Quality of moxa from Artemisia argyi and A. stolonifera in different storage years based on simultaneous thermal analysis

Abstract

The quality of moxa is an important factor affecting moxibustion therapy, and traditionally, 3-year moxa is considered optimal, although scientific data are lacking. This study focused on 1-year and 3-year moxa from Artemisia stolonifera and A. argyi(leaf-to-moxa ratio of 10∶1) as research objects. Scanning electron microscopy(SEM), Van Soest method, and simultaneous thermal analysis were used to investigate the differences in the combustion heat quality of 1-year and 3-year moxa and their influencing factors. The results showed that the combustion of A. stolonifera moxa exhibited a balanced heat release pattern. The 3-year moxa released a concentrated heat of 9 998.84 mJ·mg~(-1)(accounting for 54% of the total heat release) in the temperature range of 140-302 ℃, with a heat production efficiency of 122 mW·mg~(-1). It further released 7 512.51 mJ·mg~(-1)(accounting for 41% of the total heat release) in the temperature range of 302-519 ℃. The combustion of A. argyi moxa showed a rapid heat release pattern. The 3-year moxa released a heat of 16 695.28 mJ·mg~(-1)(accounting for 70% of the total heat release) in the temperature range of 140-311 ℃, with an instantaneous power output of 218 mW·mg~(-1). It further released 5 996.95 mJ·mg~(-1)(accounting for 25% of the total heat release) in the temperature range of 311-483 ℃. Combustion parameters such as-R_p,-R_v, D_i, C, and D_b indicated that the combustion heat quality of 3-year moxa was superior to that of 1-year moxa. It exhibited greater combustion heat, heat production efficiency, flammability, mild and sustained burning, and higher instantaneous combustion efficiency. This study utilized scientific data to demonstrate that A. stolonifera could be used as excellent moxa, and the quality of 3-year moxa surpassed that of 1-year moxa. The research results provide a scientific basis for the in-depth development of A. stolonifera moxa and the improvement of moxa quality standards.