In vitro antileishmanial and immunomodulatory activities of the synthetic analogue riparin E.

Leishmaniases are infectious diseases caused by protozoa of the genus Leishmania, that may have different clinical manifestations. First line drugs used in the treatment of leishmaniosis are high costly, and are very aggressive requiring medical monitoring. Thus new therapeutic alternatives are needed and, in this context, natural products have been considered as a source of new antileishmania agents. Riparins are alkamides found in the unripe fruits of Aniba riparia. Several biological activities are described for this group of compounds, such as antimicrobial and antiparasitic potential. The objective of this work was to evaluate the anti-leishmania activity riparin E (Rip-E) in vitro, against promastigotes and internalized amastigotes of Leishmania amazonensis. Rip-E was able to inhibit promastigote cell growth (IC50 4.7 µg/ml) and to reduce the percentage of macrophages infected with amastigotes, reducing its infectivity (survival index) (IC50 1.3 µg/ml). The cytotoxicity against BALB/c murine macrophages was also assessed (CC50 50.6 µg/ml) and the selectivity index was 38.9. Rip-E also demonstrated immunomodulatory activity, evidenced by the increase of the phagocytic capacity and lysosomal activity. However, Rip-E did not affect directly the production of nitric oxide. These results suggest that Rip-E has antileishmania potential, by both its direct inhibitory effect and its ability to activate macrophages.

Antimicrobial activity of Phyllanthus amarus Schumach. & Thonn and inhibition of the NorA efflux pump of Staphylococcus aureus by Phyllanthin.

The aim of this study was to evaluate the antimicrobial activity of ethanoic extract of P. amarus (PAEE) and its compound Phyllanthin, as well as, investigate if these natural products could modulate the fluoroquinolone-resistance in S. aureus SA1199-B by way of overexpression of the NorA efflux pump. Microdilution tests were carried out to determine the minimal inhibitory concentration (MIC) of the PAEE or Phyllanthin against several bacterial and yeast strains. To evaluate if PAEE or Phyllanthin were able to act as modulators of the fluoroquinolone-resistance, MICs for Norfloxacin and ethidium bromide were determined in the presence or absence of PAEE or Phyllanthin against S. aureus SA1199-B. PAEE showed antimicrobial activity against Gram-negative strains, meanwhile Phyllanthin was inactive against all strains tested. Addition of PAEE or Phyllanthin, to the growth media at sub-inhibitory concentrations enhanced the activity of the Norfloxacin as well as, Ethidium Bromide, against S. aureus SA1199-B. These results indicate that Phyllanthin is able to modulate the fluoroquinolone-resistance possibly by inhibition of NorA. This hypothesis was supported by in silico docking analysis which confirmed that Phyllantin is a NorA ligand. Thus, this compound could be used as a potentiating agent of the Norfloxacin activity in the treatment of infections caused by fluoroquinolone-resistant S. aureus.

Neuropharmacological effects of carvacryl acetate on δ-aminolevulinic dehydratase, Na+, K+-ATPase activities and amino acids levels in mice hippocampus after seizures.

Epileptic syndromes are highly prevalent neurological conditions and can often be disabling. In order to find an alternative for treatment, this study evaluated anticonvulsant effects of carvacryl acetate (CA), a derivative of monoterpene carvacrol, after seizures induced by pilocarpine (P400), picrotoxin (PIC) or pentylenetetrazol (PTZ). We also analyzed the CA effects on Na+, K+-ATPase and δ-aminolevulinic acid dehydratase (δ-ALA-D) activities in hippocampus mice after seizures induced by P400, PIC or PTZ. In addition, glutamate, δ-aminobutyric acid (GABA), glutamine and aspartate levels in mice hippocampus treated with CA after seizures induced by P400, PIC or PTZ were also measured. CA produced anticonvulsant effects against seizures induced by P400, PIC or PTZ, and its effects were reversed by flumazenil, suggesting that action mechanism can be mediated by GABAergic system. CA increased GABA levels, but did not alter glutamate and aspartate concentrations in mice hippocampus after seizures induced by P400, PIC or PTZ when compared with seizures induced by P400, PIC or PTZ (p<0.05), respectively, as well as decreased glutamine content in mice hippocampus after seizures induced by PIC when compared with seizures induced by PIC (p<0.05). In addition, CA also increased Na+, K+-ATPase and δ-aminolevulinic acid dehydratase activities after seizures induced by P400, PIC or PTZ when compared with seizures induced by P400, PIC or PTZ (p<0.05), respectively. This study demonstrated that CA could be a future therapeutic option for treatment of epilepsy, with a multifactorial brain action mechanism.

Behavioral tests and oxidative stress evaluation in mitochondria isolated from the brain and liver of mice treated with riparin A.

AIMS: This study aimed at evaluating the oxidative stress in mitochondria isolated from the brain and liver of mice treated with riparin A, as well as the locomotor activity and myorelaxant effect of this compound. Behavioral models of rota rod and open field tests were used for locomotor activity and myorelaxant effect evaluation. MAIN METHODS: The animals were divided into five groups (n=8), which were treated with: diazepam (1mg/kg, i.p), riparin A (5, 10, and 20mg/kg, o.r.) or vehicle (0.9% saline, o.r.). The oxidative stress evaluation was carried out in mitochondria isolated from the brain and liver of mice from five experimental groups (n=8), which were treated with: ascorbic acid (250 mg/kg; positive control), vehicle (0.9% saline; negative control) and riparin A (5, 10 and 20mg/kg). KEY FINDINGS: In an open field and rota rod test a significant difference in the number of crossings, in time of permanence on the swivel bar and in the number of falls in riparin A treated animals (5, 10 and 20mg/kg) was not observed, when compared with negative control (vehicle) (p>0.05). In comparison to the negative control, there was a reduction of lipid peroxidation levels and nitrite content in mice treated with riparin A (p<0.05). Reduced glutathione (GSH) levels (p<0.05), superoxide dismutase (SOD) and catalase activities increased in the brain (rip A 5mg/kg; p<0.05), while in the liver SOD remained unchanged (p>0.05) and catalase activity (p<0.05) was reduced. SIGNIFICANCE: Riparin A was presented as a bioactive molecule devoid of adverse effects of alteration of motor activity.

Chemical constituents and toxicological studies of leaves from Mimosa caesalpiniifolia Benth., a Brazilian honey plant.

BACKGROUND: Mimosa caesalpiniifolia Benth. (Leguminosae) is widely found in the Brazilian Northeast region and markedly contributes to production of pollen and honey, being considered an important honey plant in this region. OBJECTIVE: To investigate the chemical composition of the ethanol extract of leaves from M. caesalpiniifolia by GC-MS after derivatization (silylation), as well as to evaluate the in vitro and in vivo toxicological effects and androgenic activity in rats. MATERIALS AND METHODS: The ethanol extract of leaves from Mimosa caesalpiniifolia was submitted to derivatization by silylation and analyzed by gas chromatography-mass spectrometry (GC-MS) to identification of chemical constituents. In vitro toxicological evaluation was performed by MTT assay in murine macrophages and by Artemia salina lethality assay, and the in vivo acute oral toxicity and androgenic evaluation in rats. RESULTS: Totally, 32 components were detected: Phytol-TMS (11.66%), lactic acid-2TMS (9.16%), α-tocopherol-TMS (7.34%) and ß-sitosterol-TMS (6.80%) were the major constituents. At the concentrations analyzed, the ethanol extract showed low cytotoxicity against brine shrimp (Artemia salina) and murine macrophages. In addition, the extract did not exhibit any toxicological effect or androgenic activity in rats. CONCLUSIONS: The derivatization by silylation allowed a rapid identification of chemical compounds from the M. caesalpiniifolia leaves extract. Besides, this species presents a good safety profile as observed in toxicological studies, and possess a great potential in the production of herbal medicines or as for food consumption.

Teor de fenóis e flavonoides, atividades antioxidante e citotóxica dasfolhas, frutos, cascas dos frutos e sementes de Piptadenia moniliformisBenth (Leguminosae – Mimosoideae) / Phenols, flavonoids and antioxidant and cytotoxic activity of leaves, fruits, peel of fruits and seeds of Piptadenia moniliformis Benth (Leguminosae - Mimosoideae)

The total phenol and flavonoid content, in addition to the antioxidant and cytotoxic activities, of extracts and fractions of Piptadenia moniliformis was determined. This honey plant species is commonly known as "catanduba" or "angico de bezerro". The aqueous fraction derived from the peels of the fruits exhibited the highest antioxidant activity, remaining comparable to the standard value, and there was a general correlation between this activity and the phenol and flavonoid content. The antioxidant potential of this species provides a basis for future developments in herbal medicines and cosmetics. Only the hydro alcoholic extract, the dichloromethane fractions and the ethyl acetate fractions showed moderate cytotoxicity.

Foram determinados o teor de fenóis e flavonoides, as atividades antioxidante e citotóxica dos extratos e frações de Piptadenia moniliformis. Essa é uma espécie melitófila comumente conhecida como "catanduba" ou "angico de bezerro". Das frações testadas, a fração aquosa das cascas dos frutos apresentou a maior atividade antioxidante, com valor comparável ao padrão, e no geral houve correlação do teor de fenóis e flavonoides com essa atividade. Os resultados do potencial antioxidante para essa espécie fornecem subsídios para futuros trabalhos que visem o desenvolvimento de fitoterápicos e cosméticos. Quanto à atividade citotóxica apenas o extrato hidroalcoólico e as frações diclorometano e acetato de etila demonstraram moderada citotoxicidade.

Is there a correlation between in vitro antioxidant potential and in vivo effect of carvacryl acetate against oxidative stress in mice hippocampus?

This study investigated in vitro and in vivo antioxidant potential of carvacryl acetate (CA), a derivative of carvacrol, monoterpenic component of oregano. The correlation between in vitro and in vivo CA effects was also determined. In vitro tests measured thiobarbituric acid reactive species content, nitrite formation and hydroxyl radical levels. In vivo tests measured thiobarbituric acid reactive species content, nitrite concentration and reduced glutathione (GSH) levels, as well as glutathione peroxidase (GPx), superoxide dismutase (SOD) and catalase activities were measured, using mice hippocampus. The CA administrations for in vivo tests were intraperitoneally and acutely improved. CA reduced lipid peroxidation, nitrite and hydroxyl radical contents in vitro as well as lipid peroxidation and nitrite content in vivo. It also increased reduced GSH levels and GPx as well as catalase activities. Moreover, CA required a lower concentration to inhibit 50 % of free radicals measured in vitro than trolox. There was significant negative correlation between in vitro nitrite levels and in vivo reduced GSH levels; in vitro nitrite content and in vivo GPx activity as well as in vitro hydroxyl radical levels and in vivo SOD activity. To date, this is the first study which suggests vitro and in vivo antioxidant potential to this monoterpene and the correlation between these parameters.

Anxiolytic-like effects of carvacryl acetate, a derivative of carvacrol, in mice.

Studies showing anxiolytic-like properties of natural products have grown. This paper evaluated if carvacryl acetate (CA) could be studied as an alternative drug to treat anxiety disorders. Elevated plus maze (EPM) tests , light-dark box (LDB) tests, and marble-burying tests (MBTs) were performed on mice. In the first protocol, the anxiolytic-like activities of CA 25, 50, 75 and 100mg/kg at single doses were compared to those of the vehicle, buspirone 5mg/kg (BUSP) and diazepam 1mg/kg (DZP). In the second protocol, the anxiolytic-like actions of CA were tested for GABAergic and serotonergic systems. The time spent in the open arms (TSOA) and the number of open arms entries (NOAE) were measured in EPM; the time spent in the light box (TSLB) and the number of entries to light box (NELB) were measured in LDB; and the number of marbles buried (NMB) were measured in MBT. CA increased TSOA and NOAE in the EPM, as well as TSLB and NELB in the LDB and the NMB in the MBT. The anxiolytic-like activity of CA 25; 50; 75 and 100mg/kg was not associated with psychomotor retardation in the open field test and in the Rota rod test, contrarily with what happened with DZP. In the second protocol, to suggest the mechanism of action of CA, flumazenil 25mg/kg ip (FLU) and WAY 100,635 10mg/kg ip (WAY-5-HT1A antagonist) were also used. FLU+CA100 reduced TSOA in the EPM when compared to CA100 but WAY+CA100 did not. In LDB, FLU+CA100 reduced the TSLB when compared to CA100 but WAY+CA100 did not. In the MBT, FLU+CA100 inhibited the effect of CA100 on the NMB but WAY+CA100 did not. In conclusion, CA seems to have an anxiolytic-like effect, probably due to GABAergic agonist action, without psychomotor side effects.

Antinociceptive and Antioxidant Activities of Phytol In Vivo and In Vitro Models.

The objective of the present study was to evaluate the antinociceptive effects of phytol using chemical and thermal models of nociception in mice and to assess its antioxidant effects in vitro. Phytol was administered intraperitoneally (i.p.) to mice at doses of 25, 50, 100, and 200 mg/kg. In the acetic acid-induced writhing test, phytol significantly reduced the number of contortions compared to the control group (P < 0.001). In the formalin test, phytol reduced significantly the amount of time spent in paw licking in both phases (the neurogenic and inflammatory phases), this effect being more pronounced in the second phase (P < 0.001). Phytol also provoked a significant increase in latency in the hot plate test. These antinociceptive effects did not impaire the motor performance, as shown in the rotarod test. Phytol demonstrated a strong antioxidant effect in vitro in its capacity to remove hydroxyl radicals and nitric oxide as well as to prevent the formation of thiobarbituric acid reactive substances (TBARS). Taken as a whole, these results show the pronounced antinociceptive effects of phytol in the nociception models used, both through its central and peripheral actions, but also its antioxidant properties demonstrated in the in vitro methods used.