The Occurrence of Phenols as Degradation Products of Natural Sporopollenin – a Comparison with "Synthetic Sporopollenin"

Abstract

1. A highly purified sporopollenin fraction from Corylus avellana pollen was obtained using a gentle method employing hydrolyzing enzymes (pronase, lipase, cellulase, amylase, cellulysin) and an exhaustive extraction using different solvents. 2. The sporopollenin fractions were degraded by potash-fusion and nitrobenzene oxidation and the low molecular decomposition products were analyzed by TLC and HPLC. The investigation centered solely on the proof of phenolic compounds. 3. The degradation by potash-fusion yielded p-hydroxybenzoic acid as a main component, while the degradation by nitrobenzene oxidation (NBO) resulted in the formation of p-hydroxybenzaldehyde as the main component. In addition phenolic components such as p-coumaric acid, ferulic acid, vanillin and vanillic acid were formed to different degrees by using NBO as degradation procedure. 4. A comparison of the products formed following degradation of Corylus sporopollenin and “synthetic sporopollenin” shows, that phenolic compounds, if they indeed occurred as degradation products of “synthetic sporopollenin”, are generated only in extremely small quantities. It appears that, in contrast to several reports in the literature, phenols are integral constituents of natural sporopollenin. This view is supported by unpublished tracer experiments.