Studies on the Production of Sweet Substances in Stevia rebaudiana : 1. Simple determination of sweet glucosides in Stevia plant by thinlayer chromato-scanner and their accumulation patterns with plant growth

摘要

The purpose of this investigation is to establish a simple method for quantitative determination of sweet substances in Stevia plant and to clarify their accumulation patterns during the growing process. The results obtained were as follows. 1. Five or six kinds of glycosides existed in the dried leaves of Stevia plant. Two of them were respectively identified as stevioside and rebaudioside A by one and two dimentional thin-layer chromatography. 2. The solvent systems composing of n-butanol : methanol : water (8 : 1 : 1 V/V) and n-butanol : ethylacetate : iso-propanol : water (35 : 100 : 65 : 30 V/V) were available for separation of stevioside and rebaudioside A from other glycosides on chromo-plate. Besides, it was confirmed that application of thin-layer chromato-scanner made it possible to determine stevioside and rebaudioside A on the developed plate, quantitatively. 3. It was observed that stevioside content and its accumulation in Stevia leaves rapidly increased during the period from vegetative to reproductive growth and the content of stevioside in leaves was markedly higher than that in stem and root. Besides, the accumulation pattern of rebaudioside A was similar to that of stevioside but its content in leaves was always lower than that of stevioside at any stages of growth.