Objective: To study the anti-proliferation effect of homoisoflavonoids extracted from Polygonati Odorati Rhizoma on human lung cancer A549 cells. Method: Ethanol was used as the solvent to extract homoisoflavonoids from Polygonati Odorati Rhizoma; methylthiazolyldiphenyl-tetrazolium bromide (MTT) method was used to observe the proliferation inhibition rates of lung cancer A549 cells after being treated with homoisoflavonoids (12.5

25

50

100 mg·L-1) for 6

12

24 h. Apoptotic rate and cell cycles were analyzed through flow cytometer (FCM). And Western blot analysis was used to detect the expressions of apoptosis-related (Caspase-3

the Bcl-2

Bak) and cell cycle-related (p-Cdc

Cdc 2

p38) protein. Result: Compared with normal group

A549 cells treated by homoisoflavonoids extracted from Polygonati Odorati Rhizoma were observed as typical apoptotic cells. The results of MTT and FCM showed that homoisoflavonoids could significantly inhibit tumor cell proliferation and induce apoptosis of A549 in a dose and time-dependent manner(P<0.05

P<0.01). And the cell number in G2/M period was increased after being treated with homoisoflavonoids for 12 h (P<0.05). Compared with normal group

the cells treated with 25

50

100 mg·L-1 homoisoflavonoids

Caspase-3 and Bak were up-regulated

while Bcl-2 was down-regulated significantly (P<0.01); p-Cdc 2 and p38 were up-regulated

while Cdc 2 was down-regulated (P<0.01). Conclusion: Homoisoflavonoids extracted from Polygonati Odorati Rhizoma can promote the apoptosis of A549 cells and increase the proportion of cells in G2/M. The antitumor mechanism of homoisoflavonoids is related to mitochondria-mediated apoptosis and p38 MAPK pathway.