RESUMO
Lycoris radiata (L'Her.) Herb. (L. radiata) was traditionally used as a folk medicine in China for treatment of Alzheimer's disease. However, the specific component responsible for its considerable toxicity remained unclear thus restricting its clinical trials. Narciclasine (NCS) was isolated from L. radiata and treatment of NCS for 72â¯h exhibited significant antiproliferative effects against L02, Hep G2, HT-29 and RAW264.7â¯cells. However, what needs to be emphasized is that at safe working concentrations of 0.001-0.016⯵M, administration of NCS for 24â¯h inhibited the mRNA expression of inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-É), interleukin-1beta (IL-1ß) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-induced macrophages thereby suppressing production of nitric oxide (NO), IL-6, TNF-É and IL-1ß. NCS supplementation also inhibited nuclear factor-kappa B (NF-κB) activation by suppressing NF-κB P65 phosphorylation and nuclear translocation, IκBÉ degradation and phosphorylation, and IκKÉ/ß phosphorylation. The phosphorylation of c-Jun N-terminal kinase (JNK) and P38, and expression of COX-2 was also attenuated by NCS. These results suggested that NCS might exert anti-inflammatory effects through inhibiting NF-κB and mitogen-activated protein kinase (MAPK) pathways even at very low doses.