Phytochemical Profiling, Biosafety Evaluation, and Antimicrobial Activity of Five Plant Extracts for Sustainable Applications

Abstract

The growing need for sustainable and eco-friendly solutions in water treatment has increased interest in plant-based alternatives with proven bioactivity and safety. This study investigates the phytochemical composition, biosafety profile, and antimicrobial activity of five indigenous plant extracts, Cymbopogon citratus, Trichostema lanceolatum, Senna alata, Ficus exasperata, and Moringa oleifera, to evaluate their potential for sustainable applications. Proximate analysis revealed variations in protein, fibre, and nitrogen-free extract content, with Moringa oleifera recording the highest carbohydrate concentration and T. lanceolatum the highest protein content. Qualitative and quantitative phytochemical screening confirmed the presence of key secondary metabolites, including tannins, saponins, flavonoids, phenols, alkaloids, terpenoids, and cardiac glycosides, across all samples, with M. oleifera exhibiting the most abundant profile. Biosafety assessments indicated that all extracts were free from microbial contamination and within acceptable limits for heavy metals, although F. exasperata showed slightly elevated levels of iron and lead. Mild skin irritation was observed only with C. citratus. Antimicrobial tests showed variable effectiveness, with M. oleifera demonstrating the highest antibacterial and antifungal activities. These findings support the potential use of these plant extracts, particularly M. oleifera and S. alata, as effective, low-toxicity agents for antimicrobial and water treatment purposes. This study reinforces the role of phytochemicals in environmental remediation and provides a scientific foundation for integrating plant-based solutions into sustainable water purification strategies.