Homoisoflavonoids from the medicinal plant Portulaca oleracea.
Four homoisoflavonoids named portulacanones A-D, identified as 2'-hydroxy- 5,7-dimethoxy-3-benzyl-chroman-4-one, 2'-hydroxy-5,6,7-trimethoxy-3-benzyl-chroman-4-one, 5,2'-dihydroxy-6,7-dimethoxy-3-benzyl-chroman-4-one, and 5,2'-dihydroxy-7-methoxy-3-benzylidene-chroman-4-one, were isolated from aerial parts of the plant Portulaca oleracea along with nine other known metabolites. Their structures were established on the basis of extensive spectroscopic analyses. Portulacanones A-D is the first group of homoisoflavonoids so far reported from the family Portulacaceae. They represent a rare subclass of homoisoflavonoids in nature with a structural feature of a single hydroxyl group substituted at C-2' rather than at C-4' in ring B of the skeleton. Three homoisoflavonoids and the known compound 2,2'-dihydroxy-4',6'-dimethoxychalcone selectively showed in vitro cytotoxic activities towards four human cancer cell lines. Especially 2,2'-dihydroxy-4',6'-dimethoxychalcone showed cytotoxic activity against cell line SGC-7901 with an IC₅₀ value of 1.6 μg/ml, which was more potent than the reference compound mitomycin C (IC₅₀ 13.0 μg/ml).
Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Jian
J
Yan
Li-Rong
LR
Sun
Zhong-Yu
ZY
Zhou
Yu-Chan
YC
Chen
Wei-Min
WM
Zhang
Hao-Fu
HF
Dai
Jian-Wen
JW
Tan
D000970:Antineoplastic Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D045744:Cell Line, Tumor; D006801:Humans; D020128:Inhibitory Concentration 50; D007529:Isoflavones / Q000302:isolation & purification* / Q000494:pharmacology*; D035261:Plant Components, Aerial / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D031822:Portulaca / Q000737:chemistry*
D000970:Antineoplastic Agents; D007529:Isoflavones