Screening of Basidiomycete mushroom extracts for antigenotoxic and bio-antimutagenic activity.

In this study we screened crude methanol:water extracts of 89 different mushroom species for their antigenotoxic and bio-antimutagenic activity. The screening was performed with the SOS/umu test and we monitored the ability of extracts to inhibit UV induced expression of umuC gene in Salmonella typhimurium TA1535/pSK1002. Seventeen extracts inhibited umuC expression by more than 50%. These extracts were further evaluated for the ability to inhibit UV induced mutations in Escherichia coli WP2. Five extracts (Cortinarius evernius, Rozites caperatus, Lactarius vellereus, Russula integra and Pleurotus cornucopiae) inhibited also UV induced mutations. The study showed that certain mushrooms contain substances with bio-antimutagenic potential. Particularly interesting for further investigations are Pleurotus cornucopiae (Lentinaceae), which was the most effective and species of Russulaceae and Cortinaceae families, which might contain common family specific bio-antimutagenic substance(s).

Screening for selective thrombin inhibitors in mushrooms.

Thrombin is the key serine proteinase of the coagulation cascade and therefore a suitable target for inhibition of blood coagulation. A number of pharmacologically active secondary metabolites from mushrooms have already been isolated, thus providing the rationale for screening for new thrombin inhibitors in mushrooms. In this study, inhibitory activities of mushroom extracts on thrombin and trypsin were measured using the chromogenic substrates H-D-phenylalanine-L-pipecolyl-L-arginine-paranitroaniline dihydrochloride (S-2238) for thrombin and N-benzoyl-D,L-Arg-p-nitroanilide (BAPNA) for trypsin. The inhibitory activities of extracts from 95 Basidiomycete species have been determined. The majority of samples inhibited trypsin and thrombin with various potencies; however, some extracts showed no activity against one or both of the enzymes. An aqueous extract of Gleophyllum odoratum exhibited high inhibitory activity on both thrombin and trypsin (72 and 60%, respectively), while extracts of Clitocybe gibba, Amanita virosa, Cantharellus lutescens, Suillus tridentinus, Hypoloma fasciculare and Lactarius badiosanguineus considerably inhibited thrombin (49, 48, 36, 34, 32 and 31%, respectively) and showed no inhibitory activity on trypsin. The results at this point are promising for further research with the objective of finding an effective and safe thrombin inhibitor.

Screening of selected plant extracts for in vitro inhibitory activity on HIV-1 reverse transcriptase (HIV-1 RT).

Methanolic-aqueous extracts of 70 plants were investigated for their ability to inhibit HIV-1 reverse transcriptase activity in vitro. Two thirds of the extracts screened showed more than 50% inhibition. Two extracts inhibited the enzyme completely while four exhibited more than 90% inhibition. Tannins as nonspecific HIV-1 RT inhibitors were detected and removed from the extracts. The IC50 values of the most potent extracts after the removal of tannins for the HIV-1 RT inhibition are as follows: Sambucus racemosa 0.017 mg/ml and Geranium phaeum 0.067 mg/ml. Daunomycine was chosen as a standard substance in the non-radioactive immuno assay used for screening. As a result from the future isolation and characterization of these compounds, new leading structures are expectable.

Quantitative phytochemical analyses of six hypericum species growing in slovenia.

The 74 samples of six HYPERICUM species (H. PERFOROTUM, H. HIRSUTUM, H. MACULATUM, H. TETRAPTERUM, H. MONTANUM, AND H. HUMIFUSUM) were collected around Slovenia and analysed for the content of ten substances (rutin, hyperoside, isoquercetin, quercitrin, quercetin, I3,II8-biapigenin, amentoflavone, pseudohypericin, hypericin, and hyperforin). The flowers were analysed separately from the green parts of the plants (herbs). The highest content of most of the substances was found in the flowers of H. PERFOROTUM. Among the herbal samples (without flowers), H. MONTANUM and H. HIRSUTUM contained significantly higher levels of amentoflavone (average 3-fold and 2.5-fold higher, respectively), than the herbs of H. PERFOROTUM. In the herbal part of H. PERFOROTUM the contents of all constituents strongly correlate with the contents of the same compound in flowers, except for the content of amentoflavone, which is independent in these two parts. Rutin and hyperoside are in positive correlation, and quercitrin is in negative correlation with the altitude of the growing site.

Jasmonic acid inducible aspartic proteinase inhibitors from potato.

A new cDNA clone coding for an aspartic proteinase inhibitor homologue was isolated from a potato tuber cDNA library. Southern blot analysis was used to study the structural diversity of the aspartic proteinase inhibitor gene family in several species of the Solanaceae. The existence of sequence-homologous genes was confirmed in the genomic DNA of different potato cultivars (Solanum tuberosum L. cv. Désirée, Pentland Squire and Igor), tomato (Lycopersicon esculentum Mill.), aubergine (S. melongena L.) and a wild type of bittersweet (S. dulcamara L.). Northern blot hybridization of total RNA, isolated from leaves under non-stress conditions, of different solanaceous species and of potato tubers showed that the gene transcripts encoding aspartic proteinase inhibitors occur mainly in potato tubers. The presence of several cathepsin D inhibitor isoforms has been detected at the protein level. At least four isoforms were isolated by affinity chromatography on cathepsin D-Sepharose and characterized. Additionally, exogenous treatment of potato plantlets by jasmonic acid (JA) over a wide range of concentrations (0-100 microM) was performed in a stem node culture in vitro. We demonstrated that the expression of aspartic proteinase inhibitor mRNA was drastically induced in potato shoots at concentrations of 50-100 microM JA.

Inhibitory effect of carnosic acid on HIV-1 protease in cell-free assays [corrected].

In order to find new effective HIV protease inhibitors, two diterpenes (carnosic acid [1] and carnosol [5]) were isolated from rosemary (Rosmarinus officinalis L.), and rosmanol [2] and semisynthetic derivatives (7-O-methylrosmanol [3], 7-O-ethylrosmanol [4], and 11,12-O,O-dimethylcarnosol [6]) were prepared. The inhibitory activity of all six compounds against HIV-1 protease was tested. The carnosic acid [1] showed the strongest inhibitory effect (IC90 = 0.08 micrograms/ml). The same compound was also assayed against HIV-1 virus replication (IC90 = 0.32 micrograms/ml). The cytotoxic TC90 on H9 lymphocytes was 0.36 micrograms/ml, which is very close to the effective antiviral dose. Additionally, the tested compounds did not inhibit cellular aspartic proteases cathepsin D and pepsin at the concentration range up to 10 micrograms/ml [corrected].