Background Calophyllum inophyllum L. (Calophyllaceae) is an evergreen tree ethno-medically used along the seashores and islands of the Indian and Pacific Oceans, especially in Polynesia. Oil extracted from the seeds is traditionally used topically to treat a wide range of skin injuries from burn, scar and infected wounds to skin diseases such as dermatosis, urticaria and eczema. However, very few scientific studies reported and quantified the therapeutic properties of Calophyllum inophyllum oil (CIO). In this work, five CIO from Indonesia (CIO1), Tahiti (CIO2, 3), Fiji islands (CIO4) and New Caledonia (CIO5) were studied and their cytotoxic, wound healing, and antibacterial properties were presented in order to provide a scientific support to their traditional use and verify their safety.MethodsThe safety of the five CIO was ascertained using the Alamar blue assay on human keratinocyte cells. CIO wound healing properties were determined using the scratch test assay on human keratinocyte cells. CIO-stimulated antibacterial innate immune response was evaluated using ELISA by measuring β defensin-2 release in human derivative macrophage cells. CIO antibacterial activity was tested using oilogramme against twenty aerobic Gram- bacteria species, twenty aerobic Gram+ bacteria species, including a multi-drug resistant Staphylococcus aureus strain and two anaerobic Gram+ bacteria species e.g. Propionibacterium acnes and Propionibacterium granulosum. To detect polarity profile of the components responsible of the antibacterial activity, we performed bioautography against a Staphylococcus aureus strain.ResultsBased on Alamar Blue assay, we showed that CIO can be safely used on keratinocyte cells between 2.7% and 11.2% depending on CIO origin. Concerning the healing activity, all the CIO tested accelerated in vitro wound closure, the healing factor being 1.3 to 2.1 higher compared to control when keratinocytes were incubated after scratch with CIO at 0.1%. Furthermore, our results showed that CIO exhibit two distinct antibacterial effects: one against Gram+ bacteria by direct inhibition of mitotic growth and another potent effect against Gram- bacteria due to increased release of β-defensin 2 peptide by macrophages. Interestingly, the needed concentrations of CIO to inhibit bacteria growth and to promote wound healing are lower than concentrations exhibiting cytotoxic effects on keratinocyte cells. Finally, we performed bioautography assay against Staphylococcus aureus to determine polarity profile of the components responsible for CIO antibacterial activity. Our results showed for the five tested CIO that components responsible of the bacterial growth inhibition are the more polar one on the TLC chromatographic profile and are contained in the resinous fraction of the oil.ConclusionsThis study was conducted to evaluate cytotoxicity, wound healing and antibacterial properties of five CIO traditionally used to treat infected wounds. Using cell and bacteria cultures, we confirmed the pharmacological effects of CIO as wound he...

The in vitro susceptibilities of 75 clinical isolates of Xanthomonas maltophilia to nalidixic acid, five fluoroquinolones, latamoxef, and doxycycline were determined. Spontaneous mutants were selected, at a frequency of about 10'-to 10-from four strains by culturing the strains in the presence of each quinolone.Selection in the presence of nalidixic acid provided mutants that were either resistant only to that compound or that exhibited cross-resistance to all the fluoroquinolones tested. Cross-resistance was always observed for mutants selected on any of the five fluoroquinolones. It was always associated with chloramphenicol resistance and, frequently, with doxycycline resistance. The electrophoretic alterations of the outer membrane proteins of the mutants suggest that different mechanisms may be involved in quinolone resistance in X. maltophilia.Xanthomonas maltophilia has recently been isolated with increasing frequency and is mainly responsible for nosocomial infections in compromised hosts (17). Its natural resistance restricts the choice of antibiotics for use in the treatment of infected patients (1, 2, 11, 16), and quinolones have been considered as a possible option for therapy (17). The agar diffusion method has revealed a particular phenotype of quinolone susceptibility for this species (12). In the current study, we determined the MICs of nalidixic acid, pefloxacin, ciprofloxacin, ofloxacin, temafloxacin, sparfloxacin, latamoxef, and doxycycline for 75 clinical isolates ofX. maltophilia. Since the emergence of mutants resistant to quinolones and unrelated drugs has been described in several species of gram-negative bacilli (5-7, 14, 18, 20), especially Pseudomonas aeruginosa (8,15), from 4 of the 75 strains of X. maltophilia, we selected mutants that were resistant to six quinolones. The resistance patterns of the mutants were studied, and the electrophoretic profiles of the outer membrane proteins (OMPs) were analyzed for each type of mutant.MICs were determined by a twofold serial agar dilution method on Mueller-Hinton agar by using a replicating spot device, with an inoculum of about 104 CFU per spot.Spontaneous mutants were selected from four susceptible strains by spreading approximately 2 x 108 CFU onto plates of Mueller-Hinton agar containing each of the six quinolones at concentrations of 4, 8, and 16 times the respective MICs for the strains. After 48 h at 37°C, the frequencies of mutation were evaluated and the MICs of the six quinolones, doxycycline, latamoxef, and chloramphenicol were determined. The mutants were classified according to their patterns of resistance to these nine antibiotics. From each type of mutant, OMP fractions were prepared as described previously (6) and were submitted to sodium dodecyl sulfatepolyacrylamide gel electrophoresis for separation (13.5% acrylamide, 0.36% bisacrylamide).

A large-scale in vitro screening of tropical plants using an antibacterial assay permitted the selection of several species with significant antibacterial activities. Bioassay-guided purification of the dichloromethane extract of the leaves of the Malaysian species Vitex vestita, led to the isolation of six new labdane-type diterpenoids, namely, 12-epivitexolide A (2), vitexolides B and C (3 and 4), vitexolide E (8), and vitexolins A and B (5 and 6), along with six known compounds, vitexolides A (1) and D (7), acuminolide (9), 3β-hydroxyanticopalic acid (10), 8α-hydroxyanticopalic acid (11), and 6α-hydroxyanticopalic acid (12). Their structures were elucidated on the basis of 1D and 2D NMR analyses and HRMS experiments. Both variable-temperature NMR spectroscopic studies and chemical modifications were performed to investigate the dynamic epimerization of the γ-hydroxybutenolide moiety of compounds 1-4. Compounds were assayed against a panel of 46 Gram-positive strains. Vitexolide A (1) exhibited the most potent antibacterial activity with minimal inhibitory concentration values ranging from 6 to 96 μM, whereas compounds 2 and 6-9 showed moderate antibacterial activity. The presence of a β-hydroxyalkyl-γ-hydroxybutenolide subunit contributed significantly to antibacterial activity. Compounds 1-4 and 6-9 showed cytotoxic activities against the HCT-116 cancer cell line (1 < IC50s < 10 μM) and human fetal lung fibroblast MRC5 cell line (1 < IC50s < 10 μM for compounds 1, 2, 7, 8, and 9).