Alkaline oxidation of ¹⁴C-labelled protolignin, formed from cinnamic acid in Spruce and Aspen twigs

Authors

D.G. Smith
A.C. Neish

Document Type

Article

Journal/Book Title/Conference

Phytochemistry

Volume

3

Issue

5

First Page

609

Last Page

615

Publication Date

1964

Abstract

Cinnamic acid-¹⁴C was incorporated into the lignin of spruce twigs but not appreciably into proteins or carbohydrates. Advantage was taken of this fact to study the alkaline copper oxidation of spruce protolignin without separation from other insoluble plant constituents. Cinnamic acid-[COOH]-¹⁴C (carboxyl-labelled) fed to spruce cuttings formed lignin which on oxidation gave about 16% of the isotopic carbon as carbon dioxide and 28% as formic acid whereas cinnamic acid-α-¹⁴C lignin gave 23 % as carbon dioxide and 4–5% as formic acid. Cinnamic acid-ring β-¹⁴C lignin gave 4–3% of ¹⁴C as carbon dioxide and 5–4% as vanillin. Similar results were obtained with aspen twigs, although they incorporated a small amount of ¹⁴C into protein. The main results can be interpreted on the assumption that a guaiacyl glycerol ether unit is an important part of protolignin.

Recommended Citation

Smith, D.G., Neish, A.C. 1964. Alkaline oxidation of 14C-labelled protolignin, formed from cinnamic acid in Spruce and Aspen twigs. Phytochemistry 3(5):609-615.