Extraction, Enrichment, and Quantification of Main Antioxidant Aglycones of Flavonoids and Tannins from Melastoma Dodecandrum Lour.: Guided by UPLC-ESI-MS/MS
Table 6
The contents of antioxidants and ten main flavonoids and phenolic acids in five fractions from MD.
Calibration curves
Test range (μg)
R2
MD-0%
MD-25%
MD-50%
MD-75%
MD-100%
Gallic acid
y = 1603.6x + 0.4019
0.0115–0.1842
0.9999
81.91 ± 2.46
120.69 ± 3.11
377.73 ± 5.49
126.55 ± 6.3
15.28 ± 1.06
Coumaric acid
y = 781.24x + 1.7639
0.0447–0.3579
0.9999
—
—
—
—
—
Vitexin
y = 1632.6x + 6.0558
0.0222–0.3553
0.9998
2.68 ± 0.38
18.92 ± 4.99
173.84 ± 8.16
174.79 ± 8.01
183.87 ± 0.72
Isovitexin
y = 1468.4x + 1.3678
0.0125–0.2000
0.9999
4.38 ± 1.59
9.79 ± 3.31
128.48 ± 9.6
227.49 ± 10.98
447.33 ± 4.22
Ellagic acid
y = 9669.8x + 26.979
0.0392–0.6275
0.9999
192.92 ± 3.72
248.73 ± 4.87
1303.79 ± 9.42
300.53 ± 12.3
199.55 ± 3.73
Quercetin
y = 3370.3x + 2.1296
0.0107–0.1711
0.9999
—
—
16.67 ± 2.88
21.99 ± 2.25
55.64 ± 0.9
Naringenin
y = 471.59x + 2.1251
0.0429–0.6868
0.9998
—
—
—
—
—
Luteolin
y = 4226.9x + 3.4346
0.0103–0.1645
0.9999
—
—
—
—
5.27 ± 0.84
Kaempferol
y = 2558.7x + 2.9206
0.0184–0.2947
0.9999
—
—
—
22.93 ± 3.23
133.66 ± 1.08
Apigenin
y = 2492.2x + 2.0216
0.0087–0.1395
0.9999
—
—
—
—
80.31 ± 1.43
Trolox equivalent (μmol)
68.09 ± 2.74
570.87 ± 23.94
1406.85 ± 45.37
540.18 ± 17.66
82.42 ± 4.09
Correlation coefficient of gallic acid vs antioxidants was 0.968 (); Correlation coefficient of ellagic acid vs antioxidants was 0.929 (); —not detected.
