Screening for antibacterial potential of six (6) selected leaf extracts against food-bourne bacteria

• Main Author: Young, Carasharyl C.
• Format: text
• Language: English
• Published: Animo Repository 2010
• Subjects: Biology
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/2462
• Institution: De La Salle University

Six leaf extracts namely Indian mango (Mangifera indica), Moringa (Moringa oleifera), Lemongrass (Andropogon citratus), Guava (Psidium guajava Linn.), Bignai (Antidesma bunius Linn.), and Garlic Vine (Mansoa alliacea) were tested against the gram-positive bacterium Staphylococcus aureus and gram-negative bacteria Bacillus cereus and Escherichia coli. The grounded leaves were prepared using organic-solvent extraction using hexane (nonpolar), ethyl acetate (median) and methanol (polar) (Ragasa, 2009). Zones of inhibition were observed and Guava leaf extract was found to give the most number zones of inhibition against all three bacteria while Mango and Moringa leaf extracts followed. Leaf extracts extracted using Methanol and Ethyl acetate to generate a polar solution and median extract respectively, conferred positive results compared to Hexane (nonpolar). Hexane extracts were found to give negative results to almost all of the leaves and bacteria. However, Guava, Moringa and Indian mango generally showed a high to moderate activity for both bacteria regardless of polarity. The crude extract mixtures of Indian mango, Moringa and Guava were tested once more against the three bacteria. Indian mango plus Guava crude mixture exhibited the largest zones of inhibition qualitatively among all crude mixtures and showed better results compared to using Indian mango or Guava alone. The study certifies the antibacterial properties of these specific plant leaves and can still be used for further study for isolation and identification of leaf chemical constituents.