Analytical method development, validation and forced degradation studies for rutin, quercetin, curcumin, and piperine by RP-UFLC method.

Significance: Curcumin, rutin, and quercetin are well-known flavonoids and piperine is an alkaloid, commonly used as spices and traditionally used to treat a variety of conditions. In the current scenario, the stability problems of phytoconstituents are a major problem for regulators and because of the complex nature of the components of plant extracts.

Objective: A simple, fast, and sensitive ultra-force reverse phase liquid chromatography (RP-UFLC) has been developed, validated, and studied for degradation studies.

Methods: Seven different plant extracts were quantified and the stability of the constituents was estimated by forced degradation studies. The separation of the phytoconstituents was performed on a Phenomenex C column with a mobile phase of 80% acetonitrile and 20% (25 mM) ammonium acetate (pH 3) at a flow rate of 1 mL min detected at 380 nm.

Results: The results of the study showed that the method developed was linear with a range of correlation coefficient 0.994-0.999. The specificity, precision, and accuracy were well within the limits. Quantification showed that a maximum content of curcumin (3.61%, w/w) was found in the extract of L extract, piperine in L (13.92%, w/w), rutin in L (15.19%, w/w), and quercetin in L (0.36%, w/w). Forced degradation studies have shown that rutin was very stable in acidic media (6.65%, w/w) and curcumin was less stable in alkaline media (100%, w/w).

Conclusion: The method developed was simple, fast, accurate, sensitive, and applicable for the determination of phytoconstituents in natural extracts and herbal formulations, individually or in combination and can be used as a quality control tool.