Heartwood formation is the metabolic process that transforms living cells of sapwood into dead cells of heartwood. During this process, extractives are formed from reserve materials like non-structural carbohydrates. We studied radial distributions of non-structural carbohydrates and phenolics from Malaysian plantation-grown teak of. Sugars were analysed by thin layer chromatography coupled to an enzymatic assay. Phenolic compounds were separated and detected by HPLC. In sapwood and heartwood, we quantified main nonstructural carbohydrates (starch, sucrose, glucose and fructose) and four main phenolic compounds (one hydroxycinnamic acid derivative labelled = H1; the tectoquinone = Q1 and the 2-hydroxymethylanthraquinone= Q2; an unknown compound = P1). Seven non-structural carbohydrates (starch, glucose, fructose, sucrose, raffinose, stachyose and two unknown compounds) were detected in sapwood. Main sugars (starch, glucose, fructose and sucrose) are highly accumulated (72, 11.6, 12.8 and 4 µmol / g dry wood - dw respectively) in sapwood and decrease drastically in heartwood. H1 is only detected in sapwood. Q1 is also detected in sapwood but accumulated in high amounts (21 µmol / g dw) in heartwood. Q2 and PI are only detected in heartwood in high amounts (6.6 µmol /g dw and 3.4 mg eq. 5-methoxyflavone / g dw respectively). Our results suggested that starch represents the major reserve source of non-structural carbohydrates for the synthesis of heartwood phenolics and together with soluble nonstructural carbohydrates take part to the synthesis of phenolics accumulated in teak wood as H1, Q1, Q2 and P1 . H1 and Q1 may be the phenolic precursors of the synthesis of heartwood extractives. Hence the radial distribution of non-structural carbohydrates and of phenolic compounds can be used as chemical determinants of the heartwood formation in teak wood. (Texte intégral)