Ultrasonic‐assisted solvent extraction of phenolic compounds from Opuntia ficus‐indica peel: Phytochemical identification and comparison with soxhlet extraction

The aim of the present study is to optimize the ultrasonic‐assisted solvent extraction (UASE) variables and to identify the phytochemical compounds present in the prickly pear (Opuntia ficus‐indica) peel extract and the results are compared with the extract obtained using soxhlet extraction (SE) techniques. Box–Behnken design (BBD) was used to optimize the UASE variables and the maximum TPC (5.95 mg GAE/g dW) and TFC (9.79 mg RUE/g dW) was obtained at 17 min of time, 40°C bath temperature and 1:24 g/mL solid–solvent ratio. The SEM analysis further shows that ultrasonic cavitation caused morphological changes, which accelerates the rate of extraction. The phytochemical analysis of UASE and soxhlet extracts revealed that the components which possess pharmacological activity are about 68.08% in UASE, whereas 61.72% in SE. In addition, components like phytol, azulene, andrographolide, serverogenin acetate, and stigmasterol, possess pharmacological properties that are notably present in UASE and are absent in SE. PRACTICAL APPLICATIONS: The present study identifies the presence of phytochemicals in the prickly pear (Opuntia ficus‐indica) peel extract obtained using ultrasonic‐assisted solvent extraction (UASE) and soxhlet extraction (SE) technique. The experiments' result shows that the components, which are responsible for antimicrobial activity, are higher in UASE extract compared to SE extract. The SEM analysis shows that ultrasonic cavitation caused morphological changes, which accelerates the rate of extraction and hence reduces the extraction time. The UASE technique is identified as a promising extraction technique for extraction of bioactive components with low solvent consumption. The UASE technique gives more pharmacological nature of components compared to soxhlet extraction (SE) technique. The present study reveals that the nature of the phytochemicals present in the extract strongly depends on the extraction method.