Written in Dunhuang, Chiwu shenzhen jing (赤烏神針經) is a long lost medical work and its contents remain unknown. Based on Dunhuang manuscripts and Japanese collections of ancient Chinese medical classics, this research argues that Chiwu shenzhen jing concerns temporally sensitive needling treatment, which forms an early practice of the midnight-noon ebb-ﬂow (the commonly-used translation of Ziwu liuzhu 子 午流注) therapy, in fact, as early as the 3rd century CE. At the very end of this article, this research emphasizes the role of Dunhuang as a vehicle for promoting the ebb-ﬂow theory through the Sino-Indian medical exchanges.
The potential of polyamide as adsorbent for separation of nine compounds — (±)-catechin (DL-C), (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECg), (−)-epigallocatechin gallate (EGCg), theaflavin (TF1), theaflavin 3-gallate (TF2A), theaflavin 3′-gallate (TF2B), and theaflavin 3,3′-digallate (TF3) — was studied. Polyamide TLC plates dried with a hair dryer, application as bands, and development in a horizontal chamber gave the best results. Detection was performed using iron(III) chloride-ethanol reagent. Twofold development with chloroform-methanol 2:3 (
) as mobile phase resulted in the separation of TF1, TF2A, TF2B, and TF3 from all the other compounds. EGCg, ECg, and EGC were separated but EC and DL-C were not separated from each other. The best mobile phase for each of the compounds is reported. The best separation of the five main catechins (EC, DL-C, EGC, ECg, and EGCg) was achieved by use of
-butanol-acetone-acetic acid 5:5:3 (
). In addition, separation of the flavonols myricetin, quercetin, kaempferol, and rutin and the phenolic acids gallic acid, chlorogenic acid, and caffeic acid was achieved by twofold development with chloroform-methanol 2:3 (
). The applicability of the method was checked by screening of extracts of green, black, oolong, and pu-erh tea.