Avaliação das potencialidades terapêuticas do óleo de rã-touro (Rana catesbeiana Shaw) e de diferentes sistemas nanoestruturados desenvolvidos a base de óleo de rã-touro

Abstract

Bullfrog oil is a sub-product obtained from the adipose tissue of the amphibious Rana catesbeiana Shaw, which, due to literature reports around its chemical composition, it has been a target of several studies regarding its therapeutic proprieties. Thus, the aim of this study was to evaluate the therapeutic properties and cytotoxocity of the bullfrog oil and to develop different bullfrog oil-based nanostructured systems. Initially, a new oil extraction method was proposed, following its physicochemical and chemical characterization. The thermo-oxidative characterization was also performed. In addition, technological approaches were used to develop different nanosystems (a nanoemulsion for oral use, a nanoemulsion for topical use, a microemulsion and nanocapsules), following the evaluation of their therapeutic activities on the inflammatory process as well as their in vitro cytotoxicity against healthy and tumor cells. In vivo experiments were performed to confirm the bullfrog oil’s and nanocapsules’ anti-inflammatory activity. The physicochemical characterization showed that the extraction by heating allowed the obtainment of product with adequate quality for further use. The chemical characterization showed the presence of saturated and unsaturated fatty acids. All nanostructured systems were successfully developed and, both systems and in natura bullfrog oil did not promote toxicity against healthy cells. Additionally, the anti-inflammatory activity was confirmed. The performed experiments using tumor cells showed that the bullfrog oil and the nanosystems were able to induce a reactive oxygen species (ROS) over production leading to cell death by apoptosis (when in natura oil was tested) or necrosis (when the systems were tested). Finally, this study allowed us to elucidate different biological activities of the bullfrog oil, the ability of the nanostructured systems in increasing the therapeutic effects, without interfering in the oil biocompatibility and, lastly, allowed us to describe unprecedented data around the bullfrog oil antiinflammatory and antitumor pathways, which were involved the inhibition of the inflammatory mediators production and ROS over production, respectively. In conclusion, it was possible to prove that the bullfrog oil is a potent bioactive product able to act on inflammatory processes and with potential activity on melanoma treatment.