Table 1 Phenolic composition (μg/mg extract) of six different Quercus dilatata extracts
Standards | Retention time (min) | Samples | |||||
|---|---|---|---|---|---|---|---|
Et | CM | MEt | DA | M | D | ||
Hydroquinone | 10.07 | -- | -- | -- | -- | -- | -- |
Pyrocatechol | 12.06 | 0.049 | 0.013 | 0.361 | 0.232 | 0.111 | 0.017 |
Gallic acid | 15.24 | 0.534 | 0.499 | 2.822 | 5.282 | 2.112 | 1.382 |
Resorcinol | 17.48 | -- | -- | -- | -- | -- | -- |
Catechin | 23.61 | -- | 0.150 | 2.291 | 1.380 | 0.808 | 0.095 |
Chlorogenic acid | 25.80 | 1.009 | 2.699 | 9.478 | 15.336 | 7.122 | 5.162 |
Caffeic acid | 27.51 | -- | -- | -- | -- | -- | -- |
Vanillic acid | 28.21 | 1.271 | -- | -- | -- | -- | -- |
p-Coumaric acid | 30.16 | 0.534 | 0.146 | 0.232 | 1.026 | 0.339 | 0.036 |
Ferulic acid | 34.87 | 0.701 | 0.046 | 0.461 | 0.173 | 0.192 | -- |
Sinapinic acid | 38.48 | -- | -- | -- | -- | -- | -- |
Coumarin | 44.85 | 0.105 | 0.105 | 0.368 | -- | 0.149 | -- |
Salicylic acid | 50.05 | -- | -- | -- | -- | -- | -- |
Trans cinnamic acid | 54.44 | -- | -- | -- | -- | -- | -- |
Rutin | 58.79 | 1.181 | 0.094 | -- | 0.245 | 0.407 | -- |
Quercetin | 63.13 | 0.164 | 0.060 | 0.969 | 0.616 | 0.085 | 0.059 |
Ellagic acid | 67.35 | -- | -- | -- | -- | -- | -- |
Kaempferol | 73.06 | 0.291 | 0.069 | 0.284 | -- | 0.129 | -- |