Anastasiya S. Sokolova

Discovery of a new class of antiviral compounds: camphor imine derivatives.

A new class of compounds featuring a camphor moiety has been discovered that exhibits potent inhibitory activity against influenza A(H1N1)pdm09 and A(H5N1) viruses. The synthesized compounds were characterized by spectroscopic analysis; in addition the structures of compound 2 and 14 were elucidated by the X-ray diffraction technique. Structure-activity relationship studies have been conducted to identify the 1,7,7-trimethylbicyclo[2.2.1]heptanes2-ylidene group as the key functional group responsible for the observed antiviral activity. The most potent antiviral compound is imine 2 with therapeutic index more than 500.

New quaternary ammonium camphor derivatives and their antiviral activity, genotoxic effects and cytotoxicity.

Abstract The synthesis and biological evaluation of a novel series of dimeric camphor derivatives are described. The resulting compounds were studied for their antiviral activity, cyto- and genotoxicity. Compounds 3a and 3d in which the quaternary nitrogen atoms are separated by the C5H10 and С9H18 aliphatic chain, exhibited the highest efficiency as an agent inhibiting the reproduction of the influenza virus A(H1N1)pdm09. The cytotoxicity data of compounds 3 and 4 revealed their moderate activity against malignant cell lines; compound 3f had the highest activity for the CEM-13 cells. These results show close agreement with the data of independent studies on toxicity of these compounds, in particular that the toxicity of compounds strongly depends on spacer length.

Broad range of inhibiting action of novel camphor-based compound with anti-hemagglutinin activity against influenza viruses in vitro and in vivo

Influenza virus continues to remain one of the leading human respiratory pathogens causing significant morbidity and mortality around the globe. Due to short-term life cycle and high rate of mutations influenza virus is able to rapidly develop resistance to clinically available antivirals. This makes necessary the search and development of new drugs with different targets and mechanisms of activity. Here we report anti-influenza activity of camphor derivative 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylidene-aminoethanol (camphecene). In in vitro experiments it inhibited influenza viruses A(H1, H1pdm09, H3 and H5 subtypes) and B with EC50s lying in micromolar range. Due to low cytotoxicity it resulted in high selectivity indices (74-661 depending on the virus). This effect did not depend on susceptibility or resistance of the viruses to adamantane derivatives amantadine and rimantadine. The compound appeared the most effective when added at the early stages of viral life cycle (0-2h p.i.). In direct hemagglutinin inhibition tests camphecene was shown to decrease the activity of HAs of influenza viruses A and B. The activity of camphecene was further confirmed in experiments with influenza virus-infected mice, in which, being used orally by therapeutic schedule (once a day, days 1-5 p.i.) it decreased specific mortality of animals infected with both influenza A and B viruses (highest indices of protection 66.7% and 88.9%, respectively). Taken together, these results are encouraging for further development of camphecene-based drug(s) and for exploration of camphor derivatives as highly prospective group of potential antivirals.

Camphor-based symmetric diimines as inhibitors of influenza virus reproduction.

Abstract Influenza is a continuing world-wide public health problem that causes significant morbidity and mortality during seasonal epidemics and sporadic pandemics. The purpose of the study was synthesis and investigation of antiviral activity of camphor-based symmetric diimines and diamines. A set of C2-symmetric nitrogen-containing camphor derivatives have been synthesized. The antiviral activity of these compounds was studied against rimantadine- and amantadine-resistant influenza virus A/California/7/09 (H1N1)pdm09 in MDCK cells. The highest efficacy in virus inhibiting was shown for compounds 2a–e with cage moieties bound by aliphatic linkers. The therapeutic index (selectivity index) for 2b exceeded that for reference compounds amantadine, deitiforin and rimantadine almost 10-fold. As shown by structure–activity analysis, the length of the linker has a dramatic effect on the toxicity of compounds. Compound 2e with –C12H24– linker exhibited the lowest toxicity (CTD50 =2216μM). Derivatives of camphor, therefore, can be considered as prospective antiinfluenza compounds active against influenza viruses resistant to adamantane-based drugs.

[Curare-Like Camphor Derivatives and Their Biological Activity].

The synthesis of symmetric dimeric camphor derivatives containing two quaternary nitrogen atoms was performed and their myorelaxant activity in mice was evaluated. For the comparison, some salts derived from meta- and para-xylylene dibromides were synthesized and their activity was tested.

Synthesis and biological activity of heterocyclic borneol derivatives

A series of novel heterocyclic derivatives of (–)-borneol has been prepared by the interaction of (1S,2R,4S)-1,7,7-trimethylbicyclo[2.2.1]-heptan-2-yl 2-chloroacetate and (1S,2R,4S)-1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl 3-chloropropanoate with different N- and S-nucleophiles. The obtained products were screened for antiviral, antiulcer, and analgesic activity.

Development and Validation of a Method for Determination of a New Effective Inhibitor of Influenza Virus H1N1 in Blood Plasma

A new GC-MS method for determining an antiviral agent (camphecin) in blood plasma was developed. Sample preparation consisted of precipitating proteins using MeOH. The method was validated for selectivity, calibration curve, accuracy, precision, limit of quantitation, carryover, and stability. The analytical range was 0.1 – 2 μg/mL. The method could be used for pharmacokinetic studies.

Discovery of a New Class of Inhibitors of Vaccinia Virus Based on (−)-Borneol from Abies sibirica and (+)-Camphor

A series of the bornyl ester/amide derivatives with N‐containing heterocycles were designed and synthesized as vaccinia virus (VV) inhibitors. Bioassay results showed that among the designed compounds, derivatives 6, 13, 14, 34, 36 and 37 showed the best inhibitory activity against VV with the IC50 values of 12.9, 17.9, 3.4, 2.5, 12.5 and 7.5 μm, respectively, and good cytotoxicity. The primary structure–activity relationship (SAR) study suggested that the combination of a saturated N‐heterocycle, such as morpholine or 4‐methylpiperidine, and a 1,7,7‐trimethylbicyclo[2.2.1]heptane scaffold was favorable for antiviral activity.