Antibacterial activity of Barbatimão (Stryphnodendron adstringens) against Staphylococcus aureus: in vitro and in silico studies.

We evaluated the activity of the aqueous fraction and the ethyl acetate fraction of Stryphnodendron adstringens against Staphylococcus aureus and proposed their mechanism of action. The antibacterial activity of S. adstringens fractions was evaluated against S. aureus and the cell targets were rated by docking. The fractions showed moderate antibacterial activity against S. aureus without toxicity on two mammalian cell lines. They also showed synergistic antibacterial activity with tannic acid (TA). In silico assays indicated FabG, FabZ and FabI as probable targets. The metabolic pathway for fatty acid biosynthesis in S. aureus was affected by components of S. adstringens. The synergistic effect when combining TA with S. adstringens fractions suggests a natural alternative to S. aureus control. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study describing the possible targets of action of Stryphnodendron adstringens on Staphylococcus aureus. Molecular dynamics simulations showed that the components of S. adstringens affected the metabolic pathway for fatty acid biosynthesis (FAS II) in S. aureus, inhibiting the FabI, FabG and FabZ enzymes. As tannic acid (TA) is a known inhibitor of some targets identified, we showed synergistic antibacterial activity of S. adstringens in combination with TA. This combination did not show toxicity against HaCaT and Vero cells and based on all these results we suggest that S. adstringens can be a natural and sustainable alternative to S. aureus control.

Effect of lyophilized extracts from guaraná seeds [Paullinia cupana var. sorbilis (Mart.) Ducke] on behavioral profiles in rats.

The aim of the present study was to investigate the pharmacological properties of the crude lyophilized extract (EBPC) of Paullinia cupana seeds (guaraná) and the semi-purified extracts (EPA and EPB) after acute or chronic administration by the oral route in rats. Anxiolytic-like, antidepressant-like and motor stimulant effects were evaluated using the plus maze (PMT), forced swimming (FST) and open field (OFT) tests, respectively. Acute or chronic administration of EBPC (3.0, 30.0 or 60.0 mg/kg) did not alter the percentage of entries or the time spent in the open arm in the PMT. In the FST, chronic treatment with 30.0 mg EBPC/kg and 4.0 mg EPA/kg extract decreased the immobility time similarly to the antidepressant reference drug, imipramine (20.0 mg/kg). Locomotor activity in the OFT was not increased by these extracts. Caffeine (10.0 mg/kg) significantly reduced the immobility time in the FST, but increased locomotor activity in the OFT, indicating psychostimulant activity. The EPB extract did not induce any effect after acute or chronic treatment in the different models used. The present results suggest that the crude EBPC extract and EPA extract produced an antidepressant-like effect after long-term administration.

Ex vivo evaluation of the percutaneous penetration of proanthocyanidin extracts from Guazuma ulmifolia using photoacoustic spectroscopy.

In this work photoacoustic spectroscopy has been applied to determine ex vivo the percutaneous penetration of proanthocyanidins present in extracts obtained from Guazuma ulmifolia, in rats. Lotion formulations containing 0.0663 mg of procyanidin B2 day(-1)animal(-1) were topically applied during 7, 10 and 13 days in each group of the animals. After the end of treatment the animals were killed, the skin dissected to remove the basal content, and the measurements were carried out as a function of the period of time of treatment. The results showed that despite the very low concentration of the active principle (procyanidin B2) in the lotion, the photoacoustic method was able to show the presence of optical absorption bands from this substance in the dermis region, evidencing once again that this method may be useful for studies of topically applied formulations of interest in the pharmacokinetic area.