Lonicerin is a flavonoid that has been found in L. japonica and has diverse biological activities, including antioxidant, anti-inflammatory, and neuroprotective properties. Lonicerin inhibits xanthine oxidase (IC50 = 37.4 μg/ml) and scavenges 2,2-diphenyl-1-picrylhydrazyl , hydroxyl, and superoxide radicals (IC50s = 9.2, 236.8, and 143.9 μg/ml, respectively). It reduces paw edema in a mouse model of C. albicans cell wall- and complete Freund's adjuvant-induced arthritis when administered at doses of 1 and 2 mg/kg three times every other day. It also decreases nitric oxide (NO) production and T cell proliferation in vitro when used at concentrations of 20 and 40 μg/ml, respectively. Lonicerin is neuroprotective against glutamate-induced neurotoxicity in rat primary cortical neurons.