การประเมินศักยภาพในการต้านแบคทีเรียและการกระจายเชิงพื้นที่ของมะฮึก Clausena excavata Burm. f. ในโครงการพัฒนาป่าชุมชนบ้านอ่างเอ็ด (มูลนิธิชัยพัฒนา) จังหวัดจันทบุรี
Potential evaluation of antimicrobial activity and spatial distibution of clausena excavata burm.f. in ban ang-ed official community forest, chantaburi province
Abstract:
The main objective of this research was to isolate and characterize the purified bioactive compounds possessing antibacterial activity against Methicillin susceptible Staphylococcus aureus (MSSA) and Methicillin resistant S. aureus (MRSA) from the leaves of Clausena excavata Burm f. using bioassay guided isolation and NMR spectroscopy, respectively. Crude extract of the plant leaves was prepared using 95% ethanol and then the plant ethanol extract was subjected to further sequential extract with the other two solvents, namely hexane and ethyl acetate, respectively. Antibacterial activity of those plant extracts against the strains of MSSA (S. aureus ATCC 25923) and MRSA (S. aureus ATCC 43300) was investigated via disk diffusion method. As a result, the ethyl acetate extract revealed the most potent effect against the tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of those extracts were also determined through broth macrodilution method. With a similar activity, the MIC and MBC values of the ethyl acetate extract against both strains of the tested bacteria were within the range of 32-64 µg/ml and 128-256 µg/ml, respectively. The antibacterial compounds consisting in the ethyl acetate extracts were isolated and purified using Bioassay guided isolation technique which includes a sequential fractionation of the extract through column chromatography and antibacterial activity analysis via thin layer chromatography and bioautography, respectively. As a result, two purified active compounds were isolated from the subtractions no F3 and no F6, respectively. The chemical structure of these compounds were identified as 5-geranyloxy-7-hydroxycoumarin and Clauslactone A by NMR spectroscopy, respectively. The MIC values of their compound were in range of 2-4 and 256-512 µg/ml, respectively. The MBC values of 5-geranyloxy-7-hydroxycoumarin were in range of 2-8 µg/ml whereas the MBC values of Clauslactone A clould not detected at the highest test concentration (1024 µg/ml). Finally, the spatial distribution of the C. excavata Burm. f. in Ban Ang-Ed official community forest was investigated. Although, the C. excavate trees were found scattered throughout the studied area, most of the treesgrowth inside the forest were smaller than the outside ones