Product Code Database
Carpaine is the major piperidine alkaloid component of papaya leaves which has been studied for potential medicinal effects. Carpaine extracted from Carica papaya trees has been reported to have diverse biological properties, such as anti-malarial, anti-inflammatory, anti-oxidant, and vasodilatory effects. Especially, Carpaine possessed significant anti-plasmodium activity in vitro (IC50 of 0.2 μM) and high selectivity towards the parasites.
Circulatory effects of carpaine were studied in Wistar male rats weighing 314 +/- 13 g, under pentobarbital (30 mg/kg) anesthesia.Hornick, C. A.; Sanders, L. I.; Lin, Y. C. "Effect of carpaine, a papaya alkaloid, on the circulatory function in the rat." Research Communications in Chemical Pathology and Pharmacology (1978), 22(2), 277-289. Increasing dosages of carpaine from 0.5 mg/kg to 2.0 mg/kg resulted in progressive decrease in Systole, diastolic, and mean arterial blood pressure. Selective autonomic nervous blockade with atropine sulfate (1 mg/kg) or propranolol hydrochloride (8 mg/kg) did not alter the circulatory response to carpaine. Carpaine, 2 mg/kg, reduced cardiac output, stroke volume, stroke work, and cardiac power, but the calculated total peripheral resistance remained unchanged. It is concluded from these results that carpaine affects the myocardium directly. The effects of carpaine may be related to its macrocycle lactone structure, a possible cation chelation structure.
Then in 1953, Rapoport and his collogues at the University of California obtained a new form of Carpaine chemical structure which they found the nitrogen-containing ring had a piperidine structure instead of the pyrrolidine as previously thought; they also located the position of the lactone ring between atoms numbered 3 and 6 on the piperidine nucleus. Later work from Govindachari & Narasimhan and Tichy and Sicher further confirmed this structural formula.
However, Spiteller-Friedmann and Spiteller used Mass Spectrometry to discover that the molecular weight of Carpaine is closer to 478 g/mol, which is represented by twice of the original empirical formula. The new finding proved that Carpaine consists of two identical halves, which form a 26-membered cyclic diester, or dilactone, with an empirical formula of , and the configuration was finally determined by Coke and Rice in 1965.
One possible extraction route was accomplished first drying the leaves in an electric blast drying oven and milled to fine powder. The powdered plant material were macerated with a mixed solution of ethanol/water/ for 24 hrs at room temperature. Then the extract was dissolved in water/ mixture, filtered, and extracted with petroleum ether to remove fat materials. The acid fraction was adjusted to pH 8.0 ~ 9.0 using solution and extracted with chloroform. Finally, the chloroform fractions were pooled and evaporated and the whole operation was repeated again so the crude alkaloid Carpaine was obtained.
Another extraction route reported that mechanical blending of the leaves prior to extraction significantly enhances the yield of Carpaine. After blending the leaves with water and freeze-dried, the samples were soaked in ethanol. This mixture was then concentrated and purified using an acid-base method followed by chloroform extraction to isolate the Carpaine. Finally, the purity and structure were analyzed using NMR and LC-MS.
|
|
