Accumulation of Carotenoid in Different Cultivars of Tagetes Flowers
Background : Tagetes species which belong to Asteraceae show different characteristics including, bloom size, shape, color, plant size, and leaf shape. The color of Tagetes flowers ranging from white to dark orange is due to accumulation of different carotenoids, pathway intermediates, and amount of the same carotenoid. Methods and Results : The carotenoids were monitored in flower extracts from six cultivars of Tagetes that include three T. erecta cultivars, Discovery Orange (DO), Inca Orange (IO), and Inca Yellow (IY), and three T. patula cultivars, including Durango Bee (DB), Durango Yellow (DY), and Safari Red (SR) using HPLC analysis. It showed considerable differences in carotenoid composition depending on cultivars and types of carotenoids. The highest concentration of violaxanthin which represents orange color in plants was showed in IO, whereas the compound was not detected in DB, and DY. Yellow-colored cultivars such as IY, DB, and DY exhibited low levels of lutein. However, others that indicate orange color, DO, IO, and SR showed high levels of lutein. Also, similar pattern was found in the zeaxanthin measurements. α-carotene was significantly accumulated in SR compared to other cultivars. The highest amount of β-carotene was found in SR, followed by IO, IY, DO, DY and DB. Similarly, the highest and lowest amount of 9-cis-β-carotene was showed in SR and DB, respectively. Interestingly, all cultivars except SR in 13-cis-β-carotene showed the same pattern with β-carotene, but no detection indicated in SR. Conclusion : In this study, we determined the differences in carotenoid yields among six Tagetes cultivars. In total, seven carotenoids that include violaxanthin, lutein, zeaxanthin, α -carotene, β-carotene, 9-cis-β-carotene, and 13-cis-β-carotene were detected. Among them, all of the cultivars accumulated primarily lutein. In addition, contents of each carotenoid varied in these flowers depending on cultivars.