The wax constituents of forage grasses

Abstract

IN the present paper an account is given of an investigation into the wax constituents of two very commonly occurring foliage grasses, cocksfoot (Dactylis glomerata) and perennial ryegraos (Lolium perenne). It has not been found possible to obtain as complete an analysis as that recorded in the previous paper dealing with apple-peel wax, but the results are of great interest because they have enabled us to investigate the constitution of a long-chain primary alcohol which is the main constituent of these two waxes.This alcohol has been shown to be a fairly pure sample of n-hexacosanol. Although this substance has been assumed to be present in many natural waxes and given the name of ceryl alcohol, evidence is produced that all the samples so far recorded in the literature are mixtures which may or may not contain n-hexacosanol.No paraffin was found in the cocksfoot, although a small amount was present in the ryegrass. This had M.P. 660. The literature contains many references to paraffins melting at this temperature, and from a similarity of melting-point they were always considered to be n-triacontane C30H62. We shall discuss paraffins of this type more fully in a later paper dealing with many samples of paraffins isolated by previous workers,who have very kindly placed samples of their products at our disposal for further analysis. In the present case it was quite easy to show that the paraffin, M.P. 660, was a mixture.It is shown in the discussion later that the hippocoprosterol of Bondzynski and von Humnicki [1896] and also of Doree and Gardner [1908] is the so-called ceryl alcohol. The latter authors also show quite conclusively by feeding experiments that hippocoprosterol passes through the intestines of herbivorous animals unchanged. One can conclude therefore that the n-hexacosanol found in cocksfoot and perennial ryegrass, which may be present to the extent of 1 % of the dry weight of the grass, has no feeding value.

Wax metabolism in the leaves of Brussels sprout

“…The presence of n-nonacosane and 15-nonacosanone in the wax suggested that this secondary alcohol might be 15-nonacosanol, M.P. 83-6-83.80, which had not hitherto been found in natural products, but which had been recently synthesised by Piper et al [1931]. This was confirmed by a mixed melt, which showed no depression.…”

“…Each fraction was melted alongside a sample of synthetic 0291160. From the data for mixtures of C29H60 + C31H64 and C27H56 + C2,H given in a previous paper [Piper et al 1931] we conclude that the Brussels sprout paraffin fractions consist of C29H60 with 2*5 to 10 % of C31H64. If the second paraffin had been C30H62 we should not have expected in the case of fraction 4 a fall of nearly 1°in the heating transition-point.…”

“…59.7-60°with no definite transition temperatures, showing that it was a mixture of more than 3 paraffims of mean molecular weight corresponding to C27 [Piper et al 1931]. The primary alcohol was undoubtedly a mixture of the type which we suggested in an earlier paper [Pollard et al 1931] should be called "ceryl" alcohol.…”

Further observations on the paraffins and primary alcohols of plant waxes

“…The samples from barley and runner-bean leaves have not hitherto been described. Cocksfoot, one of several samples that collectively had been used to demonstrate that the primary alcohol was Cm, with small amounts of Cm4 and C28 (Pollard et al 1931); wheat, series no. B261 (Pollard, Chibnall & Piper, 1933); apple cuticle, series no C72 (Chibnall et al 1931);lac wax (bulked samples 5, 6, 7, 11, 13 and 14), wild white clover, cactus and white mustard (Chibnall et al 1934); lucerne, series no.…”

Chemical investigation of the leaves of Anona senegalensis. I.—Constituents of the leaf wax

“…Francis et a2., 6 Pollard et aL5) . [C with a subscript here and in succeeding pages denotes the number of carbon atoms in a long straight-chain compound, e.g. with concentrated hydrochloric acid (10 c.c.).…”