Antibacterial Activity of Resorcin[4]arene Cocrystals

Example 6

3 mg/ml stock solutions of PFD, RsC1, RsC1-PFD (1:1 complex), RsC4, and RsC4-PFD (1:1 complex) were prepared in DMSO (bcoz host soluble in DMSO solution). From the stock, a working solution 4× (highest conc. for each compound in plate) was prepared in LB media. 50 uL of LB media was first added in each well (96 well plate). Then a 4× solution of the respective compound was added to the first row (A4-A12) except A1-A3 (Positive control/bacterial innoculum). Then, the 4× was serially diluted up to well G for all 3 compounds. (A-G). Then, a 50 uL aliquot of the 100-fold diluted bacterial inoculum was added in each test well. Individual test concentrations (in triplicate wells in a 96-well plate) for the given compounds were achieved by serial dilution by using LB medium. Total volume in each well is 100 uL. The final-test concentration range for the individual test compounds for C. acnes, S. aureus and P. aeruginosa are as follows: PFD, RsC1, RsC4, RsC1-PFD complex and RsC4-PFD complex (128-2 ug/mL). The results are shown in Table 6.

FIG. 1A shows a Job's plot constructed from the chemical shift change (Δδ) of the phenyl ring protons (#2) of PFD in 1H NMR spectra by varying the ratio between PFD and RsC4. FIG. 1B shows a Job's plot constructed from the chemical shift change (Δδ) of the aromatic protons (#C) of RsC4 in 1H NMR spectra by varying the ratio between PFD and RsC4.

Diffusion coefficient of PFD in equimolar mixture has changed drastically compared to PFD alone (above spectra, FIGS. 1A and 1B) which indicates the PFD bind to RsC4 in the mixture and diffuses at slower rate compared to PFD alone. The interaction between host and guest were loose/weak, therefore RsC4 and PFD peaks do not correspond to the same diffusion constant and have different position on the y axis. The diffusion coefficient of solvent ACN-d3 is 3.17×10-9. The broad, mobile OH proton at 7.7 ppm of host RsC4 has disappeared in the spectra. The y-axis is shown as log D.

FIG. 7 is a graph showing the antibacterial activity of PFD alone and RsC1-PFD complex against S. aureus. The percent on each bar indicates growth inhibition at a specific concentration (minimum inhibitory concentration). FIG. 8 is a graph showing the antibacterial activity of PFD alone and RsC1-PFD complex against P. aeruginosa. The percent on each bar indicates growth inhibition at a specific concentration (minimum inhibitory concentration). FIG. 9 is a Job's plot (NMR titration), Stoichiometry 1:1.

All documents cited are incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.

It is to be further understood that where descriptions of various embodiments use the term “comprising,” and/or “including” those skilled in the art would understand that in some specific instances, an embodiment can be alternatively described using language “consisting essentially of” or “consisting of.”

While particular embodiments of the present invention have been illustrated and described, it would be obvious to one skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.