| from tryptophan | 5 | other |
| from animals | 4 | other |
| from the amount | 4 | other |
| melatonin → be → derived | 14 |
| melatonin → be → extracted | 3 |
| negative | neutral | positive |
| 0.122 | 0.738 | 0.140 |
| Raw frequency | 17 |
| Normalized frequency | 0.302 |
| Modifier score | 0.500 |
| Perplexity | 137.669 |