Optimization Extraction of Shikonin Using Ultrasound-Assisted Response Surface Methodology and Antibacterial Studies

Table 2

Box–Behnken design for independent variables and observed responses.

Run no.	Experimental design				Dependent variables
	Liquid-solid ratio	Ultrasonic time	Extraction temperature	Ultrasonic power	Yield (%)
1	−1	−1	0	0	1.122
2	1	−1	0	0	1.206
3	−1	1	0	0	1.11
4	1	1	0	0	1.157
5	0	0	−1	−1	1.224
6	0	0	1	−1	1.191
7	0	0	−1	1	1.213
8	0	0	1	1	1.229
9	−1	0	0	−1	1.12
10	1	0	0	−1	1.172
11	−1	0	0	1	1.128
12	1	0	0	1	1.198
13	0	−1	−1	0	1.221
14	0	1	−1	0	1.172
15	0	−1	1	0	1.217
16	0	1	1	0	1.18
17	−1	0	−1	0	1.137
18	1	0	−1	0	1.211
19	−1	0	1	0	1.154
20	1	0	1	0	1.19
21	0	−1	0	−1	1.18
22	0	1	0	−1	1.173
23	0	−1	0	1	1.189
24	0	1	0	1	1.175
25	0	0	0	0	1.253
26	0	0	0	0	1.26
27	0	0	0	0	1.247
28	0	0	0	0	1.25
29	0	0	0	0	1.258