PHYTOCHEMICAL PROFILE, NEMATICIDAL AND PHYTOTOXIC POTENTIAL OF LEAVE EXTRACT OF ACACIA AURICULIFORMIS (EAR LEAF)

Jemirin O. D., *Ibikunle G. J., Edewor T. I., Ahmed A. A.

ABSTRACT

Natural products, particularly standardized plant extracts, provide a valuable reservoir of structurally diverse secondary metabolites with pharmaceutical and agricultural potential. Acacia auriculiformis (earleaf acacia) is a multipurpose plant with recognized medicinal, nutritional, ecological, and agricultural importance. This study therefore evaluated the phytochemical profile, phytotoxic, and nematicidal activities, and bioactive compounds of the ethanolic leaf extract of A. auriculiformis. Fresh leaves of A. auriculiformis were collected, washed, air-dried, pulverised, and extracted by static maceration in ethanol at room temperature for seven days. The extract was filtered, concentrated, and its percentage yield determined gravimetrically. Qualitative and quantitative phytochemical analyses were performed using established procedures. Phytotoxicity was assessed using a seed-germination bioassay, while nematicidal activity was evaluated against juveniles of Radopholus similis. Gas chromatography–mass spectrometry (GC–MS) was employed to characterize detectable compounds. The ethanolic leaf extract yielded 5.86%, and contained alkaloids, flavonoids, saponins, cardiac glycosides, and phenolic compounds qualitatively. Quantitative analysis revealed alkaloids (28.60 mg/mL), flavonoids (20.40 mg/mL), saponins (10.40 mg/mL), and cardiac glycosides (6.20 mg/mL).The phytotoxicity assay demonstrated concentration-dependent inhibition of seedling growth, with shoot and root lengths decreasing from 12.10 and 11.00 cm at 0.25% extract concentration to 6.99 and 6.33 cm, respectively, at 2.0%, compared with 13.92 and 15.34 cm in the control. The extract also demonstrated pronounced, concentration-dependent nematicidal activity against R. similis, with mortality increasing from 89% at 0.1% to 99% at 0.5% after 24 h, compared with 1% in the distilled-water control. GC–MS analysis identified seventeen bioactive compounds, with decanoic acid ethyl ester and hexadecanoic acid ethyl ester occurring prominently, alongside octanoic acid ethyl ester, cis-9-hexadecenal, and decane,1,1′-oxybis-.This study showed that A. auriculiformis leaves contain diverse phytochemicals associated with measurable phytotoxic, and nematicidal activities.

Keywords: Acacia auriculiformis, Nematodes, Radopholus similis, Nematicida, phytotoxic, phytochemical, ear leaf.