Effect of Andrographis paniculata on Ion Transport in Human Respiratory Epithelium

Abstract

Andrographis paniculata, also known as Fah Talai Jone in Thailand, is an herb traditionally used in China, India and Southeast Asia. It has been widely used for centuries, for the treatment of respiratory infection and common cold. However, the effect of Andrographis paniculata in regulating ion transport in respiratory epithelium is currently has not well understood. Thus, the present study was aimed to determine the effect of Andrographis paniculata on ion transport in human respiratory epithelium using NCI-H441 cell line using Ussing chamber technique. The equivalent short-circuit (I_sc), an indicator of ion transport across the epithelium was calculated. The results showed that Andrographis paniculata increased transepithelial potential difference and I_sc (p < 0.001; n =5). The effect of Andrographis paniculata was abolished when the cell monolayer was pre-treated with amiloride, a potent epithelial sodium channel (ENaC) blocker (p < 0.001; n = 5). Interestingly, the effect of Andrographis paniculata was not sensitive to TMEM16A and CFTR Cl^- channel blockers. Taken together these findings suggest that Andrographis paniculata increases Na⁺ absorption via ENaC without any effect on Cl^- secretion in H441 cells.