US researchers have developed a method to produce anti-cancer viral particles from plant leaves without destroying the plants. The findings, published in npj Science of Plants, suggest it may be possible to manufacture drugs autonomously during long-duration space missions, when resupply from Earth is impossible because of vast distances. A trip to Mars, for example, can take up to 200 days, and many drugs have a limited shelf life in space, making on-site production a critical task.
Plants are already used aboard the International Space Station to purify air and recycle water. Now scientists want to add another function – drug production. For this, the authors propose using cowpea mosaic virus (CPMV). The virus is harmless to humans but can prime the immune system to fight cancer; in animal and canine experiments, such particles have helped destroy tumours.
Normally, obtaining such substances requires grinding up plants, which produces many impurities and demands complex purification. The researchers took a different approach: they immersed leaves in a solution, applied a vacuum to drive liquid into the intercellular spaces, then withdrew the fluid using a centrifuge. The plants did not die in the process.
The resulting solution was roughly 200 times cleaner than that from conventional grinding because it contained almost no plant proteins. After additional filtration, purity reached 99%, meeting medical standards. From one cycle, the authors obtained 0.49 mg of product per 100 grams of leaves – sufficient for a small number of patients.
The researchers then tested the technology under spacesimulated conditions – microgravity, oxidative stress and temperature fluctuations. They found that plants became more compact, a bonus for saving space on a spacecraft. Some stress factors, contrary to expectations, actually increased the yield of the target compound. The technology allows repeated harvesting from the same plants and, the authors believe, could be useful not only in space but also in remote regions of Earth that lack sophisticated drug purification equipment.
Earlier, private aerospace firm Varda Space Industries and drugmaker United Therapeutics announced an agreement to study the effects of microgravity on developing chronic-disease medicines. They plan to send drug samples to orbit in uncrewed capsules for chemical processing and then return them to Earth for analysis.
