RESUMEN
During the current COVID-19 outbreak, Thai traditional antipyretic recipes and antipyretic herbs have been widely studied. Antipyretic Thai/Lanna herbal decoction for relieving fever in the North consists of Tinospora crispa, Rhinacanthus nasutus, Sauropus androgynus and Alstonia scholaris. This research aimed to study the physical stability, pH, sedimentation, and color of the Lanna antipyretic decoction at 4 degrees C 25 degrees C and 40 degrees C with 75 +or- 5% RH for 7 days. The testing included the Folin Ciocalteu method for quantifying total phenolic content, the aluminium chloride colorimetry for flavonoid content, and the DPPH radical scavenging and ABTS methods for antioxidant activities. The results demonstrated that, for the decoction, the pH values at various temperatures dropped with storage time, the sediment amounts increased with storage time, but its color did not change at 4 degrees C. Its total phenolic and flavonoid contents rose with storage time. The total phenolic contents in mg GAE/g extract at Days 0 and 7 were 161.13 +or- 5.62 and 15.34 +or- 6.21 at 4 degrees C, 160.53 +or- 11.78 and 14.32 +or- 1.13 at 25 degrees C, and 160.09 +or- 7.39 and 12.82 +or- 6.91 at 40 degrees C, respectively;while the flavonoid contents in mgQE/g extract at Days 0 and 7 were 20.32 +or- 0.43 and 7.80 +or- 0.34 at 4 degrees C, 20.10 +or- 0.47 and 7.27 +or- 0.20 at 25 degrees C, and 20.06 +or- 0.55 and 6.63 +or- 0.43 at 40 degrees C, respectively. The decoction's free radical inhibition (IC50) values at 4 degrees C, 25 degrees C and 40 degrees C by DPPH ranged from 14.74 +or- 0.04 to 23.18 +or- 0.72%w/w;and by ABTS the values ranged from 2.63 +or- 0.12 to 3.95 +or- 0.05%w/w. At the storage temperature of 4 degrees C, the decoction showed the best physical stability. Thus, the results can be used in setting up storage guidelines for Thai traditional and folk decoctions to ensue the best stability.