Evaluation of Antibacterial Activity of a Sesquiterpenoid Isolated From the Leaves of Laggera tomentosa Endemic to Ethiopia

ABSTRACT The success in discovering natural therapeutic agents relies on bioassay‐guided fractionation and purification techniques. Active ingredients from herbal medicines are beneficial due to their compatibility with various other active substances. To evaluate the antibacterial activities of ses...

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Main Authors: Tesfamariam Kassa Adal, Sisay Awoke Endalew, Amualaw Birara Beshir, Moges Kibret Wondimagegn
Format: Article
Language:English
Published: Wiley-VCH 2025-04-01
Series:Natural Sciences
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Online Access:https://doi.org/10.1002/ntls.70006
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Summary:ABSTRACT The success in discovering natural therapeutic agents relies on bioassay‐guided fractionation and purification techniques. Active ingredients from herbal medicines are beneficial due to their compatibility with various other active substances. To evaluate the antibacterial activities of sesquiterpenoid compound isolated from the leaves of Laggera tomentosa endemic to Ethiopia. The crude extract was obtained using the maceration technique from the leaves of Laggera tomentosa. Hexane, ethyl acetate, and methanol were used to fractionate crude extract for phytochemical and antibacterial evaluation. The phytochemical screening of the crude was done to test the presence or absence of alkaloids, phenols, saponins, flavonoids, tannins, steroids, and glycosides. Methanol extract was subjected to silica gel column chromatography to isolate the pure compound. Structural elucidation of the isolated compound was done via IR and NMR. The fractions and the isolated compound were used to assess the antibacterial activity potentials of this plant material using disc diffusion assay against E. coli, S. aureus, and L. monocytogen. The crude extract (48 g) obtained from 300 g leaves powder was subjected to column separation and pure compound (65 mg) was isolated. The phytochemical screening of the crude indicates the presence of alkaloids, phenols, saponins, flavonoids, and tannins and the absence of steroids and glycosides. Spectral analysis results revealed that the compound isolated was identified as 3‐O‐(3′‐acetoxy‐2′‐hydroxy‐2′‐methylbutyryl)‐cuauhtemone. Regarding the antibacterial activities, the highest (15.56 ± 1.96 mm) and lowest (6.5 ± 0.01 mm) inhibition zone diameters were recorded against S. aureus at concentrations of 100 and 10 mg/mL, respectively, by the methanol soluble fraction. The antibacterial assay revealed that the methanol‐soluble portion of the extract exhibited promising antibacterial activities warranting further studies.
ISSN:2698-6248