Patent Application
20210346339
The present invention relates to flavonoid derivatives and, more particularly, to plant flavonoid derivatives or the pharmaceutically acceptable salt thereof that may be used in a pharmaceutical composition for preventing and treating viral infections
Virus are small infectious organisms—much smaller than a fungus or bacterium—that must invade a living cell to reproduce (replicate). The virus attaches to a cell (called the host cell), enters the cell, and releases its DNA or RNA inside the cell. The virus's DNA or RNA is the genetic material containing the information needed to make copies of (replicate) the virus. The virus's genetic material takes control of the cell and forces it to replicate the virus. The infected cell usually dies because the virus keeps it from performing its normal functions. When it dies, the cell releases new viruses, which go on to infect other cells. Viruses are classified as DNA viruses or RNA viruses, depending on whether they use DNA or RNA to replicate. RNA viruses include retroviruses, such as HIV (human immunodeficiency virus). RNA viruses, particularly retroviruses, are prone to mutate. Some viruses do not kill the cells they infect but instead alter the cell's functions. Sometimes the infected cell loses control over normal cell division and becomes cancerous. Some viruses, such as hepatitis B virus and hepatitis C virus, can cause chronic infections. Chronic hepatitis can last for years, even decades. In many people, chronic hepatitis is quite mild and causes little liver damage. However, in some people, it eventually results in cirrhosis (severe scarring of the liver), liver failure, and sometimes liver cancer. Viruses usually infect one particular type of cell. For example, common cold viruses infect only cells of the upper respiratory tract.
Since time immemorial the world has been plagued with many viruses some of which wiped out millions of people such as the Spanish flu of 1918. Some of the viruses such as polio and yellow fever have mostly been eliminated but for a few sporadic outbreaks in a few developing countries. The viruses that are currently known to cause chronic infections include HIV and Hepatitis viruses. The most common viruses however are those of the influenza family that have seasonal cycles recurring almost every year. In the last ten to twenty years, the world has witnessed a number of viral epidemics involving the Ebola Virus, Dengue Virus, HMI Virus, SARS Coronavirus, Swine Flu, West Nile, Chikungunya, and Zika Virus. Ebola, H1N1 and the Swine flu were the most deadly of the episodic viruses. Of all the viruses, Coronaviruses (CoV) have recently challenged global medicine through their ability to emerge as human pathogens from zoonotic sources, as shown by severe acute respiratory syndrome CoV (SARS-CoV), the Middle East respiratory syndrome CoV (MERS-CoV), and most recently the novel CoV (SARS-CoV-2). In 2019, a new strain of the Coronavirus broke out in Wuhan, China and took the world community by surprise as it was more deadly than the SARS-Coronavirus of a few years back and within 3 months, the virus had spread to over 100 countries and has been declared a pandemic by the World Health Organization (WHO). This new strain has been named, Coronavirus disease 2019 (COVID-19 or SARS-CoV-2). While the majority of COVID-19 infections result in mild symptoms, some progress to pneumonia and multi-organ failure. The deaths per number of diagnosed cases is estimated at between 1% and 5% but varies by age and other health conditions.
Currently, there is no well-established treatment for SARS-CoV-2 despite the deployment of several vaccines against the virus. Humanity would greatly benefit from a new therapy that would reduce viral loads in patient populations, and potentially reduce any symptoms exhibited by the patient as even vaccinated persons are known vulnerable to reinfection. Currently, patients who are diagnosed with the severe COVID-19 disease are managed with supportive care such as fluid and oxygen support. Most cases of COVID-19 are not severe enough to require mechanical ventilation, but the percentage of cases have proven to be able to overwhelm healthcare systems wherever the spread of the virus has been inflicted. This component of treatment is a burden to the health system capacity and societies look to “flatten the curve” in order to keep the speed at which new cases occur in a downward direction.
Of the chronic viruses, Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma affecting millions of people worldwide. Hanafiah, Groeger, Flaxman, Wiersman, Global Epidemiology Of Hepatitis C Virus Infection: New Estimates Of Age-Specific Antibody To HCV Seroprevalence, S T Hepatology, April 57(4):1333-42 (2013). According to most recent statistics from the World Health Organization the global burden of HCV is as follows:
The discovery and development of effective and affordable treatments for infectious virus remains an important research objective. The recent discovery and development of new anti HCV agents with significantly higher efficacy than the interferon (IFN) and ribavirin (RBV) regimens has improved the treatment of HCV. Liang and Ghany, Current And Future Therapies For Hepatitis C Virus Infection, N Engl J Med. May 16; 368 (20): 1907-17 (2013).
Unfortunately, the efficacies of new direct-acting antivirals (DAAs) is unknown in some groups of patients with different subtypes of the virus as well as those with advance cirrhosis. See, Hanafiah et al., 2013, supra. In other to continue the search for new antiviral agents, attention has recently been directed towards discovering molecules that target host proteins or enzymes that play significant roles in the virus life cycle. Salloum S and Tai A W, Treating Hepatitis C Infection By Targeting The Host., Transl Res 159:421-429 (2012). This approach is complementary to the DAA alternative because like all viruses, HCV and Coronaviruses are obligate parasites requiring a host cell for its own replication. See, Salloum et al., supra, (2012).
Among the several host factors responsible for HCV and Coronavirus entry and replication in humans are the phosphatidylinositol-4-kinases. Yang, N., Ma, P., Lang, J., Zhang, Y., Deng, J., Ju, X., Zhang, G. and Jiang, C., 2012. Phosphatidylinositol 4-kinase is required for severe acute respiratory syndrome coronavirus spike-mediated cell entry. Journal of Biological Chemistry, 287(11), pp. 8457-8467; Tai A W, Benita Y, Peng L F, Kim S S, Sakamoto N, Xavier R J, Chung R T., A Functional Genomic Screen Identifies Cellular Cofactors Of Hepatitis C Virus Replication, Cell host & microbe, 2009; 5:298-307; Li Q, Brass A L, Ng A, Hu Z, Xavier R J, Liang T J, Elledge S J, A Genome-Wide Genetic Screen For Host Factors Required For Hepatitis C Virus Propagation, Proc Natl Acad Sci USA, 2009; 106:16410-16415; Vaillancourt F H, Pilote L, Cartier M, Lippens J, Liuzzi M, Bethell R C, Cordingley M G, Kukolj G., Identification Of A Lipid Kinase As A Host Factor Involved In Hepatitis C Virus RNA Replication, Virology. 2009; 387:5-10; Borawski J, Troke P, Puyang X, Gibaja V, Zhao S, Mickanin C, Leighton-Davies J, Wilson C J, Myer V, Comellataracido I, et al., Class III Phosphatidylinositol 4-Kinase Alpha And Beta Are Novel Host Factor Regulators Of Hepatitis C Virus Replication, Journal of virology, 2009; 83:10058-10074; Reis, H. T., Maniaci, M. R., Caprariello, P. A., Eastwick, P. W., & Finkel, E. J., Familiarity Does Indeed Promote Attraction In Live Interaction, Journal of Personality and Social Psychology, 101, 557-570 (2011).
The family of PI4-kinases is made up of two types with two isoforms each (PI4KIIa, PI4KIIb, PI4KIIIa and PI4KIIIb) differing in subcellular localization and being responsible for the synthesis of distinct PI4P pools. Balla A., Balla T., Phosphatidylinositol 4-Kinases: Old Enzymes With Emerging Functions, Trends Cell Biol. 16:351-361 10.1016 (2006). In case of PI4KIIIa those in the ER, the plasma membrane and parts of Golgi PI4P. Balla A., Tuymetova G., Tsiomenko A., Vámai P., Balla T., A Plasma Membrane Pool Of Phosphatidylinositol 4-Phosphate Is Generated By Phosphatidylinositol 4-Kinase Type-III Alpha: Studies With The PH Domains Of The Oxysterol Binding Protein And FAPP1, Mol. Biol. Cell. 16:1282-1295 (2005); Bianco A., Reghellin V., Donnici L., Fenu S., Alvarez R., Baruffa C., Peri F., Pagani M., Abrignani S., Neddermann P., De Francesco R., Metabolism Of Phosphatidylinositol 4-Kinase Iiiα-Dependent PI4P Is Subverted By HCV And Is Targeted By A 4-Anilino Quinazoline With Antiviral Activity., PLoS Pathog. 8:e1002576 10.1371/journal.ppat.1002576 (2012). PI4KIIIa has been identified as an essential host factor of HCV RNA replication by a number of studies. Berger K. L., Cooper J. D., Heaton N. S., Yoon R., Oakland T. E., Jordan T. X., Mateu G., Grakoui A., Randall G., Roles For Endocytic Trafficking And Phosphatidylinositol 4-Kinase III Alpha In Hepatitis C Virus Replication, Proc. Natl. Acad. Sci. USA. 106:7577-7582 (2009); Trotard M, Lepere-Douard C, Regeard M, Piquet-Pellorce C, Lavillette D, Cosset F L, Gripon P, Le Seyec J., Kinases Required In Hepatitis C Virus Entry And Replication Highlighted By Small Interference RNA Screening, FASEB. J., 23:3780-3789 (2009). See, also, Tai et al. (2009), supra, and Vaillancourt et al., (2009), supra.
The involvement of PI4KIII has also been reported as well but might be restricted to genotype 1. Interestingly PI4KIII and PI4P are also closely linked to replication of enteroviruses, suggesting that dependence on PI metabolism and particularly PI4P is a common theme for many virus groups and suggesting the possibility that inhibitors of PI4KIII and PI4P may be broad acting antivirals agents.
PI4K kinases are also implicated in cancer onset and progression. PI4KIIIα and PI4KIIIβ have been linked to drug resistance and antiapoptotic effect in pancreatic and breast cancers respectively. V. Giroux, J. Iovanna, J. C. Dagom, Probing the Human Kinome for Kinases Involved in Pancreatic Cancer Cell Survival and Gemcitabine Resistance, FASEB J. 20 1982-1991 (2006); K. Chu, S. Minogue, J. Hsuan, M. Waugh, Differential Effects of the Phosphatidylinositol 4-Kinases, PI4KIIalpha And PI4KIIIbeta, oin Akt Activation And Apoptosis, Cell Death Dis. (2010) 1; V. A. Tomlinson, H. J. Newbery, N. R. Wray, J. Jackson, A. Larionov, W. R. Miller, et al., Translation Elongation Factor Eef1a2 is a Potential Oncoprotein That is Overexpressed In Two-Thirds Of Breast Tumours, BMC Cancer 5 (2005) 113; A. A. Morrow, et al. The lipid kinase PI4KIIIbeta is highly expressed in breast tumors and activates Akt in cooperation with Rab11a, Mol. Cancer Res., 12 (2014), pp. 1492-1508
PI4K kinases are also required for the synthesis of PI4P which is responsible for cell proliferation and migration. Inhibition of PI 4-kinase activity as such could potentially provide a valuable therapeutic target for combined inhibition of both the PLC and PI 3-kinase pathways through limiting the supply of PI4P and PI(4,5)P2 during receptor-activated signalling. The PI3-kinases pathway is known for its role in cancer onset and progression. T. L. Yuan, L. C. Cantley, PI3K Pathway Alterations In Cancer: Variations On A Theme, Oncogene 27, 5497-5510 (2008); A. Balla, T. Balla, Phosphatidylinositol 4-kinases: Old Enzymes With Emerging Functions, Trends Cell Biol. 16, 351-361 (2006).
Inhibition of PI4K kinases have also been shown to have beneficial effects in treating autoimmune disorder and inflammation as well the prevention of cell and organ transplant rejection. Loo, L., Wright, B. D. and Zylka, M. J., 2015. Lipid kinases as therapeutic targets for chronic pain. Pain, 156(0 1), p. S2; Herman, Jean, Louat, Thierry, Huang, Qiuya, Vanderhoydonck, Bart, Waer, Mark, Herdewijn, Piet (2014), Autoimmune and Inflammatory Disorder Therapy. See, also, U.S. Pat. No. 9,301,961 to Herman et al. issued Apr. 5, 2016. Mutations in the PI4K kinase have also recently been found to be responsible for the development of resistance to chemotherapy by antimalarial medication and is as such seen as a target for the control of drug resistant Plasmodium parasite. Plasmodium's life cycle consists of several distinct stages as mosquito-injected sporozoites rapidly populate liver cells, in which they either proliferate and produce merozoites that emerge in the bloodstream or enter a dormant phase as hypnozoites in the liver. The life cycle is regulated by several cellular factors including the kinase. McNamara et al., 2013 reported that the PI4KIIIβ is involved in all stages of the life cycle of the Plasmodium parasite and its inhibition halted the progression of parasite making this PI4KIIIβ a major therapeutic target against malaria. McNamara, C. W., Lee, M. C., Lim, C. S., Lim, S. H., Roland, J., Simon, O., & Zeeman, A. M. (2013). Targeting Plasmodium phosphatidylinositol 4-kinase to eliminate malaria. Nature, 504(7479), 248; Rajkhowa, S., Borah, S. M., Jha, A. N., & Deka, R. C. (2017). Design of Plasmodium falciparum PI (4) KIIIβ Inhibitor using Molecular Dynamics and Molecular Docking Methods. Chemistry Select, 2(5), 1783-1792; Rutaganira, F. U., Fowler, M. L., McPhail, J. A., 0, M. A., Nguyen, K., Xiong, A., . . . & Burke, J. E. (2016). Design and structural characterization of potent and selective inhibitors of phosphatidylinositol 4 kinase IIIβ. Journal of medicinal chemistry, 59(5), 1830-1839; Ren, J. X., Gao, N. N., Cao, X. S., Hu, Q. A., & Xie, Y. (2016). Homology modeling and virtual screening for inhibitors of lipid kinase PI (4) K from Plasmodium. Biomedicine & Pharmacotherapy, 83, 798-808;
The above examples are among a plethora of evidence that PI4-kinases are potential therapeutic targets and their inhibitors alone or in combination with other direct-acting antiviral agents could play a significant role in the control of viruses.
Viruses are also known to hijack other host factors during the infection cycle and one cellular process that is usurped by multiple viruses is intracellular membrane traffic. This process relies, in part, on the interactions between adaptor protein (AP) complexes and transmembrane cargo. The host cell kinases AP2-associated protein kinase 1 (AAK1) and cyclin G-associated kinase (GAK) regulate clathrin-associated adaptor-cargo trafficking in the endocytic and secretory pathways, in part by recruiting AP2 and AP1, respectively, to relevant membranes and enhancing their binding affinity for cargo (Ricotta et al., 2002; Umeda et al., 2000; Zhang et al., 2005; Ghosh and Komfeld, 2003).
Recent work has demonstrated that through AP1 and AP2 phosphorylation, AAK1 and GAK regulate early and late stages of the viral lifecycle, thereby representing “master regulators” of viral infection (Bekerman et al., 2017). SARS-CoV-2 has now been shown to infect cells after viral entry via clathrin-mediated endocytosis resulting in the repurposing of at least 1 FDA drug (Baricitinib) for the treatment of COVID-19 infection (Bayati et al., 2021; Stebbing et al., 2020, EMBO).
Another mechanism used by viruses is the Nucleocapsid protein N that targets the stress granule (SG) protein G3BP1, an essential antiviral protein which is known to induce innate immune response. Common among coronaviridae is the manipulation of SG possibly leading to suppression of SGs and host translation shutoff. This functionality seems to benefit viral replication, as SGs are inhibitory to replication of coronaviruses. The SARS-CoV-2 nucleocapsid (N) interactome includes many host mRNA binding proteins including CK2. Inhibition of CK2 has potential to promote SG function releasing antiviral activity of SGs.
Another class of molecules required by viruses particularly the coronaviruses for cell entry and replication are the proteases. The implicated proteases include: ACE-2, ADAM10, 3-chymotrypsin-like protease (3-ClPro), Calpain1, Cathepsin L, Chymase, DPPIV & TACE. Angiotensin-converting enzyme 2 (ACE-2) as one of the major proteases is used by COVID-19 for example to infect human cells by way of utilizing a spike (S) glycoprotein which binds to cell membranes of the host. As SARS-CoV-2 spike (S) glycoprotein binds to the cell membrane protein ACE-2 it allows the virus to enter into the host cells. As COVID-19 has binds to ACE2 via the S protein on its surface, the S protein is cleaved into subunits, S1 and S2. S1 contains the receptor binding domain (RBD) which allows coronaviruses to directly bind to the peptidase domain (PD) of ACE-2. S2 then likely plays a role in membrane fusion.
Flavonoids are common constituents of plants and cover a wide range of functions including acting as yellow pigments in petals and leaves to attract pollinating insects. They might also appear as bluish pigments (anthocyanins) to receive certain wavelengths of light, which permits the plant to be aware of the photoperiod. Many of these flavonoids also protect the plants by being involved in the filtering of harmful ultraviolet light. Some flavonoids play crucial roles in establishing symbiotic fungi, while at the same time they fight infections caused by pathogenic fungi.
Flavonoids have relevant pharmacological activities such as; antioxidant, antidiabetic, anti-inflammatory, antiallergic, antibiotic, antidiarrheal, CNS and against cancer. In particular administration of anthocyanoside oligomer appeared to improve subjective symptoms and objective contrast sensitivity in myopia subjects. Lee, J., Lee, H. K., Kim, C. Y., Hong, Y. J., Choe, C. M., You, T. W., & Seong, G. J., Purified High-Dose Anthocyanoside Oligomer Administration Improves Nocturnal Vision and Clinical Symptoms in Myopia Subjects, Br J Nutr., June; 93(6): 895-9 (2005).
Given the abundance of evidence supporting the health benefits of flavonoids, the present inventors have successfully isolated highly bioactive flavonoids from a supercritical fluid extract (SFE) of Vemonia acuminata and Cannabis sativa from the Blue Mountains of Jamaica. The molecule has shown activity against hepatitis C virus (HCV) and Covid-19 in-vitro in addition to other viruses. Apart from the direct-acting antiviral activity, the flavonoid has demonstrated significant inhibitory activity against Class III host phosphatidylinositol 4-kinases (PI4KA and PI4 KB), tyrosine kinases, proteases and pro-inflammatory cytokines. The present invention relates to the use of the newly isolated flavonoids alone or in combination with other flavonoids or related bioactive compounds to treat or prevent viral infections and associated malignancies. Administration of the pharmaceutical formulations may be aided by the use of appropriate carriers including but not limited to buffered solutions, mineral and vegetable oils, cyclodextrins, Tween solutions, Cremophor, Solutol 15, liposomes and nanoparticle formulations. The composition may also be delivered using an inhalation device targeting the upper respiratory track.
It is, therefore, an object of the invention to provide a therapeutic flavonoid composition alone or in combination with other direct-acting antiviral agents for inhibition of phosphatidylinositol-4-kinases, tyrosine kinases, proteases, pro-inflammatory cytokines and consequent prevention and treatment of RNA viral infections including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picornaviruses, vesicular stomatitis and associated disorders. It is another object to provide a method for isolating specific plant-based flavonoid pharmaceutical compositions from raw plant material that are biologically active in the prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders. In accordance with the foregoing objects, the present invention provides a flavonoid-based pharmaceutical composition for the prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders. The flavonoid-based pharmaceutical composition has a structure of the general formula of
Wherein,
R1-R10 may be any one or more substituents selected from the group consisting of a hydrogen molecule (H), a hydroxide molecule (OH), a methyl group comprising one carbon atom bonded to three hydrogen atoms (CH3), an alkoxy group (O—CH3), a carboxyl group (COOH), chlorine (Cl), Bromine (Br), Fluorine (F), Glutamic acid (Glu), geranyl chain, prenyl chain and any salts or derivatives of the foregoing. A and B may be linked by either a single or double bond.
A method of treatment using the specific plant-based flavonoid pharmaceutical compositions above is also disclosed, as well as a method for prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders.
Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:
Reference will now be made in detail to preferred embodiment of the present invention, examples of which are illustrated in the accompanying drawing.
The present invention is a group of plant-based flavonoid pharmaceutical compositions isolated from a supercritical fluid extract (SFE) of Vemonia acuminate and Cannabis sativa, from the Blue Mountains of Jamaica, and useful for the prevention and treatment of RNA viruses including but not limited to viral Coronaviruses, Chikigunya, Dengue, Ebola, hepatitis, HIV, influenza, picomavirus, Zika.
The plant-based flavonoid pharmaceutical composition for the prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders has the structure of the general formula of
wherein,
R1-R10 may be any one or more substituents selected from the group consisting of a hydrogen molecule (H), a hydroxide molecule (OH), a methyl group comprising one carbon atom bonded to three hydrogen atoms (CH3), an alkoxy group (O—CH3), a carboxyl group (COOH), chlorine (Cl), Bromine (Br), Fluorine (F), Glutamic acid (Glu), geranyl chain, prenyl chain and any salts or derivatives of the foregoing. A and B may be linked by either a single or double bond.
The most preferred structure of the synthesized flavonoids presented in
In an embodiment, a method for the prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picornaviruses, vesicular stomatitis and associated disorders using the specific plant-based flavonoid pharmaceutical compositions above is also disclosed. Administration may be by various routes including oral, rectal or intravenous, epidural muscle, subcutaneous, intranasal, intrauterine, or blood vessels in the brain (intracerebroventricular) injections. The flavonoid derivatives of the general and specific formulas (
The composition may be formulated for external topical application, oral dosage such as powders, granules, tablets, capsules, suspensions, emulsions, syrups, aerosols, suppositories, or in the form of a sterile injectable solution. Acceptable carriers and excipients may comprise lactose, dextrose, sucrose, sorbitol, mannitol, xylitol, erythritol, maltitol, starches, gum acacia, alginate, gelatin, calcium phosphate, calcium silicate, cellulose, methyl cellulose, microcrystalline cellulose, polyvinylpyrrolidone, water, methyl benzoate, propyl benzoate, talc, magnesium stearate, polyethylene glycol and mineral and vegetable oils.
Bioactivity of the above-described compounds have been verified by use of kinase inhibition assays to determine the effect of the flavonoids in the onset and progression of RNA viruses. The inhibition of PI4K kinases in particular has been shown to be a therapeutic target that could block the replication of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picornaviruses, vesicular stomatitis and associated disorders.
Anti-Hepatitis C Activity
Huh-7.5 cells are grown in Dulbecco's modified essential media (DMEM), 10% fetal bovine serum (FBS), 1% penicillin-streptomycin (pen-strep), 1% Non-essential amino acids (NEAA) in a 5% CO2 incubator at 37° C. Huh7.5 cells will be seeded at 1×104 cells per well into 96-well plates according to Southern Research Institute standard format. Test article will be serially diluted with DMEM plus 5% FBS. The diluted compound in the amount of 50 μl will be mixed with equal volume of cell culture-derived HCV (HCVcc), then applied to appropriate wells in the plate. Human interferon alpha-2b (rIFNα-2b) is included as a positive control compound. After 72 hr incubation at 37° C., the cells were lysed for measurement of luciferase activity using Renilla Luciferase Assay System (Promega) according to manufacturer's instruction. The number of cells in each well will be determined by CytoTox-1 reagent (Promega). Test articles are tested with 6 serial dilution in triplicate to derive, if applicable, IC50 and IC90 (concentration inhibiting HCVcc infectivity by 50% and 90%, respectively), TC50 (concentration decreasing cell viability by 50%) and SI (selective index: TC50/IC50) values.
Results of the inhibition of HCVcc are indicated in the table below:
Anti Coronavirus Activity
This test is for initial screening of potentially antiviral compounds. The antiviral activity of the compound is evaluated based on the ability of the compound to prevent virus from causing viral CPE in mammalian cell culture. Different dilutions of test compound are evaluated, and the effective antiviral concentration determined by regression analysis. The toxicity of the test compound is determined in parallel. CPE is determined by microscopic observation of cell culture monolayers as well as uptake of neutral red dye. Cell line, Vero 76, was obtained from American Type Culture Collection (ATCC; Manassas, Va., USA). Cells were cultured in Dulbecco's modified Eagle's medium (DMEM) with 10% fetal bovine serum (FBS). The HCoV-OC43 (VR-1558) strain was obtained from the ATCC. Vero-76 cells were treated with multiple concentrations of each compound then infected with virus, and the 50% effective concentration (EC50), the 50% cytotoxic concentration (IC50), and the selective index (SI) for each compound were calculated. The results of the anti coronavirus study are presented in the table below.
Kinase Inhibition Assay
In vitro profiling of lipid and tyrosine kinases was accomplished using the “HotSpot” assay platform. Briefly, specific kinase/substrate pairs along with required cofactors were prepared in reaction buffer; 20 mM Hepes pH 7.5, 10 mM MgCl2, 1 mM EGTA, 0.02% Brij35, 0.02 mg/ml BSA, 0.1 mM Na3VO4, 2 mM DTT, 1% DMSO. Compounds were delivered into the reaction, followed ˜20 min later by addition of a mixture of ATP (Sigma) and 33P ATP (PerkinElmer) to a final concentration of 10 μM. Reactions were carried out at 25° C. for 120 min, followed by spotting of the reactions onto P81 ion exchange filter paper (e.g., Whatman Ashless Filter Paper). Unbound phosphate was removed by extensive washing of filters in 0.75% phosphoric acid. After subtraction of background derived from control reactions containing inactive enzyme, kinase activity data were expressed as the percent remaining kinase activity in test samples compared to vehicle (dimethyl sulfoxide) reactions. IC50 values and curve fits were obtained using Prism™ (by GraphPad Software). Kinome tree representations were prepared using Kinome Mapper.
To determine the kd values, competition binding assays were established, authenticated and executed as described previously (Fabian et al., 2005, Karaman et al., 2008). For most assays, kinases were fused to T7 phage strains (Fabian et al. 2005) and for the other assays, kinases were produced in HEK-293 cells after which they were tagged with DNA for quantitative PCR detection (data not shown). In general, full-length constructs were used for small, single domain kinases, and catalytic domain constructs for large multi-domain kinases. The binding assays utilized streptavidin-coated magnetic beads treated with biotinylated small molecule ligands for 30 minutes at room temperature which generated affinity resins for the kinase assays. The liganded beads were blocked with excess biotin and washed with blocking buffer (SeaBlock (Pierce), 1% BSA, 0.05% Tween 20, 1 mM DTT) to remove unbound ligand and to reduce non-specific phage binding. Binding reactions were assembled by combining kinases, liganded affinity beads, and test compounds in 1× binding buffer (20% SeaBlock, 0.17×PBS, 0.05% Tween 20, 6 mM DTT). Test compounds were prepared as 40× stocks in 100% DMSO and diluted directly into the assay (Final DMSO concentration=2.5%). All reactions were performed in polypropylene 384-well plates in a final volume of 0.04 ml. The assay plates were incubated at room temperature with shaking for 1 hour and the affinity beads were washed with wash buffer (1×PBS, 0.05% Tween 20). The beads were then re-suspended in elution buffer (1×PBS, 0.05% Tween 20, 0.5 μM non-biotinylated affinity ligand) and incubated at room temperature with shaking for 30 minutes. The kinase concentration in the eluates was measured by quantitative PCR. A graphical illustration of the kinase interaction process is presented below. Kd values were determined using a standard dose response curve using the hill equation. Curves were fitted using a non-linear least square fit with the Levenberg-Marquardt algorithm.
Percent Control (% Ctrl)
The compound(s) were screened at 10 μM and results for primary screen binding interactions are reported as ‘% Ctrl’, where lower numbers indicate stronger hits in the matrix.
test compound=compound submitted by Environmental Health Foundation
negative control=DMSO (100% Ctrl)
positive control=control compound (0% Ctrl)
Results of the inhibition of 12 lipid kinases by flavonoids are shown in the table below:
A method for isolating the specific flavonoid pharmaceutical compositions from raw plant material is also disclosed. The isolation was realized according to the scheme shown in
At step 10 an appropriate amount of plant biomass is collected. For present purposes, Vemonia acuminate, a plant from the Blue Mountains of Jamaica, was collected by hand. The collected plant material was air dried under shade and pulverized into powder.
At step 20 the powder is subjected to supercritical fluid extraction (SFE) by which carbon dioxide (CO2) is used for separating one component (the extractant) from another (the matrix). The extract is evaporated to dryness resulting in a green residue.
At step 30, for experimental purposes, a bioassay-guided fractionation was employed, using a standard protocol to isolate a pure chemical agent from its natural origin. This entailed a step-by-step separation of extracted components based on differences in their physicochemical properties and assessing all their biological activity. The extracted components may, for example, be fractionated by dry column flash chromatography on Si gel using hexane/CH2Cl2/ethyl acetate and mixtures of increasing polarity to yield different fractions. The sample is then degassed by ultra-sonication to yield an insoluble solid, which solid is then filtered. The sample may then be subjected to high performance liquid chromatography (HPLC) using a column Phenomenex Luna™ C18, 5 μm, 2×50 mm; eluent, acetonitrile with 0.05% MeOH to confirm the presence of the various fractions.
At step 40, bioactivity of the extracts were verified in a kinase inhibition assay as described above. This identified the bioactive flavonoids from all the supercritical fluid extracts (SFE). As reported previously, the identified plant-based flavonoid extracts showed activity against several kinases implicated in the pathogenesis of the prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders.
The next step was to identify the plant-based flavonoid constituents responsible for the observed kinase inhibitory activities and to further isolate them.
At step 50 Nuclear Magnetic Resonance Spectroscopy and mass spectrometry (NMR/MS) was performed and the interpreted spectra were consistent with plant-based flavonoid compositions, as identified above, and as shown in step 60. The bioactive plant-based flavonoid extracts found bioactive for the prevention and treatment of RNA viruses had the structure of the general formula of
The compounds are designated FBL-02 and FBL-03G, and purity of the compounds were confirmed by HPLC prior to spectroscopic analysis.
Given the known structure of the general formula of
It should now be apparent that the above-described invention provides a pharmaceutical composition for inhibition of phosphatidylinositol-4-kinases and consequent prevention and treatment of RNA viruses including but not limited to adenoviruses, alphaviruses, coronaviruses, enteroviruses, flaviviruses, hepatitis, herpes, influenza viruses, measles, picomaviruses, vesicular stomatitis and associated disorders. The invention also provides a method for isolating the flavonoid pharmaceutical compositions from raw plant material.
It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.
The present application derives priority from U.S. provisional application No. 62/993,236 filed 23 Mar. 2020, and is a continuation of U.S. patent application Ser. No. 16/321,333 filed 19 Mar. 2019, which is the national stage entry of PCT/US17/44153, which in turn derives priority from U.S. Provisional Patent Application 62/367,345 filed 27 Jul. 2016, the entirety of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62993236 | Mar 2020 | US | |
| 62367345 | Jul 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16321333 | Mar 2019 | US |
| Child | 17210159 | US |
