Antimicrobial screening of plant extracts on selected microorganisms

• Main Authors: Dela Cruz, Kelvin Michael G., Yu, Shiny Cathlynne S.
• Format: text
• Language: English
• Published: Animo Repository 2011
• Subjects: Plant extracts > Analysis; Plant Biology; Plant Sciences
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5286
• Institution: De La Salle University

Leaf extracts from six different plants commonly found in the Philippines were studied for the presence of antimicrobial activities. These included the following: Chrysophyllum cainito Linn. (1753) (star apple), Syzygium cumini Skeels (1911) (jambul), Anona squamosa Linn. (1755) (sugar apple), Sesbania grandiflora Linn. (1806) (white dragon tree), Allamanda cathartica Linn. (1771) (yellow bell), and Lantana camara (1771) (stink grass). All the plants were purchased from Manila Seedlings Garden at Quezon City, Metro Manila. The leaf extracts were obtained using the solvent extraction technique using methanol, dichloromethane, and hexane as extracting solvents. The antimicrobial activities of the leaf extracts were screened using the modified Kirbey-Bauer disc-agar diffusion method on the following test microorganisms: Gram-negative Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 49189 and Gram-positive Staphylococcus aureus ATCC 25923. The results of the study showed that the leaf extracts of all plants inhibited at least one of the test microorganisms. Both the jambul and star apple leaf extracts exhibited inhibition of all three bacteria. While sugar apple inhibited both P. aeruginosa and S. aureus, white dragon tree, stink grass, and yellow bell only inhibited S. aureus. Moreover, among the organic solvents used, methanolic extracts exhibited antimicrobial activities for the most number of test microorganisms. The present study further demonstrated the presence of antimicrobial compounds in the different plants.