These inhibitors were investigated for (i) potency to inhibit the activity of the isolated NNMT enzyme (EC<sub>50</sub> values), (ii) cytotoxicity (IC<sub>50</sub> values) against the human OSCC cell line, SCC-4, and (iii) ability to affect cellular energy metabolism, as measured by oxygen consumption, in SCC-4 cells (plus dysplastic oral keratinocytes (DOK) cells and breast cancer MCF-7 cells). The gene discussed is NNMT; the disease is breast cancer.