Senile lentigo are hyperpigmented macules of skin that occur in irregular shapes, appearing most commonly in the sun-exposed areas of the skin such as on the face and back of the hands, and are a common component of photoaged skin. Vitamin C is well known to play an important role in maintaining skin physiology, especially as a skin whitening and blighting agent. We previously demonstrated that a new stable lipophilic pro-vitamin C derivative, tetra-isopalmitoyl ascorbic acid (VC-IP), showed significant suppressive effect for UVB-induced skin pigmentation by conversion into vitamin C in skin tissue. In addition, we reported that VC-IP showed multiple physiological activities represented by scavenging of ROS and reduction of inflammatory cytokines, IL-1α and PGE2, in keratinocytes. In this study, we evaluated that effectiveness of VC-IP on senile lentigo by conducting clinical test approved by the institutional ethical committee. VC-IP significantly improved brightness of aging spot and skin tone to evenness by mechanical measurements. Moreover, self-assessment study demonstrated that subjects were satisfied with the following parameters; appearance of aged spot, skin brightness, fading of dullness or yellowing and zero adverse reaction. Furthermore, we newly identified that VC-IP strongly suppressed the melanin delivery by inhibition of dendrite elongation stimulated by endothelin-1 in melanocytes-keratinocytes co-culture system. There are still many discussions on how senile lentigo represents in skin, however, these results suggested possibility that VC-IP is effective for improving hyperpigmented spot based on controlling of melanocytes-keratinocytes interaction.

New lipophilic pro-vitamin C,  tetra-isopalmitoyl ascorbic acid (VC-IP),  suppresses senile lentigo through controlling of melanocytes-keratinocytes interaction.