinorifamycin, against Mycobacterium marinum

The in vitro and in vivo activities of KRM-1648, one of the newly synthesized benzoxazinorifamycins, against M. marinum were compared with those of rifampin. The MIC values of KRM-1648 determined by the agar dilution method on 7H11 medium against 10 strains of M. marinum were 32-128 times and even more below those of rifampin. In an in vivo experiment, KRM-1648 was markedly effective in terms of the incidence of gross skin lesions and the number of CFUs in the lungs and spleen. Its efficacy was much greater than that of rifampin.

Chemotherapeutic efficacy of a newly synthesized benzoxazinorifamycin, KRM-1648, against Mycobacterium avium complex infection induced in mice

Newly synthesized benzoxazinorifamycin, KRM-1648, was studied for its in vivo anti-Mycobacterium avium complex (MAC) activities. When the MICs were determined by the agar dilution method with Middlebrook 7H11 agar medium, KRM-1648 exhibited similarly potent in vitro antimicrobial activities against the MAC isolated from AIDS and non-AIDS patients, indicating possible usefulness of KRM-1648 against AIDS-associated MAC infections. KRM-1648 exhibited potent therapeutic activity against experimental murine infections induced by M. intracellulare N-260 (virulent strain) and N-478, which has much weaker virulence. Similarly, KRM-1648 exhibited an excellent therapeutic efficacy against M. intracellulare infection induced in NK-cell-deficient beige mice (as a plausible model for AIDS-associated MAC infection), in which a much more progressed state of gross lesions and bacterial loads at the sites of infection were observed. When the infected beige mice were killed at weeks 4 and 8, obvious therapeutic efficacy was seen on the basis of reduction in the incidence and degree of lung lesions and bacterial loads in the lungs and spleen with infections due to M. intracellulare N-241, N-256, and N-260. In this case, the efficacy was the highest in N-260 infection, followed by strain N-241. When mice were observed until infection-induced death, survival time of the infected beige mice was found to be prolonged by KRM treatment. However, KRM-1648 was not efficacious in suppressing the progression of pulmonary lesions and the increase in bacterial loads at the sites of infection, including lungs and spleen, at the late phase of infection. This may imply some difficulty with chemotherapy for AIDS-associated MAC infection, even with KRM-1648 treatment, which has excellent in vitro and in vivo anti-MAC activities, as shown in present study.

In vitro antimycobacterial activities of newly synthesized benzoxazinorifamycins

Newly synthesized rifamycin derivatives, KRM-1648, KRM-1657, KRM-1668, KRM-1686, and KRM-1687, having the chemical structures of 3'-hydroxy-5'-(4-alkylpiperazinyl)-benzoxazinorifamycins (alkyl residues: isobutyl, propyl, sec-butyl, sec-butyl [R configuration], and sec-butyl [S configuration], respectively), were studied for their in vitro antimycobacterial activities. Representative (KRM-1648) MICs for 90% of the strains tested, determined by the agar dilution method on 7H11 medium, of various pathogenic mycobacteria (9 species, 174 strains) were as follows (in micrograms per milliliter): Mycobacterium tuberculosis (rifampin [RMP]-susceptible strains), less than or equal to 0.0125; M. tuberculosis (RMP-resistant strains), 12.5; M. kansasii, 0.05; M. marinum, less than or equal to 0.0125; M. scrofulaceum, 0.1; M. avium, 1.56; M. intracellulare, 0.1; M. fortuitum, greater than 100; and M. chelonae subsp. abscessus and M. chelonae subsp. chelonae, greater than 100. These values are more than 64 times lower than those of RMP, except for the values against RMP-resistant M. tuberculosis (8 times lower) and those against rapid growers, including M. fortuitum and M. chelonae (the same as those of RMP). The other derivatives had similar levels of in vitro activity against these mycobacteria. When murine peritoneal macrophages in which M. intracellulare was phagocytosed in vitro were cultured in the presence of the benzoxazinorifamycins (1 microgram/ml), much more rapid killing of the organisms ingested in the macrophages was seen compared with when the same amount of RMP was added to the medium. The addition of benzoxazinorifamycins at the concentration of 0.05 micrograms/ml caused more marked suppression of intracellular growth of the organisms compared with addition of RMP. KRM-1648 and KRM-1657 inhibited intracellular growth of M. tuberculosis, and their efficacies were much greater than that of RMP.

Preparation of new 7-hydroxyguanine derivatives and their biological activities

We prepared new 7-hydroxyguanine derivatives, 7-hydroxyguanosine 5'-monophosphate and N2-tetrahydropyranyl-7-hydroxyguanine, and compared biological activities of 7-hydroxyguanine derivatives including nucleosides acquired previously. 7-Hydroxyguanine and its nucleotide inhibited the focus formation of Rous sarcoma virus. Antitumor activities of these derivatives against mouse leukemia L1210 were not so different from one another. Anti-proliferative activities of the derivatives on various human cell lines were significantly different from one another.

Analgesic and anti-inflammatory activities in rats of alpha-(3,5-di-t-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), and its intestinal damage

alpha-(3,5-Di-t-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), an anti-inflammatory drug, possesses analgesic activity in rat models. In the acetic acid-induced writhing test, the oral ED50 values for KME-4, indomethacin, naproxen and ibuprofen were 5.2, 3.8, 7.0 and 18.6 mg kg-1, respectively, and the relative order of potency of these drugs correlated with their inhibitory effect on acetic acid-induced vascular permeability in rats. KME-4 also had analgesic activity in the tests of Randall-Selitto and adjuvant arthritic flexion, but the dose required was greater than that needed in the writhing test. KME-4 (10 mg kg-1 day-1 orally) has a preventive effect against adjuvant-induced arthritis in rats, and its efficacy was more potent than indomethacin (2 mg kg-1 day-1) as judged from various parameters determined. When administered orally to rats once daily for 12 days, KME-4 caused perforating ulceration of the small intestine but this action was less potent than the effect of indomethacin, naproxen and ibuprofen.

Effect of alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), a new anti-inflammatory drug, on the established adjuvant arthritis in rats

The effect of alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), a new anti-inflammatory drug, on established adjuvant arthritis in rats was compared to that of indomethacin. When administered orally daily from days 14 to 27 starting on day 14 after the adjuvant (day 0), KME-4 (2 to 10 mg/kg) produced a dose-related reduction of the swelling of both injected and uninjected hindpaws, and it retarded body weight loss. The initiation of paw swelling after the cessation of therapy was not observed at either 5 mg/kg or 10 mg/kg of KME-4. On day 42 (15 days after discontinuation of dosing), KME-4 caused the recovery of organ weight, erythrocyte sedimentation rate (ESR) and serum albumin/globulin (A/G) ratio towards normal levels, and it also decreased radiographic bone damage scores in a dose-dependent manner. The results indicate that KME-4 produces the improvement of systemic symptoms in the established adjuvant arthritis. The results obtained with indomethacin were similar to those with KME-4. However, the degree of the efficacy of indomethacin (2 mg/kg) was lower than that of KME-4 (10 mg/kg) as judged by the measured parameters (ESR, serum A/G ratio and bone damage).

The effect of alpha-(3,5-di-t-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), a new anti-inflammatory drug, on leucocyte migration in rat carrageenan pleurisy

KME-4,alpha-(3,5-di-t-butyl-4-hydroxybenzylidene)-gamma-buty rolactone was found to reduce the accumulation of leucocytes and exudate volume in the rat carrageenan pleurisy model. When administered orally 1 h before carrageenan, KME-4 (3-10 mg kg-1) induced a degree of inhibition of leucocyte migration almost equal to that of indomethacin (3-10 mg kg-1) in both 5 h and 24 h pleurisies. Furthermore, KME-4, when administered orally 5 h after the carrageenan, inhibited both monocyte numbers and exudate volume in a 24 h pleurisy and was more effective than indomethacin and BW755c which inhibited only monocyte migration. These results suggest that KME-4 has a differential anti-inflammatory activity. Dexamethasone (0.25 mg kg-1) showed strong inhibition of total cell numbers and exudate volume.

Inhibition of polymorphonuclear leukocyte 5-lipoxygenase and platelet cyclooxygenase by alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolacto ne (KME-4), a new anti-inflammatory drug

The effect of alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), a new anti-inflammatory compound, on arachidonate lipoxygenase and cyclooxygenase was investigated. KME-4 showed a dose-dependent inhibition of 5-lipoxygenase activity in both the cytosol (IC50: 0.85 microM) and ionophore A23187-stimulated cells (IC50: 11.5 microM) of guinea pig peritoneal polymorphonuclear leukocytes. KME-4 was also found to inhibit rabbit platelet cyclooxygenase (IC50: 0.44 microM), but had no inhibitory effect on platelet 12-lipoxygenase at concentrations up to 100 microM, whereas BW755C inhibited both enzymes in the same range of concentrations. The results indicate that KME-4 is a dual 5-lipoxygenase and cyclooxygenase inhibitor which is different from BW755C in affecting 12-lipoxygenase. These effects may provide information for understanding the pharmacological activity of KME-4.

Pharmacological properties of a new anti-inflammatory compound, alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolacto ne (KME-4), and its inhibitory effects on prostaglandin synthetase and 5-lipoxygenase

The pharmacological effects of a new anti-inflammatory compound, alpha-(3,5-di-tert-butyl-4-hydroxybenzylidene)-gamma-butyrolactone (KME-4), and its inhibitory effects on arachidonate prostaglandin synthetase and 5-lipoxygenase activities were examined. KME-4 showed anti-inflammatory activity. It was less active than indomethacin, but more active than naproxen and ibuprofen in carrageenin-induced paw edema in rats; and it was less active than indomethacin, equipotent as naproxen, but more active than ibuprofen in granuloma formation in rats. The ulcerogenic activity of KME-4 was weaker than indomethacin and naproxen, but stronger than ibuprofen in starved rats. The ratio of UD50 stomach to ED30 carrageenin edema or to ED25 granuloma for KME-4 showed higher values than those of the reference drugs. KME-4 showed antipyretic activity in yeast-induced fever in rats. It also inhibited platelet aggregation induced by arachidonic acid and protected rabbits from arachidonic acid-induced death. Furthermore, KME-4 was found to be equipotent in inhibiting both prostaglandin synthetase and 5-lipoxygenase activities of rat basophilic leukemia cells, unlike indomethacin, naproxen and ibuprofen. It also inhibited the prostaglandin synthetase activity of bovine seminal vesicle. The present findings indicate that KME-4 may be a new type of anti-inflammatory drug with dual prostaglandin synthetase and 5-lipoxygenase inhibition.

Notas biológicas: II. sobre Embletonia mediterranea (Costa), nudibranquio da região lagunar de Cananéia

1) - Foram estabelecidas em S. Paulo algumas colónias de E. mediterranea proveniente das águas salobras da região de Cananéia afim de completar as observações realisadas in loco. 2) - São apresentadas tanto a descrição como a classificação, incluindo uma rápida comparação com quase todas as outras espécies desse gênero que foram até hoje descritas. 3) - Descreve-se o ciclo completo desde a desova até a postura da geração seguinte. Não foi feito o estudo embriológico detalhado. 4) - Foram anotados o habitat e a alimentação, e verificada a ausência de cnidocistos em animais não alimentados com hidrozoários. 5) - Foram estabelecidas as temperaturas letais e a duração das principais fases do desenvolvimento em temperaturas diferentes. 6) - Foi feita a comparação com o ciclo de E. pallida, otimamente descrito e figurado por Rasmussen (1944). 7) - Foi verificada in loco a ausência de migrações. 8) - Considera-se essa espécie, sem dúvida eurihalina, um ótimo material para o estudo das relações entre o meio interno e a pressão osmótica externa.