Evaluation of Some Morphological Traits and Amount of Vinblastine, Vincristine and Ajmalicine Alkaloids in Different Organs of Prewinkle Cultivars (Catharanthus roseus (L.) G. DON)

Periwinkle is a plant that is highly valued in the pharmaceutical industry because of its alkaloids. Among the 130 known alkaloids in the genus, Vinblastine and Vincristine alkaloids have particular importance due to their anti-tumor properties. Since Periwinkle is the only source of these compounds, it has a special place among medicinal plants. Due to the low content of indole terpenoids alkaloids in Periwinkle and the importance of these compounds in the pharmaceutical industry, as well as the high economic value of some of its secondary metabolites, six different Prewinkle cultivars were studied for morphological and biochemical traits.

This study was conducted in factorial design based on completely randomized with three replications in field and laboratory of Gorgan University of Agricultural Sciences and Natural Resources. Treatments included six cultivars (Icy Pink, Lilac, Polka Dot, Apricot, Purple, Red Bright) and two organs (leaf and root). The measured factors included fresh and dry weight of roots and leaves, number of lateral stem and root, root length, stem length and amount of Vinblastine, Vincristine and Ajmalicine alkaloids. Alkaloids content were determined by High Performance Liquid Chromatography.

The results showed that the measured parameters had significant effect on morphological and phytochemical properties at 1% probabality level. The highest stem diameter (0.533 cm), root diameter (0.610 cm) and stem length (45.99 cm) were observed in Purple cultivar. The highest amount of Vinblastine was observed in the leaves of Purple (1.7 mg/100g DW) and the lowest level (0.02 mg/100g DW) was measured in the root of Icy Pink. Also the highest amount of Ajmalicine and Vincristine were measured in leaves of Apricot cultivar (1.89 and 3.61 mg/100gDW respectively). However, there were no Ajmalicine alkaloid in the root of Apricot and Red Bright cultivars as well as the leaves of Lilac cultivar.

Different cultivars of Periwinkle have significant differences in the amount of indole terpenoids alkaloids. Although different cultivars of a plant are a subset of the same species, however, the observed differences in different cultivars are controversial. Due to secondary metabolites originate from the primary metabolites of the plant, it is observed that different cultivars of a plant produce different amounts of an alkaloid under the same conditions. This issue can be great importance especially considering the economic value of some alkaloids of this plant. By recommending superior cultivar cultivation in the production of indole terpenoids alkaloids can greatly enhance their production efficiency.