Phytochemical Investigation and Isolation of Chemical Constituents From the Root Extract of Syzygium guineense in South Ethiopia

Abstract

Medicinal plants are a global healthcare cornerstone, with traditional communities, particularly in Ethiopia, relying on indigenous knowledge for treating various ailments. This study aimed to identify, isolate, and elucidate the structures of chemical constituents from the chloroform and methanol extracts of Syzygium guineense root using IR, 1D, and 2D NMR spectroscopic techniques in South Ethiopia of Woliata Zone. Preliminary phytochemical screening confirmed the presence of various secondary metabolites, including alkaloids, flavonoids, terpenoids, polyphenols, saponins, tannins, glycosides, and steroids. The result indicated that the powdered root material was sequentially extracted with chloroform and methanol, yielding 5 g of chloroform extract (SGA) and 9 g of methanol extract (SGB). Subsequent chromatographic fractionation of the extracts led to the isolation of two pure compounds: SGB-3 (25 mg) from the methanol extract and SGA-24 (100 mg) from the chloroform extract. The structural elucidation of both compounds was performed using 1D and 2D NMR spectroscopy. The spectroscopic data (IR, ¹H NMR, ¹³C NMR, and DEPT) of SGB-3 indicated a diterpene lactone, characterized by hydroxyl, olefinic, and lactone functionalities. Partial characterization of SGA-24 through 1D and 2D NMR (¹H NMR, ¹³C NMR, DEPT, HMBC, HSQC) revealed its identity as a terpenoid with an oleanane Δ¹²-ene skeleton, showing close similarities to arjunolic acid. These findings contribute valuable scientific evidence to the phytochemistry of Syzygium guineense roots from South Ethiopia, supporting its traditional uses and identifying potential lead compounds for further pharmacological investigations.