Black cumin (Nigella sativa L. [N.sativa]) seed extracts demonstrated numerous beneficial biological effects including, among others, antidiabetic, anticancer, immunomodulatory, antimicrobial, anti-inflammatory, antihypertensive, and antioxidant activity. To better understand the phytochemical composition of N. sativa seeds, methanol seed extracts were analyzed for phenolic acid and flavonoid content. Furthermore, we tested N. sativa methanol, n-hexane, and aqueous seed extracts for their inhibitory activity against butyrylcholinesterase (BChE) and catalase (CAT) as well as for antimicrobial activity against several bacterial and a yeast strains. The phenolic content of N. sativa was analyzed using ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). The inhibition of BChE was assessed by modified Ellman's method, and the inhibition of CAT was determined by monitoring hydrogen peroxide consumption. The extracts were tested against Bacillus subtilis, Staphylococcus aureus, Salmonella enterica, and Escherichia coli using the agar diffusion method. The UHPLC-MS/MS method allowed the identification and quantification of 23 phenolic compounds within 15 minutes. The major components found in N. sativa seed extract were sinapinic acid (7.22 ± 0.73 µg/mg) as a phenolic acid and kaempferol (11.74 ± 0.92 µg/mg) as a flavonoid. All extracts showed inhibitory activity against BChE, with methanol seed extract demonstrating the highest inhibitory activity (inhibitory concentration 50% [IC50] 79.11 ± 6.06 µg/ml). The methanol seed extract also showed strong inhibitory activity against CAT with an IC50 value of 6.61 ± 0.27 µg/ml. Finally, the methanol extract exhibited considerable inhibitory activity against the tested microbial strains. Overall, this is the first study to investigate the ability of black cumin seed extracts to inhibit CAT. Our results indicate that N. sativa seed can be considered as an effective inhibitor of CAT activity.

The effect of aluminium and cadmium on growth and physiological parameters in 60 days old basil seedlings (Ocimum basilicum L.) grown in polluted soil were investigated. Control plants, grown in unpolluted soil, were used for evaluation of the heavy metal effect. Growth parameters were analysed immediately after sample collection, leaf area and plant height were recorded. Analysis of secondary metabolite, proline, total carbohydrates content and antioxidant capacity in 60 days old seedlings was performed. The antioxidant activity of basil extracts was determined by the DPPH method, and results showed an increase of antioxidative capacity in basil seedlings exposed to heavy metal stress due to the activation of antioxidative system in plant cells. Maximum production of secondary metabolites was recorded for seedlings exposed to 100 mg/kg soil Cd and Al. Results showed that cadmium stress increased concentration of proline, while aluminium did not had that effect. The content of total carbohydrates remained almost unchanged, with exception of basil seedlings grown on soil containing 50mg/kg AlCl3.