Licorice, the roots and long-stalks of various species of Glycyrrhiza genus, has been used as a traditional folk medicine and foodstuff all over the world.2) Isoliquiritigenin is one of the plant pigments of licorice, and is a simple chalcone derivative, 4,2Ј,4Ј-trihydroxy-chalcone (see Fig. 1). We have reported the isolation of this compound from Egyptian licorice (Glycyrrhiza grabla), along with new and known 3-arylcoumarins.3) Shibata reported the anti-tumor promoter effects of various chalcone derivatives in vitro, and isoliquiritigenin exhibited potential activity. 4) Other biological activities for this compound have also been reported. For example, antitumor promoting activity on two-stage mouse skin carcinogenesis, 5) inhibitory effect on aldose reductase activity, 6) antiplatelet aggregation effect, 7) antioxidative and superoxide scavenging activities, 8) etc. However, all these experiments were in vitro or topical application in vivo, and there is no reported data of the effect by oral administration in vivo.Repetitive treatment with the organotropic colon carcinogen, azoxymethane (AOM), produces colon tumors in rodents exhibiting pathological features that are similar to sporadic forms in human colon cancer.9) The AOM-induced colon cancer model in rat has been used to evaluate the potency of chemopreventive agents against colon cancer. 10)Aberrant crypt foci (ACF) were first identified in methylene blue stained, whole-mount preparations of colonic mucosa from carcinogen-treated rodents, 11) and ACF have also been found in the colons of patients both with or without colorectal cancer.12,13) McLellan et al. reported that ACF may be a significant biological lesion in the development of colon tumors, and aberrant crypt (AC) formation is specific for exposure to colon carcinogens. 14) From these findings, the colonspecific, carcinogen-induced ACF model in rodents has been used as a short term screening to identify chemopreventive agents for colon cancer. 15,16) In the present studies, the effect of isoliquiritigenin on the AOM-induced ACF formation model in mice was studied. Based on the data obtained, AOM-induced murine colon carcinogenesis experiment was also studied. MATERIALS AND METHODSChemicals AOM was purchased from Sigma Chemical Co., Ltd. (St. Louis, MO, U.S.A.). Isoliquiritigenin (ILG) was synthesized by the methods of Hulle et al. 17) and purified by column chromatography (silica gel with a mixture of nhexane and ethyl acetate). After recrystallization, the purity was quantificated by HPLC (octadecyl silica (ODS) with a gradient of acetonitrile and water) as over 99.8%. The yield of this material was 38.6%.Animals Five-weeks old ddY male mice were obtained from Shizuoka Laboratory Animal Center (Hamamatsu, Shizuoka, Japan). Effect of Isoliquiritigenin on Murine Colon Aberrant Crypt FociFive-weeks old ddY mice were housed in temperature-and humidity-controlled animal quarters with a 12 h light/dark cycle and fed CE-2 diet. (CLEA Japan Co., Ltd.) On the 1st and 8th days, AOM (10 mg/kg b.w.) was...

The in vitro activity of KP-103, a novel triazole derivative, against pathogenic fungi that cause dermatomycoses and its therapeutic efficacy against plantar tinea pedis and cutaneous candidiasis in guinea pigs were investigated. MICs were determined by a broth microdilution method with morpholinepropanesulfonic acidbuffered RPMI 1640 medium for Candida species and with Sabouraud dextrose broth for dermatophytes and by an agar dilution method with medium C for Malassezia furfur. KP-103 was the most active of all the drugs tested against Candida albicans (geometric mean [GM] MIC, 0.002 g/ml), other Candida species including Candida parapsilosis and Candida glabrata (GM MICs, 0.0039 to 0.0442 g/ml), and M. furfur (GM MIC, 0.025 g/ml). KP-103 (1% solution) was highly effective as a treatment for guinea pigs with cutaneous candidiasis and achieved mycological eradication in 8 of the 10 infected animals, whereas none of the imidazoles tested (1% solutions) was effective in even reducing the levels of the infecting fungi. KP-103 was as active as clotrimazole and neticonazole but was less active than lanoconazole and butenafine against Trichophyton rubrum (MIC at which 80% of isolates are inhibited [MIC 80 ], 0.125 g/ml) and Trichophyton mentagrophytes (MIC 80 , 0.25 g/ml). However, KP-103 (1% solution) exerted therapeutic efficacy superior to that of neticonazole and comparable to those of lanoconazole and butenafine, yielding negative cultures for all samples from guinea pigs with plantar tinea pedis tested. This suggests that KP-103 has better pharmacokinetic properties in skin tissue than the reference drugs. Because the in vitro activity of KP-103, unlike those of the reference drugs, against T. mentagrophytes was not affected by hair as a keratinic substance, its excellent therapeutic efficacy seems to be attributable to good retention of its antifungal activity in skin tissue, in addition to its potency.

Butenafine hydrochloride, N-4-tert-butylbenzyl-N-methyl-l-naphthalenemethylamine hydrochloride (butenafine), is a novel antifungal agent of the class of benzylamine derivatives. Butenafine was investigated for its activity against guinea pig dermatophytosis caused by Trichophyton mentagrophytes or Microsporum canis in comparison with those of naftifine, tolnaftate, clotrimazole, and bifonazole. Topical butenafine showed excellent efficacy against dermatophytosis when it was applied once daily, and the effect was superior to those of all four reference drugs. When applied once at 24 or 48 h before infection, the drug exhibited excellent prophylactic efficacy against experimental T. mentagrophytes infection. The concentrations of butenafine in animal skin at 24 and 48 h after application of 0.2 ml of a 1% solution were several hundred times higher than those required to kill T. mentagrophytes and M. canis. The good efficacy of butenafine against dermatophytosis may be attributable to its fungicidal activity and long retention in the skin after topical application.

The mechanism of action of a new benzylamine antimycotic, butenafine hydrochloride, was studied in Candida albicans by using the thiocarbamate antimycotic tolnaftate as a reference drug. Butenafine completely inhibited the growth of a test strain of C. albicans at 25 ,g/ml and was cidal at 50 ,ug/ml. Tolnaftate did not show any growth-inhibitory activity up to 100 ,ug/ml. Both butenafine and tolnaftate inhibited squalene epoxidation in C. albicans, with 50% inhibitory concentrations being 0.057 and 0.17 i.g/ml, respectivel. Butenafine, but not tolnaftate, induced the release of appreciable amounts of Pi from C. albicans cells at 12.5 ,ug/ml. This effect of butenafine was augmented when the cells were pretreated with tolnaftate. The results suggest that the direct membrane-damaging effect of butenafine may play a major role in its anticandidal activity and that the drug-induced alteration in the cellular sterol composition renders the cell membrane more susceptible to the membrane-damaging effect of this drug.Butenafine, a new benzylamine antimycotic agent, has potent in vitro activity against a wide range of pathogenic fungi, including dermatophytes, yeasts such as Candida and Cryptococcus spp., and dimorphic fungi (13). In experimental studies with animal models of dermatophytosis and candidiasis and in subsequent clinical studies designed for application to humans with these superficial dermatomycoses, it has proved to have excellent therapeutic efficacy (2, 3, 7).The mechanisms of antifungal action of butenafine were investigated by Hiratani et al. (8,9), using a susceptible dimorphic fungus, Sporothrix schenckii, in the yeast phase of growth, and they demonstrated that it primarily inhibits ergosterol biosynthesis in the fungus; at low concentrations, butenafine specifically inhibited the conversion of squalene into 2,3-oxidosqualene catalyzed by squalene epoxidase, ultimately resulting in the lack of ergosterol, which is an indispensable lipid component of fungal cell membranes. This research also demonstrated that butenafine has a direct damaging effect on the cell membranes of this fungus at higher concentrations (8,9).Tolnaftate, a thiocarbamate antimycotic agent which has potent antidermatophytic activity, has been used for the topical treatment of dermatophytosis and is also known to inhibit selectively the fungal squalene epoxidase reaction in a manner similar to that of the allylamines naftifine and terbinafine (4,10,11,(14)(15)(16)(17)(18)(19). Although butenafine and tolnaftate appear to share a common mechanism of action, they are different in their antimicrobial spectra; butenafine is active against Candida albicans in vitro and in vivo, while tolnaftate is not.The present study was performed to examine possible differences in the mechanisms of anticandidal action between butenafine and tolnaftate. MATERIALS AND METHODS Drugs