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 the natural products. Results: PIHA showed a microbicidal effect against S. aureus and C. albicans, while PIAE was bacteriosctatic 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 adjuvant in the antibiotic therapy of multidrug resistant S. aureus strains overexpressing efflux pumps.

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.

Leishmaniasis is an infectious disease that affects millions of people worldwide, making the search essential for more accessible treatments. The species Platonia insignis Mart. (Clusiaceae) has been extensively studied and has gained prominence for its pharmacological potential. The objective of this work was to evaluate the antileishmania activity, cytotoxic effect and activation patterns of macrophages of hydroalcoholic extract (EHPi), ethyl acetate fractions (FAcOEt) and morelloflavone/volkensiflavone mixture (MB) from P. insignis flowers. EHPi, FAcOEt and MB demonstrated concentration-dependent antileishmania activity, with inhibition of parasite growth in all analyzed concentrations. EHPi exhibited maximum effect at 800 μg/mL, while FAcOEt and MB reduced the growth of the parasite by 94.62% at 800 μg/mL. EHPi, FAcOEt and MB showed low cytotoxic effects for macrophages at 81.78, 159.67 and 134.28 μg/mL, respectively. EHPi (11.25 µg/mL), FAcOEt (11.25 and 22.5 µg/mL) and MB (22.5 µg/mL) characterized the increase in lysosomal activity, suggesting a possible modulating effect. These findings open for the application of flowers from a P. insignis flowers and biflavones mixture thereof in the promising treatment of leishmaniasis.

Brazilian flora are highly diverse and have great potential for research into new medicines of plant origin. Platonia insignis Mart. is a fruit tree from the Amazon region with several potential pharmacological applications already demonstrated. The present study aimed to investigate the protective effect of a mixture of the biflavones volkensiflavone and moreloflavone obtained from P. insignis flowers against the lethality induced by ethidium bromide in efflux pump overproducer strains of Staphylococcus aureus. Microdilution tests were performed to determine the minimum inhibitory concentration of ethidium bromide in the absence or presence of biflavones. The addition of biflavones to the growth medium increased the minimum inhibitory concentration of ethidium bromide against all strains tested, indicating that biflavones protected the bacterial cells against cell damage induced by this biocide agent. Comparative analysis of the infrared absorption spectra of each isolated compound, as well as of the associated compounds, demonstrated the complexation reaction, indicating that there was a preferential interaction between the H2N- groups of primary amines of ethidium bromide with the carbonyls of biflavones that formed imines -C=NH. Such complexation could reduce the amount of free ethidium bromide molecules available for DNA intercalation, resulting in the observed protective effect. These results suggest a possible technological application of the biflavones from P. insignis as protective agents against cell damage induced by ethidium bromide.

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