Bioactive Constituents of <i>Adenium obesum</i> Flowers: Spectroscopic Profiling, Antioxidant, and Antibacterial Properties

Objectives The aim of this study was to investigate the therapeutic properties of Adenium obesum , a succulent plant native to the arid regions of the Arabian Peninsula, with particular reference to specimens from the Reem Valley in Rijal Alma, Asir Province, Saudi Arabia. The study specifically investigated the bioactive compounds in the methanolic cold extract of Adenium obesum flowers (CMEAOF) and evaluated its antioxidant and antibacterial properties. Methods The bioactive compounds in CMEAOF were analyzed by various analytical techniques, including gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance spectroscopy (NMR). The antioxidant potential of CMEAOF was quantitatively evaluated and its antibacterial activity was tested against both Gram-positive and Gram-negative bacteria. Results Several important bioactive compounds were identified in CMEAOF, including hexadecanoic acid methyl ester, ethyl isoallocholate and 9,12-octadecadienoic acid (Z,Z)-methyl ester. The extract showed significant antioxidant activity with a measured potency of 81.29%. In addition, the antibacterial evaluation showed a strong inhibitory effect against both Gram-positive and Gram-negative bacteria, indicating a broad antibacterial potential. Conclusion The results suggest that CMEAOF is a promising source of bioactive compounds with remarkable antioxidant and antibacterial properties. Ethyl iso-allocholate was identified as the most abundant compound, exhibiting the highest retention time and largest percent area under the curve, and is considered a potentially bioactive constituent based on both GC-MS and LC-MS analyses. These results support its potential therapeutic applications, especially in the development of natural antioxidant and antibacterial agents.