Colletodiol derivatives of the endophytic fungus Trichocladium sp.

The OSMAC (one strain many compounds) concept is a cultivation-based approach to increase the diversity of secondary metabolites in microorganisms. In this study, we applied the OSMAC-approach to the endophytic fungus Trichocladium sp. by supplementation of the cultivation medium with 2.5% phenylalanine. This experiment yielded five new compounds, trichocladiol (1), trichocladic acid (2), colletodiolic acid (3), colletolactone (4) and colletolic acid (5), together with five previously described ones (6-10). The structures were elucidated via comprehensive spectroscopic measurements, and the absolute configurations of compound 1 was elucidated by using TDDFT-ECD calculations. For formation of compounds 3-5, a pathway based on colletodiol biosynthesis is proposed. Compound 6 exhibited strong antibacterial activity against methicillin-resistant Staphylococcus aureus with a minimal inhibitory concentration (MIC) of 0.78 µM as well as a strong cytotoxic effect against the human monocytic cell line THP1 with an IC50 of 0.7 µM. Compound 8 showed moderate antibacterial activity against Mycobacterium tuberculosis with a MIC of 25 µM and a weak cytotoxic effect against THP1 cells with an IC50 of 42 µM.

Antihirudin antibodies following low-dose subcutaneous treatment with desirudin for thrombosis prophylaxis after hip-replacement surgery: incidence and clinical relevance.

Recombinant hirudin has been found to be immunogenic in patients treated with lepirudin following heparin-induced thrombocytopenia (HIT). We assessed the incidence of immunoglobulin G (IgG) antihirudin antibodies by enzyme-linked immunosorbent assay in 112 patients enrolled in a dose-finding study with desirudin. Patients received desirudin subcutaneously following orthopedic hip surgery at 10 mg twice a day (n = 17), 15 mg twice a day (n = 75), and 20 mg twice a day (n = 20). Of 112 patients, 11 (9.8%) developed antihirudin antibodies independently of the dose. The rate of immunization did not differ from that observed in HIT patients treated with lepirudin (P =.113). Plasma concentrations of desirudin did not differ between antihirudin antibody-positive and -negative patients. Antihirudin antibodies had no impact on incidences of deep vein thrombosis and/or pulmonary embolism, allergic reactions, and hemorrhage. However, the total number of immunized patients observed was low and so infrequent (but severe) effects of antihirudin antibodies cannot be excluded.