Dithymoquinone, thymohydroquinone, thymol and thymoquinone, compounds derived from N. sativa seeds, were investigated for their in vitro anti-inflammatory activities using cyclooxygenase-1 (COX-1) and -2 (COX-2) assays. Our results show that all substances tested possess significant inhibitory activity against at least one COX form at concentrations comparable to the active one of indomethacin. Thymol was the most active against COX-1 with an IC (50) value of 0.2 microM while thymohydroquinone and thymoquinone exhibited the strongest inhibitory effect on COX-2 with IC (50) values of 0.1 and 0.3 microM, respectively. Moreover, dithymoquinone and thymoquinone showed a limited COX-2-specific inhibition. We conclude that dithymoquinone, thymohydroquinone, thymol and thymoquinone can participate in the general anti-inflammatory activity of N. sativa and suggest that these agents should be further studied for possible use as non-steroidal anti-inflammatory drugs.

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Phytoremediation of selected pharmaceuticals (diclofenac, ibuprofen, and acetaminophen) using Armoracia rusticana and Linum usitatissimum cell cultures and by hydroponically cultivated Lupinus albus, Hordeum vulgaris, and Phragmites australis plants in laboratory conditions is described. During in vitro experiments, the best results for acetaminophen were achieved using Armoracia rusticana hairy root cultures, where 100% of the starting amount was removed from the media during eight days. Total removal of ibuprofen and diclofenac was achieved using a Linum usitatissimum suspension culture after one and six days, respectively. In the hydroponic arrangement, the best results were achieved for Lupinus, where acetaminophen was totally removed from media during two or four days in concentrations of 0.1 or 0.2 mM, respectively. The best effectiveness of ibuprofen removal (50% of starting amount) was found in case of Phragmites. Effectiveness of all tested plants for diclofenac removal was low. The best removal was achieved using Phragmites in the case of 0.2 mM concentration-67% of the starting amount and Hordeum for 0.1 mM starting concentration, 56%.

Since 1960, the positive effects of rare earth elements (REE) on crop physiology have been observed, and support for photosynthesis, biomass accumulation, secondary metabolites, or enzymes has been reported in 40% of studies. A higher content of chlorophylls a and b as well as carotenoids have been found along with an increased efficiency of photosystem II photochemistry and electron transfer rates. An increased activity of a key photosynthetic enzyme was also found in several plants growing in soil with a higher content of REE. An appropriate amount of REE also activates the antioxidant activity of peroxidase, superoxide dismutase, and catalase. These enzymes, together with a higher content of flavonoids and carotenoids, increase the resistance of plants to oxidative stress caused by different abiotic stresses. The positive effect of REE on biomass accumulation was also confirmed, but their affection on mycorrhizal symbiosis remains ambiguous. On the other hand, an excess of REE leads to damage to plants including the chloroplast ultrastructure. Therefore, the positive and negative effects of REE remain controversial, and the mechanisms of effects of REE in plants remain poorly understood. In addition to physiological processes, the absorption, bioavailability, and translocation of REE in plants as well as their possible ecotoxicology and hyperaccumulation are discussed in this review.

The effect of toxic metals on seed germination was studied in 23 cultivars of flax (Linum usitatissimum L.). Toxicity of cadmium, cobalt, copper, zinc, nickel, lead, chromium, and arsenic at five different concentrations (0.01-1 mM) was tested by standard ecotoxicity test. Root length was measured after 72 h of incubation. Elongation inhibition, EC50 value, slope, and NOEC values were calculated. Results were evaluated by principal component analysis, a multidimensional statistical method. The results showed that heavy-metal toxicity decreased in the following order: As3+>or=As5+>Cu2+>Cd2+>Co2+>Cr6+>Ni2+>Pb2+>Cr3+>Zn2+.

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