Total phenolic content and antioxidant activity of Ulam raja (Cosmos caudatus) and quantification of its selected marker compounds: Effect of extraction

Figures & data

Table 1. The results of 13-run with observed responses and predicted values for extraction yield.

Run	Input factors^a		Observed extraction yield^b (°Brix)	Predicted extraction yield (°Brix)
	X1	X2
1	30	45	3.3	3.3
2	30	85	4.2	4.2
3	45	65	3.4	3.3
4	45	65	3.5	3.2
5	45	65	3.5	3.2
6	45	85	3.3	3.3
7	60	65	3.0	3.7
8	30	65	3.7	3.0
9	45	65	3.3	3.5
10	45	45	3.2	3.4
11	60	85	3.2	3.3
12	45	65	3.5	3.5
13	60	45	3.3	3.5

^aX₁: extraction time (min); X₂: extraction temperature (°C).

^bMean of triplicate determinations.

Table 2. HPLC gradient program for marker compounds.

Time (min)	Solvent A^a (%)	Solvent B^b (%)	Flow Rate (mL/min)
0.00	85	15	1.00
12.00	75	25	1.00
22.00	75	25	1.00
25.00	85	15	1.00
35.00	85	15	1.00

^aSolvent A: 0.1% aqueous formic acid.

^bSolvent B: acetonitrile.

Figure 1. Three-dimensional response surface plot for yield as a function of temperature and heating time of extraction.

Table 3. Average values of total phenolic content (TPC) and antioxidant activities (TEAC_DPPH) of the extracts under different extraction conditions.

Input factors^a		TPC^b(mg GAE^c/g *db)	TEACDPPH^b(μmol TE^d/g db)
X1	X2
30	65	37.41 ± 1.54^a	140.74 ± 1.04^b
30	85	37.22 ± 1.04^a	146.84 ± 1.39^a
60	65	36.09 ± 0.70^a	121.17 ± 2.93^c
60	85	37.76 ± 0.15^a	133.57 ± 2.60^d

^aX₁: extraction time (min); X₂: extraction temperature (°C).

^bData were written as mean ± standard deviation (n = 3).

^cGallic acid equivalent.

^dTrolox equivalent means with different online letter within a column are significantly different (p < 0.05).

*dry basis.

Figure 2. A: HPLC chromatograms of standards versus UREX (at wavelength of 280 nm); B: Quantified constituents of UREX: Average amount (in mg/g of UREX). Error bars indicate mean values ± standard deviation of three replicates. Different letters on top of each bar indicate significant different (p < 0.05) from other bars.