The modifying effect of Peucedanum japonicum, a herb in the Ryukyu Islands, on azoxymethane-induced colon preneoplastic lesions in male F344 rats

Comparative Analysis of Coumarin Profiles in Different Parts of Peucedanum japonicum and Their Aldo-Keto Reductase Inhibitory Activities

Peucedanum japonicum (Umbelliferae) is widely distributed throughout Southeast Asian countries. The root of this plant is used in traditional medicine to treat colds and pain, whereas the young leaves are considered an edible vegetable. In this study, the differences in coumarin profiles for different parts of P. japonicum including the flowers, roots, leaves, and stems were compared using ultra-performance liquid chromatography time-of-flight mass spectrometry. Twenty-eight compounds were tentatively identified, including three compounds found in the genus Peucedanum for the first time. Principal component analysis using the data set of the measured mass values and intensities of the compounds exhibited distinct clustering of the flower, leaf, stem, and root samples. In addition, their anticancer activities were screened using an Aldo-keto reductase (AKR)1C1 assay on A549 human non-small-cell lung cancer cells and the flower extract inhibited AKR1C1 activity. Based on these results, seven compounds were selected as potential markers to distinguish between the flower part versus the root, stem, and leaf parts using an orthogonal partial least-squares discriminant analysis. This study is the first to provide information on the comparison of coumarin profiles from different parts of P. japonicum as well as their AKR1C1 inhibitory activities. Taken together, the flowers of P. japonicum offer a new use related to the efficacy of overcoming anticancer drug resistance, and may be a promising source for the isolation of active lead compounds.

Two new endemic species, Peucedanummiroense and P.tongkangense (Apiaceae), from Korea

Two new species of Peucedanum (Apiaceae), P.miroense and P.tongkangense, from Gangwon Province, South Korea, are described. Both species are most similar to P.elegans and P.hakuunense because of their linear ultimate leaf segments. Peucedanummiroense was found on crevices of rocks in mountain summits and can be distinguished by its pubescent ovary, purple anthers, oblong schizocarp, and 1 or (2) vittae per vallecula and 4 on the commissural face. Peucedanumtongkangense was found in open areas on rocky cliffs along the Donggang River and can be distinguished by its glabrous ovary, whitish-yellow anthers, narrowly ellipsoid schizocarp, and 3 vittae per vallecula and 4 on the commissural face. Distinguishing characteristics, full descriptions, illustrations, photographs, taxonomic notes on geographical distribution, ecology, and phenology of the two species are presented. An identification key for all Korean species of Peucedanum is also provided. In addition, the mericarp surface of two new species and their close relatives are compared using micromorphological analysis.

The Promising Effect of Peucedanum chenur Chloroformic Extract on Prevention of Human Colorectal Cancer Progression by Modulating miR-135b, miR-21, and APC Genes

PURPOSE

The therapeutic use of herbal medicines for the diseases, including cancer, is increasing due to their lower side effects. The present research evaluated the effect of Peucedanum chenur chloroformic extract (PCCE) on cell proliferation against HCT-116 human colorectal cancer cell line.

METHODS

The cytotoxic effect of PCCE was evaluated by MTT assay. The activity of the Wnt/B-catenin pathway was assayed through measuring the expression of miR-135b, miR-21, and APC genes by real-time PCR. The flow cytometry and scratch tests were used to study the cell cycle and cell migration, respectively. Also, the antioxidant activity of PCCE was measured by DPPH and iron-chelating tests.

RESULTS

The results showed the downregulation of miR-135b and miR-21 and overexpression of the APC gene. Furthermore, PCCE decreased the free radicals, cell migration, and cell proliferation. The antioxidant activity of PCCE was confirmed by standard tests.

CONCLUSION

Altogether, our findings suggest that purified compounds of PCCE could be developed as a potent chemo-preventive drug for the treatment of CRC.

Aerial Parts of Peucedanum chenur Have Anti-Cancer Properties through the Induction of Apoptosis and Inhibition of Invasion in Human Colorectal Cancer Cells

Background:

The Peucedanum species have many pharmacological effects due to the presence of coumarins, flavonoids, phenolic compounds, and essential fatty acids in these species. In this study, for the first time, the anticancer activity of Peucedanum chenur methanolic extract via the induction of apoptosis and inhibition of invasion in HCT-116 human colon cancer cells was investigated.

Methods:

P. chenur methanolic extract effect on HCT-116 cells viability and antioxidant activity were evaluated using MTT assay, DPPH, and iron chelating tests, respectively. Changes in mRNA expression level in a panel of relevant genes were assessed by the quantitative real-time PCR. Also, apoptosis was assessed by cell cycle analysis and Annexin V/PI method, and the effect on cell migration was tested using scratch test.

Results:

P. chenur methanolic extract increased significantly the expression of BAX while decreased the expression of BCL-2, AKT1, FAK, RhoA, and MMP genes compared to the control group. BAX/BCL-2 ratio and apoptosis elevated, whereas cell migration reduced significantly. Besides, our extract showed an appropriate antioxidant activity.

Conclusion:

P. chenur may be introduced as a new chemopreventive agent in medicine due to its notable power in terms of induction of apoptosis and inhibition of invasion.

Development of bioresources in Okinawa: understanding the multiple targeted actions of antioxidant phytochemicals

In research to develop healthy foods or preventive medicines from edible and medicinal herbs in Okinawa, we focused on the antioxidant activities of those bioresources. We first confirmed that the herbal antioxidant activities of such herbs increased upon ultraviolet irradiation treatment. This observation explains the high antioxidant activity of Okinawan vegetables, which grow under exposure to stronger ultraviolet light compared with those in other prefectures in Japan. Antidiabetic, hepatoprotective, cancer preventive, and cardioprotective actions were clarified using herbal extracts, and quercetin, chlorogenic acid, and gallic acid derivatives were isolated as antioxidant components from the herbs. Dimerumic acid was also isolated from the mold Monascus anka. All these antioxidants showed strong radical scavenging activities in vitro and beneficial effects in animal models. However, the concentrations of these compounds used in vivo seemed to be too low to have a physiologically important antioxidant effect based on their radical scavenging activities in vitro. Therefore, I performed a literature survey of antioxidant activities in vivo. Accumulating evidence has emerged that antioxidant phytochemicals show not only radical scavenging activities in vitro but also pleiotropic actions in vivo. The multitargeted, beneficial effects of antioxidant phytochemicals can be rationally explained using the xenohormesis concept, in which phytochemicals are the products of plant evolutionary adaptation to stress in plants, and their ability to induce a stress-adaptive response has been evolutionarily conserved in animals.

Isolation and Antimicrobial Activity of Coumarin Derivatives from Fruits of Peucedanum luxurians Tamamsch

As a continuation of searching for phytoconstituents that act as promising agents for antimicrobial therapy, rare coumarins were isolated from fruits of Peucedanum luxurians and tested. In a first step, the content of major compounds in the aerial parts and fruits of P. luxurians were compared. The results clearly showed that the fruits with dichloromethane as a solvent yielded, in most cases, higher concentrations of almost all the analyzed coumarins than the aerial parts, with peucedanin detected as the most abundant compound with a concentration of 4563.94 ± 3.35 mg/100 g. Under this perspective, the dichloromethane extract from the fruits of P. luxurians was further submitted to high performance countercurrent chromatography with a mixture of n-hexane, ethyl acetate, methanol, and water 6:5:6:5 (v/v). Combination of HPCCC and prep-HPLC yielded 6',7'-dihydroxybergamottin (1), officinalin (2), stenocarpin isobutyrate (3), officinalin isobutyrate (4), 8-methoxypeucedanin (5), and peucedanin (6). Isolated compounds were tested against several Gram-positive and Gram-negative bacteria strains. 6',7'-Dihydroxybergamottin, peucedanin, and officinalin isobutyrate appeared to be the most active against all tested bacteria strains with minimum inhibitory concentration (MIC) values between 1.20 and 4.80 mg/mL. To the best of our knowledge, this is the first report about countercurrent isolation of mentioned coumarins, as well as the first information about their antimicrobial activity.

Clinical Effects of Formulated Food of Peucedanum japonicum Extract and Saw Palmetto Extract in Male Patients with Lower Urinary Tract Symptoms

OBJECTIVES

To evaluate changes over time in subjective symptom scores and urination parameters before and after oral administration of formulated food containing a combination of Peucedanum japonicum (P. japonicum) extract and saw palmetto extract (SPE) in male patients with lower urinary tract symptoms (LUTS).

METHODS

This study was conducted in an open label manner on male patients with untreated LUTS. The urination state of patients was evaluated before and after administration of food formulated with P. japonicum extract and SPE for 4 weeks, based on urodynamic parameters and subjective symptom scores (International Prostate Symptom Score [IPSS and IPSS-QOL], Overactive Bladder Symptom Score [OABSS], Overactive Bladder Questionnaire [OAB-q], and International Index of Erectile Function [IIEF]).

RESULTS

After the administration of food formulated with these extracts, the following results were obtained: (i) Subjective findings: The IPSS-QOL score improved significantly; both parameters related to nocturia, i.e., frequency of nighttime urination and OABSS-2, improved significantly; other ratings for subjective symptoms slightly improved. (ii) Objective findings: Residual urine volume decreased significantly, and blood prostate specific antigen (PSA) and urinary 8-OHdG levels decreased slightly after the treatment. (iii) Other findings: Blood pressure decreased slightly. No adverse drug reactions were reported. (iv) Patient impressions: 75% of patients gave a rating of "Good" or higher, with 15 out of 20 patients wanting to continue treatment after the end of 4-week administration period.

CONCLUSIONS

Food formulated with P. japonicum extract and SPE may be useful to decrease frequency of nighttime urination and residual urine volume in male patients with LUTS.

Development of an Efficient Protocol for Cimifugin Isolation from Peucedanum schottii and Evaluation of Enzyme Inhibitory Activity

The dichloromethane (DCM) extract of the fruits of Peucedanum schottii Besser ex DC. (Apiaceae) was subjected to high-performance counter-current chromatography (HPCCC) for the efficient and fast separation (30 min) and isolation of cimifugin using an ethyl acetate: water (1:1 v/v, K = 1.01) system. The analytical scale-optimized separation was easily scaled to semi-preparative conditions. Cimifugin (11.25% yield, 96.5% purity) was isolated for the first time from P. schottii and characterized by NMR spectroscopy. Cimifugin and the crude DCM extract were evaluated using ELISA microtiter assays for their inhibitory potential against the cholinesterases (acetylcholinesterase - AChE and butyrylcholinesterase - BChE), and tyrosinase (TYR), which are key enzymes for the treatment of some neurodegenerative diseases, i.e. Alzheimer's and Parkinson's. The crude extract exhibited a weak inhibitory activity against AChE, BChE, and TYR (4.2, 35.5, and 0% at 100 μg mL−1 and 10.3, 40.0, and 12.2% at 200 μg mL−1, respectively), while cimifugin displayed low to moderate inhibition towards AChE and BChE (3.1 and 21.6%, respectively) at 200 μg mL−1.

Simultaneous analysis of seven marker compounds from Saposhnikoviae Radix, Glehniae Radix and Peucedani Japonici Radix by HPLC/PDA

A new combination of high performance liquid chromatography (HPLC) method coupled with photodiode array (PDA) analysis has been developed for the simultaneous quantitative determination of seven major components in Saposhnikoviae Radix (SR), Glehniae Radix (GR) and Peucedani Japonici Radix (PR), namely peucedanol 7-O-β-D-glucopyranoside (1), prim-O-glucosylcimifugin (2), cimifugin (3), 4'-O-β-D-glucosyl-5-O-methylvisamminol (4), bergapten (5), sec-O-glucosylhamaudol (6), and imperatorin (7). Clear separation of these seven components were achieved on a Phenomenex Kinetex C18 (250 × 4.6 mm, 5 μm) column by gradient elution of water (A) and methanol (B) as mobile phase. The flow rate was 1.0 mL/min and the UV detector wavelength was set at 254 nm. The method was successfully used in the analysis of SR, GR, and PR with relatively simple conditions and procedures, and the results were satisfactory for linearity, recovery, precision, accuracy, stability and robustness. The results indicate that the established HPLC/PDA method is suitable for the classification of SR, GR, and PR.

Traditional uses, phytochemistry and pharmacological properties of the genus Peucedanum: a review

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Peucedanum (Apiaceae) comprising more than 120 species is widely distributed in Europe, Asia and Africa. The ethnopharmacologial history of this genus indicated that some extracts of aerial and underground parts of several Peucedanum species have been used in folk medicine for treatment of various conditions, such as cough, cramps, pain, rheumatism, asthma and angina. This review focuses on ethnopharmacological uses of Peucedanum species, as well as the phytochemical, pharmacological and toxicological studies on this genus. Through this review, I intend to highlight the known and potential effects of the Peucedanum species or their isolated compounds and show which traditional medicine uses have been supported by pharmacological investigations.

METHODS

Information on the Peucedanum species was collected from scientific journals, books, thesis and reports via a library and electronic search (using Google Scholar, Pubmed, Scopus, Web of Science and ScienceDirect). This review covers the available literature from 1970 to the end of September 2013.

RESULTS

Although, there are about 120 species in this genus, so far many species have received no or little attention and most of pharmacological studies were performed on just about 20 species. Many phytochemical investigations on this genus confirmed that Peucedanum species are rich in essential oils and coumarins. The present review article shows that Peucedanum species have a wide spectrum of pharmacological activities and the most reported activities of Peucedanum plants come back to the presence of coumarins, flavonoids, phenolics and essential oils.

CONCLUSIONS

The present review confirms that some Peucedanum species have emerged as a good source of the traditional medicine for treatment of inflammation, microbial infections, cardiopulmonary diseases and provides new insights for further investigations on isolated compounds, especially on praeruptorins, to find novel therapeutics and aid drug discovery. However, for using Peucedanum species to prevent and treat various diseases, additional pharmacological studies to find the mechanism of action, safety and efficacy of them before starting clinical trials are required.

Colon preneoplastic lesions in animal models

The animal model is a powerful and fundamental tool in the field of biochemical research including toxicology, carcinogenesis, cancer therapeutics and prevention. In the carcinogenesis animal model system, numerous examples of preneoplastic lesions have been isolated and investigated from various perspectives. This may indicate that several options of endpoints to evaluate carcinogenesis effect or therapeutic outcome are presently available; however, classification of preneoplastic lesions has become complicated. For instance, these lesions include aberrant crypt foci (ACF), dysplastic ACF, flat ACF, β-catenin accumulated crypts, and mucin-depleted foci. These lesions have been induced by commonly used chemical carcinogens such as azoxymethane (AOM), 1,2-dimethylhydrazine (DMH), methylnitrosourea (MUN), or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Investigators can choose any procedures or methods to examine colonic preneoplastic lesions according to their interests and the objectives of their experiments. Based on topographical, histopathological, and biological features of colon cancer preneoplastic lesions in the animal model, we summarize and discuss the character and implications of these lesions.

The influence of extracts from Peucedanum salinum on the replication of adenovirus type 5

INTRODUCTION

The aim of the study was to examine the cytotoxicity and evaluate the antiviral and virucidal activity of methanol and methanol/H(2)O extracts from the herb of Peucedanum salinum. Plants belonging to the genus Peucedanum (Apiaceae family) have been used in traditional medicine for a long time.

MATERIAL AND METHODS

The examination of the cytotoxicity of the extracts in the concentrations of 0.1, 0.2, 0.5, 1, 2, 4 mg/ml was carried out on the cell culture line HEK-293. Cytotoxicity of the examined extracts was measured by the colorimetric MTT (tetrazolium) method. After determination of the highest non-toxic concentration of examined extracts, antiviral and virucidal activity against adenovirus type 5 (Adenoviridae) was established.

RESULTS

The non-toxic doses were as follows: 1 mg/ml of methanol extract and 2 mg/ml of methanol/H(2)O extract (1 : 1 v/v). Antiviral activity was observed for the methanol extract of Peucedanum salinum in concentrations of 0.5 and 1 mg/ml. The extract caused the decrease of titre of the virus by 2 log and 1.33 log, respectively. The methanol/H(2)O extract (1 : 1 v/v) decreased the titre of the virus by 1.33 log and 1.5 log in concentrations of 1 and 2 mg/ml, respectively. The examined extracts had no virucidal activity against adenovirus type 5.

CONCLUSIONS

The examined extract is a new, potentially active source of active substances possessing antiviral activity and further studies are needed.

Abnormal Savda Munziq, an Herbal Preparation of Traditional Uighur Medicine, May Prevent 1,2-dimethylhydrazine-Induced Rat Colon Carcinogenesis

The study tried to assess the chemoprotective effect of abnormal Savda Munziq (ASMq) on 1,2-dimethylhydrazine (DMH)-induced rat colon carcinogenesis. Male F344 rats were randomized into eight groups: Group 1 was served as control, no DMH injection was given and treated daily with normal saline. Rats in Groups 2–8 were given a single intraperitoneal injection of DMH (20 mg/kg body weight) at the beginning of the study. Group 2 was served as negative control, administered with normal saline until the end of the experiment after the single DMH injection. Groups 3–5 were served as pretreatment group, administered with ASMq ethanol extract at 400, 800 and 1600 mg/kg body weight, respectively, until the 45th day, continued by normal saline administration for another 45 days. Groups 6–8 were served as the treatment group, administered with normal saline for the first 45 days from the day of DMH injection, ASMq ethanol extract at three different doses to be administered until the end of the second 45th day. All rats were sacrificed at 91st day and the colons were analyzed for aberrant crypt foci (ACF) formation and crypt multiplicity. Results showed that ASMq ethanol extract reduced the number of ACF, AC and crypt multiplicity significantly (P < .05). It suggested that ASMq ethanol extract had chemoprotective effects on DMH-induced colon carcinogenesis, by suppressing the development of preneoplastic lesions, and probably exerted protection against the initiation and promotion steps of colon carcinogenesis.

Chlorogenic acid differentially alters hepatic and small intestinal thiol redox status without protecting against azoxymethane-induced colon carcinogenesis in mice

Colorectal cancer (CRC) is a leading cause of cancer-related deaths in the United States. Epidemiological data have suggested that coffee consumption is inversely related to CRC risk, which may be attributed to chlorogenic acid (CGA), an ester of caffeic acid (CA) and quinic acid. This study was conducted to determine whether chronic dietary CGA supplementation would attenuate tumorigenesis and oxidative stress in a mouse model of azoxymethane (AOM)-induced colon cancer. Mice (4-wk old; n = 15/group) were fed CGA (0%, 0.01%, or 0.1%) for 20 wk and received 6 weekly intraperitoneal AOM injections (10 mg/kg). CGA and CA dose-dependently accumulated in the small intestinal mucosa. AOM induced (P < 0.05) colonic aberrant crypt foci (14.2 +/- 1.9/field) and tumors (14.6 +/- 1.1/colon), which were correlated (r = .677; P < 0.05), and CGA at either dose did not reduce tumorigenesis. Hepatic GSH/GSSG and Cys/CySS ratios were unaffected by AOM, but CGA at 0.1% increased these ratios by decreasing GSSG and CySS. CGA did not affect the ratios of small intestinal GSH/GSSG or Cys/CySS, which were decreased in response to AOM treatment. Collectively, these data indicated that CGA did not protect against AOM-induced tumorigenesis but affected hepatic thiol redox status in this colon cancer model.

Inhibitory effect of bread crust antioxidant pronyl-lysine on two different categories of colonic premalignant lesions induced by 1,2-dimethylhydrazine

Colorectal malignancies continue to be one of the most frequent and life-threatening diseases throughout the world. Pronyl-lysine, a product obtained from bread crust, is a potent free radical scavenging antioxidant exerting chemopreventive activity by reducing oxidative stress. This study was conducted to investigate the effects of pronyl-lysine supplementation on the formation of colonic precancerous lesions, circulatory lipid peroxidation, and enzymic antioxidant status in 1,2-dimethylhydrazine-induced colon carcinogenesis. Male Wistar rats were randomized into seven groups; group 1 was control rats, group 2 received pronyl-lysine (2 mg/kg body weight orally) everyday, rats in groups 3-7 were administered subcutaneous 1,2-dimethylhydrazine (20 mg/kg body weight) once a week for 15 consecutive weeks. In addition, group 4 (pre-initiation), 5 (initiation), 6 (post-initiation), and 7 (entire period) received pronyl-lysine (2 mg/kg body weight orally) everyday. At the end of 34 weeks, indicative markers of lipid peroxidation and changes in antioxidant defense system were measured in circulation. The results showed that 1,2-dimethylhydrazine significantly increased total aberrant crypt foci formation, total number of dysplastic foci, beta-catenin accumulated crypts and proliferating cell nuclear antigen labeling index in the colon, and enhanced lipid peroxidation markers and decreased enzymic antioxidant activities in the plasma and erythrocyte lysate as compared with untreated controls. Pronyl-lysine supplementation significantly reversed the changes as compared with the rats treated with 1,2-dimethylhydrazine alone. The effect of pronyl-lysine was more pronounced when supplemented throughout the study period (group 7). These findings suggest that pronyl-lysine suppresses 1,2-dimethylhydrazine-induced colon carcinogenesis effectively.

Ursolic acid and oleanolic acid suppress preneoplastic lesions induced by 1,2-dimethylhydrazine in rat colon

Ursolic acid (UA) and oleanolic acid (OA) are pentacyclic triterpenoid compounds found in plants used in the human diet and in medicinal herbs, in the form of aglycones or as the free acid. These compounds are known for their hepatoprotective, anti-inflammatory, antimicrobial, hypoglycemic, antimutagenic, antioxidant, and antifertility activities. In the present study, we evaluated the effects of UA and OA on the formation of 1,2-dimethyl-hydrazine (DMH)-induced aberrant crypt foci (ACF) in the colon of the male Wistar rat. The animals received subcutaneous (sc) injections of DMH (40 mg/kg body weight) twice a week for two weeks to induce ACF. UA, OA and a mixture of UA and OA were administered to the rats five times a week for four weeks by gavage at doses of 25 mg/kg body weight/day each, during and after DMH treatment. All animals were sacrificed in week 5 for the evaluation of ACF. The results showed a significant reduction in the frequency of ACF in the group treated with the triterpenoid compounds plus DMH when compared to those treated with DMH alone, suggesting that UA and OA suppress the formation of ACF and have a protective effect against colon carcinogenesis.

Modifying effect of dietary sesaminol glucosides on the formation of azoxymethane-induced premalignant lesions of rat colon

Sesame, which has been reported to have preventive effects against various disordered conditions, contains small quantities of lignans and several precursors to them such as sesaminol glucosides (SG). The lignans have the potent antioxidative activity and are suggested to have chemopreventive property. In the present study, we evaluated the modulating effect of SG on the development of colon precancerous lesions, aberrant crypt foci (ACF) and beta-catenin-accumulated crypts (BCAC), in the azoxymethane (AOM)-induced short-term model using male F344 rats. Dietary SG (500 ppm) significantly decreased the incidence of AOM-induced ACF when compared to the control (P<0.01). The incidences of AOM-induced BCAC in the SG-treated groups (250 or 500 ppm) were also significantly lower than that of the control group (P<0.01). Interestingly, administration of 500 ppm SG clearly decreased serum triglyceride level and mRNA expression of intestinal fatty acid-binding protein in the colonic mucosa, as compared to the control. These findings indicate that dietary SG inhibits AOM-induced carcinogenesis and suggest SG as a possible chemopreventive agent.

Modifying effects of Terminalia catappa on azoxymethane-induced colon carcinogenesis in male F344 rats

The modifying effects of dietary administration of an herb, Terminalia catappa (TC), were investigated on rat colon carcinogenesis induced by a carcinogen azoxymethane (AOM). The number of aberrant crypt foci (ACF) and beta-catenin accumulated crypts (BCACs) in the colon, and proliferating cell nuclear antigen (PCNA) labelling index in the colonic epithelium were examined in a total of 36 male F344 rats. All animals were randomly divided into five experimental groups (4-10 rats in each group). At 6 weeks of age, rats in groups 1, 2 and 3 were given s.c. injections of AOM once a week for 2 weeks at a concentration of 20 mg/kg body weight. One week before the first injection of AOM, rats in groups 2 and 3 were fed a diet containing 0.02 and 0.1% TC, respectively, throughout the experiment. Rats in group 4 were fed a diet containing 0.1% TC. Rats in group 5 were served as untreated controls. All animals were sacrificed at the experimental week 5 after the start of the experiment. Oral administration of TC at both doses significantly decreased the numbers of both ACF/colon/rat (P<0.05 for 0.02% TC, P<0.005 for 0.1% TC) and BCAC/cm/rat (P<0.05 for both 0.02 and 0.1% TC), when compared with the control group (group 1). Colonic PCNA labelling index in groups 2 and 3 was also significantly lower than that in group 1 (P<0.001 for 0.02% TC, P<0.005 for 0.1% TC). These results suggest that TC has a potent short-term chemopreventive effect on biomarkers of colon carcinogenesis and this effect may be associated with the inhibition of the development of ACF and BCACs.

Significance and role of early-lesions in experimental colorectal carcinogenesis

Preneoplastic or precancerous lesions in the large bowel have attracted much attention, and aberrant crypt foci (ACF) topographically identified in the colonic mucosa have found application as effective endpoint lesions for detection of chemopreventive agents as well as carcinogenic risk assessment of environmental agents. While many ACF are regarded as hyperplastic in nature, lacking the potential lesion to give rise to neoplasia, a subset termed dysplastic ACF, or newly identified "mucin depleted foci (MDF)", and "beta-catenin accumulated crypts (BCAC)" are suggested to be more reliably related to colorectal tumorigenesis in rodents. ACF and MDF can be visualized on the surface of colonic mucosa and BCAC were recently identified by our laboratory in rodents en face in cross sections. In particular, BCAC having a similar pattern of beta-catenin gene mutation to that observed in colonic carcinomas appear to be direct precursors. This review provides a review and discussion of the relevant literature relative to early lesions in colorectal carcinogenesis.

Histological and immunohistochemical observations of mucin-depleted foci (MDF) stained with Alcian blue, in rat colon carcinogenesis induced with 1,2-dimethylhydrazine dihydrochloride

The usefulness of mucin-depleted foci (MDF), which have recently been proposed as a new preneoplastic biomarker in rat colon carcinogenesis, was histologically investigated in rat colonic tissues treated with 1,2-dimethylhydrazine dihydrochloride (DMH). The relationship among aberrant crypt foci (ACF), MDF and beta-catenin accumulated crypts (BCAC) was examined by comparing the corresponding computer-captured images. Twelve male F344 rats were given DMH s.c. at a dose of 40 mg/kg body weight, once a week for 2 weeks, and randomly divided into two groups. Rats in group 1 were given normal drinking water, while those in group 2 were given drinking water containing indomethacin (IND) at 16 ppm for 6 weeks. All animals were sacrificed 8 weeks after the first DMH treatment. The resected colons were fixed in 10% formalin, and stained with Alcian blue for observation of ACF and MDF. Histological and immunohistochemical analysis revealed that the numbers of ACF, MDF and overlapping lesions in group 2 (treated with IND) were significantly decreased, compared with those in group 1. The number of BCAC in group 2 was also significantly lower than that in group 1. The reduction (61.5%) of MDF by IND was much greater than that (29.3%) of ACF. Analyses of the computer-captured images indicated that MDF had more frequent dysplastic changes and overexpression of beta-catenin than did ACF. MDF having over 4 crypts or MDF with the appearance of ACF corresponded well to BCAC. These results suggest that MDF may be useful as an early biomarker in colon carcinogenesis.