11′-α-Tocomonoenol is the major α-tocomonoenol isomer in cyanobacteria and microalgae from Costa Rica

alpha-Tocomonoenols are vitamin E-derivatives with a single double-bond in the tocochromanol sidechain. Currently, two congeners are known: 11'-alpha-tocomonoenol and 12'-alpha-tocomonoenol, the later better known as marine-derived tocopheml (MDT). Information regarding their presence in photosynthetic aquatic organisms is scarce. We thus determined vitamin E congeners and derivatives in micmalgae and cyanobacteria to assess their potential as sources of alpha-tocomonoenols. Tocochromanols were extracted from freeze-dried cyanobacteria (Arthrospira platensis) and microalgae (Nannochloropsis oceanica, Chlorella vulgaris and Tetraselmis sp.) and quantified by HPLC-FLD. alpha-Tocomonoenol was quantified in N. oceanica and Tetraselmis sp. where it was the second most abundant tocochromanol following alpha-tocopherol. LC-MSn and GC-MS confirmed that 11'-alpha-tocomonoenol and not MDT was the predominant alpha-tocomonoenol form in evaluated cyanobacteria and microalgae. No significant correlations were observed between tocomonoenol or vitamin E contents and fatty acid profiles. In conclusion, microalgae and particularly Tetraselmis sp. are novel sources of 11'-alpha-tocomonoenol, a tocochromanol not previously reported in aquatic photosynthetic organisms.

Automated summary

This study identified 11'-alpha-tocomonoenol as the predominant form of tocochromanol in cyanobacteria and microalgae, particularly Tetraselmis sp., and reported its presence in aquatic photosynthetic organisms for the first time.