Alkaloids+ 31
Heterocyclic Compounds, 2-Ring+ 26
Heterocyclic Compounds, 1-Ring+ 25
Heterocyclic Compounds, 3-Ring+ 20
Heterocyclic Compounds with 4 or More Rings+ 13
Pyrans+ 11
Acids, Heterocyclic+ 10
Heterocyclic Compounds, Bridged-Ring+ 5
Heterocyclic Oxides+ 3
Phytochemicals