In conclusion, the combination of rutin with BP or BMDBM
resulted in distinct interaction profiles. Overall, rutin provided
antioxidant properties to the UVA sun care samples, and all formulations
were considered safe for human use, demonstrating a good
cutaneous compatibility. Remarkably, the association of rutin 0.1%
(w/w) and BP 6.0% (w/w) increased the SPF from 24.3 ± 1.53 to
33.3 ± 2.89. In addition, for this pair, the SPF increased after irradiation,
as was the case for the control. However, this did not occur
for the combination of rutin and BMDBM. The rutin radical scavenging
ability plays a role in preventing the inactivation of important
skin antioxidant systems and further studies must be
performed to elucidate this mechanism, involving complex chemical
interactions between the bioactive ingredient and UVA
absorbers.