Influence of the Phenological State of in the Antioxidant Potential and Chemical Composition of Ageratina havanensis. Effects on the P-Glycoprotein Function.

Ageratina havanensis (Kunth) R. M. King & H. Robinson is a species of flowering shrub in the family Asteraceae, native to the Caribbean and Texas. The aim of this work was to compare the quantitative chemical composition of extracts obtained from Ageratina havanensis in its flowering and vegetative stages with the antioxidant potential and to determine the effects on P-glycoprotein (P-gp) function. The quantitative chemical composition of the extracts was determined quantifying their major flavonoids by UPLC-ESI-MS/MS and by PCA analysis. The effects of the extracts on P-gp activity was evaluated by Rhodamine 123 assay; antioxidant properties were determined by DPPH, FRAP and inhibition of lipid peroxidation methods. The obtained results show that major flavonoids were present in higher concentrations in vegetative stage than flowering stage. In particular, the extracts obtained in the flowering season showed a significantly higher ability to sequester free radicals compared to those of the vegetative season, meanwhile, the extracts obtained during the vegetative stage showed a significant inhibitory effect against brain lipid peroxidation and a strong reductive capacity. This study also showed the inhibitory effects of all ethanolic extracts on P-gp function in 4T1 cell line; these effects were unrelated to the phenological stage. This work shows, therefore, the first evidence on: the inhibition of P-gp function, the antioxidant effects and the content of major flavonoids of Ageratina havanensis. According to the obtained results, the species Ageratina havanensis (Kunth) R. M. King & H. Robinson could be a source of new potential inhibitors of drug efflux mediated by P-gp. A special focus on all these aspects must be taking into account for future studies.

Polyphenolic Fraction Obtained From Thalassia testudinum Marine Plant and Thalassiolin B Exert Cytotoxic Effects in Colorectal Cancer Cells and Arrest Tumor Progression in a Xenograft Mouse Model.

Marine plants are important sources of pharmacologically active metabolites. The aim of the present work was to evaluate the cytotoxic and antitumor activity of a polyphenolic fraction obtained from Thalassia testudinum marine plant and thalassiolin B in human colorectal cancer cells. Human cancer cell lines, including HCT15, HCT116, SW260, and HT29 were treated with tested products for cytotoxicity evaluation by crystal violet assay. The potential proapoptotic effect of these natural products was assessed by flow cytometry in HCT15 cells at 48 h using Annexin V-FITC/propidium iodide. In addition, reactive oxygen species (ROS) generation was measured by fluorescence using DCFH-DA staining, and sulfhydryl concentration by spectrophotometry. The in vivo antitumor activity of the polyphenolic fraction (25 mg/kg) was evaluated in a xenograft model in nu/nu mice. In vivo proapoptotic effect was also evaluated by immunohistochemistry using anti-caspase 3 and anti-Bcl-2 antibodies. The results showed that tested products exert colorectal cancer cell cytotoxicity. Besides, the tested products induced a significant increase (p < 0.05) of intracellular ROS generation, and a depletion of sulfhydryl concentration in HCT15 cells. The polyphenolic fraction arrested tumor growth and induced apoptosis in the xenograft mice model. These results demonstrate the cytotoxic activity of T. testudinum metabolites associated, at least, with ROS overproduction and pro-apoptotic effects. Here we demonstrated for the first time the antitumor activity of a T. testudinum polar extract in a xenograft mice model. These results suggest the potential use of T. testudinum marine plant metabolites as adjuvant treatment in cancer therapy.

Assessment of the cytotoxic potential of an aqueous-ethanolic extract from Thalassia testudinum angiosperm marine grown in the Caribbean Sea.

OBJECTIVES: Reported antioxidant, anti-inflammatory and neuroprotective properties for one aqueous-ethanolic extract from Thalassia testudinum which grows in the Caribbean Sea compelled us to explore about extract cytotoxic effects. METHODS: Cell viability was assayed on tumour (HepG2, PC12, Caco-2 and 4T1) and non-tumour (VERO, 3T3, CHO, MCDK and BHK2) cell lines. The extract effects upon primary cultures of rat and human hepatocytes and human lymphocytes were assayed. KEY FINDINGS: The extract exhibited cytotoxicity against cancer cells compared to normal cells, and the IC50 values were 102 µg/ml for HepG2, 135 µg/ml for PC12, 165 µg/ml for Caco-2 and 129 µg/ml for 4T1 cells after 48 h, whereas IC50 could not be calculated for normal cells. Additional data from a high-content screening multiparametric assay indicated that after 24-h exposure, the extract (up to 100 µg/ml) induced death in HepG2 cells through oxidative stress-associated mechanism, DNA damage and hypercalcaemia. Comet assay corroborated extract-induced DNA damage. CONCLUSIONS: Thalassia testudinum extract is more cytotoxic and produced more DNA damage on human hepatoma cells than to other non-tumour cells. A possible mechanism is suggested for extract-induced cytotoxicity based on oxidative stress, nuclear damage and hypercalcaemia in HepG2 cells. T. testudinum may be a source for antitumour agents.

Gas Chromatography-Mass Spectrometry Analysis of Ulva fasciata (Green Seaweed) Extract and Evaluation of Its Cytoprotective and Antigenotoxic Effects.

The chemical composition and biological properties of Ulva fasciata aqueous-ethanolic extract were examined. Five components were identified in one fraction prepared from the extract by gas chromatography-mass spectrometry, and palmitic acid and its ethyl ester accounted for 76% of the total identified components. Furthermore, we assessed the extract's antioxidant properties by using the DPPH, ABTS, and lipid peroxidation assays and found that the extract had a moderate scavenging effect. In an experiment involving preexposition and coexposition of the extract (1-500 µg/mL) and benzo[a]pyrene (BP), the extract was found to be nontoxic to C9 cells in culture and to inhibit the cytotoxicity induced by BP. As BP is biotransformed by CYP1A and CYP2B subfamilies, we explored the possible interaction of the extract with these enzymes. The extract (25-50 µg/mL) inhibited CYP1A1 activity in rat liver microsomes. Analysis of the inhibition kinetics revealed a mixed-type inhibitory effect on CYP1A1 supersome. The effects of the extract on BP-induced DNA damage and hepatic CYP activity in mice were also investigated. Micronuclei induction by BP and liver CYP1A1/2 activities significantly decreased in animals treated with the extract. The results suggest that Ulva fasciata aqueous-ethanolic extract inhibits BP bioactivation and it may be a potential chemopreventive agent.

Photoprotecting action and phytochemical analysis of a multiple radical scavenger lipophilic fraction obtained from the leaf of the seagrass Thalassia testudinum.

The apolar fraction F1 of Thalassia testudinum was chemically characterized by gas chromatography-mass spectrometry, which led to the identification of 43 metabolites, all of them reported for the first time in the genus Thalassia. More than 80% of the F1 composition was constituted by aromatic metabolites including the major components 1,1-bis(p-tolyl)ethane (6.0%), 4,4'-diisopropylbiphenyl (4.8%) and a 1,1-bis(p-tolyl)ethane isomer (4.7%). This lipophilic fraction was assayed for its antioxidant effects and skin protective action. In vitro assays showed that F1 strongly scavenged DPPH* (IC(50) 312.0 ± 8.0 µg mL(-1)), hydroxyl (IC(50) 23.8 ± 0.5 µg mL(-1)) and peroxyl radical (IC(50) 6.6 ± 0.3 µg mL(-1) ), as well as superoxide anion (IC(50) 50.0 ± 0.7 µg mL(-1)). Also, F1 markedly inhibited the spontaneous lipid peroxidation (LPO) in brain homogenates (IC(50) 93.0 ± 6.0 µg mL(-1)) and the LPS-stimulated nitrite generation on RAW624.7 macrophages (58.6 ± 3.2%, 400 µg mL(-1)). In agreement with these findings, its topical application at 250 and 500 µg cm(-2) strikingly reduced skin damage on mice exposed to acute UVB radiation by 45% and 70%, respectively and significantly attenuated the LPO developed following the first 48 h after acute exposure to UVB irradiation, as manifested by the decreased malondialdehide level and by the increased of reduced gluthatione content. Our results suggest that F1 may contribute to skin repair by attenuating oxidative stress due to its antioxidant activity.

Protective effects of Mangifera indica L extract (Vimang), and its major component mangiferin, on iron-induced oxidative damage to rat serum and liver.

In vivo preventive effects of a Mangifera indica L extract (Vimang) or its major component mangiferin on iron overload injury have been studied in rats given respectively, 50, 100, 250 mg kg(-1) body weight of Vimang, or 40 mg kg(-1) body weight of mangiferin, for 7 days prior to, and for 7 days following the administration of toxic amounts of iron-dextran. Both Vimang or mangiferin treatment prevented iron overload in serum as well as liver oxidative stress, decreased serum and liver lipid peroxidation, serum GPx activity, and increased serum and liver GSH, serum SOD and the animals overall antioxidant condition. Serum iron concentration was decreased although at higher doses, Vimang tended to increase it; percent tranferrin saturation, liver weight/body mass ratios, liver iron content was decreased. Treatment increased serum iron-binding capacity and decreased serum levels of aspartate-amine transferase (ASAT) and alanine-amine transferase (ALAT), as well as the number of abnormal Kupffer cells in iron-loaded livers. It is suggested that besides acting as antioxidants, Vimang extract or its mangiferin component decrease liver iron by increasing its excretion. Complementing earlier in vitro results from our group, it appears possible to support the hypothesis that Vimang and mangiferin present therapeutically useful effects in iron overload related diseases.