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In this work, different procedures were compared for the extraction of synthetic antioxidants such as propyl gallate (PG), tert-Butylhydroquinone (TBHQ), 3-tert-butyl-4-hydroxyanisole (BHA) and 3,5-di-tertbutyl- 4 hydroxytoluene (BHT) from biodiesel samples. The efficiency of target procedures was tested using liquid-liquid extraction and solid phase extraction containing different stationary phase. To accomplish this efficiency and determine the antioxidants, a method based on high performance liquid chromatography coupled with diode array detector (HPLC/DAD) was optimized. In liquid-liquid extraction was used acetonitrile and n-hexane, however, only acetonitrile presented selectivity, able to extract just PG and BHA, with recovery between 78.3 and 96.0%. Using solid phase extraction cartridges containing C-18 as stationary phase, only the PG and BHA were extracted, which the recovery was between 52.4 and 99.7%. Moreover, the macroporous poly(divinylbenzene-co-N-vinylpyrrolidone) polymer presented satisfactory results for the extraction of PG and BHA with recovery between 77.3 and 103%. All these procedures provided elimination of the sample interferences, allowing recovery with coefficients of variation always lower than 1.00%. However, the comparison of liquid-liquid extraction and solid phase extraction techniques proved that there are many difficulties in extracting, with precision and accuracy, the PG, TBHQ, BHA and BHT antioxidants contained simultaneously in complex samples such as biodiesel. These difficulties are increased when the interest is to reduce the costs of analysis by reducing organic solvent extractors and propose extraction techniques with considerable environmental benefits. [ABSTRACT FROM AUTHOR]

Topical administration of powdered shells of the land snail Megalobulimus lopesi was evaluated in Wistar rats for their healing activity in an excision wound model. The animals were distributed into three groups-G1 (control): no therapeutic intervention; G2 (vehicle controls): Lanette cream once daily; G3 (experimental animals): treated with powdered shells. Variables investigated were: wound area contraction, angiogenic activity, morphometric data, leukocytic inflammatory infiltrate, and total leukocyte count in peripheral blood. Thermogravimetric analysis and quantification and characterization of powdered shell proteins were also performed. Wound area on days 3, 7, and 14 was smaller in G3, besides presenting wound closure on day 21 for all these animals. Topical administration of the powdered shells also led to an increased number of vessels at the wound site, higher leukocyte counts in peripheral blood, and increased leukocytic inflammatory infiltrate. The results lend support to the southern Brazilian folk use of M. lopesi powdered shells, as shown by the enhanced secondary-intention healing achieved with their topical administration to wounds in rats. Topical administration caused inflammatory response modulation, crucial to accelerating the healing process, the chronification of which increases the risks of wound contamination by opportunistic pathogens.