FTIR-Based Phytochemical Profiling of Ayurvedic Dosage Forms of Vitex negundo and Correlation with Anti-inflammatory Activity in Wistar Rats

Background: Vitex negundo (Nirgundi) is a traditional Ayurvedic medicinal plant processed into diverse pharmaceutical forms (Swarasa, Kwatha, Taila, Ghrita) and extracts with purported anti-inflammatory properties. The relationship between traditional dosage form-specific phytochemical profiles and pharmacological efficacy remains understudied. Objective: To profile six Nirgundi preparations using Fourier-transform infrared (FTIR) spectroscopy and correlate spectral functional group patterns with in vivo anti-inflammatory activity in a rat paw edema model. Methods: FTIR spectroscopy (4000–400 cm–1) was performed on Nirgundi Swarasa, Kwatha, Taila, Ghrita, aqueous extract, and lipid extract. Anti-inflammatory activity was assessed in formalin-induced paw edema in male Wistar rats (n=6/group). Paw volume was measured at 0, 30 min, 1, 2, 4, 6, and 8 hours post-induction. Percentage inhibition was calculated relative to disease control. Data were analyzed by one-way ANOVA followed by post-hoc Tukey test (p<0.05). Results: FTIR profiling revealed distinct functional group signatures. Aqueous forms (aqueous extract, Swarasa, Kwatha) demonstrated prominent O-H stretching (3255-3265 cm-1) and aromatic C=C/phenolic C-O bands (1540-1650 cm-1), consistent with polyphenol-rich matrices. Lipid forms (Taila, Ghrita, lipid extract) displayed strong ester C=O stretching (1740 cm-1) and aliphatic C-H vibrations (2800-3000 cm-1), characteristic of triglyceride-based vehicles. All treatments significantly reduced edema vs. disease control (p<0.0001). Peak antiinflammatory activity at 4 hours ranked as: aqueous extract (52.23±2.36%), Swarasa (50.03±2.90%), Kwatha (45.28±3.22%), lipid extract (32.47±2.58%), Taila (30.00±5.30%), and Ghrita (28.40±4.65%). Forms with richer phenolic/aromatic FTIR markers demonstrated higher early anti-inflammatory efficacy. All formulations significantly reduced inflammation (p<0.0001), with aqueous polyphenol-rich preparations demonstrating superior peak efficacy compared with lipid-based forms, while maintaining a favorable safety profile. Hematological parameters remained normal across all groups, indicating safety. Conclusion: FTIR spectroscopy enabled precise differentiation of Ayurvedic dosage forms of Vitex negundo, revealing a strong association between polyphenol-linked functional groups and anti-inflammatory efficacy. This integrative analytical–pharmacological framework bridges traditional pharmaceutics with modern scientific validation, offering a robust platform for standardization, rational formulation design, and evidence-based optimization of Ayurvedic therapeutics.