were clearly transported through the skin and
accumulated in the receptor compartment. The results,
shown in Fig 4, indicate that the receptor fluid of the
liposome formulation had antioxidant activity about
two times higher than that of the diffusion studies
using aqueous solution. This clearly indicates that the
liposome formulation is able to deliver more of the active
ingredients present in Roselle extracts through the skin.
The total monomeric anthocyanin contents
of the Roselle liposome formulation and the water
solution of Roselle extract was examined. It was found
that the total anthocyanin content of the Roselle extract
solution was 0.865 + 0.03 mg, whereas that in the
liposome formulation was 0.718 + 0.02 mg. In the skin
permeation study, although the percent antioxidant
activity of the receptor fluid could not truly measure
the amount of Roselle extract transported through the
skin, it showed the efficiency of liposomes as a skin
delivery system for active constituents in Roselle
extract. The antioxidant activity of Roselle extracts was
related to the total anthocyanin content via the linear
correlation shown in Fig. 1. The liposome formulation
had an advantage not only in enhancing skin
permeation of the active constituents in Roselle
extract, but also prolonging the antioxidant activity
(Table 4 and Fig. 4). In addition, liposome formulation
decreased the skin irritation of Roselle extract as shown
in Table 5A and 5B. Skins of three rabbits were
observed to show irritation with the score level 1