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Ferulate-sinapyl alcohol cross-coupling reaction improves the understanding of grass cell wall lignification.
- Source :
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Industrial Crops & Products . Sep2021, Vol. 168, pN.PAG-N.PAG. 1p. - Publication Year :
- 2021
-
Abstract
- [Display omitted] • Two SA and FA cross-coupled dimers, SA-(β–O–4)-FA and α, β de-protonated SA-(β–5)-FA, were identified for the first time in vitro. • The yield of homo-coupled β–O–4 of SA was lower than 5%, which was overestimated in previous reports. • A tetrahydrofuran β–β coupled dehydrodimer of SA was discovered. During the lignification of grass cell walls, ferulate acts like a nucleation site that can cross couple with monolignols, i.e. coniferyl alcohol and sinapyl alcohol, to form dimeric products. Here we investigated in detail the ferulate-sinapyl alcohol cross-coupling products in an effort on better understanding the nature and scope of lignin-ferulate interactions. In a biomimetic oxidative system, sinapyl alcohol (SA) reacted with ethyl ferulate (FA), a simplified model for feruloyl polysaccharides in plants, to give a mixture of dozens of dimeric products. We delineated the structure of each product by GC-MS and NMR characterizations. It was found that sinapyl alcohol readily reacts with ethyl ferulate producing various cross-coupled dimers including SA-(β–5)-FA (compound 6), SA-(β–8)-FA (both ester and lactones, compounds 7 and 9), and SA-(β–O–4)-FA (compound 8) cross-coupled products in addition to homo-coupled products from ethyl ferulate or sinapyl alcohol. SA-(β–O–4)-FA 8 was identified for the first time in a vitro free radical biomimetic system and the homo-coupled SA-(β–O–4)-SA 3 from sinapyl alcohol was accurately quantified as less than 5%, while the half-open syringaresinol 5 was discovered when dimerization of SA was catalyzed by peroxidase in a biomimetic buffer system. Moreover, one new compound 18 formed by the cross-coupled linkage SA-(β–5)-FA (de-protonated) was identified by GC-MS and NMR, and one possible FA-(8–β)-SA dimer 19* was proposed. [ABSTRACT FROM AUTHOR]
- Subjects :
- *LIGNIFICATION
*ALCOHOL
*ESTERS
*FREE radicals
*DIMERS
*GRASSES
Subjects
Details
- Language :
- English
- ISSN :
- 09266690
- Volume :
- 168
- Database :
- Academic Search Index
- Journal :
- Industrial Crops & Products
- Publication Type :
- Academic Journal
- Accession number :
- 150491414
- Full Text :
- https://doi.org/10.1016/j.indcrop.2021.113587