Figure 1.
HPLC chromatograms and UV spectra of vitamin D components in a mixed mushroom extract.
Chromatography on a Vydac® ODS column developed using (A) acetonitrile:methylene chloride (70∶30) (the solvent system used previously for quantitation of vitamin D2 [14]), showing co-migration of the putative vitamin D4 with vitamin D3 in this system; (B) developed with acetonitrile:methanol (1∶1) mobile phase, showing separation of the peak containing putative vitamin D4 and vitamin D3 into two components.
Figure 2.
High resolution mass spectral comparison of putative vitamin D4 isolated from mushroom.
(A) Spectrum of HPLC-purified mushroom isolate corresponding to vitamin D4 with structure and breakdown products highlighted. (B) Spectrum of vitamin D4 standard.
Figure 3.
Spectral analysis of putative dihydroergosterol in a mushroom isolate.
(A) High resolution mass spectrum of purified mushroom isolate corresponding to dihydroergosterol. (B) Gas chromatogram of products obtained following derivatization of the purified mushroom isolate with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). (C) Low resolution GC-MS of derivatized mushroom product at t = 17.20 min corresponding to dihydroergosterol with structure and breakdown products highlighted. (D) Low resolution GC-MS of commercially available ergosterol standard following derivatization with BSTFA.
Table 1.
Vitamin D4 and pre-vitamin D4 (22,23-dihydroergosterol; ergosta-5,7-dienol) content of ten types of mushrooms.
Figure 4.
Relationship between the vitamin D4 and vitamin D2 concentrations in ten types of mushrooms (Table 1).
Data for vitamin D2 were previously reported [14].
Table 2.
Comparison of assayed concentrations of ergosterol (vitamin D2 precursor) and 22,23-dihydroergosterol (vitamin D4 precursor) in white and brown button mushrooms.
Figure 5.
Structure of six forms of vitamin D their sterol precursors.