Radical scavenging activities of flavonoids from roots of Akschindlium godefroyanum.

Chemical constituents of crude ethyl acetate extract of roots of Akschindlium godefroyanum (Kuntze) H. Ohashi were investigated and seven flavonoids were isolated. Their structures were identified based on spectroscopic methods as well as by comparison with spectral data reported in the literature as six flavanonols and a flavonol including 7,4'-dihydroxy-5,3'-dimethoxyflavanonol (1), neophellamuretin (2), taxifolin (3), erycibenin D (4), geraldol (5), fustin (6) and garbanzol (7).

Complexation of bisphosphonates with ytterbium(III): application of phosphate and ATP detection assay based on Yb(3+)-pyrocatechol violet.

The coordination chemistry of bisphosphonates with Yb(3+) was investigated to evaluate the potential of the UV-vis based detection method using the Yb(3+)-pyrocatechol complexation reaction as a sensor for bisphosphonates. The complexation chemistry of Yb(3+) with phosphate and ATP analogs was previously described (E. Gaidamauskas, K.

Metal complexation chemistry used for phosphate and nucleotide determination: an investigation of the Yb3+-pyrocatechol violet sensor.

Metal complexation reactions can be used effectively as sensors to measure concentrations of phosphate and phosphate analogs. Recently, a method was described for the detection of phosphate or ATP in aqueous solution based on the displacement by these ligands of pyrocatechol violet (PV) from a putative 2:1 (Yb3+)2PV complex. We have not been able to reproduce this stoichiometry and report this work in order to correct the coordination chemistry upon which sensor applications are based.