Table 4 Phenolic compounds and avenanthramide-C content in oat grains (µg/g) affected by Cu-BTC treatments and oat extracts under calcareous soil conditions

Catechol

nd

nd

0.748

0.774

nd

nd

nd

nd

nd

nd

1.828

Caffeiec acid

nd

1.132

1.226

nd

1.844

0.112

0.932

nd

0.088

1.122

0.866

Ferulic acid

3.066

0.866

nd

0.21

1.428

1.624

nd

1.234

1.532

2.748

2.816

O-Coumaric acid

nd

nd

nd

nd

nd

nd

nd

2.292

1.194

nd

nd

Gallic acid

0.836

nd

nd

3.736

2.258

nd

1.174

0.812

1.494

1.014

1.536

Chlorogenic acid

0.916

nd

0.138

0.09

nd

nd

nd

nd

2.338

0.96

nd

Syringenic acid

nd

nd

nd

1.512

1.25

nd

1.934

0.776

nd

nd

1.738

P-OH benzoic acid

nd

nd

1.662

nd

nd

0.246

1.502

nd

1.686

nd

nd

Cinnamic acid

nd

1.712

2.378

0.992

2.61

0.538

0.0156

1.498

nd

0.91

1.53

Salicylic acid

1.196

0.63

nd

nd

0.428

1.538

nd

1.628

0.156

nd

nd

Ellagic acid

nd

1.932

nd

0.534

2.956

nd

nd

1.246

0.138

nd

3.472

Pyrogallol

nd

nd

nd

nd

nd

1.094

nd

nd

nd

nd

nd

Protocatechulic

0.732

nd

1.974

nd

nd

2.016

nd

nd

0.026

0.738

nd

Cumulative free phenolics

6.746

6.272

8.126

7.848

12.774

7.168

5.5576

9.486

8.652

7.492

13.786

Avenantheramide C

14.262

22.7

57.47

51.094

62.112

20.564

41.634

51.042

47.29

27.038

107.95