Assessing Anti-Inflammatory Activities and Compounds in Switchgrass (Panicum virgatum)

Switchgrass is a bioenergy feedstock that potentially possesses multiple health benefits. However, the biological properties and associated bioactive compounds of switchgrass have not been adequately investigated. In the current study, we assessed the anti-inflammatory properties of switchgrass. Results from in vitro bioassays indicated that the methanolic extracts of switchgrass contained compounds exerting inhibitory effects on the expression of inflammatory mediators (TNF-alpha, IL-6, IL-8, and IL-10) induced in the U-937 model system. The extracts derived from four switchgrass cultivars (Alamo, Kanlow, Liberty, and Show Me) inhibited the secretion of all inflammatory mediators examined, with the only exception of the Liberty extract, which showed no significant effect on IL-10 expression. The degree of cytokine inhibition was variable, depending on the particular cultivar, the concentrations tested, and the cytokines examined. A global metabolomics approach was utilized to putatively identify possible molecules with known anti-inflammatory capacities in different switchgrass cultivars using ultra-high performance liquid chromatography with high-resolution mass spectrometry (UHPLC-HRMS). The content of multiple bioactive anti-inflammatory compounds in switchgrass was determined by liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analyses. Our results suggest that switchgrass, particularly the Alamo and Kanlow cultivars, may represent a promising natural anti-inflammatory source for the cosmetic, nutraceutical, and pharmaceutical industries.