Selective extraction of cannabinoid compounds from cannabis seed using pressurized hot water extraction

What if the key to unlocking cannabis's therapeutic potential lies not in harsh chemicals, but in plain hot water? A new study shows how pressurized hot water can selectively extract cannabinoids from hemp seeds.

Cannabis is a treasure trove of phytochemicals, with delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) leading the charge for industrial applications. But traditional extraction methods often rely on organic solvents, which are neither fast nor particularly green. Enter pressurized hot water extraction (PHWE) — a technique that uses water under high pressure and heat to pull out polar and semi-polar compounds from plant material. It's efficient, quick, and kind to the environment.

In this study, researchers applied PHWE to Cannabis sativa seeds, tweaking extraction time (5–60 minutes), extraction temperature (50–200°C), and collector vessel temperature (25–200°C) to see how these variables affected the recovery of five key cannabinoids: THC, CBD, CBN, CBG, and CBC. They used response surface methodology to map the optimal conditions and analyzed the extracts with GC×GC-TOFMS, a powerful analytical technique.

The results were striking: as the temperature climbed from 140°C to 160°C, the amounts of THC and CBN in the liquid extract plummeted. Meanwhile, the sweet spot for maximizing CBD, CBC, and CBG — while minimizing THC and CBN — was found at 150°C extraction temperature, 160°C collector temperature, and 45 minutes. At these settings, the predicted ratio of THCt (THC + CBN) to CBDt (CBD + CBC + CBG) was 0.17, and the experimental ratio was 0.18, showing excellent agreement.

This means PHWE isn't just a green alternative; it's a selective one. By fine-tuning temperature and time, you can tailor the cannabinoid profile of the extract, favoring the non-psychoactive compounds. That's a game-changer for industries looking to harness the benefits of cannabis without the high.

Key Points

• PHWE selectively extracts cannabinoids from cannabis seeds.
• Temperature 140–160°C drastically reduces THC and CBN.
• Optimal conditions: 150°C, 160°C, 45 min for CBD-rich extract.