9-Hydroxycrisamicin A, a new cytotoxic isochromanquinone antibiotic produced by Micromonospora sp. SA246

9-Hydroxycrisamicin A, a new cytotoxic isochromanquinone antibiotic, was isolated from a soil microorganism SA246 which was identified as Micromonospora sp. The molecular formula of 9-hydroxycrisamicin A was determined as C32H22O13 based on the HRFAB-MS analysis, and the structure was determined by various NMR experiments. 9-Hydroxycrisamicin A showed weak antimicrobial activity against Gram-positive bacteria and strong cytotoxic activity against some human cancer cell lines such as SK-OV-3 (ovarian), HCT15 (colon), SK-MEL-2 (melanoma), A549 (lung), XF498 (central nervous system) with ED50 of 0.47-0.65 microgram/ml.

Capillary electrophoresis of organotin compounds with indirect UV detection

A capillary electrophoresis (CE)-indirect UV absorbance detection method for organotin compounds is described. The five triorganotin cations, viz., trimethyltin (TMT), triethyltin (TET), tripropyltin (TPT), tributyltin (TBT) and triphenyltin (TPhT), were efficiently separated by CE in 10 min with a 5 mM acetate buffer (pH 4.5) containing 3 mM 4-aminopyridine (4-AP). 4-AP also functioned as a UV-absorbing coion for the indirect detection of these UV-transparent organotin species. Simultaneous separation of di- and triorganotins was achieved with the addition of alpha-cyclodextrin (alpha-CD) as a modifier in the electrophoresis buffer. Linearity (r > or = 0.995) of about two orders of magnitude was generally obtained. The concentration limits of detection for the organotin compounds studied were between 2 and 20 microM (as tin). The relative standard deviation (RSD) values were in the range 1.3-7.1%. The applicability of the method for the analysis of marine sediment was examined.