Isolation and characterization of carpaine and dihydroxy derivative of carpaine from leaves of Carica papaya: Development of fast HPLC method and standardization of formulations.

Carpaine, a major alkaloid of Carica papaya leaves, is widely studied for its anti-thrombocytopenic activity. The objective of present work was to isolate carpaine from dried leaves of Carica papaya. Isolation of carpaine was carried out by solvent extraction techniques followed by column chromatography by gradient elution using dichloromethane: methanol (80:20, v/v) as eluent. Dihydroxy derivative of carpaine was also identified for the first time from leaves of Carica papaya. Structures of carpaine and dihydroxy derivative of carpaine were confirmed by LC-MS/MS followed by IR studies. Fast HPLC method was developed using Sunniest C18 column (150 mm × 4.6 mm) as stationary phase and water (pH 8.5): acetonitrile (60: 40, v/v) as mobile phase at flow rate of 1.0 mL/min. Carpaine was eluted with mean retention time of 6.017 min. The developed HPLC method was used to estimate carpaine in extract and marketed formulations containing Carica papaya leaves.