Antibacterial Evaluation and Biochemical Characterization of Thais savignyi Gastropod Extracts from the Persian Gulf

Abstract

Objectives: This study aimed to screen Thais savignyi whole body extracts for antibacterial activity against clinical isolates of some human pathogenic bacteria and analyze its biochemical compounds, including carbohydrate, proteins, alkaloids, cholesterol, unsaturated fatty acids, as well as functional groups and elements. Methods: Well agar diffusion was used for screening of acetone and methanol extracts against clinical isolates of E. coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus. Biuret and SDS-PAGE methods were applied for quantitative and qualitative protein evaluation. Anthrone method was used for quantitative and qualitative analysis of carbohydrates. Wagner and Mayer's reagents were employed for alkaloid screening. The Liebermann-Burchard test was performed for the detection of cholesterol, infrared for identifying functional groups, and Dumas method for elemental analysis. Results: Acetone and methanol crude extracts at 0.2 mg/mL concentration inhibited the growth of all the test bacteria; however, the methanol extract was more effective than the acetone extract. The maximum zone of inhibition of the methanol extract was observed against B. cereus (16 mm). Minimal inhibitory concentration of the most effective fraction ranged between 12.5 and 100 µg/mL. Elemental analysis of the bioactive fraction showed 41.55% carbon, 9.49% hydrogen, 6.13% nitrogen, and 1.64% sulfur. IR spectra confirmed the presence of aliphatic, alkenes, secondary amines, and disulfide groups in the most effective fraction of methanol extract of Thais savignyi. Carbohydrate and protein analysis revealed 4.5% carbohydrate and 9% protein. SDS-PAGE disclosed 5 separate bands with 70, 53, 41, 30, and 22 kilodaltons. Wagner and Mayer test showed the presence of alkaloids; mercuric and iodine solutions indicated the presence of unsaturated fatty acids; cholesterol was detected by Liebermann-Burchard reaction and Salkowski test. Conclusions: The findings of this study suggest that Thais savignyi has antibacterial potential and can be recommended as a source of bioactive compounds of medicinal value.