Phytochemical profiling and antioxidant evaluation of Rhododendron arboreum Sm leaf and flower: integrative analysis using advanced analytical techniques.

ABSTRACT

OBJECTIVE: This study investigates the biological activities of Rhododendron arboreum Sm from the eastern Himalayas, addressing a literature gap on its properties. It explores the plant's phytochemical, antioxidant, and medicinal characteristics. SIGNIFICANCE: Evaluating methanolic extracts of R. arboreum offers valuable insights into its bioactive potential. Comprehensive GC-MS analysis identified a diverse array of compounds, highlighting the plant's chemical composition. METHODS: Methanolic leaf and flower extracts underwent sequential extraction and phytochemical profiling using column chromatography, TLC, and GC-MS analysis. Spectral studies aided compound identification, and antioxidant activity was assessed via spectrophotometric assays. RESULTS: Column chromatography separated methanol leaf and flower extracts into 17 and 24 distinct fractions, respectively. TLC analysis showed specific Rf values for leaf (0.58, 0.65, 0.75, 0.8, 0.86, 0.9) and flower samples (0.91, 0.38, 0.48, 0.51, 0.56, 0.6, 0.65, 0.75, 0.85, 0.96). GC-MS analysis revealed a variety of organic functional groups, including aliphatic hydrocarbons, aromatic compounds, heterocyclic molecules, phenolic compounds, steroids, terpenoids, alcohols, esters, and other bioactive compounds. FTIR spectra identified functional groups such as hydroxyls, primary amines, alkanes, and alkynes. NMR data indicated a complex molecular composition with diverse proton environments. Leaf extracts demonstrated superior antioxidant activity compared to flower extracts in DPPH, ABTS, hydrogen peroxide scavenging, lipid peroxidation inhibition, and FRAP assays. CONCLUSION: The study identifies diverse phytochemicals in R.arboreum extracts and highlights their potential applications in pharmaceuticals, nutraceuticals, and functional foods, owing to the superior antioxidant activity of leaf extracts compared to flowers.