Researchers at the St. Petersburg State University (SPbSU) and their colleagues from the local Research Center for Environmental Safety have reportedly discovered a brand new organic compound that shows variable activity when impacted by the light.

This compound is said to inhibit the activity of cholinesterase, a key human enzyme that is responsible for the functioning of many systems in the human body. Existing substances that possess similar properties are used to treat, for example, Alzheimer’s and a range of eye disorders.

The new discovery in St. Petersburg is expected to help “turn off” the biological activity of a drug using a laser, thus making therapeutic impact on human cells as safe and precise as possible.

From experience, physicians and patients cannot “turn” most modern drugs off or on at will; a pill taken by a patient remains biologically active for as long as it travels along the human body—and even after that. There is a widespread problem, for example, of deactivating antibiotics that inevitably get into the environment from the human body and stimulate rapid development of new antibiotic-resistant germ strains.

One of promising ways of solving the problem may be the development of photopharmacology, a nascent segment of pharmaceutical sciences which studies substances capable of “turning off and on” when impacted by the light. Photopharmacological agents typically consist of two parts: a therapeutic drug per se and a photoactive “switcher.” The St. Petersburg team, however, has apparently managed to develop a compound that performs both functions at the same time.