Nalanthalide is a diterpenoid pyrone fungal metabolite that has been found in Nalanthamala and has potassium channel inhibitory and antiviral activities. It inhibits binding of the potassium channel inhibitor charybdotoxin to Jurkat cell membranes (IC50 = 3 μM) and inhibits rubidium efflux from CHO cells expressing the voltage-gated potassium (Kv) channel Kv1.3 (IC50 = 3.9 μM). Nalanthalide depolarizes T cells in vitro with an EC50 value of 500 nM. It also inhibits HIV-1 integrase activity with IC50 values of 10 and 25 μM in coupled and strand transfer assays, respectively.
