In vitro and in vivo structure and activity relationship analysis of polymethoxylated flavonoids: identifying sinensetin as a novel antiangiogenesis agent.
METHODS
Polymethoxylated flavonoids are present in citrus fruit in a range of chemical structures and abundance. These compounds have potential for anticarcinogenesis, antitumor, and cardiovascular protective activity, but the effect on angiogenesis has not been well studied.


RESULTS
Human umbilical vein endothelial cells (HUVECs) in vitro and zebrafish (Danio rerio) in vivo models were used to screen and identify the antiangiogenesis activity of seven polymethoxylated flavonoids; namely, hesperetin, naringin, neohesperidin, nobiletin, scutellarein, scutellarein tetramethylether, and sinensetin. Five, excluding naringin and neohesperidin, showed different degrees of potency of antiangiogenesis activity. Sinensetin, which had the most potent antiangiogenesis activity and the lowest toxicity, inhibited angiogenesis by inducing cell cycle arrest in the G0/G1 phase in HUVEC culture and downregulating the mRNA expressions of angiogenesis genes flt1, kdrl, and hras in zebrafish.


CONCLUSIONS
The in vivo structure-activity relationship (SAR) analysis indicated that a flavonoid with a methoxylated group at the C3' position offers a stronger antiangiogenesis activity, whereas the absence of a methoxylated group at the C8 position offers lower lethal toxicity in addition to enhancing the antiangiogenesis activity. This study provides new insight into how modification of the chemical structure of polymethoxylated flavonoids affects this newly identified antiangiogenesis activity.
Institute of Chinese Medical Sciences, University of Macau, Avenue Padre Tomás Pereira S.J., Taipa, Macao SAR, PR China.
In Kei
IK
Lam
Deepa
D
Alex
You-Hua
YH
Wang
Ping
P
Liu
Ai-Lin
AL
Liu
Guan-Hua
GH
Du
Simon Ming Yuen
SM
Lee
D020533:Angiogenesis Inhibitors / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*; D000818:Animals; D030801:Animals, Genetically Modified; D001681:Biological Assay; D001808:Blood Vessels / Q000187:drug effects* / Q000196:embryology; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects; D005419:Flavonoids / Q000009:adverse effects / Q000737:chemistry* / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects*; D006801:Humans; D008745:Methylation; D015689:Oncogene Protein p21(ras) / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000235:genetics / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D013329:Structure-Activity Relationship; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
D020533:Angiogenesis Inhibitors; D005419:Flavonoids; D012333:RNA, Messenger; D029961:Zebrafish Proteins; C059295:sinensetin; D040262:Receptors, Vascular Endothelial Growth Factor; D015689:Oncogene Protein p21(ras)