LC‐Orbitrap‐HRMS Determination of Two Novel Plastochromanol Homologues

Abstract

ScopeThe antioxidant plastochromanol‐8 (PC‐8) is a tocochromanol which differs from γ‐tocotrienol in having an unsaturated side chain of eight instead of three isoprene units. The recent isolation of PC‐8 from flaxseed oil indicates the additional presence of lower shares of two previously unknown homologues, plastochromanol‐7 (PC‐7) and plastochromanol‐9 (PC‐9), which feature seven and nine isoprenoid units respectively on the γ‐chromanol backbone. Here, a fast LC‐Orbitrap‐HRMS method is applied for the determination of PC‐7 and PC‐9 in seven plant oils and a plant extract.Methods and resultsThe presence of PC‐7, PC‐8, and PC‐9 is confirmed in all eight investigated samples by LC‐Orbitrap‐HRMS analysis after saponification. PC‐8 amounts of ≈315–350 mg kg−1 in two flaxseed oils, ≈75 mg kg−1 in rapeseed oil, ≈38 mg kg−1 in camelina oil, ≈80–120 mg kg−1 in two mustard oils, ≈90 mg kg−1 in candle nut oil, and ≈900 mg kg−1 dry weight in Cecropia leaves are determined by quantification. Semi‐quantification of PC‐7 and PC‐9 indicated the presence of ≈0.1–1% of PC‐7 and PC‐9 in varied relative ratios.ConclusionThe novel plastochromanol homologues are of particular interest to researchers with focus on vitamin E and other tocochromanols because of their unexplored bioactivity.