Scientists from Prince of Songkla University in Thailand have discovered a more natural and environmentally friendly way to extract medicinal compounds from cannabis that shows promising results against cancer cells.

“We wanted to move away from the harsh chemicals typically used in cannabis extraction,” explains lead researcher Dr. Pharkphoom Panichayupakaranant. “Not only are they toxic to humans, but they’re also harmful to the environment.”

The breakthrough came when researchers used D-limonene—the same natural compound that gives citrus fruits their distinctive smell—to extract cannabinoids from cannabis flowers. Using a microwave-assisted extraction method that’s faster and more efficient than traditional techniques, they created what they call a “D-limonene extract of cannabis” or DEC.

When tested against human breast cancer cells, the results were encouraging.

The extract significantly slowed cancer cell growth while causing minimal harm to normal healthy cells—a critical distinction from conventional cancer treatments that often damage healthy tissue.

“What’s particularly interesting is that the whole extract performed better than isolated compounds like THC and CBD,” notes researcher Wiwit Suttithumsatid. “Pure THC and CBD were more potent against cancer cells, but they also harmed healthy cells. Our extract showed better selectivity—meaning it targeted the cancer cells while largely leaving healthy cells alone.”

The research also revealed that D-limonene itself has anti-cancer properties, suggesting a potential synergistic effect when combined with cannabinoids.

This approach could eventually lead to new treatments that cause fewer side effects than traditional chemotherapy. However, the researchers caution that more studies are needed before any clinical applications.

“We’re seeing promising early results, but there’s still much work to be done to understand exactly how these extracts work and to ensure they’re safe and effective,” adds Dr. Panichayupakaranant.

The findings also offer a greener alternative for the rapidly growing cannabis industry, which has been criticized for its environmental impact and use of harsh chemicals in processing.

The research was published in the Turkish Journal of Pharmaceutical Sciences.

Step-by-Step Guide: Green Microwave-Assisted Extraction of Cannabis

Materials Needed:

• Dried Cannabis sativa inflorescences (flowers)
• D-limonene or palm oil (as green extraction solvents)
• Microwave device with adjustable power settings
• Electric blender
• Sieve
• Filter paper or filtration system
• Glass containers for collection

Preparation Steps:

1. Dry the cannabis flowers
   • Place cannabis flowers in a hot air oven until completely dried
2. Create cannabis powder
   • Grind the dried flowers using an electric blender
   • Pass the ground material through a sieve to ensure homogeneity and uniform particle size

Extraction Procedure:

3. Prepare the extraction mixture
   • Measure cannabis powder at 4g per 20mL of solvent (optimal ratio)
   • Combine with D-limonene or palm oil in a microwave-safe container
4. Set up the microwave extraction
   • Set microwave power to 900W for D-limonene or vegetable oil extraction
   • Prepare for irradiation cycles (each cycle: 70 seconds power-on, 50 seconds power-off)
5. Perform the microwave extraction
   • Run 3 complete irradiation cycles
   • This will bring the extraction temperature to approximately 110-115°C
   • The total extraction time is about 6 minutes (3 cycles of on/off periods)
6. Filter the extract
   • Allow the mixture to cool slightly
   • Filter the mixture to separate the liquid extract from plant material
   • Collect the filtered extract in a clean container
7. Measure the yield
   • Record the volume of extract obtained
   • This can be used to calculate extraction efficiency

Notes on the Process:

• The microwave extraction method is significantly faster than traditional methods
• The process uses less solvent and energy than conventional extraction techniques
• The temperature reaches 110-115°C, which is optimal for cannabinoid extraction without degradation
• D-limonene extracts contain approximately 0.03% w/w CBD and 1.37% w/w THC
• No additional purification steps are needed if the extract is to be used as a whole-plant preparation

This method provides a green alternative to toxic solvents like hexane, chloroform, and methanol traditionally used in cannabis extraction, while maintaining high extraction efficiency for cannabinoids.