GA 2018

In recent years the main goal in hearing loss treatment has focused in prevention, since noise exposure or ototoxic agents damages cochlear sensory hair cells which lack the capacity to regenerate, leading to permanent hearing impairment [1]. Thus, natural products have become important as preventive agents due to their protective activity in the inner ear, activity attributed mainly to bioactive compounds such as flavonoids [2]. Onion peel extract (OPE) is well known for its high content of flavonoids, among these quercetin, isoquercetin, quercitrin, rutin and others. Quercetin has shown protective effect against noise-induced hearing loss and aminoglycosides-induced ototoxicity in animal models, however OPE activity has not yet been studied in hearing loss [3]. Therefore, in this study, we demonstrated that OPE effectively increased recovery of auditory function and protection of sensory hair cells in vitro (using mouse auditory cell line: HEI-OC1 cells) and in vivo (zebrafish model of neomycin-induced ototoxicity and noise-induced hearing loss mice model). Moreover, OPE protection, in HEI-OC1 cells against neomycin-induced ototoxicity, might be mediated by anti-apoptosis mechanism. Furthermore, since it is well known that the use of extracts has advantages over the use of isolated compounds, we demonstrated the synergistic effects of the flavonoids contained in OPE by using isobologram. [1] Furness DN. Cell Tissue Res 2015; 361(1): 387-99. [2] Sanz-Fernández R, Sánchez-Rodriguez C, Granizo JJ, Durio-Calero E, Martín-Sanz E. Eur Arch Otorhinolaryngol 2016; 273(2): 341-7. [3] Hirose Y, Sugahara K, Kanagawa E, Takemoto Y, Hashimoto M, Yamashita H. Quercetin protects against hair cell loss in the zebrafish lateral line and guinea pig cochlea. Hear Res. 342 (2016) 80-85.