Gas chromatographic-mass spectrometry-based chemotaxonomic profiling of Senna, Cassia, and Albizia species of the Fabaceae family

Abstract

Senna, Cassia and Albizia are diverse genera within the Fabaceae family, characterised by complex taxonomy of morphological plasticity and hybridisation. This study employed Gas Chromatography-Mass Spectrometry (GC-MS) to profile the diethyl ether leaf extracts of nine species: Senna alata, C. fistula, S. podocarpa, S. obtusifolia, S. occidentalis, S. siamea, Albizia lebbeck, A. adianthifolia, and A. zygia. A total of 117 phytocompounds were identified across all the species studied, with 28 to 40 identified per species. Alcohols (34.19%) and carboxylic acids (17.95%) were the most prominent compounds. Four compounds: -3,7,11,15-Tetramethyl-2-hexadecen-1-ol, Phytol, 9-Octadecenamide, and n-Hexadecanoic acid- were present in all the species. Similarity indices ranged from 19.61% (S. siamea and S. podocarpa) to 58.62% (S. alata and S. occidentalis). Multivariate analyses revealed distinct groupings, notably the divergence of Albizia lebbeck, which formed a separate cluster characterized by a high abundance of 1-Monolinoleoylglycerol trimethylsilyl ether, Benzeneacetic acid, and 6,10-Dodecadien-3-ol, among other compounds. Conversely, S. podocarpa showed close affinity with Albizia species, defined by their shared abundance of alcohols (n-Nonadecanol-1 and 2-Pentadecyn-1-ol) and sterols (Lupeol and β-Sitosterol). These chemotaxonomic findings complement existing morphological data and provide refined differentiation among closely related species. The study demonstrates the value of GC-MS phytochemical profiling in resolving systematic relationships within Fabaceae.