Invia SMS: ISOLATION FROM ALEXA-LEIOPETALA AND X-RAY CRYSTAL-STRUCTURE OF ALEXINE, (1R,2R,3R,7S,8S)-3-HYDROXYMETHYL-1,2,7-TRIHYDROXYPYRROLIZIDINE [(2R,3R,4R,5S,6S)-2-HYDROXYMETHYL-1-AZABICYCLO[3.3.0]OCTAN-3,4,6-TRIOL], A UNIQUE PYRROLIZIDINE ALKALOID