Antibacterial activity of selected medicinal plant extracts against methicillin-resistant (MRSA) / by Shela B. Lebasnon.

Thesis (BS Biology) Cavite State University

Includes bibliographical references.

College of Arts and Science (CAS)

LEBASNON, SHELA BADION. ANTIBACTERIAL ACTIVITY OF SELECTED MEDICINAL PLANT EXTRACTS AGAINST METHICILLIN-RESISTANT Staphylococcus aureus (MRSA). Undergraduate Thesis, Bachelor of Science in Biology. Cavite State University, Indang, Cavite. April 2010. Adviser: Dr. Yolanda A. Ilagan.
The study was conducted to determine the potential antibacterial activity of selected medicinal plant extracts against MRSA. Thirty medicinal plant samples commonly used against skin infections were collected and subjected to different extraction procedures. Decoctions, juice, Dichloromethane (DCM), and methanolic extracts were tested against S. aureus and three different strains of MRSA. Antimicrobial activity was determined by disk diffusion assay. Water, DCM, and methanol blanks served as negative control and gentamycin (10µg/ml) served as positive control. The data were analyzed using one-way Analysis of Variance (ANOVA) and compared using Duncan Multiple Range Test (DMRT). Different extracts obtained from the same plant sample showed differences in antibacterial activity. All extracts of ampalaya, garlic, guava, damong maria, and black pepper showed antibacterial activity against the test organisms. Akapulko and mango also inhibited bacterial growth using juice, DCM, and methanolic extracts. Malunggay leaves using juice and DCM extract also showed antibacterial activity. Similar results also obtained from DCM and methanolic extracts of gumamela flowers. Juice and DCM extracts of avocado, calamansi fruit, and oregano also showed inhibitory activity. Only juice extracts of alugbati, kaimito, gumamela leaves and tamarind also inhibited the test organisms. Alibangbang, kakawate, katakataka, calamansi leaves, pandan, banana, sampaguita, and eggplant did not inhibit the growth of any of the test organisms. Results revealed that juices have better activity as compared to other extracts because of the number of plant extracts that demonstrated growth inhibition of MRSA. Guava juice demonstrated the highest antibacterial activity among all extracts tested. Among decocted plants, garlic showed the highest inhibitory activity against MRSA-41 and MRSA-144. DCM extract of guava leaves also exhibited the highest antibacterial activity against 1VIRSA_144. Methanolic extract of ginger also significantly demonstrated the highest effect against IV1RSA-112. All extracts which demonstrated antibacterial activity were subjected to phytochemical screening. Presence of tannin, resin, oil, saponin, alkaloid, flavonoid, and carbohydrates in the extracts were determined qualitatively. Phytochemical analysis revealed the variations in phytocompounds present in different type of extracts obtained from the same plant. Saponins were present in all decocted plants. Juice extracts except mayana and oregano were positive for the presence of oils. DCM extract of gumamela flowers did not show positive result to any of the phytochemical tests. Resin was not present in DCM extracts. Flavonoids were also present in methanolic extracts except gumamela flower, malunggay root and mayana. Other phytoconstiuents found present in extracts were alkaloids, tannins, and carbohydrates. The extracts that showed antibacterial activity were also tested to determine the Minimum Inhibitory Concentration (MIC) through Disk Diffusion Assay. Different concentrations used were 10% (1:10v/v), 20% (2: 10v/v), 50% (5:10v/v), and 80% (8: I Ov/v). The concentration used during the screening for the antibacterial activity was
100% (1 0:10v/v) concentrated extract. MIC shows that decoctions and juice extracts have its inhibitory activity at 100% concentrated extract only while DCM and methanolic extracts inhibited the MRSA strains at different concentrated extract. Most of the DCM extracts inhibited the growth of the tested organisms at its 80% concentration while methanolic extracts at 50% concentration.

Submitted to the University Library 05/31/2010 T-4192