Fluorescence Characteristics of Tylophorinidine : Effect of pH and Buffer Molarity

Biochemistry and Food Technology Division

Bio-Organic Division, Bhabha Atomic Research Centre, Trombay, Bombay-400 085

Manuscript received 11 February 1980 revised 16 August 1980, accepted 5 November 1980

The fluorescence characteristics of tylophorinidine were examined in methanol, water and in increasing molarity of buffer at varying pH, 5-9.

In methanol the fluorescence spectra were closely similar to the excitation spectra. The fluorescence maximum was observed at 380 nm with a second band at 365 nm and a shoulder at 400 nm. These characteristic features were retained when the solvent was changed from methanol to water except that fluorescence maximum was shifted to longer wavelength by 5 nm.

In phosphate buffer of varying pH, 5-9, tylophorinidine fluoresced maximally at pH 5.0. However, fluorescence emission decreased with increasing pH. There was no alteration in the spectral pattern in this pH range which remained the same as in water. Buffer concentration, 0.06-0.2M, examined at various pH values, showed slight effect in the acidic pH range but had no effect in the alkaline region.