Otwarty dostęp

Estimating flavonoid oxidation potentials: mechanisms and charge-related regression models


Zacytuj

Figure 1

The dependence of experimental Ep1 (pH = 3) on ∑s(C)AOSPRad for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.920, S.E. = 0.071, and S.E.cv = 0.080 (Model 1 in Table 2)
The dependence of experimental Ep1 (pH = 3) on ∑s(C)AOSPRad for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.920, S.E. = 0.071, and S.E.cv = 0.080 (Model 1 in Table 2)

Scheme 1

As an example, the structure of 3,3’,4’-tryhydroxyflavone (3,3’,4’THF) is given with the numbering of atoms in the skeleton
As an example, the structure of 3,3’,4’-tryhydroxyflavone (3,3’,4’THF) is given with the numbering of atoms in the skeleton

Figure 2

The dependence of experimental Ep1 (pH = 3) on ∑s(C)ΔNACCat-Neut for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.943, S.E. = 0.060, and S.E.cv = 0.065 (Model 2 in Table 2)
The dependence of experimental Ep1 (pH = 3) on ∑s(C)ΔNACCat-Neut for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.943, S.E. = 0.060, and S.E.cv = 0.065 (Model 2 in Table 2)

Figure 3

The dependence of experimental Ep1 (pH 3) on ∑s(C)ΔNACRad-Anion for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.942, S.E. = 0.061, and S.E.cv = 0.066 (Model 3 in Table 2)
The dependence of experimental Ep1 (pH 3) on ∑s(C)ΔNACRad-Anion for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.942, S.E. = 0.061, and S.E.cv = 0.066 (Model 3 in Table 2)

Figure 4

The dependence of experimental Ep1 (pH 3) on ∑s(C)ΔNACRad-Neut for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.844, S.E. = 0.100, and S.E.cv = 0.108 (Model 4 in Table 2)
The dependence of experimental Ep1 (pH 3) on ∑s(C)ΔNACRad-Neut for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.844, S.E. = 0.100, and S.E.cv = 0.108 (Model 4 in Table 2)

Figure 5

The dependence of experimental Ep1 (pH 3) on the mean values of ∑s(C)ΔNACCat-Neut, ∑s(C)ΔNACRad-Anion and ∑s(C)ΔNACRad-Neut (variables 1, 2, and 3, Table 1) for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.970, S.E. = 0.043, and S.E.cv = 0.046 (Model 5 in Table 2)
The dependence of experimental Ep1 (pH 3) on the mean values of ∑s(C)ΔNACCat-Neut, ∑s(C)ΔNACRad-Anion and ∑s(C)ΔNACRad-Neut (variables 1, 2, and 3, Table 1) for the set of 35 flavonoids. Quadratic regression yielded R2 = 0.970, S.E. = 0.043, and S.E.cv = 0.046 (Model 5 in Table 2)

Figure 6

Correlation of experimental vs. theoretical Ep1 values for the set of 35 flavonoids at pH 3 and 7 (N = 70). Theoretical values were calculated by the model: Ep1 = a1 (mean of variables 1, 2, and 3) + a2 (mean of variables 1, 2, and 3)2 + a3 NOH + a4 pH + b; r = 0.991, S.E. = 0.039, and S.E.cv = 0.042
Correlation of experimental vs. theoretical Ep1 values for the set of 35 flavonoids at pH 3 and 7 (N = 70). Theoretical values were calculated by the model: Ep1 = a1 (mean of variables 1, 2, and 3) + a2 (mean of variables 1, 2, and 3)2 + a3 NOH + a4 pH + b; r = 0.991, S.E. = 0.039, and S.E.cv = 0.042

The values for the first oxidation potential, Ep1, for 35 flavonoids at pH 3 and 7, active site (A site), the sum of atomic orbital spin populations over the carbon atoms in the skeleton of a flavonoid radical molecule, ∑s(C)AOSPRad, the sum of differences in the net atomic charges between cation and neutral flavonoid (∑s(C)ΔNACCat-Neut), radical and anion (∑s(C)ΔNACRad-Anion) and radical and neutral flavonoid (∑s(C)ΔNACRad-Neut) calculated using the PM6 in water method and their mean values, and the number of OH groups in a flavonoid.

No. Flavonoid A site Ep1/V (pH=3) Ep1/V (pH=7) s(C)AOSPRad s(C)ΔNACCat-Neut (var. 1) s(C)ΔNACRad-Anion (var. 2) s(C)ΔNACRad-Neut (var. 3) Mean var. 1-3 NOH
1 3,3′,4′THF 4′ 0.456b 0.197b 0.527 0.353 0.333 0.249 0.312 3
2 3′,4′DHF 4′ 0.513b 0.283b 0.631 0.373 0.387 0.272 0.344 2
3 3HF 3 0.751b 0.566b 0.697 0.428 0.44 0.239 0.369 1
4 5HF 5 1.164b 0.909b 0.845 0.516 0.493 0.358 0.456 1
5 7,8DHF 8 0.456b 0.225b 0.538 0.339 0.361 0.217 0.306 2
6 Apigenin 4′ 0.928c 0.696g 0.792 0.467 0.46 0.335 0.421 3
7 Chrysin 5 1.162c 0.956g 0.923 0.508 0.493 0.375 0.459 2
8 Galangin 3 0.655c 0.430b 0.733 0.437 0.444 0.244 0.375 3
9 Luteolin 4′ 0.513b 0.288g 0.631 0.366 0.38 0.266 0.337 4
10 Quercetin 4′ 0.435c 0.180g 0.519 0.350 0.325 0.248 0.308 5
11 Myricetin 4′ 0.351c 0.089d 0.364 0.281 0.253 0.229 0.254 6
12 EGC 4′ 0.307e 0.028e 0.471 0.283 0.293 0.248 0.275 6
13 EC 4′ 0.390f 0.150f 0.621 0.372 0.374 0.28 0.342 5
14 Morin 3 0.458c 0.227g 0.591 0.380 0.335 0.239 0.318 5
15 EGCG 4′ 0.367c 0.051e 0.472 0.298 0.294 0.248 0.28 5
16 ECG 4′ 0.477c 0.162f 0.622 0.362 0.374 0.276 0.337 4
17 Naringenin 4′ 0.929c 0.704h 0.790 0.480 0.462 0.356 0.433 3
18 Kaempferid 3 0.584c 0.369h 0.654 0.414 0.407 0.233 0.351 3
19 Dyhidromyricetin 4′ 0.354d 0.098d 0.470 0.305 0.302 0.245 0.284 6
20 Rutin 4′ 0.504c 0.267h 0.610 0.361 0.367 0.271 0.333 4
21 Hesperetin 3′ 0.737i 0.510i 0.751 0.423 0.429 0.322 0.391 3
22 Daidzein 4′ 0.795i 0.592i 0.772 0.451 0.432 0.328 0.404 2
23 Kaempferol 3 0.498i 0.235i 0.659 0.419 0.409 0.234 0.354 4
24 Acacetin 5 1.174i 0.952i 0.925 0.509 0.491 0.374 0.458 2
25 Naringin 4′ 0.959i 0.732i 0.791 0.466 0.463 0.348 0.426 2
26 Neohesperidin 3′ 0.766i 0.549i 0.750 0.424 0.424 0.322 0.39 2
27 Hesperidin 3′ 0.739i 0.542i 0.750 0.424 0.424 0.322 0.39 2
28 Quercitrin 4′ 0.500i 0.270i 0.610 0.361 0.367 0.271 0.333 4
29 Gossypin 4′ 0.416i 0.132i 0.515 0.349 0.328 0.244 0.307 5
30 567THF 6 0.411a 0.162a 0.409 0.304 0.293 0.233 0.277 3
31 Fisetin 4′ 0.435a 0.183a 0.524 0.355 0.331 0.252 0.313 4
32 37DHF 3 0.643a 0.474a 0.726 0.436 0.448 0.246 0.377 2
33 4′7DHF 4′ 0.948a 0.692a 0.793 0.474 0.466 0.339 0.426 2
34 Genistein 4′ 0.809a 0.613a 0.773 0.450 0.433 0.328 0.404 3
35 6HF 6 0.975a 0.751a 0.742 0.449 0.467 0.322 0.413 1

Quadratic regression models (Ep1 = ax2 + bx + c) for the estimation of Ep1 based on ∑s(C)AOSPRad, ∑s(C)ΔNACCat-Neut (var. 1), ∑s(C)ΔNACRad-Anion (var. 2), ∑s(C)ΔNACRad-Neut (var. 3) and the mean of variables 1, 2, and 3.

Model No. Independent variable (x) a (S.E.) b (S.E.) Intercept c (S.E.) R2 S.E. S.E.cv
1 s(C)AOSPRad 3.04(58) −2.27(76) 0.76(24) 0.920 0.071 0.080
2 s(C)ΔNACCat-Neut (1) 14.3(24) −7.7(19) 1.39(38) 0.943 0.060 0.065
3 s(C)ΔNACRad-Anion (2) 20.1(26) −11.9(20) 2.14(38) 0.942 0.061 0.066
4 s(C)ΔNACRad-Neut (3) 37(11) −17.3(63) 2.47(90) 0.844 0.100 0.108
5 Mean (var. 1, 2 and 3) 17.2(24) −8.2(18) 1.30(31) 0.970 0.043 0.046
eISSN:
1848-6312
Języki:
Angielski, Slovenian
Częstotliwość wydawania:
4 razy w roku
Dziedziny czasopisma:
Medicine, Basic Medical Science, other