Attenuation of experimental TPA-induced dermatitis by acetylenic acetogenins is associated with inhibition of PLA2 activity.

Topical application of acetylenic acetogenins (AAG) from avocado (0.01-1.0mg/ear), was effective in inhibiting both 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced mouse ear edema, and in decreasing tissue myeloperoxidase activity (indicative of polymorphonuclear leukocyte influx). Maximum edema inhibition of 72% was achieved by AAG at lower concentration (0.6 mg/ear) than that of the anti-inflammatory drug indomethacin (2mg/ear). The maximum myeloperoxidase inhibition of 60% was obtained at AAG concentration 0.1mg/ear. Chemical reduction of unsaturated bonds in aliphatic chain of AAG molecules almost abrogated inhibition effect of AAG at high concentration. In vitro AAG administration reduced secretion of PGE(2) in TPA-induced keratinocytes, and inhibited total PLA(2) and sPLA(2) activities in HaCaT cells. The results indicate a topical anti-inflammatory effect of acetylenic acetogenins which is associated with inhibition of PLA(2) activity in skin.

Polyhydroxylated fatty alcohols derived from avocado suppress inflammatory response and provide non-sunscreen protection against UV-induced damage in skin cells.

Exposing skin to ultraviolet (UV) radiation contributes to photoaging and to the development of skin cancer by DNA lesions and triggering inflammatory and other harmful cellular cascades. The present study tested the ability of unique lipid molecules, polyhydroxylated fatty alcohols (PFA), extracted from avocado, to reduce UVB-induced damage and inflammation in skin. Introducing PFA to keratinocytes prior to their exposure to UVB exerted a protective effect, increasing cell viability, decreasing the secretion of IL-6 and PGE(2), and enhancing DNA repair. In human skin explants, treating with PFA reduced significantly UV-induced cellular damage. These results support the idea that PFA can play an important role as a photo-protective agent in UV-induced skin damage.