Claudia Masrouah Jamal

Determination of the antimutagenicity of an aqueous extract of Rhizophora mangle L. (Rhizophoraceae), using in vivo and in vitro test systems

An aqueous extract of Rhizophora mangle L. bark is used as raw material in pottery making in the State of Espirito Santo, Brazil. This extract presents large quantities of tannins, compounds possessing antioxidant properties. Tannin antioxidant activity, as a plant chemical defense mechanism in the process of stabilizing free radicals, has been an incentive to studies on anti-mutagenicity. The present work aimed to evaluate possible antimutagenic activity of a R. mangle aqueous extract, using the Allium cepa test-system and micronuclear (MN) assay with blockage of cytokinesis in Chinese hamster ovary cells (CHO-K1). The Allium cepa test-system indicated antimutagenic activity against the damage induced by the mutagenic agent methyl methanesulfonate. A reduction in both MN cell frequency and chromosome breaks occurred in both the pre and post-treatment protocols. The MN testing of CHO-K1 cells revealed anti-mutagenic activity of the R. mangle extract against methyl methanesulfonate and doxorubicin in pre, simultaneous and post-treatment protocols. These results suggest the presence of phyto-constituents in the extract presenting demutagenic and bio-antimutagenic activities. Since the chemical constitution of Rhizophora mangle species presents elevated tannin content, it is highly probable that these compounds are the antimutagenic promoters themselves.

Evaluation of the genotoxicity/mutagenicity and antigenotoxicity/antimutagenicity induced by propolis and Baccharis dracunculifolia, by in vitro study with HTC cells.

The ethanolic extract of propolis, especially the Brazilian green type, is widely and mainly used for therapeutic purposes despite the lack of knowledge about its effects and its cellular mode of action. This type of propolis, derived from Baccharis dracunculifolia (alecrim-do-campo), has been extensively commercialized and the consumers use it to enhance health. This work aimed to assess the genotoxic/mutagenic and antigenotoxic/antimutagenic potentials of the ethanolic extracts of Brazilian green propolis and of B. dracunculifolia, on mammalian cells. It was not observed genotoxic and mutagenic effects by both extracts. After evaluate the exposure of the cells to each extract with a recognized mutagen, simultaneously, the results showed a significant reduction on DNA damage. The experiment carried out with a pre-incubation period was more effective than without incubation test, showing that the tested extracts were able to inactivate the mutagen before it could react with the DNA.

Antigenotoxicity and antimutagenicity of ethanolic extracts of Brazilian green propolis and its main botanical source determined by the Allium cepa test system.

Abstract Brazilian green propolis is a resinous substance prepared by bees from parts of the plant Baccharis dracunculifolia. As it possess several biological properties, this work assessed the cytotoxic/anticytotoxic, genotoxic/antigenotoxic and mutagenic/antimutagenic potential of ethanolic extracts of Brazilian green propolis (EEGP) and of B. dracunculifolia (EEBD), by means of the Allium cepa test system. The effects were evaluated by assessing the chromosomal aberrations (CA) and micronuclei (MN) frequencies on meristematic and F1 generation cells from onion roots. Chemical analyses performed with the extracts showed differences in flavonoid quality and quantity. No genotoxic or mutagenic potential was detected, and both extracts were capable of inhibiting cellular damage caused by methyl methanesulfonate (MMS) treatment, reducing the frequencies of CA and MN. By these data, we can infer that, independent of their flavonoid content, the extracts presented a protective effect in A. cepa cells against the clastogenicity of MMS.

Chemical analysis and toxicity of seaweed extracts with inhibitory activity against tropical fruit anthracnose fungi

BACKGROUND Banana and papaya are among the most important crops in the tropics, with a value amounting to millions of dollars per year. However, these fruits suffer significant losses due to anthracnose, a fungal disease. It is well known that certain seaweed extracts possess antifungal activity, but no published data appear to exist on the practical application of this property. In the present study, five organic Brazilian seaweed extracts were screened for their activity against banana and papaya anthracnose fungi. Furthermore, cytotoxic and mutagenic effects of the extracts were evaluated by the brine shrimp lethality assay and the Allium cepa root-tip mutagenicity test respectively, while their major components were identified by gas chromatography/mass spectrometry. RESULTS Strong fungus-inhibitory effects of Ochtodes secundiramea and Laurencia dendroidea extracts were observed on both papaya (100 and 98% respectively) and banana (89 and 78% respectively). This impressive activity could be associated with halogenated terpenes, the major components of both extracts. Only Hypnea musciformis extract showed cytotoxic and mutagenic effects. CONCLUSION The results of this study suggest the potential use of seaweed extracts as a source of antifungal agents with low toxicity to control anthracnose in papaya and banana during storage.

Anti-Helicobacter pylori effect of the antioxidant extract from Baccharis trimera Less. (DC)

One of the main risk factors for the development of stomach ulcers and cancer is infection with Helicobacter pylori bacteria, which is accompanied by considerable oxidative stress. Therefore, the aim of the present study was to assess the anti-Helicobacter pylori activity of B. trimera hydroalcoholic extract (HE) and aqueous (AqF), hexanic (HxF), and acetonitrile/chloroform (ACF) fractions, as well as their oxidant potentials. A preliminary phytochemical screening was carried out. Anti-Helicobacter pylori activity was assessed using a microdilution assay. After exposure to the investigated samples, the bacterial morphology was analysed under a scanning electron microscope (SEM). The antioxidant activity was evaluated in hydrogen peroxide (H 2 O 2 ), superoxide anion (O 2 •- ), hypochlorous acid (HOCl), hydroxyl radical (HO • ) and nitric oxide (NO • ) assays. The highest concentration of polyphenols was found in HE, the highest concentration of flavonoids was found in ACF, and of tannins was found in AqF. In the anti-H. pylori assay, the MIC 90 was 512 µg/mL for HE and 1024 µg/mL for ACF, which was bactericidal. The SEM showed morphological alterations such as cell lysis in the tested samples. In the O 2 •- inhibition assay, the EC 50 of AqF was 5.85 ± 0.86. In the HOCl, HO • radical, NO • and H 2 O 2 scavenging assays, the best results were in ACF, with an EC 50 of 15.50 ± 0.80, 2.90 ± 0.48, 132.13 ± 7.38 and 66.70 ± 2.30 µg/mL, respectively. The analyses indicate that compounds present in B. trimera, especially in HE and ACF, are promising candidates for the prevention and treatment of diseases caused by H. pylori.