Bioscience Evidence 2026, Vol.16, No.4, 277-290 http://bioscipublisher.com/index.php/be 284 5 Effects of Harvest Time and Post-Harvest Processing on the Quality of Atractylodes macrocephala 5.1 Growth stage determines rhizome maturity The medicinal part of Atractylodes macrocephala Koidz. is the underground rhizome, and its medicinal quality depends on full rhizome development and maturity. The rhizome is not only the main storage organ for nutrients but also the primary site for the accumulation of atractylenolides, volatile oils, and other sesquiterpenes. Therefore, the transition from vegetative growth to rhizome maturation is a key biological process that determines the final quality of the medicinal material. As the plant develops, the leaves continue to produce photosynthates through photosynthesis, which are transported to the underground organs to promote rhizome enlargement, vascular tissue development, and storage compound accumulation, eventually producing mature rhizomes suitable for medicinal use. Ruan et al. (2021) compared the metabolite profiles and transcriptomes of five tissues, including the rhizome, root, stem, leaf, and bud. Sesquiterpenes were mainly accumulated in the rhizome, while their levels were much lower in the aerial tissues. Transcriptome analysis identified several highly expressed transcription factors in the rhizome and 73 candidate genes associated with sesquiterpene biosynthesis. The study also confirmed the important role of farnesyl pyrophosphate synthase (AmFPPS) in sesquiterpene production. Rhizome maturation was characterized not only by increased accumulation of bioactive compounds but also by the gradual specialization of metabolism among different plant tissues. However, a longer growing period does not necessarily result in better medicinal quality. 5.2 Harvest time Harvesting too early results in incompletely developed rhizomes with insufficient dry matter and bioactive compound accumulation. In contrast, harvesting too late may increase the risk of rhizome decay, mechanical damage, and reduced market quality because of low temperatures, prolonged rainfall, or disease development. Therefore, selecting the proper harvest time is essential for achieving both high yield and good medicinal quality. Jeong et al. (2022) continuously monitored rhizome growth and the accumulation of atractylenolides I, II, and III throughout the growing season. The aerial parts of the plants gradually senesced after mid-October, whereas the underground rhizomes continued to enlarge until mid-November. The total content of the three major atractylenolides reached its highest level in mid-November, with the second highest level occurring before flowering in August. These results indicate that the accumulation of bioactive compounds continues even after shoot growth has stopped. Harvesting after the rhizomes have fully matured is therefore more favorable for obtaining high-quality medicinal materials. According to the Chinese Pharmacopoeia, A. macrocephala should be harvested in autumn after the aerial parts have withered. The fibrous roots and soil should be removed, followed by prompt post-harvest processing. This recommendation agrees well with the findings above, indicating that harvesting mature rhizomes provides a better balance between yield and quality. In major production regions such as Zhejiang, harvest timing should also be adjusted according to local rainfall and soil conditions. Harvesting during periods of continuous rainfall should be avoided because excessive rhizome moisture and soil contamination may reduce drying efficiency and commercial quality. 5.3 Post-harvest processing Traditional post-harvest processing includes washing, trimming, drying, and, when necessary, further processing for medicinal use. The main objectives are to reduce moisture content, prevent mold development, and preserve volatile oils, atractylenolides, and other bioactive compounds as much as possible. Excessively high drying temperatures, rapid dehydration, or improper processing may cause the degradation of heat-sensitive compounds and reduce the quality of the final medicinal product. Yang et al. (2021) systematically reviewed the processing methods of A. macrocephala and reported that natural sun drying and low-temperature drying are the two most commonly used methods. Both methods can produce
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