Table 1. Experimental design for plant extracts using the D-optimal method

No. Independent variable (%)
A: Ecklonia cava B: Psidium guajava C: Paeonia japonica (Makino) Miyabe & Takeda
1 49 48 3
2 4 25 71
3 1 72 27
4 94 1 5
5 49 48 3
6 3 94 3
7 94 1 5
8 26 71 3
9 47 4 49
10 1 50 49
11 4 2 94
12 47 4 49
13 32 35 33
14 64 17 19
Where A+B+C=100%.