In vitro: |
Die Pharmazie - An International Journal of Pharmaceutical Sciences,2011,66(6):421-3. | Antimicrobial activity of liposome encapsulated cyclo(L-tyrosyl-L-prolyl)[Reference: WebLink] | Various studies have shown the potentially beneficial biological activities of cyclic dipeptides and in particular, cyclo(L-tyrosyl-L-prolyl) (Cyclo(Tyr-Pro)) has shown fair antibacterial activity in vitro. This study aimed to determine if liposome encapsulation would have any significant effects on the antibacterial activity of this compound. METHODS AND RESULTS: The thin-film hydration method with extrusion was used to produce small unilamellar vesicles containing Cyclo(Tyr-Pro) that were shown to have an average encapsulation of 9.4% with a mean particle size of 160.4 nm. Minimum inhibitory concentrations tested against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus subtillis were shown to be lower in liposome encapsulated Cyclo(Tyr-Pro) than for the free form, while no antimicrobial activity was noted for either encapsulated nor non-encapsulated drug against the fungus Candida albicans or two methicillin-resistant strains of Staphylococcus aureus (MRSA). A positive control of liposome encapsulated amoxicillin was shown to be extremely active against both MRSA strains. CONCLUSIONS: The results confirm that liposome encapsulation has the potential to enhance activity as well as to overcome bacterial resistance towards current antibacterial agents. | J Nematol. 2007 Sep;39(3):243-7. | Two Cyclic Dipeptides from Pseudomonas fluorescens GcM5-1A Carried by the Pine Wood Nematode and Their Toxicities to Japanese Black Pine Suspension Cells and Seedlings in vitro.[Pubmed: 19259494 ] | METHODS AND RESULTS:
Pseudomonas fluorescens GcM5-1A, isolated from the pine wood nematode (PWN), Bursaphelenchus xylophilus, was cultured in Luria Broth medium (LB). The clarified culture was extracted with ethyl acetate, and two dipeptides were purified from the extract. The chemical structures of 1 and 2 were identified as cyclo(-Pro-Val-)and Cyclo(Tyr-Pro), respectively, by MS, (1)H NMR, (13)C NMR,(1)H-(1)H COSY, 1H -(13)C COSY spectra.
CONCLUSIONS:
Bioassay results showed that the two compounds were toxic to both suspension cells and seedlings of Pinus thunbergii, which may offer some clues to research the mechanism of pine wilt disease caused by PWN. | Natural Product Research & Development, 2009,21(3): 420-3. | Antibacterial Metabolites from Marine Bacterium Pseudomonas sp.[Reference: WebLink] | METHODS AND RESULTS:
Nine cyclic dipeptides,Cyclo(Tyr-Pro)(1),cyclo-(Tyr-Ile)(2),cyclo-(Phe-Pro)(3),cyclo-(Val-Pro)(4),cyclo-(Ile-Pro)(5),cyclo-(Leu-Pro)(6),cyclo-(Ala-Pro)(7),cyclo-(Ala-Val)(8),cyclo-(Ala-Leu)(9) together with two benzene compounds p-hydroxy-benzaldehyde(10),bis(2-ethylhexyl) phthalate(11) were isolated from the culture broth of marine bacterium Pseudomonas sp.,and identified on the basis of spectroscopic evidences and by comparison of the data reported compounds 1-4 showed antibacterial activity towards several marine bacterial species. |
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