| | | Preparation method | Identified compounds | Country of origin | Conclusion | Observational method |
| | Liang, et al. [39] | Softened by water and then steamed in an autoclave for four hours at 121°C and under 2.03 pounds per square inch | 15 | Guangdong and Hong Kong | The contents of emodin-8-O-(6′-O-malonyl)-glucoside and physcion-8-O-(6′-O-malonyl)-glucoside are disappeared or decreased significantly, and the contents of THSG, emodin-8-O-β-D-glucopyranoside and physcion-8-O-β-D-glucopyranoside are decreased after processing. On the other hand, the contents of emodin and physcion generally increased after processing. | HPLC and MS | | Liu et al. [40] | Not mention | 23 | Not mention | The relative amounts of gallic acid, emodin, and physcion are very high in PHSW samples compared to those in RHSW samples; catechin, flavanol gallate dimer, polygonimitin B, emodin-1-O-glucoside, emodin-8-O-(6′-O-malonyl)-glucoside, and physcion-8-O-(6′-O-malonyl)-glucoside are disappeared after processing | RRLC/DAD/ESI-MS | | Chen et al. [42] | Softened by water and then steamed, and dried at a low temperature | 5 | Deqing County, Guangdong province | The content of stilbene glycoside is decreased in the process of time during processing and both the dissociative anthraquinones, emodin and emodin monomethyl ether, are increased by processing; anthraquinone, emodin and emodin monomethyl ether, both of them are increased by processing, and after 32 h the content reaches the maximum. | RP-HPLC | | Wang et al. [43] | Not mention | 23 | Different regions of China | The contents of sucrose, gallic acid, procyanidin B, catechin, THSG, torachrysone-O-glu, emodin-8-O-glu, and emodin-O-(malonyl)-glu are destroyed due to long-time steaming | UHPLC-LTQ-Orbitrap MSn | | Zhao et al. [44] | Mixed with black bean juice and steamed by water | 16 | Sichuan | Compared with RHSW, the contents of procyanidine B1, catechin, epigallocatechin, Polydatin, Rhaponticin, resveratrol, rhein, THSG, emodin -8-O-β-D- glucoside, and physcion -8-O-β-D- glucoside are decreased after processing; the contents of gallate, emodin, and physcion are increased after processing. The content of other components remained unchanged. | HPLC | | Yang et al. [45] | Nine cycles of steaming and sundrying | 3 | Hunan | The content of THSG decreased from 3.021% to 0.905%; the content of bombined anthraquinone decreased from 0.401% to 0.015%; the content of total anthraquinone decreased from 0.681% to 0.445%; the free anthraquinone content increased from 0.281% to 0.432% | HPLC | | Liang et al. [46] | Nine cycles of steaming and sundrying | 87 | Kaili City in Guizhou | The contents of gallic acid continuously increased, while trans-THSG continuously decreased, after each processing cycle. The contents of emodin and physcion are first decreased and then increased with the increasing of processing cycles. In terms of the other eight analytes, namely cis-THSG, emodin-8-O-β-D-glucosides and physcion-8-O-β-D-glucosides, catechin, epicatechin, epicatechin-3-gallate, proanthocyanidin B1, and proanthocyanidin B2, the contents are first increased and then decreased after the increase of processing cycles. | UPLC-QTOF-MS/MS and UPLC-QTOF-MS/MS |
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