Plant antimicrobial peptides (AMPs) are a component of barrier defense system of plants. They have been isolated from roots, seeds, flowers, stems, and leaves of a wide variety of species and have activities towards phytopathogens, as well as against bacteria pathogenic to humans. Thus, plant AMPs are considered as promising antibiotic compounds with important biotechnological applications. Plant AMPs are grouped into several families and share general features such as positive charge, the presence of disulfide bonds (which stabilize the structure), and the mechanism of action targeting outer membrane structures.

We determined the level of flavonoids, citric acid and ascorbic acid in hips of rose species from the Caninae section occurring in Poland. We performed phytochemical analyses of 75 samples representing 11 species: Rosa agrestis Savi, R. canina L., R. dumalis Bechst., R. glauca Pourret, R. inodora Fries, R. jundzillii Besser, R. rubiginosa L., R. sherardii Davies, R. tomentosa Sm., R. villosa L. and R. zalana Wiesb. Flavonoid content was determined spectrophotometrically, and organic acid concentrations by HPLC. The content of the studied compounds varied greatly. Interspecific differences in the amount of flavonoids and ascorbic acid were highly significant. The most common species, Rosa canina, showed low average content of vitamin C (0.51 g/100 g of dry matter) and flavonoids (41 mg/100 g DM) and high content of citric acid (3.48 g/100 g DM). Ascorbic acid was highest in R. villosa hips (avg. 2.25 g/100 g DM), flavonoids were highest in R. rubiginosa (72 mg/100 g DM), and citric acid was highest in R. tomentosa (4.34 g/100 g DM). Flavonoid level correlated negatively with the amount of citric acid (r=-0.47, p<0.001). Cluster analysis of rose species based on the content of the investigated compounds confirmed the validity of the division of sect. Caninae into three subsections: Rubiginosae, Vestitae and Rubrifoliae. The phytochemical variation of these roses reflects their probable phylogenetic relationships as determined from morphology.

The aim of the study was to evaluate analgesic activity (“hot plate” test), anti-inflammatory activity (carrageenan-induced paw edema) and locomotor activity in rats under the influence of three fractions of Chelidonium majus herb extract: full water extract (FWE), protein enriched fraction (PEF), and non-protein fraction (NPF). Effects of the fractions on the level of chosen cytokines and their mRNA levels were also assessed using lipopolysaccharide (LPS) administration as a proinflammatory cue. All fractions and diclofenac did not affect the locomotor activity of rats in comparison with the control group. FWE and PEF three hours after administration showed statistically significant analgesic activities comparable to morphine (p < 0.05). A slight reduction in rat paw edema was observed after three (comparable with diclofenac) and six hours in the NPF group. FWE revealed a statistically significant pro-inflammatory effect after three hours in comparison with the control group. Peripheral IL-1 and IL-4 cytokine concentrations were reduced under FWE and NPF, PEF fractions. The combination of FWE, PEF and NPF together with LPS showed only the effects of LPS. We suggest that protein enriched fraction (PEF) produced centrally mediated (morphine-like) analgesic action, whereas the anti-inflammatory potential was shown only after LPS-induced inflammation. The precise mechanisms involved in the production of anti-nociceptive and anti-inflammatory responses of studied fractions are not completely understood, but they may be caused rather by the presence of protein more than alkaloids-enriched fraction. This fraction of the extract could be used as an alternative therapy for the prevention of inflammatory-related diseases in the future, but further studies are needed.

Coltsfoot (Tussilago farfara L.) is a common species, widely used in European and Chinese traditional medicine for the treatment of respiratory diseases. However, raw material from this plant contains hepatotoxic pyrrolizidine alkaloids (PAs). The aim of the study was to determine the variability of the level of PAs (senkirkine and senecionine) in leaves of coltsfoot originated from natural populations in Poland. In the phytochemical analysis, 20 samples of T. farfara were used. This plant material was obtained from the Garden of Medicinal Plants in Plewiska near Poznań and originated from different regions of Poland. Coltsfoot leaves were harvested in the middle of July of 2010 and then dried at room temperature. The alkaloid content was detected using the HPLC-DAD method. The amount of PAs in leaves of T. farfara changed in a wide range from 0.06 to 1.04 μg g−1 of dry matter (DM). The content of senkirkine and senecionine was positively correlated (r = 0.68, P = 0.001). There was no statistically significant correlation between the amount of PAs as well as leaf weight and water content in leaves of T. farfara. Our results showed that a medium-sized leaf of coltsfoot (0.33 g DM) may contain from 0.02 to 0.34 μg of PAs (on average 0.14 μg). The level of PAs was not associated with the region of Poland, but phytochemical similarity of samples was usually visible at the local scale. Coltsfoot leaves are characterized by a high variability of the content of toxic PAs, much higher than in the case of the main active compounds, especially flavonoids and mucilage. This phytochemical variability is mainly genetically determined (samples came from a garden collection), and it can be increased by environmental factors. Our investigations indicate that Polish natural populations of T. farfara may provide raw material with a low level of toxic PAs.