Abstract
In the field of inflammation research the inducible nitric oxide synthase (iNOS) became
an important pharmacological target, since overproduction of nitric oxide (NO) after
induction of this enzyme seems to be associated with numerous pathological conditions.
NO released from cells can be detected and quantified photometrically as its stable
product nitrite by a simple colorimetric reaction (Griess reaction). The aim of our
study was to investigate whether this method might be suitable for the bio-guided
fractionation of anti-inflammatory plant extracts. For this purpose we assayed extracts
as well as fractions of the roots of Curcuma zanthorrhiza Roxb. which contain the known iNOS inhibitor curcumin, and compared the obtained
activity with their curcumin content. Furthermore, leaf extracts of Betula pendula Roth, to which defined amounts of curcumin were added, were examined to clarify the
question whether chlorophyll might interfere with the test system. The presented results
suggest that the Griess assay is indeed suitable to guide fractionation of plant extracts
in order to isolate highly active compounds. Factors, however, which might restrict
the broad application of this assay are the limited selection of solvents which do
not interfere with the system and high contents of chlorophyll in plant extracts.
Key words
Bio-assay - nitric oxide - Griess reaction - anti-inflammatory - plant extracts
