Optimization of Gentisides Extraction from Gentiana rigescens Franch. ex Hemsl. by Response Surface Methodology

Figure 3

Experimental results of univariate test in four kinds of extraction conditions; (a) effect of the ethanol concentration selected as 60%, 70%, 80%, and 90%; (b) effect of the extraction temperature set at 55, 65, 75, and 85°C; (c) effect of the extraction time set at 0.5, 1, 2, 3, and 4 h; (d) effect of the ratio of liquid to material selected as 4, 6, 8, 10, and 12 mL/g.

(a)

(b)

(c)

(d)