Herbal ingredients are increasingly used in nutritional supplements and functional
foods, products which can often claim health benefits in terms of reducing risk of
disease and which are part of the overall well-being trend.
Analytically, these natural ingredients are sometimes very complex due to their unknown
matrix effect. In some cases, a mixture of different herbal extracts is needed in
order to achieve an adequate level of activity either by a synergistic effect or by
acting at different areas in the body to ensure a satisfactory effect. In these cases,
the analytical complexity increases with the number of ingredients, their concentration,
their polarity, their different responses and their level of interaction.
To ensure the quality of any complex formulation and to fulfill legal requirements,
complete analytical control is necessary. High performance chromatography is the most
popular method for carrying out analysis of non-volatile natural ingredients. A suitable
sample preparation is important to reduce the complexity and ensure a reliable result.
An analytical method for a mixture containing five different natural ingredients –
lutein esters, natural vitamin E, bilberry extract, passion flower extract and green
tea extract – was successfully developed. The recovery of each ingredient is more
than 90% except for passion flower that is lower (more than 70%). This method is suitable
for routine quality control of the final product to ensure that the active ingredients
are used at the right dosage, and for product stability tests and bioavailability
studies.
