Antibacterial, Antifungal, and Cytotoxic Activity of Excoecaria agallocha Leaf Extract

Kuzhunellil Raghavanpillai Sabu; Sujith Sugathan; Akbar Idhayadhulla; Melat Woldemariam; Addis Aklilu; Gelila Biresaw; Behailu Tsegaye; Aseer Manilal

doi:10.2147/JEP.S339383

Antibacterial, Antifungal, and Cytotoxic Activity of Excoecaria agallocha Leaf Extract

J Exp Pharmacol. 2022 Jan 14:14:17-26. doi: 10.2147/JEP.S339383. eCollection 2022.

Authors

Kuzhunellil Raghavanpillai Sabu¹, Sujith Sugathan², Akbar Idhayadhulla³, Melat Woldemariam⁴, Addis Aklilu⁴, Gelila Biresaw⁴, Behailu Tsegaye⁵, Aseer Manilal⁴

Affiliations

¹ Department of Chemistry, College of Natural and Computational Sciences, Arba Minch University, Arba Minch, Ethiopia.
² Department of Botany, Sree Narayana College, Kollam, Kerala, India.
³ Research Department of Chemistry, Nehru Memorial College (affiliated with Bharathidasan University), Tiruchirappalli, Tamil Nadu, India.
⁴ Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia.
⁵ Department of Biomedical Sciences, College of Medicine and Health Science, School of Medicine, Arba Minch University, Arba Minch, Ethiopia.

Abstract

Background: Mangroves contain several bioactive compounds, some of which have been used for centuries as remedies for several ailments.

Methods: Foliar parts of Excoecaria agallocha were extracted in organic solvents and in water using a Soxhlet apparatus and evaluated for antimicrobial activity against nine type-culture pathogens, six clinical isolates, and two fungal pathogens with agar well diffusion assays. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth dilution and extracts further subjected to brine-shrimp cytotoxic assays using Artemia salina. Chemical constituents were analyzed with thin-layer chromatography (TLC), gas chromatography-mass spectroscopy (GC-MS), and Fourier-transform infrared spectroscopy (FT-IR).

Results and discussion: Ethyl acetate extract displayed the broadest antimicrobial activity. Isolates of Staphylococcus aureus were found to be the most susceptible among the clinical and type-culture groups corresponding to inhibition zones: 17.3±1.1 and 23.5±1.3 mm in diameter, respectively. Anticandidal activity was found to be lower against Candida albicans and C. tropicalis (10.3±0.6 and 11.9±0.85 mm diameter). Also, this extract was found to be bactericidal for S. aureus and Micrococcus luteus (MBC:MIC ≤2). _C cytotoxic activity LD₅₀ was 521 µg/mL. On GC-MS, squalene [(6E, 10E, 4E, 18E)-2,6,10,15,19,23-hexamethyltetracosa-2,6,10,14,18,22-hexaene] was the major compound. Bioassay-guided (antibacterial) TLC revealed the presence of one major active fraction, F2, with an R_f value of 1.21. FT-IR analysis of this fraction also implied that it was squalene, which might have a functional role in the mechanism of chemical defense.

Keywords: antimicrobial; bioactive compounds; cytotoxicity; mangrove; plant extract; squalene.

Grants and funding

No financial support was received for this study.