Comparative Analysis of Purine Alkaloids and Main Quality Components of the Three Camellia Species in China

Tea (Camellia sinensis var. sinensis) is a widely consumed caffeine-containing beverage, however the Camellia genus also includes other species, which are consumed as tea in their local growing regions. Presently, HPLC analysis assessed 126 unique Camellia germplasms belonging to three Camellia species, C. sinensis var. pubilimba Chang (Csp), C. gymnogyna Chang (CgC) and C. crassicolumna Chang (CcC). Theobromine was the predominant purine alkaloid in all species, representing over 90% of purine alkaloids in Csp and CgC, and 50% in CcC. Significant variability existed in purine alkaloid patterns both between and within species, and some germplasms possessed highly unique alkaloid profiles. Sensory evaluation and quality composition analysis of green tea products produced from the three Camellia species suggested their unsuitability for use in tea production due to their unpalatable flavor. The results of this study revealed the differences in purine alkaloids and main quality components between Camellia species and tea, which contributed to understand why tea, rather than other Camellia species, has become a popular beverage in the world after long-term artificial selection. In addition, unique alkaloid profiles suggest usefulness of these germplasm resources in future breeding of decaffeinated tea plant varieties and alkaloid metabolism research.