GC-MS profiling and biological evaluation of ethyl acetate extract of the bark of morinda lucida benth

Abstract

This study investigates the allelopathic effects of Morinda lucida stem bark extract on seed germination, alongside its antimicrobial and antioxidant properties, as well as the Gas Chromatography-Mass Spectrometry (GC-MS) profiling of compounds found in the extract. The objectives included assessing antimicrobial activities against various microbial strains, evaluating antioxidant capacities using 1,1-diphenylpicrylhydrazyl (DPPH) and 2,2'-Azinobis-3-Ethylbenzothiazolin-6-sulfonic acid (ABTS) assays, conducting anti-germination bioassays, and profiling phytochemical compounds via Gas Chromatography-Mass Spectrometry (GC-MS). The antimicrobial evaluation, employing agar well diffusion and broth micro-dilution methods, revealed that the extract demonstrated bactericidal activity against Salmonella typhi, Staphylococcus aureus, and Escherichia coli, with minimum inhibitory consentrations (MICs) of 10 mg/mL and an MBC/MIC ratio of 2. Phytophthora megakarya had an Minimum Inhibitory Concentration (MIC) of 0.313 mg/mL and an MFC/MIC ratio of 2, indicating strong susceptibility and a fungicidal effect, meaning all the organisms were killed at this lower concentration. Antioxidant assays demonstrated a concentration-dependent raise in free radical scavenging, confirming potent antioxidant activity comparable to Vitamin C that was used as control. Phytotoxicity tests on Lactuca sativa seeds demonstrated a dose-dependent suppression of root and shoot development. At the highest concentration (TR3, 78.4 μg/μL), shoot and root lengths was decrease by 80 % and 85 %, respectively. GC-MS profiling identified 24 bioactive compounds, with Ergosta-4,22-dien-3-one being the most abundant (14.2 %). These findings indicate that Morinda lucida stem bark extract possesses strong antimicrobial, antioxidant, and allelopathic properties. The results provide a foundation for further exploration of its potential applications as a natural herbicide or in therapeutic contexts.