Biodistribution properties of cleistanthin A and cleistanthin B using magnetic resonance imaging in a normal and tumoric animal model

Aim: To determine the biodistribution properties of cleistanthin A and cleistanthin B in rodents using magnetic resonance imaging (MRI). Materials and Methods: Cleistanthins A and B, constituents of Cleistanthus collinus Roxb., were labelled with gadolinium (Gd3+) directly and injected into normal and tumoric nude mice. The tissue signal intensity was measured using MRI to perform a noninvasive kinetic assay. Wistar rats were used for determination of the grayscale intensity to observe the distribution patterns of of cleistanthins A and B. Results: Cleistanthin A is kinetically more attractive to the gastrointestinal tract than is cleistanthin B, which gets accumulated in muscular tissues of mice in greater concentrations compared with cleistanthin A. Cleistanthin B but not cleistanthin A showed tumoric affinity and exhibited a tumor kinetic attraction in tumoric mice. In rats, cleistanthin A showed greater grayscale intensities in the brain, liver, and skeletal muscles in immediate post contrast MRI images, whereas the gadolinium tagged cleistanthin B showed higher grayscale intensities in the cardiac muscle and skeletal muscles in delayed post contrast MRI images. Conclusions: Cleistanthin A is more pharmacokinetically attractive to the gastrointestinal tract than cleistanthin B.