In vitro Anti-inflammatory Effects of Edible Igusa Soft Rush (Juncus effusus L.) on Lipoxygenase, Hyaluronidase, and Cellular Nitric Oxide Generation Assays: Comparison with Matcha Green Tea (Camellia sinensis L.)

Soft rush (Juncus effusus L. var decipiens), known as igusa, is locally cultivated as an edible organic crop, and the dried powder is applied to the processing of unique foods in Japan. The current study investigates the anti-inflammatory effects of edible soft rush using lipoxygenase and hyaluronidase assays, and an activated macrophage cell model in vitro. Matcha green tea powder was tested for comparison. Hot-water and ethanol extracts of soft rush as well as matcha showed comparable lipoxygenase inhibition, with IC50 values of 123 to 145 µg/mL. For the hyaluronidase assay, IC50 values of the samples were 1.16 mg/mL or more. Macrophages cultured in the presence of hot-water and ethanol extracts of soft rush showed strongly suppressed nitric oxide production (IC50 of 120 µg/mL and 35.2 µg/mL, respectively) compared to matcha in a lipopolysaccharide-activated cell model. These results support the potential usefulness of edible soft rush powder for anti-inflammatory purposes.