*Article*

## **Bioactivity-Guided Fractionation and NMR-Based Identification of the Immunomodulatory Isoflavone from the Roots of** *Uraria crinita* **(L.) Desv. ex DC**

**Ping-Chen Tu 1, Chih-Ju Chan 2, Yi-Chen Liu 3, Yueh-Hsiung Kuo 2,4,5, Ming-Kuem Lin 2,\* and Meng-Shiou Lee 2,\***


Received: 7 August 2019; Accepted: 10 October 2019; Published: 3 November 2019

**Abstract:** *Uraria crinita* is used as a functional food ingredient. Little is known about the association between its immunomodulatory activity and its metabolites. We applied a precise strategy for screening metabolites using immunomodulatory fractions from a *U. crinata* root methanolic extract (UCME) in combination with bioactivity-guided fractionation and NMR-based identification. The fractions from UCME were evaluated in terms of their inhibitory activity against the production of pro-inflammatory cytokines (IL-6 and TNF-α) by lipopolysaccharide (LPS)-stimulated mouse bone marrow-derived dendritic cells (BMDC). The role of the isoflavone genistein was indicated by the 1H NMR profiling of immunomodulatory subfractions (D-4 and D-5) and supported by the result that genistein-knockout subfractions (D-4 *w*/*o* and D-5 *w*/*o*) had a lower inhibitory activity compared to genistein-containing subfractions. This study suggests that genistein contributes to the immunomodulatory activity of UCME and will help in the standardization of functional food.

**Keywords:** *Uraria crinita*; isoflavone; genistein; NMR-based identification; dendritic cells
