Dear Dr.Radhakrishnan,

profiling or assay of markers in polyherbal formulations, as a measure of standardisation, is a nightmare for analytical chemists.

Considering the multiple (class of) chemistries in most medicinal herbal materials, it is wise to develop standardisation of individual starting herb material (eg. extracts) rather than looking for methods of assays in a polyherbal formulation.

In a number of instances we find a lot of overlapping classes of chemistry: for eg. flavonoids being ubiquitous in occurrence, there will be large overlaps and it becomes extremely difficult to separate and detect all the constituents in a single chromatographic method.

In most instances, QBI (quantitated by input) is the method that ensures confirmation of inclusion of individual herbal material (standardised to one or multiple markers) in to a polyherbal formulation.

It is again a general thumb rule that anything less than 3-4 herbal materials in a formulation gives a semblance of a chance of analysing the final formulation. more the herbs and/or more the complexity of chemistry, more difficult it becomes to develop any meaningful assay.

Most of the European countries allow only single herb formulations making it easy to analyse the formulated product.

There are a number of papers on analytical method development (in turn assay of standard markers) in literature. However, the combination (of herbs and in turn, the chemistry) in every polyherbal formulation will be unique; this actually provides an unique 'sample matrix' for separation and analysis. This means, for every type of formulation, the method development and validation will be unique.

Hope these points atleast partially answers your complex question...