Changes in the content of D-chiro-inositol and its α-D-galactosyl derivatives during vegetation and desiccation of common buckwheat (Fagopyrum esculentum Moench)

Common buckwheat (Fagopyrum esculentum Moench) is the only crop that contains D-chiro-inositol (DCI) in significant contents in vegetative tissues and its α-D-galactosyl derivatives in seeds. Besides DCI, buckwheat tissues contain small contents of D-pinitol (PIN) and myo-inositol (MIN) and their α-D-galactosyl derivatives. D-chiro-inositol is a health-promoting cyclitol of increasing importance in the treatment of some human diseases. However, changes in DCI content in stems, leaves and maturing buckwheat seeds during plant vegetation and under desiccation were not known. The present study analyzed the concentration of cyclitols and their galactosides in the stems, leaves and seeds of plants harvested on 79th, 94th and 123th days after sowing (DAS) and after desiccation at ambient temperature (23° ±2°C). D-chiro-inositol content in stems and leaves increased with vegetation, while the opposite trend was found in developing and maturing seeds. In the seeds, the accumulation of mono-galactosyl DCI derivatives increased, but at the same time, the content of mono-galactosyl PIN and MIN derivatives decreased. The desiccation process drastically increased the content of di-galactosyl derivatives of DCI and MIN in the seeds. The obtained results suggest a protective role of DCI and MIN di-galactosides against desiccation stress in buckwheat tissues.