Processing technology of rice-steamed Rehmanniae Radix unearthed from tomb of Haihunhou in the Western Han Dynasty / 中国中药杂志

ABSTRACT

With the rice-steamed Rehmanniae Radix unearthed from the tomb of Haihunhou in the Western Han Dynasty as the re-ference, the present study evaluated the quality of Rehmanniae Radix and investigated the processing technology of rice-steamed Rehmanniae Radix to lay the foundation for the research on rice-steamed Rehmanniae Radix products. With catalpol and rehmannioside D as the investigation indexes, the quality and grade of Rehmanniae Radix from different producing areas were evaluated with the methods in 2020 edition of Chinese Pharmacopoeia. UPLC method was established for the determination of catalpol and rehmannioside D in the rice-steamed Rehmanniae Radix. The effects of steaming time, the amount of supplementary rice, and steaming times in the rice-steamed processing on the quality of products were investigated by L_9(3~4) orthogonal test and multi-index comprehensive balance scoring method combined with the content of catalpol and rehmannioside D and appearance characteristics. At last, the stability of the processing technology was tested. The results showed that the optimal processing technology for rice-steamed Rehmanniae Radix was as follows Rehmanniae Radix and rice(200 g∶4 g) were steamed twice at atmospheric pressure, four hours each time. The mass fractions of catalpol and rehmannioside D were 0.184% and 0.335%, respectively, and the character score was 6.5. The processing conditions are reaso-nable, stable, and feasible. It can provide a basis for the restoration of the ancient rice-steamed processing technology and references for the development of rice-steamed Rehmanniae Radix products in the future.