Strong antimicrobial activity of collinin and isocollinin against periodontal and superinfectant pathogens in vitro.

Periodontitis pathogenesis involves activation of host immune responses triggered by microbial dysbiosis. Therefore, controlling periodontal pathogens in-vivo is a main goal of periodontal therapy. New antimicrobials might help to control periodontal infection and improve treatment outcomes at "the dark times" of increasing antibiotic resistance. Here, we determined the biological activity of collinin and isocollinin against 8 bacterial strains. Antimicrobial activity of collinin and isocollinin, chlorhexidine digluconate (CHX) and sodium hypochlorite (NaClO) was evaluated against clinically relevant periodontal bacteria, like Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum, Prevotella intermedia, Dialister pneumosintes strains and superinfectants like Escherichia coli, Staphylococcusaureus, and Pseudomonasaeruginosa strains. A broth microdilution test was carried out to determine the minimum inhibitory concentration of collinin and isocollinin against those strains, and bacterial viability was determined by resazurin assay at diverse concentration and exposure times. P. gingivalis was the most susceptible strain to collinin and isocollinin (MIC 2.1 µg/mL and 4.2 µg/mL respectively). Other periodontal pathogens showed MICs <17 µg/mL for collinin and MICs between 20 and 42 µg/mL for isocollinin, whereas CHX and NaClO showed MICs of 62 and 326 µg/mL, respectively. Collinin and isocollinin also exhibited antimicrobial activity against superinfectant bacteria (MIC < 21 and < 42 µg/mL, respectively). Overall, collinin and isocollinin showed a remarkable antibacterial activity against relevant periodontal and superinfective bacteria, especially against P. gingivalis (MIC 2.1 µg/mL and 4.2 µg/mL respectively) and the highly virulent P. aeruginosa (MIC 5.2 and 20.8 µg/mL, respectively).

In vitro activity of collinin isolated from the leaves of Zanthoxylum schinifolium against multidrug- and extensively drug-resistant Mycobacterium tuberculosis.

BACKGROUND: Tuberculosis is a very serious infectious disease that threatens humanity, and the emergence of multidrug-resistant (MDR), extensively drug-resistant (XDR) strains resistant to drugs suggests that new drug development is urgent. In order to develop new tuberculosis drug, we have conducted in vitro anti-tubercular tests on thousands of plant-derived substances and finally found collinin extracted from the leaves of Zanthoxylum schinifolium, which has an excellent anti-tuberculosis effect. PURPOSE: To isolate an anti-tubercular bioactive compound from the leaves of Z. schinifolium and evaluate whether this agent demonstrates any potential in vitro characteristics suitable for the development of future anti-tubercular drugs to treat MDR and XDR Mycobacterium tuberculosis. METHODS: The methanolic extracts of the leaves of Z. schinifolium were subjected to bioassay-guided fractionation against M. tuberculosis using a microbial cell viability assay. In addition, following cell cytotoxicity assay, an intracellular anti-mycobacterial activity of the most active anti-tubercular compound was investigated after it was purified. RESULTS: The active compound with anti-tubercular activity isolated from leaves of Z. schinifolium was identified as a collinin. The extracted collinin showed anti-tubercular activity against both drug-susceptible and -resistant strains of M. tuberculosis at 50% minimum inhibitory concentrations (MIC50s) of 3.13-6.25 µg/ml in culture broth and MIC50s of 6.25-12.50 µg/ml inside Raw264.7 and A549 cells. Collinin had no cytotoxicity against human lung pneumocytes up to a concentration of 100 µg/ml (selectivity index > 16-32). CONCLUSIONS: Collinin extracted from the leaves of Z. schinifolium significantly inhibits the growth of MDR and XDR M. tuberculosis in the culture broth. In addition, it also inhibits the growth of intracellular drug-susceptible and drug-resistant tuberculosis in Raw264.7 and A549 cells. To our knowledge, this is the first report on the in vitro anti-tubercular activity of collinin, and our data suggest collinin as a potential drug to treat drug-resistant tuberculosis. Further studies are warranted to assess the in vivo efficacy and therapeutic potential of collinin.

Bioactive Constituents from the Leaves of Zanthoxylum schinifolium

Activity-guided separation of the methylene chloride-soluble fraction of the leaves of Zanthoxylum schinifolium, resulted in the isolation of four coumarinoids (1 - 4), two triterpenoids (5, 6) and three fatty acid derivatives (7 - 9) as active principles. Their chemical structures were identified as collinin (1), 8-methoxyanisocoumarin (2), 7-(6'R-hydroxy-3',7'-dimethylocta-2',7'-dienyloxy)-coumarin (3), (E)-4-methly-6-(coumarin-7'-yloxy) hex-4-enal (4), lupeol (5), epi-lupeol (6), phytol (7), hexadec-3-enoic acid (8) and palmitic acid (9), on the basis of spectroscopic (1D, 2D and MS) data analyses and comparing with the data published in the literatures. Compounds 1 and 7 showed potent cytotoxicity against Jurkat T cells with IC50 values of 45.58 and 47.51 microM, respectively. The others showed moderate activity with IC50 values ranging around 80.58 to 85.83 microM, while the positive control, auraptene, possessed an IC50 value of 55.36 microM.