Table 5.
Glucosinolate hydrolysis products (nmol/g fresh weight, mean ± SD) of P. novae-zelandiae and P. cheesemanii
| Glucosinolates | Isothiocyanates | Nitriles/epithionitriles | ||||
|---|---|---|---|---|---|---|
| compound | mean ± sd | % | compound | mean ± sd | % | |
| P. novae-zelandiae | ||||||
| S-2-OH-3-butenyl | goitrin | 1394 ± 698 | 12.4 | 2OH3but-CN | 590 ± 100 | 5.3 |
| epithio-2OH3B-I | 2446 ± 397 | 21.8 | ||||
| epithio-2OH3B-II | 2269 ± 371 | 20.2 | ||||
| allyl | allyl-ITC | 1622 ± 668 | 14.4 | epithio-allyl | 1868 ± 450 | 16.6 |
| 3-butenyl | 3-but-ITC | 162 ± 45 | 1.4 | - | - | |
| 3MTP | 3MTP-ITC | 449 ± 226 | 4 | 3MTP-CN | 67 ± 27 | 0.6 |
| 3MSOP | 3MSOP-ITC | 30 ± 41 | 0.3 | - | - | |
| 4MTB | 4MTB-ITC | 210 ± 122 | 1.9 | 4MTB-CN | 22 ± 14 | 0.2 |
| 4MSOB | 4MSOB-ITC | 58 ± 48 | 0.5 | - | - | |
| 8MTO | 8MTO-ITC | 27 ± 9 | 0.2 | - | - | |
| 9MTN | 9MTN-ITC | 28 ± 6 | 0.2 | - | - | |
| all | 35.3 | all | 64.7 | |||
| P. cheesemanii | ||||||
| S-2-OH-3-butenyl | goitrin | 5115 ± 981 | 60.7 | 2OH3but-CN | 32 ± 15 | 0.4 |
| allyl | allyl-ITC | 3261 ± 997 | 38.7 | epithio-allyl | 4 ± 2 | 0.1 |
| 3-butenyl | 3-but-ITC | 9 ± 4 | 0.1 | - | - | |
| all | 99.5 | all | 0.5 | |||
Note that P. novae-zelandiae is capable of converting its main glucosinoalates (S-2-hydroxy-3-butenyl and allyl) into its corresponding nitriles ((S)-3-hydroxy-pent-4-enenitril) and epithionitriles (diastereomers 1 and 2 of (S)-3-hydroxy-3-((R, S)-thiiran-2-yl)propanenitril, 2-((R, S)-thiiran-2-yl)ethanenitril) whereas P. cheesemanii is not. Despite minor glucosinolates being converted to isothiocyanates in P. novae-zelandiae, 65% of its glucosinolate breakdown products are nitriles/epithionitriles. In P. cheesemanii, 99.5% of glucosinolates are converted to isothiocyanates indicating nitrile/epithionitrile forming activity in P. novae-zelandiae but not P. cheesemanii.
Abbreviations: goitrin, goitrin; allyl-ITC, 2-propenylisothiocyanate; 3-but-ITC, 3-butenylisothiocyanate; 3MTP-ITC, 3-methylthiopropylisothiocyanate; 3MSOP-ITC, 3-methylsulfinylpropylisothiocyanate; 4MTB-ITC, 4-methylthiopropylisothiocynate; 4MSOB-ITC, 4-methylsulfinylbutylisothiocyanate; 8MTO-ITC, 8-methylthiooctylisothiocyanate; 9MTN-ITC, 9-methylthiononyl-isothiocyanate; 2OH3but-CN, S-3-hydroxy-pent-4-enenitrile; epithio-2OH3B-I, diastereomer 1 of (S)-3-hydroxy-3-((R, S)-thiiran-2-yl)propanenitril; epithio-2OH3B-II, diastereomer 2 of (S)-3-hydroxy-3-((R, S)-thiiran-2-yl)propanenitril; epithio-allyl, 2-((R, S)-thiiran-2-yl)ethanenitril; 3MTP-CN, 4-methylthiobutanenitrile; 4MTB-CN, 5-methylthiopentanenitrile.