A team of Indian researchers achieved a 100-fold reduction in tuberculosis bacterial load in lungs of mice after 60 days of treatment using bergenin.
Bergenin is a phytochemical isolated from tender leaves of sakhua or shala tree (Shorea robusta).
Unlike the regularly used antibiotic drugs that target the TB bacteria, the bergenin compound modulates the immune system to kill the bacteria found inside the macrophages, which is a type of white blood cells.
The result was published recently in the journal Frontiers in Cellular and Infection Microbiology.
• The study conducted by the Indian researchers show that the bergenin compound can be used to clear the bacteria. In fact, when it is used in combination with other TB drugs, the compound can produce good results.
• The researchers undertook several studies to understand the mode of action of the compound.
• The compound was unable to directly kill TB bacteria when treated with the compound.
• However, in the case of in vitro studies, the compound was able to kill the bacteria found inside infected cells.
• In mice infected with TB and treated with the compound, there was significant reduction in the bacterial load in the lungs.
• Unlike in the case of in vitro studies, in mice the compound was found to activate not only the macrophages but also other cell types (T cells) that led to effective killing of the bacteria.
• A significant reduction in the number of granulomatic lesions was seen in animals treated with the compound. Also, the bacterial load was 100-fold lower in mice treated with the compound compared with animals that were not treated with bergenin.
• The bergenin compound was selectively enhancing the frequency of interferon-gamma and interleukin-17-producing T cells in the TB infected animals. Interferon-gamma promotes bacteria-killing nitric oxide inside macrophages thus promoting the generation of protective immune responses against TB bacteria.
• The compound can be used in patients with drug-resistant TB too, as it does not target the bacteria directly but modulates the immune system to kill the bacteria.