Identification of pinitol as a main sugar constituent and changes in its content during flower bud development in carnation (Dianthus caryophyllus L.)

An unknown sugar-like compound other than glucose, fructose, sucrose and mya-inositol was detected in the ethanol extract of carnation (Dianthus caryophyllus L.) leaves and isolated using high performance liquid chromatography. The isolated compound was identified as D-(+)-chiro-inositol monomethylether (pinitol) by H-1-NMR and C-13-NMR spectra. Pinitol was the most abundant sugar in the leaf and also was present in st em, petal and the remaining part of flower in large amounts in 4 cultivars tested. In petals, the pinitol content remained constant during flower bud development on a fresh weight basis, but the organ pinitol content increased markedly. The pinitol content was also high in the other parts of the flower. These findings suggest that pinitol, a major sugar constituent, contributes to the bud growth and subsequent petal opening in the carnation together with other metabolic sugars, such as glucose and sucrose.