Sara Elis Bianchi

A bioanalytical HPLC method for coumestrol quantification in skin permeation tests followed by UPLC-QTOF/HDMS stability-indicating method for identification of degradation products

Coumestrol is present in several species of the Fabaceae family widely distributed in plants. The estrogenic and antioxidant activities of this molecule show its potential as skin anti-aging agent. These characteristics reveal the interest in developing analytical methodology for permeation studies, as well as to know the stability of coumestrol identifying the major degradation products. Thus, the present study was designed, first, to develop and validate a versatile liquid chromatography (HPLC) method to quantify coumestrol in a hydrogel formulation in different porcine skin layers (stratum corneum, epidermis, and dermis) in permeation tests. In the stability-indicating test coumestrol samples were exposed to stress conditions: temperature, UVC light, oxidative, acid and alkaline media. The degradation products, as well as the constituents extracted from the hydrogel, adhesive tape or skin were not eluted in the retention time of the coumestrol. Hence, the HPLC method showed to be versatile, specific, accurate, precise and robust showing excellent performance for quantifying coumestrol in complex matrices involving skin permeation studies. Coumestrol recovery from porcine ear skin was found to be in the range of 97.07-107.28 μg/mL; the intra-day precision (repeatability) and intermediate precision (inter-day precision), respectively lower than 4.71% and 2.09%. The analysis using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight high definition mass spectrometry detector (UPLC-QTOF/HDMS) suggest the MS fragmentation patterns and the chemical structure of the main degradation products. These results represent new and relevant findings for the development of coumestrol pharmaceutical and cosmetic products.

Pterostilbene reduces oxidative stress, prevents hypertrophy and preserves systolic function of right ventricle in cor pulmonale model

In cor pulmonale, the increased afterload imposed on the right ventricle (RV) generates a maladaptive response, impairing the contractile cardiac function. Oxidative mechanisms play an important role in the pathophysiology and progression of this disease. The administration of pterostilbene (PTS), a phytophenol with antioxidant potential, may represent a therapeutic option. In the present study, we evaluated the effect of PTS complexed with hydroxypropyl‐β‐cyclodextrin (HPβCD) on hypertrophy, contractile function and oxidative parameters in the RV of rats with pulmonary hypertension, induced by the administration of monocrotaline (MCT).

Effect of pterostilbene complexed with cyclodextrin on rat liver: potential reduction of oxidative damage and modulation redox-sensitive proteins

The objectives of this study were to promote the aqueous solubility of pterostilbene (PTS) by complexation with hydroxypropyl-β-cyclodextrin (HPβCD), characterize the complex under physical aspects, to make its oral administration feasible in biological tests, and to investigate their pharmacological properties. For 14 days, rats received daily PTS:HPΒCD complex at doses of 25, 50, or 100 mg kg−1 per day orally. The results showed no kidney or liver damage, nor any induction of apoptosis by the administered doses. Also, the complex showed dose-dependent antioxidant effects in the rat liver, as evidenced by a reduction in lipid peroxidation and reactive oxygen species, as well as an increase in non-enzymatic antioxidant. PTS:HPΒCD complex also increased the expression of sensitive redox proteins such as AKT and GSK-3β related to the insulin signaling pathway in the liver. Thus, the complexation demonstrated to be able to increase the apparent solubility of PTS making feasible dose curve administration and could be a food alternative complementary to antioxidant therapeutic. Therefore, the PTS:HPβCD complex can be used for prevention of diseases related to oxidative damage and insulin signaling.

Hydroxypropyl‐β‐cyclodextrin‐containing hydrogel enhances skin formononetin permeation/retention

This study was aimed to investigate the in vitro permeation potential of hydrogel formulations containing the isoflavones formononetin and biochanin A and cyclodextrins in different combinations.

Stilbenoid pterostilbene complexed with cyclodextrin preserves left ventricular function after myocardial infarction in rats: possible involvement of thiol proteins and modulation of phosphorylated GSK-3β

Abstract Oxidative stress alters signalling pathways for survival and cell death favouring the adverse remodelling of postmyocardial remnant cardiomyocytes, promoting functional impairment. The administration of pterostilbene (PTS), a phytophenol with antioxidant potential, can promote cardioprotection and represents a therapeutic alternative in acute myocardial infarction (AMI). The present study aims to explore the effects of oral administration of PTS complexed with hydroxypropyl-β-cyclodextrin HPβCD (PTS:HPβCD complex) on the glutathione cycle, thiol protein activities and signalling pathways involving the protein kinase B (AKT) and glycogen synthase kinase-3β (GSK-3β) proteins in the left ventricle (LV) of infarcted rats. Animals were submitted to acute myocardial infarction through surgical ligation of the descending anterior branch of the left coronary artery and received over 8 days, by gavage, PTS:HPβCD complex at dose of 100 mg kg−1 day−1 (AMI + PTS group) or vehicle (aqueous solution with HPβCD) divided into Sham-operated (SHAM) and infarcted (AMI) groups. The results showed that the PBS: HPβCD complex decreased lipid peroxidation, prevented the decrease in thioredoxin reductase (TRxR) activity, and increased the activity of glutathione-S-transferase (GST) and glutaredoxin (GRx). Additionally, the expression of nuclear factor-erythroid two (Nrf2) and p-GSK-3β was increased, whereas the p-GSK-3β/GSK-3β ratio was reduced in the LV of the infarcted animals. Overall, the PTS:HPβCD complex modulates activity of thiol-dependent enzymes and induces to the expression of antioxidant proteins, improving systolic function and mitigating the adverse cardiac remodelling post infarction.

Coumestrol/hydroxypropyl-β-cyclodextrin association incorporated in hydroxypropyl methylcellulose hydrogel exhibits wound healing effect: in vitro and in vivo study

ABSTRACT Several beneficial effects on the skin have been reported for coumestrol (COU), such as protection against photoaging and improvement of skin elasticity and thickness in postmenopausal women. However no reports on the effect of COU on wound healing were found. Nevertheless, COU has low aqueous solubility, which is a crucial limitation for biological tests. The present study was designed as a two‐step experiment to evaluate the wound healing effect of COU. First, we used fibroblasts and the experimental in vitro artificial wound model, scratch assay, to compare the effects of COU free, dissolved in dimethyl sulfoxide (DMSO) or Dulbeccos modified Eagles medium (DMEM), or associated with hydroxypropyl‐&bgr;‐cyclodextrin (HP&bgr;CD). The 50&mgr;M (66.1%) and 10&mgr;M (56.3%) COU/HP&bgr;CD association induced cell proliferation and migration in inflicted wounds. Subsequently, the in vivo wound healing experimental model (Wistar rats) revealed that COU/HP&bgr;CD incorporated into hypromellose (HPMC) hydrogel had similar efficacy in wound healing in comparison to the positive control (Dersani®), with the advantage that 50% wound healing was achieved within a shorter period. In summary, the results successfully demonstrated, for the first time, the wound healing effect of COU/HP&bgr;CD incorporated into HPMC hydrogel and describe the feasibility of the biological tests with the use of HP&bgr;CD instead DMSO.