Antineoplastic and Antiviral Screening of Pyrrolizidine Alkaloids from Heliotropium subulatum

Abstract

The phytochemical investigation of Heliotropium subulatum, guided by bioassay, led to the isolation of heliotrine, 7-angeloyl heliotrine, retronecine, subulacine and subulacine- N -oxide. It has been reported that 7-angeloyl heliotrine was the major alkaloid both in vivo (0.42%) and in vitro (0.25%) cell cultures. Antineoplastic, cytotoxic and antiviral activities of ethanol, hexane, dichloromethane crude extracts and isolated pyrrolizidine alkaloids have been screened by packed cell volume and plaque inhibition methods. The 7-angeloyl heliotrine and retronecine showed activity at 5µg/kg/day of 41.7 and 38.6% inhibition against Sarcoma 180. The hexane extract (3µg/ml) and 7-angeloyl heliotrine (10 and 5µg/ml) showed selective cytotoxicity against Chinese hamster V 79 cells. The ethanol and hexane crude extract showed significant antiviral activity to Coxsackie, Poliomyelitis and Measles at 500 and 100µg/ml concentrations, while heliotrine and 7-angeloyl heliotrine possess activity against Poliomyelitis and Vesicular stomatitis at a concentration of 10µg/ml.