Seasonal and tissue variation of falcarindiol, an antimycobacterial constituent of the Canadian medicinal plant Heracleum Maximum

Abstract

First Nations peoples of the Canadian Maritime provinces use the roots of Heracleum maximum as a treatment for tuberculosis, traditionally collecting the roots in the fall. A recent study confirmed that H. maximum roots exhibit significant antimycobacterial activity in vitro and identified falcarindiol as the bioactive constituent. Our objective was to determine whether there is a correlation between the amount of falcarindiol and the bioactivity of H. maximum crude extracts. Extracts of four H. maximum tissues collected over three seasons for three consecutive years were tested for antimycobacterial activity and analyzed for their falcarindiol content. Although there was no difference in bioactivity between seasons, flower extracts exhibited the highest bioactivity whilst the summer root extracts contained the most falcarindiol. There was no relationship between antimycobacterial activity and falcarindiol content of the extracts suggesting the presence of other compounds in the extracts that may be responsible for the observed antimycobacterial activity.