This new discovery could lead to safer and more natural alternatives to the currently available imaging techniques.

It’s not just in science fiction movies that we see plants glowing under ultraviolet (UV) light. The roots of a traditional medicinal plant known as the orange climber, or Toddalia asiatica, can also fluoresce with an ethereal blue hue.

A team of researchers from ACS Central Science has now identified two natural coumarin molecules present in the plant that are responsible for this unique fluorescent property. The team believes that one of these compounds could potentially be used for medical imaging in the future.

Fluorescent substances, when exposed to ultraviolet (UV) light, absorb it and emit brightly colored visible light. The phenomenon of these compounds glowing even brighter when clustered together is called aggregation-induced emission luminogens (AIEgens).

These compounds play a vital role in optical devices, cellular imaging techniques, and environmental sensors. However, many of these molecules are toxic and typically made in a laboratory.

To overcome this, a group of researchers led by Ben Zhong Tang, Zheng Zhao, and Xiao-Dong Luo have turned to nature to find safer and naturally occurring AIEgens.

The team focused on plants, which have already evolved to produce these compounds, and identified fluorescent blue coumarins in the roots of the orange climber plant.

The team dried the roots and turned them into a powder before isolating and identifying two coumarin compounds, 5-methoxyseselin (5-MOS) and 6-methoxyseselin (6-MOS). When dissolved in an organic solvent, the 5-MOS compound exhibited a blue-green glow while the 6-MOS compound had a slightly dimmer blue glow.

In a final series of experiments, the researchers found that 5-MOS stained live cells clearly, without any additional processing, making cell imaging quicker and easier than current methods.

The newly reported compound is a natural alternative that could significantly advance bioimaging, according to the researchers.

Source: 10.1021/acscentsci.3c00012

Image Credit: Adapted from ACS Central Science 2023