Table 2. Binding interactions of 15 compounds including 10 top alkaloid compounds, namely radicamine A, perlolyrine, epibisdehydroneotuberostemonine J, bisdehydroneostemoninine, stemoninoamide, bisdehydrostemoninine A, bisdehydrostemoninine B, bisdehydrostemoninine, tuberocrooline, croomine, and 5 reference compounds (fenofibrate, gemfibrozil, clofibrate, bezafibrate and ciprofibrate), respectively and the PPARα (PDB id: 5HYK)

No	Compound name	Binding affinity (kcal.mol-1)	Hydrogen bonds	Hydrophobic interactions
1	Radicamine A	-8.2	Ser280, His440, Tyr464	Ile354, Ile447, Ala454
2	Perlolyrine	-9.1	Phe273, Cys276,	Ile354, His440, Val444, Ile447, Ala454
3	Epi-Bisdehydroneotuberostemonine J	-8.5	Ser280, Tyr314	Ile354, Val444, Ile447, Lys448, Leu456
4	Bisdehydroneostemoninine	-9.1		Ala455
5	Bisdehydrostemoninine A	-8.5	Ser280, His440	Ile354, Val444, Ile447, Leu456
6	Bisdehydrostemoninine B	-8.5	Cys276	Ile354, Val444, Ile447, Leu456
7	Bisdehydrostemoninine	-8.1	His440, Leu456	Phe273, Ile354, Val444, Ile447, Leu456
8	Tuberocrooline	-10.5	Ser280, Tyr314, Ala455
9	Croomine	-8.9	Ser280, His440	Ile354, Val444, Ile447
10	Stemoninoamide	-9.8		Ile354, His440, Val444, Ile447, Leu456
11	Fenofibrate	-10.2	Ser280, His440	Phe273, Ile354, Val444, Ile447, Ala454, Leu456 Val270, Phe351,
12	Gemfibrozil	-8.2	His440	Val444, Ile447, Lys448, Ala454, Ala455, Leu456
13	Clofibrate	-7.3		Phe273, Cys276, Ile354, Met355
14	Bezafibrate	-9.1	Ser280, Tyr314, His440, Val444	Ile354, Val444, Ala454 Val270, Phe273,
15	Ciprofibrate	-8.6	Ser280, Tyr314, His440	Phe351, Val444, Ile447, Ala454