Guaiazulene is a sesquiterpene that has been found in M. chamomilla and has diverse biological activities.1,2,3 It inhibits lipid peroxidation in rat hepatic microsomes (IC50 = 9.8 μM), as well as scavenges hydroxyl and 2,2-diphenyl-1-picrylhydrazyl radicals in cell-free assays.1 It inhibits LPS-induced nitric oxide production in RAW 264.7 cells (EC50 = 10.1 μM) but is cytotoxic to RAW 264.7 cells at higher concentrations with cytotoxic concentration (CC50) values of 29.8 and 30.8 μM in the presence and absence, respectively, of LPS.2 Guaiazulene is cytotoxic to N2a neuroblastoma cells and primary rat neurons in a concentration-dependent manner.3 It inhibits decreases in hepatic glutathione (GSH) levels induced by paracetamol in rats when administered at a dose of 250 mg/kg.1
1.Kourounakis, A.P., Rekka, E.A., and Kourounakis, P.N.Antioxidant activity of guaiazulene and protection against paracetamol hepatotoxicity in ratsJ. Pharm. Pharmacol.49(9)938-942(1997) 2.Hashiba, K., Yokoyama, K., Wakabayashi, H., et al.Inhibition of LPS-stimulated NO production in mouse macrophage-like cells by azulenesAnticancer Res.24(6)3939-3944(2004) 3.Togar, B., Turkez, H., Hacimuftuoglu, A., et al.Guaiazulene biochemical activity and cytotoxic and genotoxic effects on rat neuron and N2a neuroblastom cellsJ. Intercult. Ethnopharmacol.4(1)29-33(2015)