Homoisoflavonoids from the medicinal plant Portulaca oleracea

► Four homoisoflavonoids and nine known compounds were isolated from Portulaca oleracea. ► Each of the homoisoflavonoids is featured with a rare 2′-OH substituent in ring B. ► This is the first finding of homoisoflavonoids from the plant family Portulacaceae. ► Four compounds selectively showed in vitro cytotoxicity towards four cancer cell lines.