Two new alkaloids identified as 2-(((S,Z)-1-(1H-azirin-1-yl)-5-methylhex-1-en-3-yl)oxy)-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol and (S,Z)-1-(1H-azirin-1-yl)-5-methylhex-1-en-3-ol, named olerazirin A (1), olerazirin B (2), together with five known alkaloids, identified as cyclo (L-Val-L-Ala) (3), cyclo-(glycyl-L-leucine) (4), cyclo-(Gly-Phe) (5), cyclo (Ser-Phe) (6), (3S,6S)-3-[(1R)-1-hydroxyethyl]-6-(phenyl-methyl)-2,5-piperazinedione (7) were obtained from Portulaca oleracea L. using a range of chromatographic techniques, 1D and 2D NMR, and high-resolution electrospray ionisation time-of-flight mass spectroscopic methods, in which the compounds 3-7 were isolated from P. oleracea for the first time. In addition, the results showed that the compounds 1 and 2 have anti-inflammatory activities and compounds 1-3 and 5-7 exhibit the anticholinesterase activities.
Keywords: Portulaca oleracea L; alkaloids; anti-inflammatory activity; anticholinesterase activity.