Effect of Different Extraction Techniques of Persicaria odorata Extracts Utilizing Anti-bacterial Bioassay.

Persicaria odorata is a common plant and well known in Malaysia as “Daun kesum” that is commonly used in cuisines and has various medicinal properties. This study was conducted to investigate the antimicrobial activity and the extraction technique that produce the most active plant extract. The leaves were extracted using decoction, maceration assisted by ultra-sonication and percolation with soxhlet extractor to produce the respective extracts. All extracts were tested against four bacterial strains which included gram positive and gram negative bacteria using disc diffusion method. In this research gentamicin 10 μg were used as the antibacterial standard. The antimicrobial activity of the active extract was evaluated quantitatively using three different concentrations. The result from this study shows that Persicaria odorata leaves have high potential to be used as natural antibacterial agent against some bacterial infections depending on the method used to extract the active ingredient. The results shows that the extract obtained with percolation with soxhlet technique shows the best antibacterial activity followed by maceration with ultrasonication. Decoction extracts shows the weakest antibacterial activity. The extract obtain from both maceration with ultra-sonication and percolation using soxhlet extractor show significant (P=0.05) antimicrobial activity against all four bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Salmonella spp.).

Phytochemical Screening and Antibacterial Activity of Five Malaysian Medicinal Plants.

Natural drugs play important and vital role in the modern medicine. It is usually used to cure some ailments which may not be treated by conventional medicine. Natural drugs may exhibit many biological activities, such as antimicrobial, anticancer, anti-diabetic and antioxidant. Five medicinal plants were screened, namely Moringa oleifera, Cymbopogon citrates, Cynodon dactylon, Manihot esculenta and Plectranthus ambonicus, for potential antibacterial activity against five clinical pathogens (Escherichia coli, Klebsiella peumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis). The purpose of this study is extracting, analyzing and screening phytochemicals and antibacterial activity in selected plant leaves. The ethanolic extracts of plant leaves were prepared using Soxhlet extraction and the in-vitro testing were conducted using disc diffusion method. The diameter of inhibition zones were measured in millimetre (mm), and test were conducted in three replicates. At concentration 5mg/mL, no inhibition zones detected in all extracts. As the concentration of extract increases, the bacterial inhibition zones also increases; thus, the more effective the antibacterial properties. The most active antibacterial plant was P. ambonicus, followed by M. oleifera and C. citratus; and the weakest were C. dactylon and M. esculenta. The most susceptible bacteria were S. aureus, followed by K. peumoniae and the most resistant bacteria were P. aeruginosa and Bacillus subtilis. The phytochemical analysis revealed the presence of tannins, alkaloids, steroids, flavonoids and saponins in most of the plant extracts. The result of this study supports the use of all the selected five medicinal plants as a source of antibiotic substance for the possible treatment of human pathogenic organisms. These plants can be further subjected to isolation of the therapeutic antimicrobials and further pharmacological evaluation.