Simultaneous Estimation of Cinnamaldehyde, Cinnamic Acid, and Eugenol in Herbal Formulation by Ultraviolet Spectrophotometry

A validated, rapid, and cost-effective UV spectrophotometric method was developed for the simultaneous quantification of three major cinnamon phytoconstituents—cinnamaldehyde, cinnamic acid, and eugenol—in a polyherbal formulation. The method employed a simultaneous equation approach using λmax values of 290, 270, and 280 nm, respectively. Excellent linearity was observed for each analyte (R² > 0.999), with calibration ranges of 2–12 μg/mL (cinnamaldehyde), 2–10 μg/mL (cinnamic acid), and 1–8 μg/mL (eugenol). The limits of detection (0.127, 0.108, and 0.090 μg/mL) and quantification (0.385, 0.328, and 0.274 μg/mL) confirmed high analytical sensitivity. Accuracy was demonstrated by recovery values of 98.5–101.2%, while intra- and interday precision studies yielded %RSD values <2.0%. Robustness testing showed minimal variability with deliberate changes in wavelength (±1 nm) and solvent composition (±2% methanol). Compared with chromatographic methods (high-performance liquid chromatography, gas chromatography–mass spectrometry), the proposed method requires minimal sample preparation, shorter analysis time, and substantially lower cost, while maintaining reliability. Its green advantage was confirmed by low solvent consumption, i.e., 3 mL methanol per sample, and an Analytical Eco-Scale score of 87, indicating excellent environmental compatibility. Owing to these attributes, the method offers a practical alternative for routine quality control of herbal formulations, particularly in small- and medium-scale industries where cost-effective and sustainable analytical tools are in demand.