Catecholic Isoquinolines from Portulaca oleracea and Their Anti-inflammatory and β-Adrenergic Receptor Agonist Activity.

Isoquinoline alkaloids possess a wide range of structural features and pharmaceutical activities and are promising drug candidates. Ten water-soluble catecholic isoquinolines were isolated from the medicinal plant Portulaca oleracea， including three new (1-3) and seven known compounds (4-10)， along with the known catecholamines 11 and 12 and four other known compounds (13-16). A method of polyamide column chromatography using EtOAc-MeOH as the mobile phase was developed for the isolation of catecholic isoquinolines. Alkaloids 1-12 exhibited anti-inflammatory activities (EC = 18.0-497.7 μM) through inhibition of NO production in lipopolysaccharide-induced murine macrophage RAW 264.7 cells. Among these compounds， 11， 2， 5， 4， and 8 were more potent than was the positive control， 3，4-dihydroxybenzohydroxamic acid (EC = 82.4 μM)， with EC values of 18.0， 18.1， 35.4， 36.3， and 58.7 μM， respectively. Additionally， at 100 μM， compounds 1-12 showed different degrees of β-adrenergic receptor (β-AR) agonist activity in the CHO-K1/GA15 cell line which stably expressed β-AR as detected by a calcium assay. The EC values of 2 and 10 were 5.1 μM and 87.9 nM， respectively.