Undetectable anti-bacterial activity of Andrographis paniculata (Burma) wall. ex ness

Andrographis paniculata (Burma) Wall. ex Ness (AP) is a herbal medicine and has been used for therapy of upper respiratory tract infection (URI) as well as acute diarrhea with reported efficacy of 75-100 per cent. To investigate whether anti-bacterial activity was responsible for the reported therapeutic success of AP, we carried out a number of studies. The first study was a direct assay of anti-bacterial activity of AP suspended in water. The tested pathogens included Salmonella, Shigella, E.coli, gr. A Streptococci and S.aureus. Anti-bacterial activity was not demonstrable even in a solution containing 25,000 mg per litre of crude powder. The second was designed to detect serum bactericidal activity after oral intake of stem and leaves of AP. Ten healthy volunteers were enrolled in the study. They received a single oral dose of AP (1, 2, 3 and 6 g) in a randomized, cross-over manner. The washout period was one week. Blood samples were taken at 0, 1, 2, 4, 8 and 24 hours after ingestion. Serum bactericidal activity was assayed by agar diffusion technique using Bacillus spores and five strains of each pathogen (Shigella, Salmonella typhi, S.aureus and gr. A Streptococci) incubated for 24 hours. Again serum bactericidal activity was not detected in any of the sera tested. In a third study, ninety-six rats were daily fed with high doses of AP ranging 0.12-24 g per kg body wt. for six months before sacrifice. Antibacterial activity was still undetectable when lung parenchyma and liver tissue was placed on culture media containing bacteria tested. In conclusion, anti-bacterial activity of AP is undetectable in our study.