Modulation of the Drug Resistance by Platonia insignis Mart. Extract, Ethyl Acetate Fraction and Morelloflavone/Volkensiflavone (Biflavonoids) in Staphylococcus aureus Strains Overexpressing Efflux Pump Genes.

BACKGROUND: Microbial resistance to antibiotics is a global public health problem, which requires urgent attention. Platonia insignis is a native species from the eastern Brazilian Amazon, used in the treatment of burns and wounds. OBJECTIVES: To evaluate the antimicrobial activity of the hydroalcoholic extract of P. insignis (PIHA), the ethyl acetate fraction (PIAE), and its subfraction containing a mixture of biflavonoids (BF). Moreover, the effect of these natural products on the antibiotic activity against S. aureus strains overexpressing efflux pump genes was also evaluated. METHODS: Minimal inhibitory concentrations were determined against different species of microorganisms. To evaluate the modulatory effect on the Norfloxacin-resistance, the MIC of this antibiotic was determined in the absence and presence of the natural products at subinhibitory concentrations. Inhibition of the EtBr efflux assays were conducted in the absence or presence of natural products. RESULTS: PIHA showed a microbicidal effect against S. aureus and C. albicans, while PIAE was bacteriostatic for S. aureus. PIAE and BF at subinhibitory concentrations were able to reduce the MIC of Norfloxacin acting as modulating agents. BF was able to inhibit the efflux of EtBr efflux in S. aureus strains overexpressing specific efflux pump genes. CONCLUSION: P. inignisis, a source of efflux pump inhibitors, including volkensiflavone and morelloflavone, which were able to potentiate the Norfloxacin activity by NorA inhibition, being also able to inhibit QacA/B, TetK and MsrA. Volkensiflavone and morelloflavone could be used as an adjuvant in the antibiotic therapy of multidrug resistant S. aureus strains overexpressing efflux pumps.

Behavioral and neurochemical studies in mice pretreated with garcinielliptone FC in pilocarpine-induced seizures.

Garcinielliptone FC (GFC) isolated from hexanic fraction seed extract of species Platonia insignis Mart. It is widely used in folk medicine to treat skin diseases in both humans and animals as well as the seed decoction has been used to treat diarrheas and inflammatory diseases. However, there is no research on GFC effects in the central nervous system of rodents. The present study aimed to evaluate the GFC effects at doses of 25, 50 or 75 mg/kg on seizure parameters to determine their anticonvulsant activity and its effects on amino acid (γ-aminobutyric acid (GABA), glutamine, aspartate and glutathione) levels as well as on acetylcholinesterase (AChE) activity in mice hippocampus after seizures. GFC produced an increased latency to first seizure, at doses 25mg/kg (20.12 ± 2.20 min), 50mg/kg (20.95 ± 2.21 min) or 75 mg/kg (23.43 ± 1.99 min) when compared with seized mice. In addition, GABA content of mice hippocampus treated with GFC75 plus P400 showed an increase of 46.90% when compared with seized mice. In aspartate, glutamine and glutamate levels detected a decrease of 5.21%, 13.55% and 21.80%, respectively in mice hippocampus treated with GFC75 plus P400 when compared with seized mice. Hippocampus mice treated with GFC75 plus P400 showed an increase in AChE activity (63.30%) when compared with seized mice. The results indicate that GFC can exert anticonvulsant activity and reduce the frequency of installation of pilocarpine-induced status epilepticus, as demonstrated by increase in latency to first seizure and decrease in mortality rate of animals. In conclusion, our data suggest that GFC may influence in epileptogenesis and promote anticonvulsant actions in pilocarpine model by modulating the GABA and glutamate contents and of AChE activity in seized mice hippocampus. This compound may be useful to produce neuronal protection and it can be considered as an anticonvulsant agent.