Fitchia nutans Hook.f. (Asteraceae), a Polynesian endemic plant locally called “'anei”, was previously used as a skin care ingredient included in a sacred traditional monoï preparation in French Polynesia [1]. Such use indicated interesting skin care properties to investigate. For that purpose, leaves extract of F. nutans was tested on ex-vivo human skin for anti-ageing activity assays as ex-vivo systems could mirror the morphological and immunophenotypic properties of the tissues [2]. Abdominal skin ex-vivo tissues used in this study were collected from surgical procedures. Follow-up at histological level using histochemical and immunomarking techniques were performed within observation by high resolution electron microscopy [3]. Qualitative and quantitative changes of dermal collagens (I; III and IV) and elastin fibres were investigated for tested ex-vivo skins. The results indicate its potential to stimulate collagens and elastin dermal growth. To the best of our understanding, only one species (F. speciosa) in the Fitchia genus has been investigated for its chemical composition [4]. We report herein, the first phytochemical study of this plant using spectrometric and spectroscopic methods (MS, 1D and 2D NMR analysis) for structure elucidation and showing that main constituents are composed by sesquiterpenoids (such as costunolide derivatives including a new natural product: 15-isovaleroyloxydihydrocostunolide), phenylpropanoids (like butanoic acid, 3-methyl-4,'-(1-propen-1-yl)phenyl ester), and phenolic derivatives (like atranorin). All identified components contained ester functions (mostly as isovaleroyl esters). The sesquiterpene lactone costunolide is well-known for its interesting biological activities such as an antifungal on dermatophytes or as an anti-inflammatory agent [5, 6]. The presence of costunolide derivatives as the main components of F. nutans extract may contribute to the observed anti-ageing properties