**4. Conclusions**

In the present study, we assessed the effect of UC roots on the immune function of DCs and found that the immunomodulatory effect of UCME was mainly associated with its EtOAc-soluble fraction. After one-step chromatography, genistein was rapidly identified by the 1H NMR profiling of the immunomodulatory subfractions (D-4 and D-5). The central role of genistein in the immunomodulatory activity of UC roots was supported by the result that the genistein-knockout subfractions (D-4 *w*/*o* and D-5 *w*/*o*) had a lower inhibitory activity.

Importantly, this work elucidates a rapid strategy for identifying immunomodulatory phytochemicals, distinguishing the chemical marker(s) for quality control and providing a rationale for the traditional immunomodulatory use of UC roots. The findings indicated that UC roots can potentially be used as an immunosuppressive functional food, of which genistein can be a chemical marker for quality control. In conclusion, our strategy will help in the standardization of *U. crinita* roots, a famous Taiwanese functional food.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2304-8158/8/11/543/s1, Figure S1: Selected 13C NMR spectrum (acetone-*d*6, 125 MHz) of subfraction D-4; Figure S2: Selected HSQC spectrum (acetone-*d*6) of subfraction D-4; Figure S3: Selected HMBC spectrum (acetone-*d*6) of subfraction D-4; Figure S4: Chromatogram of genistein-containing subfractions D-4 and D-5; Figure S5: The effects of the compounds LA (lupinalbin A), MS (*p*-hydroxybenzoic acid), HA (*p*-hydroxybenzoic acid), DDA (*p*-hydroxybenzoic acid), and ST (a mixture of β-sitosterol and stigmasterol) on the production of pro-inflammatory cytokines in LPS-stimulated DCs; Figure S6: The effects of the compounds SA (salicylic acid) and VA (vanillic acid) on the production of pro-inflammatory cytokines in LPS-stimulated DCs.

**Author Contributions:** Conceptualization, M.-K.L. and M.-S.L.; methodology, Y.-H.K. and M.-K.L.; investigation, P.-C.T., C.-J.C., and Y.-C.L.; resources, Y.-H.K., M.-S.L., and M.-K.L.; writing—original draft preparation, P.-C.T. and C.-J.C.; writing—review and editing, P.-C.T., M.-K.L., and M.-S.L.; supervision, M.-K.L. and M.-S.L.

**Funding:** This research was funded by grants from China Medical University and the Ministry Science and Technology of Taiwan, ROC (grant number, CMU 107-5-49 and MOST 107-2313-B-039-001).

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