Cannabis Leaves Could Be Valuable Source of Antioxidant Compounds, New Study Finds
- A study in Molecules revealed that discarded cannabis leaves contain valuable antioxidant phenolic compounds useful for medicinal and cosmetic products.
- Researchers from Argentina used ultrasound-assisted extraction on dried Cannabis sativa leaves, finding this method more efficient than conventional maceration in recovering bioactive compounds quickly.
- The optimized process used 46% ethanol and a 1:10 solid-to-solvent ratio, yielding high levels of phenolic compounds and flavonoids with antioxidant properties, while avoiding THC extraction.
- The extract showed strong antioxidant activity, was non-toxic in tests, and the study suggests repurposing cannabis leaf powder for sustainable production, pending further pilot-scale validation.
A new study published in Molecules found that cannabis leaves, often discarded as a byproduct of cultivation, could be a valuable source of antioxidant phenolic compounds for use in medicinal, cosmetic and other products.
Researchers from Argentina examined Cannabis sativa leaves from a local variety grown in Tucumán, using ultrasound-assisted extraction to recover bioactive compounds from dried and powdered leaf material. The study notes that while cannabis inflorescences and upper leaves are used in Argentina’s pharmaceutical industry, mature leaves obtained through pruning, defoliation or cuttings are typically treated as waste or composted.
Researchers tested several extraction conditions, including different ethanol concentrations, extraction times and solid-to-liquid ratios. They found that ultrasound-assisted extraction was more efficient than conventional maceration, producing higher levels of total phenolic compounds and flavonoids in a much shorter period of time. While conventional maceration took 72 hours, the ultrasound method achieved strong results in minutes.
The optimized process used 46% ethanol and a 1:10 solid-to-solvent ratio. Under those conditions, researchers obtained 1,746.83 µg GAE/mL of total phenolic compounds and 858.41 µg QE/mL of total flavonoids. The extract was enriched with flavonoids such as luteolin, rutin, kaempferol, diosmetin and apigenin, all of which have been associated with antioxidant properties.
The study also found that lower ethanol concentrations favored the recovery of phenolic compounds while avoiding the co-extraction of THC-type cannabinoids. Researchers said this could make such extracts suitable, under Argentine regulations, for the development of THC-free cannabis-based medicinal products.
The optimized extract showed strong antioxidant activity and was considered non-toxic in an Artemia salina acute toxicity model. Researchers also found that the process had relatively low energy use at the laboratory scale.
The study concludes that cannabis leaf powder could be repurposed as a sustainable source of antioxidant compounds, supporting a circular economy approach within the cannabis industry. However, researchers said future pilot-scale validation and life cycle assessment studies are needed.