Effects of temperature, time, and solvent ratio on the extraction of phenolic compounds and the anti-radical activity of Clinacanthus nutans Lindau leaves by response surface methodology

Table 4 ANOVA for the quadratic polynomial models developed for the response variables; extraction yields, DPPH radical scavenging activity and TPC of C. nutans leaves

Extraction yield (weight %)						DPPH radical scavenging activity (inhibition %)					TPC (mg GAE/g extract)
Source	Sum of squares	DF	Mean square	F value	p value	Sum of squares	DF	Mean square	F value	p value	Sum of squares	DF	Mean square	F value	p value
Model	100.54	9	11.17	2923.40	<0.0001	1185.13	9	131.68	7138.07	<0.0001	957.55	9	106.39	267.02	<0.0001
A-extraction temperature	8.28	1	8.28	2166.64	<0.0001	750.41	1	750.41	40,677.85	<0.0001	200.12	1	200.12	502.24	<0.0001
B-extraction time	11.29	1	11.29	2954.88	<0.0001	156.47	1	156.47	8481.93	<0.0001	7.81	1	7.81	19.60	0.0115
C-solvent ratio	0.72	1	0.72	187.46	0.0008	24.00	1	24.00	1301.24	<0.0001	12.34	1	12.34	30.97	0.0051
AB	51.89	1	51.89	13,579.03	<0.0001	147.54	1	147.54	7997.49	<0.0001	126.61	1	126.61	317.75	<0.0001
AC	12.22	1	12.22	3198.83	<0.0001	15.41	1	15.41	835.51	<0.0001	27.26	1	27.26	68.41	0.0012
BC	3.01	1	3.01	787.41	<0.0001	49.40	1	49.40	2678.06	<0.0001	215.12	1	215.12	539.88	<0.0001
A²	0.055	1	0.055	14.52	0.0318	269.62	1	269.62	14,615.39	<0.0001	226.83	1	226.83	569.26	<0.0001
B²	15.45	1	15.45	4042.51	<0.0001	7.77	1	7.77	421.14	<0.0001	0.00006	1	0.00006	0.00016	0.9905
C²	3.59	1	3.59	938.88	<0.0001	6.81	1	6.81	369.24	<0.0001	1.37	1	1.37	3.45	0.1368
Residual	0.011	3	0.0038			0.092	5	0.018			1.59	1	0.40
Lack of fit	0.0083	2	0.0041	1.29	0.5283	0.064	3	0.021	1.53	0.4192	0.65	3	0.22	0.23	0.8721
Pure error	0.0032	1	0.0032			0.028	2	0.014			0.94	1	0.94
Cor total	100.55	12				1185.22	14				959.15	13
R²	0.9999					0.9999					0.9983
Adj. R²	0.9995					0.9998					0.9946
Pred. R²	0.9975					0.9991					0.9826
Adequate precision	181.223					308.944					61.461

DF is the degree of freedom, A is the extraction temperature, B is the extraction time, C is the solvent ratio (water: ethanol)

ISSN: 2661-801X