Development of an HPLC-DAD Method for the Quantification of Ten Compounds from Moringa oleifera Lam. and Its Application in Quality Control of Commercial Products.

An HPLC-DAD separation method for the simultaneous quantification of ten compounds from Moringa oleifera plant was developed. The method was validated with pure solvent and different matrices of M. oleifera products. This method was found to be linear in the concentration range of 1 to 10 mg L-1 for all the compounds in the solvent and from 3 to 10 mg kg-1 in the different matrices. The correlation coefficients ranged between 0.9900 and 0.9999. Intra-day and inter-day variability showed that the developed method is both repeatable and precise with percent relative standard deviation values less than 10% and 20%, respectively. Limits of detection ranged between 0.06 and 0.8 mg L-1 for the solvent and 0.1-1.5 mg kg-1 for the matrices, while the limit of quantification ranged between 0.2 and 2.8 mg L-1 and 0.4-4.8 mg kg-1, respectively. The validated method was applied successfully to thirty-two different M. oleifera products, whereby all ten compounds were detected in one of the samples. Principal component analysis was used to assess the correlation and variance between the products. Variations were observed in products from different regions and from different manufacturers.