Screening of Novel Bioactive Natural Compounds and their Antibacterial Property from Resilient Marine Gastropod Planaxis sulcatus (Born, 1778) Collected from Karwar coast, West coast of India

Abstract

The study aimed at identifying novel bioactive natural compounds from intertidal marine gastropod Planaxis sulcatus (Born, 1778) Collected from Karwar coast, West coast of India. Crude methanolic extract of intertidal marine gastropod Planaxis sulcatus was tested for preliminary zoochemical screening using standard methods to determine the presence of different chemical compounds: The crude extract was analysed using GC-MS to identify the bioactive components. The disc diffusion method was used to conduct an antibacterial experiment. Accordingly, the inhibition zone around the disc impregnated with gastropod extract was used to test the antibacterial activity. By using the micro broth dilution technique, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract were determined. Standard zoochemical testing of the Planaxis sulcatus whole body extract revealed the presence of steroids, alkaloids, flavonoids, glycosides, tannins, and saponins. A total of 130 chemicals were identified as the bioactive components in the extract using GC-MS. Seventeen of these compounds have antimicrobial properties while eleven of these compounds have antioxidant properties, six of these have anticancer properties based on published literature. Some of the other compounds also suggest biological activities other than antimicrobial, antioxidant and anticancer which indicates potential biomedical applications. The gastropod extract showed noteworthy antibacterial activity with minimum inhibitory zone of 12 mm against Pseudomonas aeruginosa and maximum 30 mm against Staphylococcus aureus at 40 μg/ml concentration. The Minimum Inhibitory Concentration (MIC) was found to be 1.72 μg/ml, 1.87μg/ml, 1.99 μg/ml, and 1.87 μg/ml against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli respectively. The MIC value decrease with higher concentration of methanol extracts than that of the pure antibiotic. As a result, Klebsiella pneumonia exhibits higher MIC values and MIC-CFU (214). The tissue extract of Planaxis sulcatus possess bioactive compounds that have potent antibacterial effect