RESUMO
AIMS: The aim of this work was to evaluate the efficacy and safety of Lippia origanoides essential oil as a preservative in industrial products. METHODS AND RESULTS: The composition, antimicrobial activity, mutagenic and toxic potential of L. origanoides were determined. Then, the effect of essential oil as a preservative in food, cosmetics and pharmaceutical products was evaluated. The essential oil of L. origanoides consisted mainly of oxygenated monoterpenes (38·13%); 26·28% corresponded to the compound carvacrol. At concentrations ranging from 0·312 to 1·25 µl ml-1 and in association with polysorbate 80, the essential oil of L. origanoides inhibited the growth of all the tested micro-organisms. The medium lethal dose in mice was 3·5 g kg-1 , which categorizes it as nontoxic according to the European Union criteria, and negative results in the Ames test indicated that this oil was not mutagenic. In combination with polysorbate 80, the essential oil exerted preservative action on orange juice, cosmetic and pharmaceutical compositions, especially in the case of aqueous-based products. CONCLUSIONS: Lippia origanoides essential oil is an effective and safe preservative for orange juice, pharmaceutical and cosmetic products. SIGNIFICANCE AND IMPACT OF THE STUDY: This study allowed for the complete understanding of the antimicrobial action and toxicological potential of L. origanoides essential oil. These results facilitate the development of a preservative system based on L. origanoides essential oil.
Assuntos
Cosméticos , Conservantes de Alimentos/farmacologia , Lippia/química , Óleos Voláteis/farmacologia , Conservantes Farmacêuticos/farmacologia , Animais , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Cimenos , Conservantes de Alimentos/química , Conservantes de Alimentos/toxicidade , Camundongos , Monoterpenos/química , Óleos Voláteis/química , Óleos Voláteis/toxicidade , Excipientes Farmacêuticos/química , Excipientes Farmacêuticos/farmacologia , Excipientes Farmacêuticos/toxicidade , Óleos de Plantas/química , Óleos de Plantas/farmacologia , Óleos de Plantas/toxicidade , Conservantes Farmacêuticos/química , Conservantes Farmacêuticos/toxicidadeRESUMO
PURPOSE: In photodynamic therapy (PDT), topically applied aminolevulinic acid (5-ALA) is converted to protoporphyrin IX (PpIX), which upon light excitation induces tumor destruction. To optimize 5-ALA-PDT via improving the highly hydrophilic 5-ALA limited penetration into the skin, we propose the use of the known skin penetration enhancer, oleic acid (OA). METHODS: In vitro skin penetration and retention of 5-ALA (1% w/w) were measured in the presence or absence of OA (2.5, 5.0, and 10.0% w/w) in propylene glycol (PG) using porcine ear skin as the membrane. In vivo accumulation of PpIX, 4 h after application, was determined fluorometrically in healthy mice skin by chemical extraction of skin samples. In vivo PpIX fluorescence kinetics was also investigated by noninvasive techniques using an optical fiber probe, for 30 min up to 24 h after topical application of 1.0% 5-ALA + 10.0% OA in PG on hairless mice skins. RESULTS: The flux and in vitro retention of 5-ALA in viable epidermis increased in the presence of 10.0% (w/w) OA. The amounts of PpIX, evaluated both by chemical tissue extractions and in vivo measurements by an optical fiber probe, increased after applying 5-ALA formulations containing 5.0 or 10.0% OA. Moreover, in vivo kinetic studies showed an increase in skin PpIX accumulation when formulations containing 10% OA were used; PpIX accumulation was also maintained longer compared to controls. CONCLUSIONS: Both in vitro and in vivo results show the OA potential as an optimizer of 5-ALA skin delivery.