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Constituents of the Unsaponifiable Lipid Fraction from the Spadix of Arum maculatum

F. W. Hemming, R. A. Morton and J. F. Pennock
Proceedings of the Royal Society of London. Series B, Biological Sciences
Vol. 158, No. 972 (Oct. 22, 1963), pp. 291-310
Published by: Royal Society
Stable URL: http://www.jstor.org/stable/90493
Page Count: 20
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Constituents of the Unsaponifiable Lipid Fraction from the Spadix of Arum maculatum
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Abstract

The mature spadix of Arum maculatum is a site of metabolic activity on a scale which can cause a localized rise in temperature of about 15 degC. The tissue contains relatively high concentrations of cytochromes and of ubiquinone. Spadices (2 kg) were digested with alkali and the hydrolysate extracted with ether to yield almost 3 g of unsaponifiable matter. Chromatography on alumina resulted in a good preliminary separation of constituents. The weakly adsorbed fractions were further studied to yield a saturated hydrocarbon fraction (80 mg) m.p. 55 degrees C and consisting mainly of C25H52 (34%) and C27H56 (53%). Evidence was also obtained for β -carotene (3· 7 mg), phytoene (0· 7 mg), phytofluene (0· 12 mg) and squalene (ca. 4 mg). A small amount of plastoquinone (1· 4 mg) was also shown to be present. More polar fractions yielded ubiquinone (50) (64· 3 mg) and α -tocopherol (7 mg) together with a small amount (1· 6 mg) of α -tocopherylquinone. A still more polar fraction was obtained and further fractionated to give a saturated alcohol m.p. 69· 5 degrees C and three highly unsaturated alcohols: (i) dolichol (24 mg), (ii) a new alcohol C50H81OH now named spadicol (12 mg), and (iii) an alcohol similar to spadicol but less polar in nature (12 mg). The most strongly adsorbed materials included a mixture of sterols (525 mg) and a number of polar carotenoids probably xanthophylls. The presence of traces of phytoene and phytofluene and the failure to find lycopersene fits current ideas of carotenogenesis; the relatively high concentration of ubiquinone (32· 3 μ g/g of tissue) matches the high cytochrome oxidase activity of the spadix, while the low content of plastoquinone echoes the virtual absence of chlorophyll and implies little photosynthetic activity in the mature spadix. The discovery of spadicol (C50H81OH) is important since the ubiquinone present in this tissue has a C50H81 side-chain.

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