Considering the skin´s function, different dermal pharmaceutical forms can be developed according to the type of therapeutic activity, active principle and excipients involved in the formulation, such as “transdermal preparations”. In the present study, the permeation parameters of the non-steroidal antiinflammatory drug, salicylic acid (SA) through synthetic membrane, polyvinyliden difluoride, and a biological membrane, egg shell membrane, with different vehicles, propylene glycol, isopropyl alcohol and carbopol gel, were determined. The reported physicochemical parameters of SA from CG were significantly higher than those obtained using PG and IP. This is attributed to the lipophilic nature of the vehicle that facilitates the release and penetration of the active principle, thus acting sinergically. The permeation profiles of SA allow us to state that permeation kinetics is of first order, so that the flux values obtained are in direct proportion to the specific rates of drug release.

In our previous studies, bacteriostatic action of flavonoids against Staphylococcus aureus ATCC 25 923 and Escherichia coli ATCC 25 922 was demostrated. In the present work synergism of their combinations in order to improve the bacteriostatic action against the same microorganisms was determined. The experiences were made in nutritive broth, maintaining constant one drug concentration (20 µg/ml) and increasing the other one. A turbidimetric kinetic method was used and by means of a mechanism previously proposed, the minimal inhibitory concentrations (MIC´s) of each flavonoid combination were determined. The MIC´s for assayed combinations against S. aureus were: variable morin - constant rutin: 157.44 µg/ml and variable quercetin - constant morin: 29.9 µg/ml. The values obtained against E. coli were: variable morin - constant rutin: 78.5 µg/ml; variable quercetin - constant rutin: 47.4 µg/ml; variable quercetin - constant morin: 25 µg/ml; variable morin - constant quercetin: 27.4 µg/ml.

In previous work the bacteriostatic action of trihydroxylated chalcones against Staphylococcus aureus ATCC 25 923 was investigated. In this work the action of 2´,4´,2-(OH)3-chalcone, 2´,4´,3-(OH)3- chalcone and 2´,4´,4-(OH)3 -chalcone against Escherichia coli ATCC 25 922 was evaluated. Growth kinetic curves of E.coli were made in nutritive broth added with increasing drug concentrations. The specific growth rates of the microorganisms were calculated by a kinetic turbidimetric method, which was previously probed and the minimal inhibitory concentrations (MIC´s) were evaluated by a mechanism of action proposed. The MICs of 2´,4´,3-(OH)3-chalcone and 2´,4´,2-(OH)3-chalcone were 46 mg/ml and 122 mg/ml, respectively. The 2´,4´,4-(OH)3-chalcone was inactive. The MIC value of 2´, 4´, 3-(OH) 3-chalcone (46 mg/ml), more active than 2´, 3-(OH) 2-chalcone (72.2 mg/ml) may be due to the introduction of an electron donating group (-OH) at position 4´ in the aromatic A- ring, which activates the region that includes the 2´-hydroxyl neighbur group and the a,b- unsaturated carbonyl group.

Os flavonóides apresentam, entre outras, uma notável atividade bacteriostática. Neste trabalho determinaram-se as concentrações inibitórias mínimas de 5,7,4'-trihidroxiflavanona (naringenina), 5,7-dihidroxiflavona e 2',4',4-trihidroxichalcona (isoliquitirigenina) frente a Staphylococcus aureus ATCC 25 923 e comparadas com valores obtidos para outras chalconas e flavanonas investigadas previamente. As velocidades específicas de crescimento e as MICs foram avaliadas por um método cinético-turbidimétrico. A sequência observada MICflavanona(inactiva) >MIC7-hidroxiflavanona (197,6 µgml-1) > MIC5,7,4'-trihidroxiflavanona (120 µgml-1) mostrou que a introdução de um grupo doador de elétrons (-OH) provoca um aumento da bioatividade. Por outro lado, MIC5,7,4'-trihidroxiflavanona (120 µg ml-1) >>> MIC2',4',4-trihidroxichalcona (29 µg ml-1) e MIC5,7-dihidroxiflavona (105 µg ml-1) >>> MIC2',4'-dihidroxichalcona (28,8 µg ml-1) permitiram concluir que a estrutura chalcona é a mais favorável para a atividade bacteriostática dentro da família dos flavonóides.

Among other properties, flavonoids present a notable bacteriostatic activity. In this paper, minimal inhibitory concentrations (MICs) of 5,7,4'-trihydroxyflavanone (naringenin), 5,7-dihydroxyflavone and 2',4',4- trihydroxychalcone (isoliquitirigenin) against Staphylococcus aureus ATCC 25 923 were determined and compared to values obtained for other chalcones and flavanones previously investigated. Specific growth rates and MICs were determined by a turbidimetric kinetic method. The observed sequence MICflavanone (inactive) >MIC7-hidroxyflavanone (197.6 µgml-1)>MIC5,7,4'-trihydroxyflavanone (120 µgml-1) showed that the introduction of an electron donating group (-OH) causes an increase in bioactivity. On the other hand, the comparisons MIC5,7,4'-trihydroxyflavanone (120 µgml-1) >>> MIC2',4',4-trihydroxychalcone (29 µgml-1) and MIC5,7-dihydroxyflavone (105 µgml-1) >>> MIC2',4'-dihydroxychalcone (28.8 µgml-1) indicated that the chalcone structure is the most favourable for bacteriostatic activity within the flavonoid family.

A atividade bacteriostática de 2’,4’,2-trihidroxichalcona, 2’,4’,3-trihidroxichalcona e 2’,4’,4-trihidroxichalcona, preparadas por condensação de 2,4-dihidroxiacetofenona e benzaldeido convenientemente substituído, contra Staphylococcus aureus ATCC 25923 foi avaliada pela técnica de difusão em placas. Importantes halos de inibição foram observados para os três compostos. Com o propósito de esclarecer a relação estrutura-atividade biológica, as concentrações inibitórias mínimas (CIM) frente a S. aureus foram determinadas, empregando o método da diluição em caldo. Os resultados obtidos foram semelhantes à 2’,4’-dihidroxichalcona, observando-se a seguinte ordem: CIM 2’,4’,3-(OH)3 > CIM 2’,4’-(OH)2 > CIM 2’,4’,4-(OH)3 > CIM 2’,4’,2-(OH). A seqüência obtida mostra que a introdução de um grupo doador de eletrons (OH) no anel aromático B provoca um aumento da bioatividade, sendo a intensidade dependente da posição do substituinte -OH.

The bacteriostatic activity of 2’,4’,2-trihydroxychalcone; 2’,4’,3-trihydroxychalcone and 2’,4’,4-trihydroxychalcone, prepared by condensation of 2,4-dihydroxyacetophenone and benzaldehyde substituted, against Staphylococcus aureus ATCC 25923 was assayed by agar plate method. The three compounds presented important inhibition halos. In order to elucidate structure-activity relationships, the minimal inhibitory concentrations against S. aureus were determined by the broth dilution method and the results obtained were compared to that of 2',4'-dihydroxychalcone. The sequence observed was: MIC 2’,4’,3-(OH)3 > MIC 2’,4’-(OH)2 > MIC 2’,4’,4-(OH)3 > > MIC 2’,4’,2-(OH)3. These results showed that the introduction of an electron donating group (-OH) in the aromatic B-ring causes an increase in bioactivity, and that the intensity of action depends on the position of the OH substitute.