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J. Cosmet. Sci., 68, 183–194 (March/April 2017) 183 Evaluation of molecules or extracts modulating seborrhea and its consequences, using normal human culture of sebocytes and keratinocytes, skin explants models and in vivo methods: a case study PHILIPPE MONDON, ROBERTO DAL TOSO, CAROLINE RINGENBACH, LAURENT LAVAISSIÈRE, EMMANUEL DORIDOT, ÉMILIE OUVRAT, SANDRA BRAHIMI, SEDERMA, 78612 Le Perray-en-Yvelines, France (M.P., R.C., L.L., D.E., O.E., B.S.), IRB, 36077 Altavilla Vicentina, Italy (D.T.R.) Accepted for publication August 31, 2016. Synopsis Skin produces sebum through sebocytes. Hyper-seborrhea creates conditions for the development of infl amed cutaneous alterations through bacteria colonization triggering dead cell accumulation and pro-infl ammatory mediator release. Study of sebum production, its modulation, and its consequences requires complementary in vitro models in order to evaluate the effect of molecules on cell metabolisms. Clinical studies need to be performed to confi rm in vitro results. Effects of phenylpropanoids, obtained by elicitation and purifi cation from plant cell culture of Syringa vulgaris (CCSV), were studied on sebocytes, keratinocytes, and explants, all derived from normal human skins. Normal human sebocytes (NHSs) expressed markers such as cytokeratin-7, cytokeratin-4, and perilipin-2 (PLIN-2) (1) the latter being colocalized with lipid droplets. Lipid droplets clearly appeared and their size increased rapidly when lipogenic agents were used. NHS, normal human keratinocytes (NHK), and explants reacted to presence of bacterial fragments which trigger pre-infl ammatory mediator release. CCSV reduced lipid storage and release of pre-infl ammatory mediators in NHS, NHK and explants. CCSV also reduced P. acnes growth and triggered beta-defensin-2 and cathelicidin synthesis by NHS, two natural antimicrobial peptides. On volunteers, sebum production, infl amed blemishes, and retentional lesions were signifi cantly reduced after 1 month treatment with CCSV. INTRODUCTION Sebaceous glands are found in the skin of almost all mammals and are present all over the human body except palms of the hands and soles of the feet. The glands are numerous on the face, where 400–900 glands/cm² can be found ears, scalp, and upper part of the trunk are also rich in glands. Their main function is to produce sebum, a mixture of relatively Address all correspondence to Pascaline Criton at pascaline.criton@sederma.fr. Presented at the 28th Congress of IFSCC, October 27–30, 2014, Paris, France.