Pharmacognostic Standardization and In Vitro Glycemic and Radical Scavenging Properties of Tabebuia rosea (Bertol.) DC. Aqueous Floral Extract

Research Article

Abstract

Tabebuia rosea (Bertol.) DC. (Bignoniaceae) holds significant ethnomedicinal prominence across the Neotropics and tropical Asia for managing metabolic and inflammatory disorders. Despite widespread reliance on traditional aqueous decoctions, standardized pharmacognostic parameters and metabolite profiles of the floral anatomy remain insufficiently defined. Macroscopic, anatomical, and micromorphological criteria of the floral structures were systematically established. Aqueous floral extraction yielded 35.1% dry weight. Gas chromatography-mass spectrometry profiling resolved twenty-one volatile and semi-volatile secondary metabolites, predominantly composed of 4-vinylphenol (23.47%), (Z)-9-octadecenamide (18.76%), hexadecanamide (10.85%), and 2-hydroxy--butyrolactone (10.28%), alongside long-chain polyunsaturated fatty acids and the sesquiterpene lactone parthenolide (1.73%). Functional pharmacological assays showed concentration-dependent attenuation of carbohydrate digestion via porcine pancreatic -amylase inhibition, progressing from 12.45% at 0.5 mg/mL to 59.27% at 2.5 mg/mL (). Radical clearance evaluation utilizing 2,2-diphenyl-1-picrylhydrazyl (DPPH) revealed marked free radical scavenging potential, where the aqueous extract neutralized DPPH radicals in a typical concentration-dependent progression across 20 to 100 g/mL, reaching 82.72% scavenging at peak concentration alongside an ascorbic acid reference standard (96.86%). The observed bioactivities correlate directly with the synergistic matrix of alkyl amides, phenolics, and lactones identified within the metabolome. These findings establish authentic diagnostic standards and validate traditional aqueous formulations of T. rosea flowers as functional multi-target therapeutic candidates against postprandial hyperglycemia and systemic oxidative stress.