Nanoencapsulation and bioaccessibility of polyphenols of aqueous extracts from Bauhinia forficata link.

Bauhinia forficata Link is a plant rich in polyphenols that has been used mainly for its hypoglycemic activity, which is related to its antioxidant and anti-inflammatory potential. However, the beneficial effect of these bioactive compounds is directly dependent on their bioaccessibility and bioavailability, requiring processing techniques that can improve and preserve their biological activities. This work aimed to obtain nanocapsulated extracts from the infusion (ESIN) and decoction (ESDC) of B. forficata Link leaves, by spray drying. The encapsulating agents used were maltodextrin and colloidal silicon dioxide. The nanocapsules were characterized by HPLC-PDA-ESI-IT-MS n , evaluated the bioaccessibility of polyphenols after simulated digestion and their antioxidant activity. Additionally, an extensive physicochemical characterization of the nanocapsulated extracts was carried out and their stability and technological parameters were evaluated. The ESIN and ESDC extracts had yields of 57.3 % and 62.7 %, with average nanocapsules sizes of 0.202 µm and 0.179 µm, low humidity and water activity (<0.5), powder density and proper flow properties (Hausner ratio ≤ 1.25; Carr index 18-19 %). Scanning electron microscopy showed a spherical and amorphous morphology and low viscosity, which may have favored the solubility profile. The phenolic compounds of the nanocapsules degraded after 400 °C, showing high thermal stability. The infrared spectra identified the presence of maltodextrin and phenolic compounds and that there were no reactions between them. Chromatography confirmed the presence of phenolic compounds, mainly flavonols and their O-glycosylated derivatives, as well as carbohydrates, probably maltodextrin. Simulated in vitro digestion showed that polyphenols and flavonoids from ESIN and ESDC nanocapsules were bioaccessible after the gastric phase (49.38 % and 64.17 % of polyphenols and 64.08 % and 36.61 % of flavonoids) and duodenal (52.68 % and 79.06 % of polyphenols and 13.24 % and 139.03 % of flavoids), with a variation from 52.27 % to 70.55 % of the antioxidant activity maintained, by the ORAC method, after gastric digestion and still 25 %, after duodenal. Therefore, the nanoencapsulation of extracts of B. forficata is a viable option for the preservation of their bioactive compounds, making them bioaccessible and with antioxidant activity, which make them suitable for incorporation into various nutraceutical formulations, such as capsules, tablets and sachets.

Acaricide activity of extract and an isolated compound of Lithraea brasiliensis on Rhipicephalus microplus and selectivity actions against a non-target organism.

Rhipicephalus microplus, known as the cattle tick, is a cause of great economic losses for dairy cattle farming because of its high frequency of occurrence and the difficulty in controlling it. This research characterized the chemical profile and evaluated the in vitro toxicity of crude Lithraea brasiliensis extract and its isolated compound against acaricide-resistant and acaricide-susceptible R. microplus strains. Acaricidal activity was evaluated using a larval immersion test and the selectivity against non-target organisms was assessed on Artemia salina assay. The chemical investigation by high-performance liquid chromatography coupled with mass spectrometry (i.e., HPLC-MS) analysis showed the presence of hydrolysable tannins as well as urushiol derivatives. Column chromatography (CC) was carried out on the extract to obtain fractions and an isolated compound. The extract exhibited significant activity against acaricide-resistant (LC50 0.64 mg/mL) and acaricide-susceptible (LC50 0.76 mg/mL) strains of R. microplus larvae. The isolated compound from the extract (urushiol II), exhibited LC50 of 1.11 mg/mL for acaricide-resistant larvae. For acute toxicity in A. salina, the extract showed LC50>100 µg/mL. Thus, our findings represent the first effort to demonstrate the potential of L. brasiliensis extract and urushiol II as potential natural acaricides to replace or to be integrated into the conventional control of R. microplus larvae.

Mechanism of the lethal effect of Riparin E against bacterial and yeast strains.

Riparins are alkamides naturally found in the fruits of Aniba riparia (Nees) Mez, but currently synthetic molecules as Riparin E (Rip-E) can be obtained. Potential biological of Rip-E as schistosomicidal agent against Schistosoma mansoni worms, as well as against Staphylococcus aureus strains has already been described. However, the mechanism of action related to antimicrobial activity of Rip-E against bacterial or fungi species has not yet been reported. This study had as objective to evaluate the Rip-E antimicrobial activity against Gram-positive and Gram-negative bacteria, as well as against yeast species of clinical importance. Minimal inhibitory concentrations of the compound against bacterial and yeast strains were determined by microdilution method. To verify if a possible lethal effect caused by Rip-E were related to plasma membrane damage, microbial cells treated with Rip-E were stained with 7-aminoactinomycin D (7-AAD) and analyzed by flow cytometry. Rip-E showed a bactericide effect against Gram-positive species S. aureus and S. epidermidis, as well as, against Gram-negative species Escherichia coli and Salmonella enterica Typhimurium, but was inactive against Pseudomonas aeruginosa. Moreover, Rip-E showed activity against fungi species Candida albicans and C. tropicalis. S. aureus, E. coli and C. albicans cells treated with Rip-E were marked with 7-aminoactinomycin D (7-AAD) indicating that Rip-E can cause plasma membrane damage, acting as a potential microbicide agent for prevention or treatment of infectious diseases.

Development of microemulsion of tamsulosin and dutasteride for benign prostatic hyperplasia therapy.

Benign prostatic hyperplasia (BPH) is a condition characterized by a benign enlargement of the prostate that interferes with the normal flow of urine. This disease is treated with the oral administration of combination therapy comprising α-blockers (tamsulosin) and 5α-reductase inhibitors (dutasteride). However, these compounds have low bioavailability. Thus, transdermal microemulsions aimed at promoting permeation and efficient targeted drug delivery through the skin are used. The objectives of this study were to obtain microemulsions of the combined doses of dutasteride and tamsulosin and evaluate their anti-hyperplastic activity in vivo. A phase diagram (4:1) was obtained for the choice of microemulsions. The microemulsions were characterized in terms of the droplet size, rheology, pH, conductivity, refractive index, in vitro release profile, and antihyperplastic effect in vivo. A method for the simultaneous quantification of drugs was developed using UV-vis spectroscopy. The microemulsions had an average size less than 116 nm, an acidic pH and low viscosity. The conductivity ranged from 6.18 to 185.2 µS/cm. The in vitro release profile was sustained for 6 h. Microemulsions promoted the reduction in the size of testosterone-dependent organs (prostate and seminal vesicles). Transdermal formulations for the treatment of BPH were obtained as a therapeutic alternative to conventional treatments.

Antimicrobial activity and inhibition of the NorA efflux pump of Staphylococcus aureus by extract and isolated compounds from Arrabidaea brachypoda.

Arrabidaea brachypoda is a native shrub of the Brazilian Cerrado widely used in the folk medicine for treatment of renal diseases and articular pains. This study aimed to, first, evaluate the antimicrobial activity of both extracts and isolated molecules Brachydins BR-A and BR-B obtained from the flowers of A. brachypoda against Staphylococcus aureus, Escherchia coli and Candida albicans species. A second objective was to investigate if these natural products were able to potentiate the Norfloxacin activity against the strain Staphylococcus aureus SA1199-B that overexpress the norA gene encoding the NorA efflux pump. Extracts and isolated compounds were analyzed by HPLC-PDA and LC-ESI-MS respectively. Minimal inhibitory concentrations of Norfloxacin or Ethidium Bromide (EtBr) were determined in the presence or absence of ethanolic extract, dichloromethane fraction, as well as BR-A or BR-B by microdilution method. Only BR-B showed activity against Candida albicans. Addition of ethanolic extract, dichloromethane fraction or BR-B to the growth media at sub-inhibitory concentrations enhanced the activity of both Norfloxacin and EtBr against S. aureus SA1199-B, indicating that these natural products and its isolated compound BR-B were able to modulate the fluoroquinolone-resistance possibly by inhibition of NorA. Moreover, BR-B inhibited the EtBr efflux in the SA1199-B strain confirming that it is a NorA inhibitor. Isolated BR-B was able to inhibit an important mechanism of multidrug-resistance very prevalent in S. aureus strains, thus its use in combination with Norfloxacin could be considered as an alternative for the treatment of infections caused by S. aureus strains overexpressing norA.

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.

Mutagenicity and antimutagenicity of six Brazilian Byrsonima species assessed by the Ames test.

BACKGROUND: In various regions of Brazil, several species of the genus Byrsonima (Malpighiaceae) are widely used to treat gastrointestinal complications. This genus has about 150 species of shrubs and trees distributed over the entire Neotropical region. Various biological activities have been identified in these plants, especially antioxidant, antimicrobial and topical and systemic anti-inflammatory activities. The aim of this study was to investigate the mutagenicity and antimutagenicity of hydroalcoholic leaf extracts of six species of Byrsonima: B. verbascifolia, B. correifolia, B. coccolobifolia, B. ligustrifolia, B. fagifolia and B. intermedia by the Salmonella microsome assay (Ames test). METHODS: Mutagenic and antimutagenic activity was assessed by the Ames test, with the Salmonella typhimurium tester strains TA100, TA98, TA97a and TA102, with (+S9) and without (-S9) metabolization, by the preincubation method. RESULTS: Only B. coccolobifolia and B. ligustrifolia showed mutagenic activity. However, the extracts of B. verbascifolia, B. correifolia, B. fagifolia and B. intermedia were found to be strongly antimutagenic against at least one of the mutagens tested. CONCLUSIONS: These results contribute to valuable data on the safe use of medicinal plants and their potential chemopreventive effects. Considering the excellent antimutagenic activities extracted from B. verbascifolia, B. correifolia, B. fagifolia and B. intermedia, these extracts are good candidate sources of chemopreventive agents. However, B. coccolobifolia and B. ligustrifolia showed mutagenic activity, suggesting caution in their use.