Microwave Extraction Method Maximizes Antioxidants and CBD from Cannabis Leaves

OG Article  Written By Anthony Martinelli in News, Studies Watch Today's LIVE Episode on YouTube, X, and Rumble

June 27, 2025

Investigators from Kasetsart University and the University of the Thai Chamber of Commerce in Thailand employed response surface methodology and a Box-Behnken design to refine Microwave-Assisted Extraction (MAE) conditions.

Their objective was to obtain the highest concentrations of total phenolic content (TPC), total flavonoid content (TFC), antioxidant activity, and CBD utilizing only water as a solvent—an approach emblematic of sustainability and environmental responsibility.

The investigation evaluated various combinations of temperature (90°C to 150°C), extraction duration (10 to 30 minutes), and solid-to-solvent proportion (1:10 to 1:30 g/ml). The most effective extraction parameters were ascertained to be a solid-to-solvent proportion of 1:28.5 g/ml, a temperature of 150°C, and an extraction duration of 23 minutes.

Under these conditions, the cannabis leaf extract produced 19.08 mg GAE/g dw TPC, 8.98 mg QE/g dw TFC, 42.09 mg Trolox/g dw in Ferric Reducing Antioxidant Power (FRAP) capacity, and 44.14 mg Trolox/g dw in ABTS activity.

Significantly, the study determined that the antioxidant values for CBD exhibited a robust correlation with its phenolic composition. FRAP values displayed an especially strong correlation with CBD content (r = 0.914), indicating that CBD likely contributes substantially to the plant’s antioxidant profile.

This research underscores the burgeoning promise of cannabis leaves—a part of the plant typically underutilized—as a sustainable reservoir of bioactive compounds. The outcomes could inform the creation of functional food products, nutraceuticals, and cosmetics through eco-friendly extraction techniques.

The study’s concluding section affirms:

The implementation of MAE considerably boosts the extraction yields of phytochemicals and antioxidant activities from cannabis leaves, thereby establishing them as a valuable wellspring of bioactive compounds, particularly antioxidants. The primary effect experiments revealed that the solid-to-solvent ratio (SSR) was the paramount factor influencing phytochemical and antioxidant yields, followed by temperature and extraction time.

A greater SSR led to enhanced extraction of phytochemicals and antioxidant activities. Elevating the temperature favorably impacted antioxidant activities and CBD content, whereas extraction time exerted a less pronounced effect on these parameters. Optimization of the extraction parameters, with an SSR of 1:28.5 g-dried cannabis leaves/ml water, a temperature of 150°C, and an extraction time of 23 min, yielded elevated levels of phytochemicals (TPC of 19.08 ± 0.50 mg GAE/g dw and TFC of 8.98 ± 0.30 mg QE/g dw) and antioxidant activities (FRAP of 42.09 ± 0.55 mg Trolox/g dw and ABTS activity of 44.14 ± 0.39 mg Trolox/g dw). These discoveries emphasize the potential of these optimized conditions as an ecologically sound and efficient methodology for manufacturing functional ingredients suitable for deployment within the food industry.