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a b s t r a c tA wild variety of bitter melon Momordica charantia L. (Cucurbitaceae) has been used in bush medicine of Trinidad and Tobago for treatment of diabetes, inflammations and cancer. Despite many studies regarding the cultivated bitter melon, the wild variety has been poorly investigated. This study evaluates the biological activities of the ethanol/water extract of aerial parts and correlates these activities with the presence of phenolic compounds. The extract exhibited antioxidant activity in the four assays (DPPH, reducing power, ␤-carotene bleaching and TBARS). The key role of oxidative stress in inflammation and tumorigenesis was supported by the results of anti-inflammatory (inhibition of nitric oxide production) and cytotoxicity (human tumor cell lines, namely HeLa, HepG2, MCF-7, and NCI-H460) assays. In contrast, no toxicity was observed in non-tumor cells. In the antibacterial screening, clinical resistant isolates were significantly affected (MIC 50 = 10-0.625 g/mL), being Listeria monocytogenes the most susceptible. Three phenolic acids and eleven flavonol glycosides derivatives were identified, quercetin-3-O-pentosylhexoside being the most abundant.

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In this study, the antioxidant capacities of main quinone constituents of Nigella sativa seeds, namely dithymoquinone (1), thymohydroquinone (2) and thymoquinone (3), were compared using DPPH and ORAC methods. The best scavenging activity was produced by 2, which showed a remarkable activity of 2.60 Trolox equivalents (TE) in a concentration range between 1.6 and 6.4 μg/mL and IC50 value of 2.4 μg/mL in ORAC and DPPH assays, respectively. Contrastingly, 3 possessed only weak DPPH scavenging efficacy (IC50 = 170 μg/mL) but significant antioxidative action of 1.91 TE in ORAC assay. No effect has been observed for 1. Additionally, modified protocol for synthesis of 2 has been developed with aim to enhance its availability for further studies as well as for its future potential use. Based on the results of this study, we conclude that 2 could be considered as a compound with prospective antioxidative properties.

Extracts prepared from leaves, roots, and stems of Solanum stramoniifolium Jacq. (Solanaceae) in 80% ethanol have been tested for their in vitro antioxidant, anti-inflammatory, antimicrobial, and cytotoxic activities with an aim to find new sources of substances for functional foods and food additives. The root extract revealed the highest antioxidant activity in all assays exceeding the trolox capacity, and was the only extract that inhibited nitric oxide production in mouse macrophage cells, showing also the capacity to suppress the growth of all tested human tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2). The leaf extract showed the strongest antimicrobial activity inhibiting all tested clinical isolates. To the author's best knowledge it was the first time that all individual parts of this plant were tested for biological activity together with the phenolic compound characterization.

The antiyeast activity of the black cumin seed (Nigella sativa) quinones dithymoquinone, thymohydroquinone (THQ), and thymoquinone (TQ) were evaluated in vitro with a broth microdilution method against six dairy spoilage yeast species. Antifungal effects of the quinones were compared with those of preservatives commonly used in milk products (calcium propionate, natamycin, and potassium sorbate) at two pH levels (4.0 and 5.5). THQ and TQ possessed significant antiyeast activity and affected the growth of all strains tested at both pH levels, with MICs ranging from 8 to 128 μg/ml. With the exception of the antibiotic natamycin, the inhibitory effects of all food preservatives against the yeast strains tested in this study were strongly affected by differences in pH, with MICs of ≥16 and ≥512 μg/ml at pH 4.0 and 5.5, respectively. These findings suggest that HQ and TQ are effective antiyeast agents that could be used in the dairy industry as chemical preservatives of natural origin.

Chemical composition plant parts (roots, stalks, leaves, blossoms) of common buckwheat (Fagopyrum esculentum Moench) and selected products made from its seeds (peels, whole seed, wholemeal flour, broken seeds, crunchy products Natural and Cocoa, flour, and pasta) was determined. Samples were dried and ground to a fine powder. All analyses were performed according to the Commission Regulation no. 152/2009, while rutin concentration was determined by the modified HPLC method. The lowest content of moisture was found in roots (4.3%) and in peels (almost 8%) and the highest moisture (nearly 11%) was discovered in seeds. The lowest amount of crude protein (3.5%) was found in peels, the highest crude protein amount (>13%) in both flours and leaves (23%). The starch content (>50% in dry matter) differs from one sample to another. Only in peels the content of starch was about 3.5%. From all examined samples, the lowest content of fat was found in crunchy products Cocoa, 1.7%. The lowest amount of histidine was determined in all studied samples, except peels, the highest content of glutamic acid was determined in almost all samples, except peels. Whole-meal flour is very rich source of Ca and Fe. The content of these elements was 1172 mg.kg -1 and 45.9 mg.kg -1, respectively. On the other hand, the highest content of Pb (>1 mg.kg -1 ) was found in broken seeds. The greatest concentration of rutin was determined in blossoms and leaves (83.6 and 69.9 mg.g -1 ), respectively. On the other hand, the lowest concentrations of rutin were found in buckwheat products (generally less then 1 mg.g -1 , i.e. in wholemeal flour, 702 μg.kg -1 , the lowest (almost 10 μg.kg -1 ) in pasta.

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