(1) Background: Thymoquinone (TQ) is the leading compound accounting for the pharmacological effects of Nigella sativa seed oil, also known as black seed oil. This study aimed to analyze the TQ ...content of commercial black seed oils and black seed oil-containing capsules to obtain information on the quality of the products and to find a promising and safe study medication for a putative clinical study. (2) Methods: Six black seed oils and five black seed oil-containing capsules were analyzed. TQ was quantified using a validated method consisting of a simple methanolic extraction and a fast HPLC-UV analysis. (3) Results: The TQ content varied from 3.08 to 809.4 mg/100 g (mean). The highest TQ content was found in a bottled oil, which might be considered for a clinical study. A dose of 4 mL of this oil per day contains 30 mg TQ, which is unlikely to be harmful. Based on the literature, a safe daily TQ dosage appears to be <48.6 mg per adult. (4) Conclusions: These findings suggest that black seed products should be regulated regarding TQ content to enable consumers to buy black seed food supplements of known content for the maintenance and improvement of health.
High stocking density and Cu and trichlorfon exposure are typical inducers of physiological stress in fish. It is well known that the stress response may be harmful to aquatic animals, inhibiting ...growth, causing reproductive failure, and reducing resistance to pathogens. Hence, it is important to attenuate the detrimental effects induced by these stressors in modern farming systems. Although Scoparia dulcis relieved cadmium-induced oxidative stress in rats, little information is available on the effects of high stocking density and CuSOsub.4 and trichlorfon exposure in fish. Therefore, this study investigates the protective effects of dietary supplementation with Scoparia dulcis extract on fish maintained at a high stocking density and exposed to CuSOsub.4 and trichlorfon. The present study may offer a feasible way of relieving the effects induced by these stressors. The objective of this study was to investigate the effects of Scoparia dulcis extract (SDE) on stress induced by high stocking density and Cu and trichlorfon exposure in crucian carp (Carassius auratus). The results showed that these stressors exerted detrimental effects in fish, such as inhibition of growth performance, reduced feed intake, and interruption of fish locomotion. Under high stocking density, dietary SDE supplementation increased the content of reduced glutathione (GSH) and the activities of amylase, catalase (CAT), and glutathione reductase (GR) and decreased the content of malonaldehyde (MDA) in the intestine of crucian carp. A similar trend was presented in the hepatopancreas under Cu exposure. Dietary SDE supplementation enhanced the activities of CAT, superoxide dismutase (SOD), glutathione peroxidase (GPx), lactate dehydrogenase, glutamate-oxaloacetate transaminase, and glutamate-pyruvate transaminase in the muscle of crucian carp under trichlorfon exposure. The optimum dietary SDE supplementation levels were 4.07, 4.33, and 3.95 g kgsup.−1 diet based on the recovery rate of weight gain (RWG), feed intake (FI), and inhibitory rate of rollover (IR) for crucian carp under high stocking density and Cu and trichlorfon exposure, respectively. Overall, dietary supplementation with SDE may be a useful nutritional strategy for relieving these stresses in aquatic animals.