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ABSTRACT: Overproduction of sebum is very common and results in an undesirable oily, shiny complexion with enlarged pores. Sebum secretion is basically under the control of 5-α reductase, and more particularly under that of type 1 isozyme. But it is also highly sensitive to environmental factors such as temperature, humidity and food. Moreover, in Asia, the edicts of a flawless facial skin turn oily skin into a major concern for Asian women. We identified Orthosiphon stamineus leaf extract as an interesting ingredient for reducing the oily appearance of skin thanks to its ability to reduce 5-α reductase type 1 expression in normal human epidermal keratinocytes in vitro. This was confirmed ex vivo, where Orthosiphon stamineus leaf extract was shown to reduce 5-α reductase activity as well as the production of squalene, one of the main components of sebum that was used as a tracer of sebum. To evaluate the efficacy of Orthosiphon stamineus leaf extract at reducing sebum-related skin imperfections in vivo, we performed two different clinical studies, one in France on a panel of Caucasian volunteers and the other one in Thailand on a panel of Asian volunteers. Using instrumental techniques as well as clinical evaluation and self-evaluation, we could highlight that an O/W cosmetic formula containing 2% of Orthosiphon stamineus leaf extract could visibly reduce the oily appearance of skin as well as the size of pores, thus leading to a significant improvement of complexion evenness and radiance. Overall, the results obtained were better than those observed with the same formula containing 1% of zinc gluconate, an ingredient frequently used in oily skin care products.
International journal of cosmetic science 02/2011; 33(1):44-52.
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ABSTRACT: A new study was carried out to bring more information on the effect of the potato proteins ferment. Basal keratinocytes obtained from freshly excised skin samples of two groups of five donors, a young one (25-36-year-old) and an aged one (59-70-year-old) were established in culture. The results showed a downward trend in the content of all lipid fractions in untreated keratinocytes of aged donors when compared with young ones. We found major differences in the response of keratinocytes to potato proteins ferment treatment between young and old donors. Whereas the lipid content of cells from young donors increased either moderately or actually decreased in some cases in comparison with the untreated controls, the lipid biosynthesis was strongly stimulated in aged donors' keratinocytes whose lipid contents globally became close to those found in young donors. However, the changes elicited by potato proteins ferment treatment were not seen at the same extent for all lipid classes. Cholesterol content increased up to three-fold and alpha-hydroxy fatty acids were augmented up to seven-fold, whereas the increase in normal fatty acids was quite moderate. In sphingolipids labelled by incubation of keratinocytes in culture medium containing [(14)C]-serine, ceramides and glucosylceramides in cells from aged donors showed the highest uptake of radioactivity, with somewhat less incorporation in sphingomyelin and gangliosides. Therefore, it seems that potato proteins ferment has a much more potent stimulatory activity on the lipid biosynthesis of basal keratinocytes of aged donors, thereby normalizing the cellular lipid content that obviously decreases along with ageing. Although our results were obtained only with basal keratinocytes in this study, potato proteins ferment could be beneficial to maintain an efficient skin barrier in ageing people, provided that the peptides can get through to the basal membrane upon topical application.
International journal of cosmetic science 04/2010; 32(3):225-32.
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ABSTRACT: SynopsisSeveral products are known to inhibit the biosynthesis of ceramides and glucosylceramides, but very few stimulate this process. We studied the influence of a hydrolysate of potato proteins (Lipidessence®) in vitro on the sphingolipid metabolism of normal human epidermal keratinocytes. By measuring growth with the thymidine uptake assay, it was seen that Lipidessence®, added in the culture medium up to an 8% concentration, did not change significantly the proliferation rate of keratinocytes, but beyond this concentration a progressive dose-dependent inhibition of growth was noticeable. Following incubation of cells with the product at 5% and 10% concentrations for 2 days, the lipids were extracted. The different lipid classes were separated by fractionation on columns of aminopropyl silica gel and analyzed by high-performance thin-layer chromatography. When keratinocytes were cultivated in the presence of Lipidessence®, the biosynthesis of cholesterol, phosphatidylcholine, phosphatidylserine and gangliosides was stimulated, and a major increase was noticeable in the biosynthesis of free fatty acids, free ceramides, glucosylceramide and sphingomyelin. Radioactive [14C]-serine was used as a precursor of sphingoid bases to study sphingolipid biosynthesis. After migration of lipid fractions on thin-layer plates, autoradiography showed that free ceramides and glucosylceramide were labeled, thus suggesting that de novo biosynthesis was accounting for the increased cellular content in sphingolipids.RésuméPlusieurs produits sont connus pour inhiber la biosynthèse des céramides et des glucosylcéramides, mais un très petit nombre peuvent stimuler ces processus. Nous avons étudiéin vitro l'influence d'un hydrolysat de protéines de pommes de terre (Lipidessence®) sur le métabolisme des kératinocytes de l’épiderme humain normal. En mesurant la croissance par incorporation de thymidine, il a été constaté que Lipidessence®, ajouté au milieu de culture jusqu’à une concentration de 8%, ne changeait pas significativement le taux de prolifération des kératinocytes, mais au-delà de cette concentration, une inhibition de croissance dépendant de la dose a été observée. Après incubation des cellules avec le produit pendant deux jours, les lipides ont été extraits. Les différentes classes de lipides ont été séparées par fractionnement sur colonnes de gel de silice aminopropyle et analysées par chromatographie en couche mince à haute performance. Quand les kératinocytes ont été cultivés en présence de Lipidessence®, la biosynthèse de cholestérol, phosphatidylcholine, phosphatidylsérine et gangliosides a été stimulée, et une augmentation majeure a été observée dans la biosynthèse des acides gras libres, des céramides libres, du glucosylcéramide et de la sphingomyéline. La [14C]-serine radioactive a été utilisée en tant que précurseur des bases sphingoides pour étudier la biosynthèse des sphingolipides. Après migration des fractions lipidiques sur plaques de chromatographie en couche mince, l'autoradiographie a montré que les céramides libres et le glucosylcéramide étaient marqués, suggèrant ainsi qu'une biosynthèse de novo rendait compte de l'augmentation du contenu cellulaire en sphingolipides.
International journal of cosmetic science 01/2006; 28(1):53 - 59.
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ABSTRACT: To show the benefits of retinol encapsulation in cosmetic industry, we compared the diffusion of two different retinol preparations through skin:oil-in-water (o/w) emulsions of retinol, also called 'free retinol', and suspension of Cylasphere including retinol, also called 'encapsulated retinol'. Two methods were used: Franz cell elucidated retinol release and storage in a hairless mouse skin according to time for the two types of preparations. The dosage of retinol by high performance liquid chromatography (HPLC) showed that encapsulated retinol was maintained into the skin for a longer time than free retinol. Raman microspectrometry measurements established a spectral image of the skin and determined the localization of retinol. Maps were collected according to time. They detailed the shifts of free and encapsulated retinol in the epidermis of a human biopsy. Spheres were smaller than droplets and they moved two times faster at this level of the skin.
International journal of cosmetic science 05/2004; 26(2):71-7.
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ABSTRACT: The effects of L-thyroxine on phospholipid biosynthesis, via (32)P incorporation, were studied in gill, kidney, liver and muscle tissue of eels acclimatized at 11 degrees C. L-thyroxine treatment had no effect on tissue content of lipid, inorganic and organic acid-soluble phosphorus. Only an increase of the specific radioactivities of lipid, inorganic and organic acid-soluble phosphorus was observed in the muscle. Percentage distribution of (32)P among classes of phospholipid were significantly altered in liver and muscle, without change in phospholipid composition. A specific effect of L-thyroxine on (32)P incorporation into phosphatidic acid in muscle and liver has been shown. As expected by the higher specific radioactivity of muscle inorganic and organic acid-soluble phosphorus, the increased incorporation of (32)P into phosphatidic acid probably results from a higher specific radioactivity of muscle ATP phosphorus.
Comparative Biochemistry and Physiology Part B Biochemistry and Molecular Biology 04/2001; 128(3):493-500. · 1.92 Impact Factor
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ABSTRACT: We have examined whether the passage of a paramyxovirus in a cell (BGM, African green monkey kidney) or animal (Swiss mouse)
can permanently modify its metabolism. In an in vitro model in which cells had been cured of a measles virus persistent infection,
the cells retained the modifications affecting lipid metabolism and composition induced during the infection. In a canine
distemper virus mouse model, the same virus-induced modifications were observed in mice after the virus had been eliminated.
Lipids 08/1986; 21(9):608-611. · 2.13 Impact Factor
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Biochemical and Biophysical Research Communications 01/1979; 85(3):916-20. · 2.48 Impact Factor
