Abstract: Objective To explore the effects of different harvest seasons and years of growth on contents of anthraquinone in Polygoni Multiflori Radix (PM) grown in Deqing District, Zhaoqing, Guangdong Province. Methods The contents of nine types of anthraquinones, including emodin-1-O-glucoside, emodin-8-O-β-D-glucoside, emodin- 8-O-(6’-methylmalonyl)-glucopyranoside, emodin-6-O-glucoside, physcion-8-O-β-D-glucoside, physcion-8-O-(6’-methylmalonyl)-glucopyranoside, 1-methyl emodin, emodin, and physcion were determined while the data on seasons of harvest and years of growth of Polygoni Multiflori Radix was collected. Results The total amounts of nine anthraquinones in the samples collected in autumn ranged from 1 465.82 to 1 707.76 μg·g^-1, which were much lower than those of the samples collected in spring (ranging from 2 826.56 to 3 100.61 μg·g^-1) and summer (ranging from 3 616.38 to 5 777.23 μg·g^-1). The contents of anthraquinone in physcion-8-O-β-D-glucoside and physcion-8-O-(6’-methylmalonyl)-glucopyranoside trended down with the season, while those of the other seven anthraquinons increased in spring and summer, but decreased sharply in autumn. The contents of emodin, emodin-8-O-β-D-glucoside and other components in PM that had grown for three to four years were low. The contents of emodin-8-O-β-D-glucoside and physcion-8-O-β-D-glucoside in the four-year-old samples collected in autumn were the highest. Conclusion The season of harvest has a more significant effect on the content of anthraquinones than years of growth. With anthraquinones as an index of liver toxicity, the content of anthraquinones collected in autumn is lower than that of samples collected in spring and summer, so autumn is a good season for harvest as is defined in the Pharmacopoeia. The contents of anthraquinones in PM grown for three to four years are relatively low.

Key words: Polygoni Multiflori Radix, UPLC-MS/MS, anthraquinones, season of harvest, years of growth