Anonna crassiflora suppresses colonic carcinogenesis through its antioxidant effects, bioactive amines, and phenol content in rats.

Marolo (Annona crassiflora) is an underutilized Brazilian Cerrado fruit with few reports in the literature about its bioactive compounds and functional properties. In this context, the chemoprevention against the carcinogen 1,2-dimethylhydrazine (DMH)-induced pre-neoplastic lesions in Wistar rat colon was investigated and correlated with marolo's antioxidant activity and the contents of phenolic compounds and bioactive amines. Total phenolic compounds (TPC) and total flavonoids compounds (TFC) were determined in the marolo pulp extract by spectrophotometric and Ultra-Performance Liquid Chromatography and diode array detection (UPLC-DAD) analysis. Free bioactive amines were determined by High Performance Liquid Chromatography and fluorescence detection (HPLC-FLD) after post column derivatization with o-phthalaldehyde. In addition, the in vitro antioxidant activity was determined by DPPH, and ABTS. Wistar rats were treated orally with marolo pulp at 0.7, 1.4 and 2.8 g/kg body weight (bw)/day added to a standard ration. Four subcutaneous injections of DMH (40 mg/kg bw) were used to induce a pre-neoplastic lesion that was assessed by the aberrant crypt foci (ACF) assay. The marolo pulp (fresh weigh) showed high content of total phenolic compounds (9.16 mg GAE/g), with predominance of chlorogenic acid (1.86 µg/g) and epicatechin (0.99 µg/g), and total flavonoids (7.26 mg CE/g), ∼85 % of the TPC. The marolo pulp had significant contents of tyramine (31.97 mg/kg), putrescine (20.65 mg/kg), and spermidine (6.32 mg/kg). The marolo pulp inhibited (p < 0.05) pre-neoplastic lesions induced by DMH administration at the all concentrations tested. These findings indicate that marolo pulp has a colon carcinogenesis chemopreventive effect, which could be due to, at least in parts, its antioxidant action associated with its phenolics and flavonoids content as well of spermidine.

A synthetic resveratrol-curcumin hybrid derivative exhibits chemopreventive effects on colon pre-neoplastic lesions by targeting Wnt/ß-catenin signaling, anti-inflammatory and antioxidant pathways.

ABSTRACT: Based on the effectiveness of resveratrol and curcumin in carcinogenesis, (E)-3-(4-hydroxy-3-methoxyphenyl)-N'-((E)-4-methoxybenzylidene) acrylohydrazide (PQM-162), curcumin-resveratrol hybrid derivative, was designed by molecular hybridization using a hydrazone functionality as a spacer moiety between pharmacophoric fragments inspired by the parent compounds. OBJECTIVES: The present study aimed to evaluate the chemopreventive effects of the hybrid against pre-neoplastic lesions induced in the colon of rodents. METHODS: The doses were determined based on the reduction in DNA damage induced by doxorubicin [15 mg/kg body weight (b.w.)] in peripheral blood of Swiss mice. Doses of 8, 16, 32, and 64 mg/kg b.w. were antimutagenic. For the evaluation of pre-neoplastic lesions in the colon, Wistar rats were treated with PQM-162 at doses of 0.5, 1, and 2 mg/kg b.w. for 6 weeks using three approaches: simultaneous treatment, pre-treatment, and post-treatment. Pre-neoplastic lesions were induced with 1,2 dimethylhydrazine (160 mg/kg b.w.). KEY FINDINGS: PQM-162 reduced the formation of aberrant crypt foci in the simultaneous treatment and post-treatment. TNF-α and COX-2 mRNA levels decreased, while Nrf2 mRNA levels increased. PQM-162 also reduced the expression of COX-2, PCNA, and ß-catenin protein markers and increased Nrf2 expression. CONCLUSION: Our findings suggest a chemopreventive potential of PQM-162 in colorectal carcinogenesis, which acts on anti-inflammatory, antioxidant, and cell proliferation pathways.

Hypericin, a medicinal compound from St. John's Wort, inhibits genotoxicity induced by mutagenic agents in V79 cells.

This study evaluated the cytotoxic, genotoxic, and the modulatory effects on DNA damage of hypericin in Chinese hamster lung fibroblasts (V79 cells). The hypericin is a natural polycyclic quinone, mainly extracted from St. John's Wort (Hypericum perforatum L.). Along with hyperforin, the hypericins are responsible for the antidepressant activity of St. John's Wort. Cytotoxicity was assessed by the XTT colorimetric assay and the nuclear division index (NDI). The genotoxic activity was studied by the micronucleus test at concentrations of 30, 60, 120, and 240 µg/mL. Mutagenic agents, methyl methanesulfonate (MMS, 44 µg/mL), doxorubicin (DXR, 0.5 µg/mL), and etoposide (VP16, 1 µg/mL) were used in combination with different concentrations of hypericin in order to evaluate the modulatory effect on DNA damage. Results showed that the hypericin was cytotoxic at concentrations above 156.2 µg/mL and genotoxic above 120 µg/mL. The hypericin significantly reduced DNA damage frequency induced by DXR, at concentrations of 30 and 60 µg/mL, and MMS at a concentration of 30 µg/mL, but was unable to reduce damage when combined with VP-16. These results demonstrate the non-photoactivated hypericin toxicological safety limits, its protective effect on DNA damage and provide a basis for future studies that may characterize better its chemopreventive mechanism.

Styrax camporum, a typical species of the Brazilian cerrado, attenuates DNA damage, preneoplastic lesions and oxidative stress in experimental rat colon carcinogenesis.

Styrax camporum Pohl, a typical species from the Brazilian cerrado, commonly known as "benjoeiro", is used to treat gastroduodenal diseases. In previous studies carried out by our research group, hydroalcoholic extract of S. camporum stems (SCHE) exhibited antigenotoxic and antiproliferative effects. For a comparative analysis of the chemopreventive effect of SCHE, the aim of this study was to investigate the influence of SCHE against carcinogen 1,2-dimethylhydrazine (DMH)-induced DNA damage and pre-neoplastic lesions in Wistar rat colon. Animals were treated orally with SCHE at 250, 500 or 1000 mg/kg body weight in conjunction with a subcutaneous injection of DMH. DNA damage was assessed using the comet assay while tpre-neoplastic lesions by aberrant crypt foci (ACF) assay. The following hepatic oxidative stress markers were determined including activities of catalase (CAT) and glutathione S-transferase (GST) as well as levels of reduced glutathione (GSH) and malondialdehyde (MDA). Treatment with SCHE was not genotoxic or carcinogenic at the highest dose tested (1000 mg/kg b.w.). The extract effectively inhibited DNA damage and pre-neoplastic lesions induced by DMH administration at all concentrations tested. Measurement of CAT, and GST activities and levels of GSH showed that SCHE did not reduce oxidative processes. In contrast, treatment with SCHE (1000 mg/kg b.w.) decreased liver MDA levels. Taken together, these findings suggested the chemopreventive effect attributed to SCHE in colon carcinogenesis, may be related to its capacity to inhibit DNA damage as well as an antioxidant action associated with its chemical constituents egonol and homoegonol.

Antigenotoxicity of Roupala montana extract in the mouse micronucleus and comet assays.

Roupala montana Aubl. (Proteaceae) is a typical savannah species and native to tropical South America that has a moderate mortality for adult forms of Schistossoma mansoni. Because this species has been little studied, the aim of this investigation was to evaluate the influence of R. montana extract on DNA damage induced by methyl methanesulfonate (MMS) in peripheral blood cells and liver of Swiss mice using the micronucleus and comet assay, respectively. R. montana dichloromethane extract was prepared from a stock solution (0.5 mg/mL) in 5% dimethyl sulfoxide in water. Animals received a single dose of different concentrations of R. montana (5, 10 and 20 mg/kg body weight) by gavage (0.5 mL/animal). For antigenotoxicity assessment, different concentrations of R. montana were administered simultaneously with MMS diluted in water (40 mg/kg, intraperitoneally; 0.3 mL/animal). Peripheral blood and hepatocyte samples were obtained 48 and 24 h after treatment, respectively. Results showed that R. montana administered alone indicated the absence of genotoxicity in the mouse micronucleus or comet assay. On the other hand, administration of different doses of R. montana concomitantly with MMS led to a significant reduction in frequency of micronucleated polychromatic erythrocytes and DNA damage, when compared to the group treated only with MMS. Further, for the micronucleus assay, the gradual increase of R. montana concentration led to a proportional increase in the reduction of genotoxicity induced by MMS, indicating a dose-response relationship.

In vivo protective activity of Styrax camporum hydroalcoholic extract against genotoxicity induced by doxorubicin and methyl methanesulfonate in the micronucleus and comet assays.

Styrax camporum Pohl is a tall shrub or a tree with small white flowers, which grows in the states of São Paulo and Minas Gerais and is popularly used for the treatment of gastroduodenal diseases. Considering this last fact, the aim of this study was to evaluate the genotoxic potential of S. camporum hydroalcoholic extract and its influence on genotoxicity induced by doxorubicin and methyl methanesulfonate in Swiss mice using the micronucleus and comet assays, respectively. The animals were treated by gavage with different doses of the extract (250, 500, and 1000 mg/kg body weight). For antigenotoxicity assessment, different doses of the S. camporum extract were administered simultaneously with doxorubicin (micronucleus test; 15 mg/kg) and methanesulfonate (comet assay; 40 mg/kg). The results showed that the S. camporum extract itself was not genotoxic in the mouse micronucleus or comet assay. The number of micronucleated polychromatic erythrocytes was significantly lower in animals treated with the S. camporum extract and doxorubicin when compared to animals treated only with doxorubicin. In the comet assay, the S. camporum extract, at the doses tested, significantly reduced the extent of DNA damage in liver cells induced by methanesulfonate. The putative activity of the active compounds of S. camporum extract may explain the effect of this plant on genotoxicity induced by doxorubicin and methanesulfonate.

Evaluation of the frequency of micronuclei in exfoliated cells from oral lesions previously identified by toluidine blue.

OBJECTIVE: Patients using a removable prosthesis are susceptible to a variety of oral lesions that may progress to cancer. Toluidine blue (TB) staining is used to identify premalignant lesions, but the results are still controversial. Since micronuclei (MN) are a biomarker of genetic instability, the objective of this study was to determine the frequency of MN in white lesions of the oral mucosa and to compare the results with those of the TB test. STUDY DESIGN: The study included 20 removable prosthesis users with white lesions that were previously classified as toluidine positive or negative. The frequency of MN was evaluated in exfoliated cells from lesions and normal mucosa. Nuclear anomalies were also registered. RESULTS: A significant increase (p < 0.05) in the frequency of MN was observed in exfoliated cells from lesions compared to normal mucosal cells, and no relationship was seen with TB staining. Lifestyle factors or gender did not influence the results. CONCLUSIONS: The frequency of MN is a sensitive biomarker and can be used to predict genomic instability in white oral lesions. The MN assay may serve as a good parameter in the battery of tests used to identify high-risk individuals, contributing to the identification of the biological conditions of oral lesions.