Navegando por Autor "Alencar, Severino Matias de"

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Antimicrobial activity of Rheedia brasiliensisand 7-epiclusianone against Streptococcus mutans.
(2008) Almeida, Luciana Salles Branco de; Murata, Ramiro Mendonça; Yatsuda, Regiane; Santos, Marcelo Henrique dos; Nagem, Tanus Jorge; Alencar, Severino Matias de; Koo, Hyun; Rosalen, Pedro Luiz
This in vitro study evaluated the antimicrobial activity of extracts obtained from Rheedia brasiliensis fruit (bacupari) and its bioactive compound against Streptococcus mutans. Hexane, ethyl-acet ate and ethanolic extracts obtained (concentrations ranging from 6.25 to 800mg/ml) were tested against S. mutans UA1 59 through MIC /MBC assays. S. mutans5-days -old biofilm s were treat ed with the active extra cts (100 MIC ) for 0, 1, 2, 3 an d 4 h (time-k ill) and plate d for colony counting (CFU/m l). Active extracts were submitted to exploratory chemical analyses so as to isolate and identify the bioactive compound using spectroscopic method s. The bioactive compo und (concentration s ranging from 0.625 to 80mg/ml) was then tested through MIC /MBC assays . Pee l and seed hexane extracts showed antimicrobial activity against planktonic cells at low concentrations and were thus selected for the time kill test. These hexane extracts reduced S. mutans biofilm viability after 4 h, certifying of the bioactive compo und presence. The bioactive compound identified was the polyprenylated benzophenone 7-epiclusianone, which showed a good antimicrobial activity at low concentrations (MIC : 1.25–2 .5 mg/ml; MBC: 10–20mg/ml). The results indicated that 7-epi clusian one may be used as a ne w agent to control S. mutans biofilms; however, more studies are needed to further elucidate the mechanisms of action and the anticariogenic potential of such compound found in R. brasiliensis.
Antiproliferative effect of benzophenones and their infl uence on cathepsin activity.
(2010) Murata, Ramiro Mendonça; Yatsuda, Regiane; Santos, Marcelo Henrique dos; Kohn, Luciana K.; Martins, Felipe Terra; Nagem, Tanus Jorge; Alencar, Severino Matias de; Carvalho, João Ernesto de; Rosalen, Pedro Luiz
The antiproliferative activity of two prenylated benzophenones isolated from Rheedia brasiliensis, the triprenylated garciniaphenone and the tetraprenylated benzophenone 7-epiclusianone, was investigated against human cancer cell lines. The antiproliferative activity on melanoma (UACC-62), breast (MCF-7), drug-resistant breast (NCI-ADR), lung/non-small cells (NCI460), ovarian (OVCAR 03), prostate (PC03), kidney (786-0), lung (NCI-460) and tongue (CRL-1624 and CRL-1623) cancer cells was determined using spectrophotometric quantifi cation of the cellular protein content. The effect of these benzophenones on the activity of cathepsins B and G was also investigated. Garciniaphenone displayed cytostatic activity in all cell lines, whereas 7- epiclusianone showed a dose-dependent cytotoxic effect. The IC50 values for cell proliferation revealed that 7-epiclusianone is more active than garciniaphenone against most of the cell lines. Furthermore, the antiproliferative effects demonstrated by garciniaphenone and 7-epiclusianone were related to their cathepsin inhibiting properties. In conclusion, 7-epiclusianone is a promising naturally occurring agent which displays multiple inhibitory effects which may be working in concert to inhibit cancer cell proliferation in vitro. The putative pathway by which 7-epiclusianone affects cancer cell development may involve cathepsin inhibition.
Bioassay - guided isolation of proanthocyanidins with antioxidant activity from peanut (Arachis hypogaea) skin by combination of chromatography techniques.
(2016) Oldoni, Tatiane Luiza Cadorin; Melo, Priscilla Siqueira; Massarioli, Adna Prado; Moreno, Ivani Aparecida Marchetto; Bezerra, Rosangela Maria Neves; Rosalen, Pedro Luiz; Silva, Gil Valdo José da; Nascimento, Andréa Mendes do; Alencar, Severino Matias de
Purification and bioassay-guided fractionation were employed to isolate proanthocyanidins with antioxidant activity from peanut skin (Arachis hypogaea Runner 886). The crude extract was prepared with acetone (60% v/v) and purified using chromatographic methods, including a semipreparative HPLC technique. As a result, two proanthocyanidins were isolated and identified using NMR, epicatechin-(2 b?O?7, 4 b?8)-catechin (proanthocyanidin A1) and epicatechin-(b?2 O?7, 4 b?8)-epicatechin (proanthocyanidin A2). Despite the structural similarity, differences were observed in their antioxidant activity. Proanthocyanidin A1 proved to be more active, with EC50 value for DPPH radical scavenging of 18.25 lg/mL and reduction of Fe3+–TPTZ complex of 7.59 mmol/g, higher than that of synthetic antioxidant BHT. This compound evaluated by ABTS+_ was similar to that of natural quercetin. Therefore, peanut skin is an important source of bioactive compounds that may be used as a mild antioxidant for food preservation.
Identification of a bioactive compound isolated from Brazilian propolis type 6.
(2009) Castro, Myrella Lessio; Nascimento, Andréa Mendes do; Ikegaki, Masaharu; Costa Neto, Cláudio Miguel da; Alencar, Severino Matias de; Rosalen, Pedro Luiz
A prenylated benzophenone, hyperibone A, was isolated from the hexane fraction of Brazilianpropolistype6. Its structure was determined by spectral analysis including 2D NMR. This compound exhibited cytotoxic activity against HeLa tumor cells (IC50 = 0.1756 μM), strong antimicrobial activity (MIC range—0.73–6.6 μg/mL; MBC range—2.92–106 μg/mL) against Streptococcus mutans, Streptococcus sobrinus, Streptococcus oralis, Staphylococcus aureus, and Actinomyces naeslundii, and the results of its cytotoxic and antimicrobial activities were considered good.
Isolation and analysis of bioactive isoflavonoids and chalcone from a new type of Brazilian propolis.
(2011) Oldoni, Tatiane Luiza Cadorin; Cabral, Ingridy Simone Ribeiro; d’Arce, Marisa Aparecida Bismara Regitano; Rosalen, Pedro Luiz; Ikegaki, Masaharu; Nascimento, Andréa Mendes do; Alencar, Severino Matias de
Activity-directed fractionation and purification processes were employed to identify isoflavonoids with antioxidant and antimicrobial activities from Brazilian red propolis. Crude propolis was extracted with ethanol (80%, v/v) and fractioned by liquid–liquid extraction technique using hexane and chloroform. Since chloroform fraction showed strong antioxidant and antimicrobial activities it was purified and isolated using various chromatographic techniques. Comparing our spectral data (UV, NMR, and mass spectrometry) with values found in the literature, we identified two bioactiveisoflavonoids (vestitol and neovestitol), together with one chalcone (isoliquiritigenin). Vestitol presented higher antioxidant activity against β-carotene consumption than neovestitol. The antimicrobial activity of these three compounds against Staphylococcus aureus, Streptococcus mutans, and Actinomyces naeslundii was evaluated and we concluded that isoliquiritigenin was the most active one with lower MIC, ranging from 15.6 to 62.5 μg/mL. Our results showed that Brazilian red propolis has biologically active isoflavonoids that may be used as a mild antioxidant and antimicrobial for food preservation.