Development and characterization of photoprotective formulations containing keratin particles

This work deals with development and evaluation of MFQ protective formulation, which contains two organic filters, namely: octyl-p-methoxycinnamate (OMC) and benzophenone-3 (BP-3); a photostabilizing agent called ethylhexylmethoxycrylene (EHMCR) and keratin particles. The MFQ formulation was evaluated in order to measure its pH, spin-spin lattice relaxation time (T2H), occlusivity factor, formulation efficacy, photostability and skin permeation, as well as keratin particle properties. Keratin particle size increased when incorporated to formulation, however, it did not affect pH. The MFQ formulation was found to be photostable and photoprotective, as evidenced by sunlight photostability test, sun protection factor (SPF), UVA/UVB ratio and critical wavelength. Interaction between keratin particles and active substances (OMC, BP-3 and EHMCR) was evidenced by T2H measurements. Evidences suggest that keratin reduces the permeation of both UV filters employed along this study, therefore, it can be stated that keratin has a promising potential for use in sunscreen formulations.

In vitro and in vivo evaluation of efficacy and safety of photoprotective formulations containing antioxidant extracts

ABSTRACT Chronic exposure to solar radiation could contribute to premature skin aging and skin cancer. Skin presents its own antioxidant defense, however when defenses are out of balance, reactive oxygen species could damage biological structures. In the present work, an oil-in-water photoprotective emulsion was developed and Bauhinia microstachya var. massambabensis Vaz, Fabaceae, extracts at 1% (obtained by extraction with different solvents) were added to this emulsion. In vitro and in vivo efficacy and safety of the formulations were evaluated. Spectrophotometric methods and in vivo Colipa test were performed to evaluated efficacy of the formulations, through sun protection factor (SPF) determination and UVA protection factor assessment. To the in vitro safety assessment HET-CAM, CAM-TBS and Red Blood Cell tests were performed. Results showed that both extracts contributed to a higher in vivo photoprotection (SPF 18) when compared to the formulation without extract (SPF 13), this result could be attributed to the antioxidant activity of the plant extracts that act by capturing reactive oxygen species. Concerning safety, all formulations were considered non-irritant according to in vitro tests. Formulations containing extracts could be considered efficient and safe for cosmetic use since they presented higher sun protection factor and passed the toxicity tests.

Identification and properties of two extracellular proteases from Brevundimonas diminuta

Extracellular proteases from Brevundimonas diminuta (syn. Pseudomonas diminuta) were studied in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) containing a copolymerized substrate. Two proteases were detected migrating at 67kDa and 50 kDa: both of them hydrolysed preferentially gelatin, but casein was also degraded and a slight hydrolysis was observed with hemoglobin. No detectable extracellular proteolytic activity was found in bovine serum albumin-containing gels. The optima temperature and pH for proteolytic activity were between 40ºC and 50ºC in a pH ranging from 7.0 to 11.0, respectively. These enzymes were isolated by analytical high performance liquid chromatography (HPLC). Proteases assays with the synthetic substrate Z-Phe-Arg-MCA and inhibitors EGTA, EDTA and 1, 10 phenanthroline point out that these enzymes are metalloproteases.

Extracellular serine-proteinases isolated from Streptomyces alboniger: Partial characterization and effect of aprotinin on cellular structure

Streptomyces alboniger ATCC 12461 grown in brain heart infusion (BHI) medium produced two extracellular serine-proteinases, denoted SP I and SP II, which were purified by ammonium sulfate precipitation and aprotinin-agarose affinity chromatography. SP I was purified 88,9-fold and SP II 66,7- fold, with 33.4 percent and 10.4 percent yield, respectively. The optimum pH for the proteinases activity, using a-N-p-tosyl-L-arginine-methyl ester (TAME) as substrate, was 9-10 and the optimum temperature was 37ºC. The proteolytic activity of SP I and SP II was inhibited by aprotinin and SP I was partially inhibited by leupeptin, both serine-proteinase inhibitors. S. alboniger growth in BHI-liquid medium decreased when 5 mg/ml, 10 mg/ml of aprotinin was used, being completely inhibited with 20 mg/ml and 40 mg/ml. At the ultrastructural level, aprotinin-treated S. alboniger cells showed swelling of the bacterial body and condensation of the genetic material, probably related to the inhibition of its growth

Use of the detergent Triton in biochemical and biological research: a minireview

The use of nonionic detergents such as Triton X-100 and X-114, is of immense value in biological and biochemical research. These detergents have found numerous applications in the analysis of membrane proteins, enzymes, glycoconjugates and in the study of cytoskeleton structure. The method offers an excellent resolution when used in coordination with immunological methods such as, immunoelectrophoresis, immunoprecipitation and western blot analysis.

Detection of extracellular proteases from microorganisms on agar plates

We present herein an improved assay for detecting the presence of extracellular proteases from microorganisms on agar plates. Using different substrates (gelatin, BSA, hemoglobin) incorporated into the agar and varying the culture medium composition, we were able to detect proteolytic activities from Pseudomonas aeruginosa, Micrococcus luteus and Serratia marcescens as well as the influence that components displayed in the expression of these enzymes. For all microorganisms tested we found that in agar-BHI or yeast extract medium containing gelatin the sensitivity od proteinase detection was considerably greater than in BSA-agar or hemoglobin-agar. However, when BSA or hemoglobin were added to the culture medium, there was an increase in growth along with a marked reduction in the amount of proteinase production. In the case of M. luteus the incorporation of glycerol in BHI or yeast extract gelatin-agar induced proyease liberation. Our results that the technique described here is of value for detecting extracellular proteases directly in the culture medium, by means of a qualitative assay, simple, inexpensive, straight forward method to assess the presence of the proteolytic activity of a given microorganism colony with great freedom in substrate selection.

Sialoglycoconjugates in Trypanosoma cruzi-host cell interaction: possible biological model - a review

A number of glycoconjugates, including glycolipids and glycoproteins, participate in the process of host-cell invasion by Trypanosoma cruzi and one of the most important carbohydrates involved on this interaction is sialic acid. It is known that parasite trans-sialidase participates with sialic acid in a coordinated fashion in the initial stages of invasion. Given the importance of these sialogycoconjugates, this review sets out various possible biological models for the interaction between the parasite and mammalian cells that possess a sialylated receptor/ligand system