The fungus Aspergillus terreus Thorn var. terreus isolated from an Ecuador soil sample was cultured in liquid and solid media and yielded three main metabolites identified as terreic acid (1), butyrolactone I (2) and lovastatin (3). The natural products as well as three synthetic butyrolactone I derivatives were assessed for antimicrobial activity against Gram-positive and Gram-negative bacteria and fungi as well as for seed germination and seedling growth. Furthermore, the compounds were assessed as inhibitors towards the enzymes acetylcholinesterase, b-glucosidase, and b-glucuronidase. Terreic acid, butyrolactone I, butyrolactone 4¢,4¢¢-diacetate (2.1), and 3¢-(3-methylbutyl)-butyrolactone II (2.2) were active towards the phytopathogenic bacteria Erwinia carotovora with IC 50 of 5 and 4-18 lg/ml, respectively. Under the same experimental conditions, the IC 50 of streptomycin was 1.9 lg/ml. 3¢-(3-Methylbutyl)-butyrolactone II was moderately active against Pseudomonas syringae and Botrytis cinerea with IC 50 of 21lg/ml and MIC of 15.6 lg/ml, respectively. Butyrolactone I also inhibited germination of the dicot Lactuca sativa with an IC 50 of 5 · 10 )5 M. The IC 50 of reference herbicide acetochlor was 1 · 10 )5 M. The effect of 2.2 and 2.3, known as butyrolactone III on Panicum millaceum germination and growth was stronger than that of 2 and 2.1. Reduction of the double bond in the isoprenyl side chain of butyrolactone I increased the antibacterial effect against E. carotovora as well as acetylation. To our best knowledge, this is the first report on the antibacterial effect of butyrolactone derivatives towards Erwinia carotovora and the phytopathogenic fungus Botrytis cinerea. The butyrolactone I derivative 2.2 presented a moderate inhibitory effect against the enzyme acetylcholinesterase with an IC 50 of 47 lg/ml. Under the same experimental conditions, the reference inhibitor galanthamine had an IC 50 of 3 lg/ml.
The resin of the tree Araucaria araucana (Araucariaceae) is used by the Mapuche Amerindians in southern Chile and Argentina to treat ulcers and has been shown to display a gastroprotective effect in animal models. A study was undertaken to isolate, identify and assess the gastroprotective effect of the resin constituents and its semisynthetic derivatives as well as to evaluate the cytotoxicity of the products in cell cultures. Eleven diterpenes (ten labdane and a pimarane) were isolated from a resin sample collected in Chile. The labdane derivatives 15-acetoxylabd-8(17)-en-19-ol as well as 15,19-diacetoxylabd-8(17)-en are reported for the first time as natural products. Six diterpenes previously described from other plant sources are reported for the first time for the A. araucana resin. The structure of all compounds was elucidated by spectroscopic means. Some 24 diterpenes isolated/prepared in amounts over 10 mg were evaluated for gastroprotective effects in the ethanol/HCl-induced ulcer model in mice at 100 mg/kg. The highest gastroprotective activities were provided by 15-hydroxyimbricatolal, 15-acetoxyimbricatolal, 15-acetoxylabd-8(17)-en-19-oic acid methyl ester and 15-acetoxy-19-labdanoic acid, all of them being as active as the reference drug lansoprazole at 20 mg/kg. The cytotoxicity of 30 diterpenes as well as lansoprazole was assessed towards human lung fibroblasts (MRC-5) and 26 compounds were evaluated on the human gastric epithelial cell line AGS by means of the neutral red uptake assay. A concentration-dependent cell viability inhibition was found with IC 50 values ranging from 27 up to > 1000 µm. The relationship between the cytotoxicity data and lipophilicity of the products is also discussed.
The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red) tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato seeds with values 36.9 ± 0.8, 33.3 ± 00.5, and 17.6 ± 0.9 mg GAE/100 g, respectively (P < 0.05). Tomato peels had the highest antioxidant activity, both, as measured by the FRAP (46.9 ± 0.9 μmol Fe+2/g, P < 0.05) and the DPPH assays (97.4 ± 0.2%, 1000 μg/mL, P < 0.05). Pomace extracts showed the highest antiplatelet activity induced by ADP, collagen, TRAP-6, and arachidonic acid. While the maturation stage of the tomato fruit affected the antioxidant effect, antiplatelet activity was independent of fruit ripeness. Finally, based on the present results, tomato and its byproducts may be considered as a valuable source of antioxidant and antiplatelet activities.
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