Release of Propolis Phenolic Acids from Semisolid Formulations and Their Penetration into the Human Skin In Vitro

Figure 1

Chromatographic determination of vanillic acid (1), caffeic acid (2), vanillin (3), coumaric acid (4), and ferulic acid (5) in aqueous propolis extract (a), epidermis (b), and dermis (c).

(a)

(b)

(c)