Chemical Composition, Antimicrobial and Antioxidant Activities of Essential Oils from Two Avicennia schaueriana Stapf & Leechm. Ex Moldenke (Acanthaceae) Populations.

BACKGROUND: Avicennia schaueriana Stapf & Leechm. ex Moldenke (Acanthaceae) is a native species from the Brazilian mangroves presenting ecological and economic significance. This study compared the composition and the biological activities from the essential oils obtained from two A. schaueriana populations collected at Jureia-Itatins and Ilha do Cardoso. METHODS: Essential oils were obtained by conventional means, and their compositions were analyzed by GC-MS. Screening assays for antimicrobial activity were carried out by the microdilution method and the antioxidant potential was assessed by the DPPH scavenging method. RESULTS: The GC-MS analysis indicated that the Jureia oil (1) was composed mostly of the fatty acids palmitic (46.5%) and myristic (11.6%) acids, while the main components for the Ilha do Cardoso oil (2) were eugenol (19.7%), eugenol acetate (12.9%) and palmitic acid (15.1%). The oils showed an IC50 of 0.9 ± 0.011 mg/mL for 1 and 1.13 ± 0.028 mg/mL for 2 in the DPPH assay. The antimicrobial assay indicated MIC > 217 µg/mL for all tested microorganisms. CONCLUSIONS: The different essential oil composition may indicate the presence of chemotypes for A. schaueriana. The antioxidant activity of the oils was weak if compared with flavonoids. Despite the high MIC values, these oils presented some antibacterial potential against Pseudomonas aeruginosa.

Total flavonoids quantification from O/W emulsion with extract of Brazilian plants.

A new derivative spectrophotometric (DS) method was proposed and validated for quantification of total flavonoids from in O/W emulsion with polyacrylamide (and) C13-14 isoparaffin (and) laureth-7 containing Catuaba (Trichilia catigua Adr. Juss) (and) Marapuama (Ptychopetalum olacoides Bentham) extract. DS method was optimized to perform the assay in most favorable conditions. Linearity, specificity and selectivity, recovery (Rc, %), precision (R.S.D., %), accuracy (E, %), detection (LOD, microg ml(-1)) and quantification limits (LOQ, microg ml(-1)) were established for method validation. First-derivative at 388.0 nm (zero-to-peak; amplitude= +/- 0.12; wavelength range= 300.0-450.0 nm and Deltalambda = 4 nm) offered linearity for rutin concentrations ranging from 10.0 to 60.0 microg ml(-1) in ethanol 99.5%. Second-derivative provided to be unsuitable for interval evaluation obtaining unacceptable accuracy. Analytical method was validated for first-derivative, according to the experimental results: correlation coefficient (r = 0.9999); specificity to total flavonoids quantification, expressed in rutin, at wavelength 388.0 nm and selectivity with elimination of interference from matrix; Rc = 108.78%; intra- and inter-run precision (1.30-3.65% and 3.48-4.68%), and intra- and inter-run accuracy (100.00-112.19% and 101.25-118.44%); LOD = 0.62 microg ml(-1) and LOQ = 1.86 microg ml(-1).

Influence of sodium metabisulfite and glutathione on the stability of vitamin C in O/W emulsion and extemporaneous aqueous gel.

Vitamin C exerts several functions on skin as collagen synthesis, depigmentant and antioxidant activity. Vitamin C is unstable in the presence of oxygen, luminosity, humidity, high temperatures and heavy metals, which presents a significant challenge to the development of cosmetic formulations. Therefore, the utilization of an effective antioxidant system is required to maintain the vitamin C stability. The purpose of this research work was to develop prototypes of cosmetic formulations, as O/W emulsion and extemporaneous aqueous gel, containing vitamin C and to evaluate the influence of sodium metabisulfite (SMB) and glutathione (GLT), as antioxidants, on the stability of the active substance. A HPLC stability-indicating method was developed and validated for this study and stability assays were performed in 90 and 26 days and storage conditions were 5.0+/-0.5, 24+/-2 and 40.0+/-0.5 degrees C. The HPLC stability-indicating method showed linearity (r(2)>0.99), specificity, R.S.D.<1.22% and accuracy/recovery ranging from 95.46 to 101.54%. Preparations with SMB or GLT and the antioxidant-free presented results statistically distinct, demonstrating the necessity of the antioxidant system addition. O/W emulsions with SMB or GLT retained the vitamin C content >90.38% stored at 5.0+/-0.5 and 24+/-2 degrees C. For the aqueous gel with SMB or GLT, the active substance concentration was maintained >94.03%. Considering the vitamin C stability, the SMB and the GLT showed to be statistically adequate, as antioxidants, for the cosmetic formulations.

UV spectrophotometric determination of bioflavonoids from a semisolid pharmaceutical dosage form containing Trichilia catigua Adr. Juss and Ptychopetalum olacoides Bentham standardized extract: analytical method validation and statistical procedures.

A precise, accurate, and sensitive UV spectrophotometric method was developed and validated for routine quantification of total bioflavonoids, expressed as rutin, from a topical oil-in-water pharmaceutical emulsion containing the extract of Trichilia catigua Adr. Juss and Ptychopetalum olacoides Bentham. The method was validated experimentally, and the data were treated rigorously by statistical analysis. The following analytical parameters were assessed: linearity, specificity, intra- and interrun precision measured as relative standard deviation (RSD, %), intra- and interrun accuracy (E, %), recovery (Rec., %), limit of detection (LOD, microg/mL), and limit of quantification (LOQ, microg/mL). The UV spectrophotometric method was linear (r = 0.9995) for standard rutin over the concentration range of 5.0-15.0 microg/mL with specificity for total bioflavonoids (expressed as rutin) at 361.0 nm with an absence of interferents from the complex matrix; RSD of < or = 1.79%, intrarun (E = 97.88 +/- 1.75 to 99.0 +/- 0.33%) and interrun (E = 98.38 +/- 1.12 to 100.79 +/- 1.30%) accuracy; Rec. = 98.64 +/- 0.42 to 100.74 +/- 0.41%; LOD = 0.20 microg/mL; and LOQ = 0.30 microg/mL.

Validation assay for total flavonoids, as rutin equivalents, from Trichilia catigua Adr. Juss (Meliaceae) and Ptychopetalum olacoides Bentham (Olacaceae) commercial extract.

An ultraviolet spectrophotometric method was validated for total flavonoid quantitation, as rutin equivalents, present in the Trichilia catigua Adr. Juss (Meliaceae) and Ptychopetalum olacoides Bentham (Olacaceae) commercial extract. Parameters as linearity, interval (range), specificity, estimated limit of detection (LOD, microg/mL), estimated limit of quantitation (LOQ, microg/mL), recovery (R, %), precision or relative standard deviation (RSD, %), and accuracy (E, %) were established. The analytical method was validated according to the experimental results: correlation coefficient (r = 0.9997); interval (RSD = 0.15-0.47%; E = 98.98-101.24%); specificity to total flavonoids quantitation, as rutin equivalents, at wavelength 361.0 nm; LOD = 0.09 microg/mL and LOQ = 0.27 microg/mL; R = 99.36-102.14%; adequate intra- and interrun precision (0.30-0.49% and 0.31-0.81%), and intra- and interrun accuracy (100.60-102.38% and 98.58-100.38%).

Evaluation of percutaneous absorption of 4-nerolidylcathecol from four topical formulations.

Antioxidants such as vitamins E and C are known to play a significant role in ameliorating or preventing oxidative damage to the skin. However, to provide a satisfactory protection they must first permeate the skin, which serves as a permeation barrier. In this study we evaluated the influence of three different formulations (gel, gel-emulsion and emulsion) on the percutaneous absorption of 4-nerolidylcathecol, an antioxidant compound isolated from Pothomorphe umbellata root extracts. Also, the absorption of the isolated 4-nerolidylcathecol was compared with its absorption when dried P. umbellata root ethanolic extract was incorporated into a gel formulation. The 'lag time method' was employed for the analysis of the in vitro permeation data. All formulations showed satisfactory percutaneous penetration with the 4-nerolidylcathecol-gel presenting a higher rate of penetration leading to higher dry drug levels in the tissue.

Determination of diclofenac sodium in eagle's minimum essential medium with Earle's balanced salt solution.

A validated method was developed for determination of diclofenac sodium, considered a model hydrophilic drug for in vitro permeation studies, in Eagle's Minimum Essential Medium (MEM) with Earle's balanced salt solution. Liquid chromatography was used to determine diclofenac sodium. This method was developed with a reversed-phase column Supercosil LC 18, DB 25 cm x 4.5 mm; the mobile phase was methanol with 3% (v/v) acetic acid-Milli-Q water (74 + 26), and detection was at 283 nm. The detection and quantitation limits were 2.41 x 10(-8) and 3.31 x 10(-5) microg/microL, respectively. The accuracy within-day (n = 3) and day-to-day (n = 7) was 98.83%; the mean variation coefficient for inter- (n = 7) and intraday precision (n = 3) was 12.20%, thus, not exceeding 15%. This method can be used as an analytical procedure for the determination of diclofenac sodium in MEM for in vitro permeation studies.

Native Brazilian plants against nosocomial infections: a critical review on their potential and the antimicrobial methodology.

The growing incidences of drug-resistant pathogens have increased the attention on several medicinal plants and their metabolites for antimicrobial properties. These pathogens are the main cause of nosocomial infections which led to an increasing mortality among hospitalized patients. Taking into consideration those factors, this paper reviews the state-of-the-art of the research on antibacterial agents from native Brazilian plant species related to nosocomial infections as well as the current methods used in the investigations of the antimicrobial activity and points out the differences in techniques employed by the authors. The antimicrobial assays most frequently used were broth microdilution, agar diffusion, agar dilution and bioautography. The broth microdilution method should be the method of choice for testing new antimicrobial agents from plant extracts or isolated compounds due to its advantages. At the moment, only a small part of the rich Brazilian flora has been investigated for antimicrobial activity, mostly with unfractionated extracts presenting a weak or moderate antibacterial activity. The combination of crude extract with conventional antibiotics represents a largely unexploited new form of chemotherapy with novel and multiple mechanisms of action that can overcome microbial resistance that needs to be further investigated. The antibacterial activity of essential oil vapours might also be an interesting alternative treatment of hospital environment due to their ability in preventing biofilm formation. However, in both alternatives more studies should be done on their mode of action and toxicological effects in order to optimize their use.

Validation of HPLC stability-indicating method for Vitamin C in semisolid pharmaceutical/cosmetic preparations with glutathione and sodium metabisulfite, as antioxidants.

HPLC stability-indicating method was validated for Vitamin C (ascorbic acid) in semisolid pharmaceutical/cosmetic formulations containing glutathione and sodium metabisulfite, as antioxidants. The described procedure included a reliable, precise, accurate and specific method determination employing a 250mm x 4.6mm C(18) column, 0.2% metaphosphoric acid/methanol/acetonitrile (90:8:2, v/v/v) as the mobile phase and detection at 254nm. Nicotinic and ascorbic acids were employed as standards, both presenting purity of 99.0%. Linearity was established for the ascorbic acid concentrations ranging form 1.0 to 12microg mL(-1), accuracy/recovery percentage was 95.46-101.54%, precision values were 0.38 (intra-day) and 1.22% (inter-days), and LOD and LOQ were found to be 0.05 and 0.17microg mL(-1), respectively. The working mobile phase elevated the ascorbic acid retention time to approximately 3.5min at a flow rate of 1.0mL min(-1) and provided resolution of the active from the nicotinic acid (internal standard), degradation product (oxalic acid) and other excipients from the pharmaceutical/cosmetic preparations.

Thermal characterization and cytotoxicity of complexes formed by papain and cyclodextrin.

Papain is a proteolytic enzyme with restricted applications due to its limited stability. Cyclodextrins are widely used in pharmaceutical formulations once they are able to form complexes with other molecules, improving their stability and bioavailability. The purpose of the present paper was to analyze complexes formed by papain/hydroxypropyl-beta-cyclodextrin and papain/beta-cyclodextrin by thermal analysis and cytotoxicity tests to verify their possible interactions and toxicological behavior. Complex solutions were prepared at different molar ratios and collected as a function of time to be lyophilized and analyzed. Results showed changes in endothermic events and cytotoxicity profiles. A complex formation for both complexes is observed; nevertheless, beta-cyclodextrin was able to change the enzyme characteristics more efficiently.

Métodos para avaliação da atividade antimicrobiana e determinação da Concentração Mínima Inibitória (CMI) de plantas medicinais / Methods for evaluation of the antimicrobial activity and determination of Minimum Inhibitory Concentration (MIC) of plant extracts

Várias pesquisas vêm sendo desenvolvidas e direcionadas no descobrimento de novos agentes antimicrobianos provenientes de extratos de plantas e outros produtos naturais, para serem aplicados em produtos farmacêuticos e cosméticos. Atualmente, existem vários métodos para avaliar a atividade antibacteriana e antifúngica dos extratos vegetais. Os mais conhecidos incluem método de difusão em ágar, método de macrodiluição e microdiluição. A proposta dessa revisão é apresentar diferentes métodos comumente utilizados na pesquisa de novos agentes antimicrobianos, provenientes de extratos vegetais, e elucidar os principais fatores interferentes. Dessa maneira, contribuir como fonte de pesquisa para o desenvolvimento de futuros trabalhos relacionado ao estudo de atividade antimicrobiana de produtos naturais.

Several researches have been developed to search for new antimicrobial agents from extracts of plants and other natural products to be used in pharmaceutical and cosmetic products. Nowadays there are many methods to evaluate the antibacterial and antifungal activity of the plant extracts. The most known assays have been based on diffusion in agar; and micro and macrodilution methods. The purpose of this review is to describe the different methods commonly used for the determination of new antimicrobial agents from the plants extracts and elucidate the main interference factors. Moreover, this contributes as research source for future development of investigations related to the study of antimicrobial activity from natural products.

Atividade antimicrobiana de Leonorus sibiricus L.

A espécie vegetal Leonurus sibiricus L. (Lamiaceae) é utilizada pela população brasileira para os mais diversos fins, principalmente como anti-inflamatória. No presente trabalho é estudada a atividade antimicrobiana do extrato hidroalcodico a 70 por cento liofilizado (extrato bruto) de Leonurus sibiricus L.O extrato foi testado frente a Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans e Aspergillus niger, pela determinação da concentração minima inibitória, atraves do método de diluicão em tubos. O extrato bruto de Leonurus sibiricus L. inibiu o crescimento de Candida albicans, Staphylococcus aureus e Pseudomonas aeruginosa.

The present study evaluated the antimicrobial activity of the 70 percent hydroalcoholic extract from Leonurus sibiricus L., Lamiaceae. The antimicrobial activity was determined through the minimum inihibitory cancentration (MIC). The extract of Leonurus sibiricus L. was active against Candida albicans, Staphylococcus aureus and Pseudomonas aeruginosa.