Protective effect of kavain in meristematic cells of Allium cepa L.

Kavain is one of the main kavalactones of Piper methysticum (Piperaceae) with anxiolytic, analgesic, and antioxidant activities. Therefore, the aim of the study was to evaluate the cytotoxic, mutagenic, and antimutagenic potential of kavain in Allium cepa cells. Roots of A. cepa were transferred to the negative (2% acetone) and positive (10 µg/mL of Methylmethanesulfonate, MMS) controls and to the concentrations of kavain (32, 64 and 128 µg/mL) for 48 h. A total of 5,000 meristematic cells were analyzed under an optical microscope to determine the mitotic index, mean number of chromosomal alterations and percentage of damage reduction. Data were analyzed by Kruskal-Wallis test (p <0.05). All concentrations of kavain were not cytotoxic and did not show significant chromosomal changes when compared to 2% acetone. Kavain showed a cytoprotective effect in the pre (128 µg/mL) and in the post-treatment (32 and 64 µg/mL) and reduced damage against the mutagenic action of MMS in all concentrations of the pre and simultaneous and at the highest of post (128 µg/mL). Kavain promoted a significant reduction in micronuclei, nuclear buds and chromosomal losses in relation to MMS. The observed data indicate the importance of kavain for the inhibition of damage and chemoprevention.

Acute high-intensity interval exercise versus moderate-intensity continuous exercise in heated water-based on hemodynamic, cardiac autonomic, and vascular responses in older individuals with hypertension.

OBJECTIVES: This crossover study design aimed to assess hemodynamic, cardiac autonomic, and vascular responses to high-intensity interval (HIIE) vs moderate-intensity continuous exercise (MICE) in older individuals with hypertension. METHODS: Twenty (67 ± 7 y) older individuals with hypertension were randomly assigned to perform HIIE, MICE, or control (CON) sessions in the heated swimming pool (30-32°C). Blood pressure (BP), arterial stiffness, endothelial reactivity, and heart rate variability (HRV) were measured pre, post, and 45 min (recovery) after each intervention followed by 24-h ambulatory BP and HRV. RESULTS: One single aerobic exercise session was not effective to provoke post-exercise hypotension and vascular improvements. HIIE was superior to MICE and CON to increasing parasympathetic modulation at post and recovery. Exercise sessions showed to disturb the autonomic system at nighttime compared to CON. CONCLUSIONS: These results may have important implications in water-based therapy and the elderly with hypertension.

Phytochemical and antioxidant characterization, cytogenotoxicity and antigenotoxicity of the fractions of the ethanolic extract of in Poincianella bracteosa (Tul.) L.P. Queiroz.

POINCIANELLA BRACTEOSA: has been widely used in folk medicine to treat catarrhal infections, diarrhea, and anemia; however, phytochemical and toxicogenetic data are still lacking. The objective of this study was to examine the phytochemical and antioxidant characteristics as well as assess cytogenotoxicity and antigenotoxicity in hexane (HF), ether (EF) and ethyl acetate (AF) fractions of P. bracteosa leaves using Allium cepa bioassay. Phytochemical analysis revealed the presence of saponins and phenolic groups. EF fraction contained a higher content of total phenolics (441.23 ± 1.82 mg GAE/g), while HF fraction showed a higher content of total flavonoids (84.77 ± 5.33 mg QE/g). Higher antioxidant activity was observed in EF (EC50 25.06 ± 0.07 µg/ml). Cytotoxic effect was verified for all fractions, but no chromosomal alterations were observed in the A. cepa assay. With respect to antigenotoxicity, the protective effect of EF and AF fractions was attributed to as evidenced by the modulation of mutagenic action of methyl methanesulfonate (MMS), mainly by inhibiting the development of micronuclei. Among the fractions, EF was considered the most promising, as it exhibited higher antioxidant activity, was not genotoxic, exerted protective activity against the damage induced by MMS and also presented cytotoxic activity, a desired quality in the search for natural anticarcinogenic compounds.

Zebrafish embryo sensitivity test as in vivo platform to anti-Shiga toxin compound screening.

Shiga toxin-producing Escherichia coli (STEC) pathotype secretes two types of AB5 cytotoxins (Stx1 and Stx2), responsible for complications such as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS) in infected patients, which could lead to sequels and death. Currently, there is no effective treatment against the cytotoxic effect of these toxins. However, in order to approve any therapy molecule, an animal experiment is required in order to evaluate the efficacy and safety of therapeutic approaches. The use of alternative small host models is growing among human infectious disease studies, particularly the vertebrate zebrafish model, since relevant results have been described for pathogen-host interaction. In this sense, the present work aimed to analyze the toxic effect of Shiga toxins in zebrafish embryo model in order to standardize this method in the future to be used as a fast, simple, and efficient methodology for the screening of therapeutic molecules. Herein, we demonstrated that the embryos were sensitive in a dose-dependent manner to both Stx toxins, with LD50 of 22 µg/mL for Stx1 and 33 µg/mL for Stx2, and the use of anti-Stx polyclonal antibody abolished the toxic effect. Therefore, this methodology can be a rapid alternative method for selecting promising compounds against Stx toxins, such as recombinant antibodies.

Hypotensive Effect of Heated Water-based Exercise in Older Individuals with Hypertension.

Blood pressure (BP) and hemodynamic response to heated water-based (HEx) vs. land-based exercise (LEx) were assessed in 15 (6 men) older hypertensives (age 66.4±4.9 yr) under pharmacological treatment. Participants were randomly assigned to perform 30 min of moderate-intensity HEx (walking inside the pool), LEx (walking on a treadmill) and non-exercise control (CON) intervention. Resting BP, arterial stiffness, endothelial reactivity and heart rate variability (HRV) were measured before, immediately after, and 45 min after interventions. 24-h ambulatory BP monitoring was performed after interventions. Resting systolic (but not diastolic) BP reduced 9.9±3.1 mmHg (P<0.01) 45 min after HEx only. 24-h systolic and diastolic, daytime diastolic and nightime systolic BP were lower (P<0.05) after HEx than both LEx and CON. Daytime systolic BP was also lower (P<0.05) after HEx than CON. Nighttime diastolic was not different between interventions. HEx-induced ambulatory BP reduction ranged 4.5±1.3 mmHg (24-h diastolic BP) to 9.5±3.0 mmHg (nighttime systolic BP), and persisted for 18/11 h in systolic/diastolic BP, when compared with CON. No significant changes in arterial stiffness, endothelial reactivity and HRV were found during any intervention. These results suggest that HEx may have important implications for managing BP in older hypertensive under pharmacological treatment.