Abstract
In the preceding papers of this series, the author dealt with such subjects as (a) systematic separation and identification of the volatile components of various seaweeds, (b) the so-called “tang of the sea”, and the principle of aromatic and odoriferous compounds of seaweeds and (c) pharmacological activity of these volatile components.
In the present report, the author discusses the biochemical significance of the volatile constituents and the difference between the volatile constituents of Chlorophyceae, Pheophyceae and Rhodophyceae, bassing on the data hitherto reported as well as those newly presented here. The results obtained are as follows:
1. Dimethylsulfide and acrylic acid are found in Chlorophyceae and some species of Rhodophyceae, but not in Pheophyceae.
2. Higher boiling parts of the fatty acid fraction and the neutral fraction, as well as and the phenolic fraction, do not differ with seaweeds, but the contents of n-valeraldehyde is larger in Pheophyceae than in Chlorophyceae (Fig. 8, Fig. 9).
3. The lower boiling part of the neutral fraction shows difference between Chlorophyceae, Pheophyceae and Rhodophyceae: Furfuryl alcohol is present both in Chlorophyceae and Pheophyceae but not in Rhodophyceae. The alcohol with the Rf 0.21 on the chromatostrip is present only in Rhodophyceae, and the alcohol of Rf 0.35 occurs only in Pheophyceae.
4. The biochemical significance of the compounds which are obtained as volatile constituents is discussed. It should be noted that acrylic acid, which has been detected in Chlorophyceae by gas chromatographic technique (Fig. 6), may be derived to β-alanine by algae in the process of assimilating ammonium, nitrite or nitrate.
5. Of the volatile constituents, dimethylsulfide, benzaldehyde, n-valeraldehyde, α-methylfurfural, furfural, furfuryl alcohol, linalool, geraniol, and 1; 8-cineol are aromatic compounds of seaweed, while methanthiol, trimethylamine, lower boiling part of fatty acids, unsaturated fatty acids, p-cresol are odoriferous compounds.
