**4. Discussion**

The clinical efficacy of TCM is determined by its chemical constitution [40]. The Chinese Pharmacopoeia officially recorded that the medicinal part of AC was only the corolla of FAM. However, the phenomenon of doping non-medicinal parts in AC was common. Therefore, the chemical constituents of medicinal and non-medicinal parts of FAM were analyzed. A total of 20 differential constituents, including 1 organic acid and 19 flavonoids, were screened out by multivariate statistical analysis and their relative contents were compared. Among them, the relative content of 19 differential constituents in the corolla of FAM was significantly higher than that in the non-medicinal parts. Many studies have shown that the flavonoids of AC such as hyperin and isoquercitrin possess anti-inflammatory and renal injury protective properties [41–43], which is consistent with the clinical efficacy of AC [44,45]. Due to the grea<sup>t</sup> difference in chemical constituents between the medicinal part and the non-medicinal parts, the latter may not have the same therapeutic effect as the medicinal part. The screened differential constituents might be the pharmacodynamic substances of AC, which provide ideas for the research of pharmacodynamic substance basis of AC.

In summary, 51 constituents from medicinal and non-medicinal parts of FAM were identified and their metabolic profiles were compared. 20 differential constituents were screened to distinguish the medicinal part and non-medicinal parts of FAM. The grea<sup>t</sup> difference in the relative content of them indicates that the non-medicinal parts of FAM are hardly a substitute for the corolla part. Our study could be conducive to the quality evaluation and quality stability improvement of AC and provide a scientific basis for strictly regulating the harvest and market standards of AC.

**Supplementary Materials:** The following is available online at https://www.mdpi.com/article/10.3 390/horticulturae8040317/s1, Figure S1. Chemical structures of constituents identified in medicinal and non-medicinal parts of Flos *Abelmoschus manihot*.

**Author Contributions:** Conceptualization, X.L., S.Y. and Z.C.; data curation, S.Y., Y.M., L.W. and Z.C.; formal analysis, S.Y., N.W., J.Y., D.W. (Dianguang Wang) and D.W. (Dandan Wang); writing—original draft preparation, S.Y.; writing—review and editing, X.L., L.Z., Z.C., C.C., S.L. and H.G.; funding acquisition, X.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China (NO. ysxk-2014) and General Project of Natural Science Research in Universities of Jiangsu Province (20KJD360001).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available in this article or in supplementary material.

**Conflicts of Interest:** The authors declare no conflict of interest.
