The distribution of inole alkaloids in different organs of Catharanthus roseus G. Don. (Vinca rosea L)

Abstract

The study of alkaloid extract of the leaf of Vinca rosea by TLC showed the existence of 13 bands, 7 bands of them were: Serpentine, Vincristine, Vinblastine, Ajmaline, Catharantine, Vindoline and Ajmalicine. The existence of these 7 alkaloids was confirmed in the young leaves, old leaves and the roots of the plant by HPLC. Furthermore, two alkaloids with the short retention times and one alkaloid with the medium retention time in the young leaf, three alkaloids with the short retention time and one alkaloid with long retention time in the old leaf, and one alkaioid with the short retention time and two other alkaloids with the long retention times in the root, were observed.
The study of absorption spectrum of alkaloid extract and its comparison with absorption spectrum of ajmalicine showed that the latter can be used for drawing a standard curve and detecting the amount of total alkaloids. The total alkaloids in fresh root, old leaf and young leaf were 2.1 mg , 1.3 mg and 0.9 mg/g respectively, Vindoline and Catharantine were major alkaloids in all of them. However, their amount were more in the root (1.2 mg/ g of fresh material, 0.85 in the old leaf and 0.38 in the young leaf). Vinblastine existed in all three samples but its amount was more in the root {0.22 mg per gramme of the fresh material in the root, 0.26 in the young leaf and 0.003 in the old leaf).
Ajmalicine was detected only in the leaf and its amount was more in young leaf than the old leaf (0.141 mg/g of the fresh material in the young leaf and 0.013 in the old leaf). Serpentine was seen in all of the studied organs but its amount was more in the young leaf than other organs (0.192 mg/ g of the fresh material in the young leaf, 0.11 in the root and 0.07 in the old leaf). Ajmaline existed in all of the organs in minute amount but in the old leaf was more (0 .07 mg/g of the fresh material in the old !eaf,0.044 in the young leaf and 0.04 in the root) . The percentage of unknown alkaloids were low, except in the root (20.5% of total alkaloid).