Table 3.

Results of the Box–Behnken design (BBD) for the extraction of tryptanthrin, indigo and indirubin.

Run	Factors			Extraction Yields
	A (HBD–HBA Molar Ratio)	B (Liquid–Solid Ratio, mL/g)	C (Temperature, ℃)	Tryptanthrin (mg/g)	Indigo (mg/g)	Indirubin (mg/g)
1	3	50	50	0.344	1.727	0.571
2	3	20	25	0.305	0.542	0.460
3	3	80	75	0.371	1.078	0.571
4	3	50	50	0.334	1.720	0.551
5	5	50	75	0.364	0.912	0.569
6	1	50	25	0.320	1.038	0.470
7	3	20	75	0.379	0.588	0.585
8	5	80	50	0.330	1.710	0.536
9	5	20	50	0.333	0.622	0.495
10	1	50	75	0.370	0.935	0.528
11	3	50	50	0.340	1.466	0.544
12	3	50	50	0.344	1.446	0.558
13	1	20	50	0.342	0.818	0.518
14	5	50	25	0.319	1.039	0.503
15	3	50	50	0.337	1.458	0.549
16	3	80	25	0.328	1.660	0.522
17	1	80	50	0.351	1.990	0.553