An Integrated Extraction-Purification Process for Raspberry Leaf Polyphenols and Their In Vitro Activities.

Area of Science:

• Phytochemistry
• Natural Product Chemistry
• Food Science

Background:

• Raspberry leaves are a potential source of valuable bioactive compounds.
• Efficient extraction and purification methods are needed to maximize their utilization.
• Phenolic compounds in raspberry leaves exhibit various biological activities.

Purpose of the Study:

• To optimize extraction and purification of phenolic compounds from raspberry leaves.
• To evaluate the biological activities of the purified extracts.
• To enhance the medicinal and economic value of raspberry leaves.

Main Methods:

• Steam explosion pretreatment followed by homogenization and ultrasound-assisted extraction.
• Adsorption studies using XDA-6 macroporous resin, analyzed with Langmuir and pseudo-second-order models.
• Evaluation of total phenolic content (TPC), antioxidant activity, and alpha-glucosidase inhibition.

Main Results:

• Optimized extraction yielded TPC of 136.30–140.51 mg GAE/g.
• Purification increased TPC to 738.98 mg GAE/g (one cycle) and 905.27 mg GAE/g (two cycles).
• The two-cycle purification resulted in the highest antioxidant and alpha-glucosidase inhibitory activities, with quercetin-3-glucuronide reaching 199.69 mg/g.

Conclusions:

• Steam explosion is an effective pretreatment for releasing active substances from raspberry leaves.
• The integrated extraction-purification process significantly enhances phenolic content and bioactivity.
• This study provides a basis for the efficient utilization of raspberry leaves, increasing their value.