Green extracts of black raspberry fruit as sustainable sources of antioxidant compounds: Potential application in modern pharmacy

Abstract

Green extraction has gained increasing importance in recent years due to the application of environmentally friendly solvents and the concept of sustainable development in the pharmaceutical and cosmetic industries. Black raspberry fruit represents a valuable source of bioactive compounds with pronounced antioxidant potential, resulting in considerable interest in the development of efficient and safe extraction methods. The aim of this study was to evaluate the content of polyphenol compounds (PP) and antioxidant potential (AP) in extracts of black raspberry fruit (Rubus occidentalis L., Rosaceae) grown in Serbia, obtained using different extraction methods and solvents. Extracts were prepared in drug:extract ratio of 1:5 (m/V) by maceration and ultrasonic extraction using glycerol-water system, as well as natural deep eutectic solvents (NADES) based on glycerol and citric acid. Total polyphenol content (TPC) was determined by Folin-Ciocalteu assay, while AP was assessed by FRAP method. The results showed that the extracts obtained using NADES system and ultrasonic extraction had the highest TPC (39.94±1.24 mg GAE/g), compared to the glycerol-water system and maceration (31.62±0.37 mg GAE/g). Similarly, these extracts showed significantly higher AP (892.81±5.61 μmol Fe²+/g) compared to conventionally obtained extracts (692.40±10.61 μmol Fe²+/g). NADES systems enabled more efficient extraction of PP and might represent an effective and sustainable alternative to conventional solvents, while ultrasonic extraction showed greater efficiency compared to maceration. The obtained results indicate that green extracts of black raspberry fruit grown in Serbia represent a valuable source of antioxidant polyphenolic compounds with potential application in the pharmaceutical and cosmetic industry.