Variation of loganin content in Cornus officinalis fruits at different extraction conditions and maturation stages

Figures & data

Fig. 1. Chemical structure of loganin from C. officinalis fruits.

Table 1. A BBD for extraction conditions on loganin content.

Run order	Actual variables (Coded variables)			Observed values
	Extraction time (min) X1	Extraction temperature (°C) X2	Ethanol concentration (%) X3	Loganin^a (μg/mg dried fruit)
1	60 (0)	30 (−1)	0 (−1)	8.35
2	90 (1)	50 (0)	0 (−1)	6.52
3	30 (−1)	50 (0)	0 (−1)	8.03
4	60 (0)	30 (−1)	100 (1)	5.61
5	60 (0)	50 (0)	50 (0)	8.99
6	90 (1)	30 (−1)	50 (0)	5.45
7	60 (0)	70 (1)	0 (−1)	8.02
8	30 (−1)	70 (1)	50 (0)	8.95
9	60 (0)	70 (1)	100 (1)	5.18
10	30 (−1)	30 (−1)	50 (0)	9.49
11	90 (1)	50 (0)	100 (1)	3.25
12	90 (1)	70 (1)	50 (0)	4.49
13	60 (0)	50 (0)	50 (0)	9.18
14	60 (0)	50 (0)	50 (0)	9.80
15	30 (−1)	50 (0)	100 (1)	5.22

^a Loganin content was calculated by HPLC analysis.

Table 2. Regression coefficients and their significances in the second-order polynomial regression equation for loganin content.

	Coefficient	Standard error	t-value	p-value
Intercept	9.3233	0.4905	19.008	<0.001
X1	−1.4975	0.3004	−4.986	0.004
X2	−0.2825	0.3004	−0.941	0.390
X3	−1.4575	0.3004	−4.853	0.005
X12	−1.6317	0.4421	−3.691	0.014
	−0.5967	0.4421	−1.350	0.235
	−1.9367	0.4421	−4.380	0.007
X1X2	−0.1050	0.4248	−0.247	0.815
X1X3	−0.1150	0.4248	−0.271	0.797
X2X3	−0.0250	0.4248	−0.059	0.955

Fig. 2. Response surface plots of extraction variables on loganin content of C. officinalis fruits.

Table 3. Predicted and observed values of loganin content under optimized condition.

Extraction condition			Loganin (μg/mg dried fruit)
Extraction time (min)	Extraction temperature (°C)	Ethanol concentration (%)	Predicted	Observed
46.7	46.2	32.0	9.94	10.41

Table 4. Color measurement of C. officinalis fruits of three different maturation stages.

	CF1	CF2	CF3
L*	45.05 ± 0.004	43.83 ± 0.12	44.01 ± 0.06
a*	3.65 ± 0.01	10.21 ± 0.14^#	17.82 ± 0.03^#
b*	9.29 ± 0.03	10.83 ± 0.04	10.00 ± 0.04

Values were measured by color-difference meter.

^# Significantly different from CF1.

Fig. 3. Photographs of C. officinalis fruits of different maturation stages (A), HPLC chromatogram of extract (B), and loganin content in the extract (C).