Spectrophotometric method for quantification of total flavonoids in Paederia lanuginosa Wall. leaf extracts

Abstract

Paederia lanuginosa Wall. is a plant belonging to Rubiaceae family. Kaempferol,
quercetin, and quercitrin were flavonoids isolated from the leaf extract of P. lanuginosa.
The chemical name of kaempferol is 3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-1-
benzopyran-4-one. Kaempferol is a yellow-colored compound with a low molecular weight
(286.2 g/mol). Kaempferol is a representative of the flavonol group and is a common
natural compound. Ultra violet (UV) – visible spectrophotometric method can be used to
determine the content of kaempferol. Therefore, the development and validation of a
procedure for quantifying total flavonoid content (with standard of kaempferol) in P.
lanuginosa soft extract is necessary. The spectrophotometric detection of kaempferol was
done at absorption maximum (λmax) of 365 nm using ethanol as solvent when this solution
was scanned between the wavelength regions of 300-400 nm. The developed method was
validated as per ICH guidelines. Kaempferol demonstrated good linearity in concentration
range of 2-10 μg/ml (R2 > 0.99) at 365 nm. Precision and mean recoveries were found to
be in the range of 97,13% and 98,21% at 365 nm. Flavonoids total of P. lanuginosa leaves
extract account for 8,558 percent. A quantitative procedure was developed and validated
according to ICH guidelines on the following criteria: system compatibility, linearity and
precision.