| to good health | 9 | purpose |
| in preventing breast cancer | 2 | transitive-object |
| melatonin → be → key | 11 |
| melatonin → be → the key | 6 |
| melatonin → be → a key player | 3 |
| negative | neutral | positive |
| 0.083 | 0.586 | 0.331 |
| Raw frequency | 20 |
| Normalized frequency | 0.330 |
| Modifier score | 0.500 |
| Perplexity | 55.795 |