An ultrasound-assisted method was used for the extraction of phenolics from defatted black cumin seeds (Nigella sativa L.), and the effects of several extraction factors on the total phenolic content and DPPH radical scavenging activity were investigated. To improve the extraction efficiency of phenolics from black cumin seed by ultrasonic-assisted extraction, the optimal extraction conditions were determined as follows: ethanol concentration of 59.1%, extraction temperature of 44.6 °C and extraction time of 32.5 min. Under these conditions, the total phenolic content and DPPH radical scavenging activity increased by about 70% and 38%, respectively, compared with conventional extraction. Furthermore, a complementary quantitative analysis of individual phenolic compounds was carried out using the HPLC-UV technique. The phenolic composition revealed high amounts of epicatechin (1.88–2.37 mg/g) and rutin (0.96–1.21 mg/g) in the black cumin seed extracts. Ultrasonic-assisted extraction can be a useful extraction method for the recovery of polyphenols from defatted black cumin seeds.

Until now, there is no documentation concerning the composition, biological and pharmaceutical activities of Algerian grape (Vitis vinifera L.) seeds. The present study aims to evaluate the phytochemical analysis, antioxidant and antimicrobial activities of grape seed extracts (GSEs) from the Algerian Red globe and Valenci varieties. The total polyphenols content (TPC) in the GSEs was evaluated by spectrophotometry, it was 398.01 ? 18.12 mg GAE/g GSEs and 335.11 ? 11.44 mg GAE/g GSEs for the Red globe and Valenci varieties respectively. The antioxidant activity of GSEs was also evaluated by spectrophotometry on stable free radicals of DPPH. The IC50 for the Red globe variety was 4 ? 0.2 ?g/ml, while for the Valenci variety it was 4.6 ? 0.36 ?g/ml. The antimicrobial activity was determined using the disk diffusion method. Both extracts showed antimicrobial activity against the eight studied strains: Escherichia coli, Pseudomonas aeruginosa, Pasteurella sp., Salmonella sp., Staphylococcus aureus, Streptococcus faecalis, Clostridium sp., and Candida albicans. The extracts produced a clear inhibition zone for all the tested strains. Inhibition diameters greater than 19 mm were registered. The obtained results in this study indicate the differences between the Red globe and Valenci varieties, in terms of polyphenol content, antioxidant and antimicrobial activities in Algerian GSEs.