Metabolomic profiling and biological evaluation demonstrate the antioxidant, PPAR-γ, TAAR1, and FABP4 modulatory potential of Strelitzia species

Strelitzia species, commonly known as the bird of paradise, are herbaceous perennial plants used as ornamentals owing to the beauty of their colored flowers. Due to lack of sufficient data on their chemical and pharmacological properties, the current study aimed to investigate the chemical profiles of two Egyptian Strelitzia species namely S. reginae Banks and S. nicolai Regel & Körn using multiplex of GC-MS and ESI-MS/MS metabolomics. Major components in the hexane extract of S. reginae Banks flowers were heneicosane, linoleic acid, and 17-octadecynoic acid whereas for S. nicolai Regel & Körn they were cumene, pseudocumene, hexahydrocumene, and propenyl cyclohexane. The hydrodistilled oil of S. reginae Banks flowers was enriched in caprylyl acetate, cembrene, caryophyllene, thunbergol, and verticilla-4(20),7,11-triene while for S. nicolai Regel & Körn they were heptacosane and 7-hexyleicosane. LC-MS/MS analysis of the methanol extracts of the leaves and flowers of both species revealed intra-and interspecies variations with general domination of phenolic acids, flavonoids, fatty acids, and phenolic derivatives. DPPH and FRAP analysis showed promising antioxidant activity for S. reginae Banks leaves. The hexane extract of S. reginae Banks showed agonistic activity to peroxisome proliferator activated receptor gamma (PPAR-γ) with EC50 value of 1.203 ± 0.045 µg/ml compared to rosiglitazone (EC50 = 0.292 ± 0.011 µg/ml), hinting at promising antidiabetic effect. Quantitative measurement of TAAR1 (trace amine associated receptor 1) levels in NCI-H810 cells treated with the hexane extract of S. reginae Banks flowers revealed remarkable decrease in its levels to 0.743 ± 0.025 ng/ml compared to untreated cells, hence showing premise for the treatment of depression and Parkinson disorders. The hexane extract of S. reginae Banks flowers moderately inhibited FABP4 (fatty acid binding protein 4) with IC50 value at 1.051 ± 0.028 µg/ml so it might be valuable for the management of hyperlipidemia and atherosclerosis. Our results were further supported by molecular docking studies to show the binding mechanisms of the natural ligands on their target proteins.