Seasonal Fluctuations of Plastochromanol‐8 and α‐Tocopherol Amounts in the Leaves of <scp> <i>Cecropia</i> </scp> Trees

ABSTRACT Plastochromanol‐8 (PC‐8) is a homologue of γ‐tocotrienol with a longer side chain (eight instead of three isoprene units) and therefore also a representative of the tocochromanol (vitamin E) group. PC‐8 has been determined in various plants and seeds, with Cecropia sp. leaves showing unusually high levels. In this study it was aimed to quantify PC‐8 and other tocochromanols in Cecropia leaves and to assess seasonal variations in their levels. Therefore, an LC‐MS/MS‐MRM method was developed to measure PC‐8 and other tocochromanols in leaf samples from five Cecropia plants grown in greenhouses. MALDI‐TOF‐MS and sterol pattern analysis were performed to characterize the leaves. Leaf samples from all trees were taken in summer and fall, and for one tree also in winter and spring. PC‐8 levels in leaves taken in summer ranged from ~400 to 1280 mg/kg dry weight (DW), with levels in all trees increasing ~1.5‐fold until fall (up to 1840 mg/kg DW). Samples taken in all four subsequent seasons of one tree showed maximum levels in spring. α‐Tocopherol (~610–3140 mg/kg DW in summer) was also very abundant, and its levels also varied strongly from season to season. However, contrary to PC‐8, α‐tocopherol levels were lower in fall than in summer. The recently discovered homologues of PC‐8, namely PC‐7 and PC‐9, were also identified in leaf samples of all trees, with between 0.45% and 1.95% of the PC‐8 level. In conclusion, Cecropia leaves represent an exceptionally rich source of PC‐8, with pronounced seasonal variations in tocochromanol content. The detection of PC‐7 and PC‐9 further expands the known plastochromanol profile of Cecropia sp.