Lipophilic Antioxidants in Human Sebum and Aging

Skin surface lipids (SSL), a very complex mixture of sebum mixed to small amounts of epidermal lipids, mantle the human epidermis, thus representing the outermost protection of the body against exogenous oxidative insults. The present work is a systematic and quantitative analysis of upper-chest SSL and their content in antioxidants in 100 healthy volunteers, divided into five age groups using TLC, HPLC, and GC-MS methods. Further, the effect of exposing SSL in vitro to increasing doses of UV irradiation was examined. Straight monounsaturated and diunsaturated as well as branched monounsaturated fatty acids of triglycerides and pooled fractions were found to be higher at maturity than in childhood and in advancing age. Diunsaturated fatty acids were below 3% of the total and constituted exclusively of C18:2 &#106 5,8 , C20:2 &#106 7,10 , C18:2 &#106 9,12 . Squalene, vitamin E (vit. E) and Coenzyme Q 10 (CoQ 10 ) were found to increase from childhood to maturity to decrease again significantly in old age. Vitamin E and CoQ 10 were the only known lipophilic antioxidants present in SSL. In spite of their low levels they were found to synergically inhibit the UV induced depletion of squalene, cholesterol and of unsaturated fatty acids of SSL. In fact, exposure of SSL to increasing amounts of UV irradiation led preferentially to lowering of the levels of vit. E and CoQ 10 . Four minimal erythema dose (MED) (5.6 J/cm 2 ) were able to deplete 84% vit. E and 70% ubiquinone, and only 13% squalene. Diunsaturated and monounsaturated fatty acids as well as cholesterol were unaffected even following 10 MED UV exposures, which produced a 26% loss of squalene. The same UV dose when applied in the absence of vit. E and CoQ 10 produced a 90% decrease of squalene.     

Intraspecific polymorphism of pollen sculpture inParis tetraphylla A. Gray (Liliaceae)

Paris tetraphylla has a greater diversity of pollen exine sculpture than was previously thought. On the basis of 357 plants from 52 localities of Japan, we distinguished seven sculpture types that are tentatively referred to here as G₁, G₂, G₃, R₁, R₂, R₃ and S. G₁, G₂ and G₃ have gemmate sculpture in which the gemmae are characteristically large, medium and small in size, respectively; likewise, R₁, R₂ and R₃, have coarsely to finely ruglate sculpture; and S, scrobiculate sculpture. In general, any one of the seven types always or predominantly occurs in each plant, thus allowing us to make comparisons among plants and further among local populations. We thus found that G₂ and G₃, respectively, are the most and the second most widespread and occur in plants of 41 and 22 respectively, of the localities examined, although their frequencies differ with locality. Generally R₃ occurs in plants distributed at higher latitudes, while R₂ is rather widespread and common to plants growing on high mountains. G₁ and R₁ are restricted to plants occurring south of Ibaraki Pref. and north of Gunma Pref., respectively. Such localized distributional patterns of some types may reflect the reproductive nature and the history of geographical isolation inParis tetraphylla over the Japanese Islands.