An-Najah Staff

The antimicrobial activities of 56 Palestinian medicinal plants against etiologic agents of acne vulgaris, mainly Propionibacterium acnes and Staphylococcus aureus was studied using disc diffusion and broth dilution methods. The results from the disc diffusion method demonstrated that these plants differ significantly in their activity against the studied microorganisms. The most active plants against all bacterial strains were Rhus coriaria, Ricinus communis, and Sarcopoterium spinosum. Test microorganisms differed significantly in relation to their susceptibility to different plant extracts used. Generally, anaerobic bacteria were more susceptible to plant extracts than aerobic bacteria. Those plants which could inhibit the growth of P. acnes, R. coriaria, R. communis, and S. spinosum had strong inhibitory effects. 43 plants could inhibit the growth of all aerobic bacteria. Based on a broth dilution method, the R. coriaria extract had the greatest antimicrobial effect against P. acnes (MIC 6 mg/ml, MBC 6 mg/ml), S. aureus (MIC 4 mg/ml, MBC 6 mg/ml), E. coli (MIC 6 mg/ml, MBC 8 mg/ml)and P. aeruginosa (4 and 6 mg/ml).Taken together, our data indicate that R. coriaria, R. communis had a strong inhibitory effect on P. acnes and most other test bacteria. Therefore, the two plants would be an interesting topic for further study and possibly for an alternative treatment for acne.

Organic and aqueous solvent extracts and fractions of Micromeria nervosa (Desf.) Benth. (Labiatae) were investigated for antimicrobial activities on several microorganisms including bacteria and yeast. The different extracts differed significantly in their antimicrobial activities with the ethanolic extract being most active, followed by ethyl acetate and petroleum ether extracts. The least active extract was the aqueous. No significant difference between the different test microorganisms in their susceptibility to different extracts, with Candida albicans being the most susceptible to ethanolic extract giving 1.5 times the effect of nystatin. One of the main active ingredients of M. nervosa was isolated and identified as carvacrol. No significant difference in antimicrobial activity was found between carvacrol and its isomer thymol. The most susceptible test microorganism was Proteus vulgaris to carvacrol, and P. vulgaris and C. albicans to thymol. The least susceptible bacterium to both fractions was Pseudomonas aeruginosa. Minimum inhibitory concentration (MIC) and minimum bactericidal or fungicidal concentrations (MBC or MFC) were determined for both compounds.

A novel series of Pd(II) complexes derived from 2-thiophenecarboxaldehyde and 1,8-diaminonaphthalene has been synthesized and characterized by various physico-chemical and spectroscopic techniques viz., elemental analyses, IR, UV-Vis, 1H and 13C NMR spectroscopy, and ESI-mass spectrometry. The structure of ligand, 2-(2-thienyl)-2,3-dihydro-1H-perimidine has been ascertained on the basis of single crystal X-Ray diffraction. All Pd(II) complexes together with the corresponding ligand have been evaluated for their ability to suppress the in vitro growth of microbes, E. coli, S. aureus, P. aeruginosa, Citrobacter sp., B. subtilis and S. acidaminiphila and results show that Pd(II) complexes have more significant antimicrobial activity than their corresponding ligand. Fluorescence spectroscopic measurements clearly support that both of the Pd(II) complexes show significant DNA binding with calf thymus DNA.

Borneol is a monoterpene that is a part of traditional Chinese and Japanese medicine. (−) borneol reacted with methanesulfonyl chloride in THF/pyridine to afford the new 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate derivative in excellent yield. The product is characterized by H1NMR, C13NMR, mass spectroscopy as well as elemental analysis and its structure was identified by X-ray single crystal diffraction. The packing of 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methanesulfonate exhibits the non-classical C-H...O hydrogen bonding in C(4) and R2 2(8) chain and ring motifs as structural determinants. This was also confirmed by the analysis of Hirshfeld surfaces. The 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate antimicrobial activity was tested and compared with its parent (−) borneol against three different pathogens. Particularly, 1,7,7-trimethylbicyclo[2.2.1]hept-2-yl methane sulfonate showed high sensitivity, compared to Chloramphenicol reference material, against Escherichia coli.

Aromatic and heteroaromatic N-methyl-N-(2-pyridyl)-hydrazones 3a-f were synthesized and characterized by elemental analyses and spectral data. 1H, 13C NMR and mass spectra supported the formation of the E-isomer. N-Methyl-N-(2-pyridyl)hydrazone carboxaldehydes can be readily characterized by mass spectrometry. The new hydrazones 3a-h have been screened for antimicrobial activity.

A series of curcumin derivatives containing heterocyclic moiety have been synthesized and evaluated for their antibacterial activities. The chemical structures of the synthesized compounds were verified on the basis of spectral data and elemental analyses. Investigation of antimicrobial activity of the derivatives demonstrated the ability to inhibit Gram-positive microorganisms with zone of inhibition ranging from 14-18 mm, MIC ranging between 0.0625 and 0.25 mg/mL. Among all tested derivatives, diazepine 4 exhibited remarkable potency against Gram-positive bacteria S. aureus. An extensive study is underway to optimize the effectiveness of diazepine type of compounds and to determine their mode of action.