Activity of andrographolide against dengue virus.

Dengue is the most prevalent arthropod-transmitted viral illness of humans, with an estimated 100 million symptomatic infections occurring each year and more than 2.5 billion people living at risk of infection. There are no approved antiviral agents against dengue virus, and there is only limited introduction of a dengue vaccine in some countries. Andrographolide is derived from Andrographis paniculata, a medicinal plant traditionally used to treat a number of conditions including infections. The antiviral activity of andrographolide against dengue virus (DENV) serotype 2 was evaluated in two cell lines (HepG2 and HeLa) while the activity against DENV 4 was evaluated in one cell line (HepG2). Results showed that andrographolide had significant anti-DENV activity in both cell lines, reducing both the levels of cellular infection and virus output, with 50% effective concentrations (EC50) for DENV 2 of 21.304 μM and 22.739 μM for HepG2 and HeLa respectively. Time of addition studies showed that the activity of andrographolide was confined to a post-infection stage. These results suggest that andrographolide has the potential for further development as an anti-viral agent for dengue virus infection.