Nanoemulsion of Minthostachys verticillata essential oil. Evaluation of biocompatibility and adjuvant activity of the immune response.

BELLINGERI R; PAOLONI C; CAMPRA NA; GROSSO C; PICCO N; CARIDDI LN

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

This study determined the morphology, biocompatibility and adjuvant effect of M. verticillata essential oil (EO) nanoemulsion. Morphometric parameters were studied by transmission electron microscopy (TEM). Wistar rat lymphocytes were exposed to EO nanoemulsion (0.3, 0.6, 30 and 60 ug/ml) for 24 h and viability was determined by trypan blue test. Balb/c mice (n=4 per group) were immunized (day 0) and revaccinated (day 14 and 28) as follows: Group 1:100 μl PBS; Group 2: 100 μl ovalbumin (OVA) 0.2 mg/ ml; Group 3: OVA + Al(OH)3 0.5 mg/ml; Group 4: OVA+EO(2.5 mg/ ml) nanoemulsion. Seven days after revaccination, serum sampleswere collected and analyzed for antigen-specific total antibodies (Ab) by indirect ELISA. For delayed-type hypersensitivity (DTH) test, animals (n=2 per group) were immunized by subcutaneous injection on days 0 and 14. Seven days after immunization animals were challenged with OVA by intradermal injection in the left footpads. The thickness of hind footpads was measured before and 24 and 48 h after the OVA injection. The difference in thickness of footpads after and before the inoculation was analyzed. TEM images show regular spheres of approximately 8.33±1.1 nm. EO nanoemulsion was not cytotoxic for rat lymphocytes at any evaluated concentration. A significant increase in Ab levels was observed in the group 3 respect to group 2 (p