SOLUBLE HONOKIOL DERIVATIVES

Abstract

The invention provides a soluble honokiol derivative (such as a water soluble honokiol derivative) and its application in antagonizing glycoprotein VI receptor and providing antioxidant and neuroprotective effects.

Claims

1. A method of antagonizing glycoprotein VI receptor, comprising administration of a therapeutically effective amount of the following compound of Formula (I) to a subject: ##STR00005## wherein X is (CH.sub.2).sub.1-6; R.sub.1 is phosphate or carbonate; R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl, C.sub.1-10alkyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl, wherein the alkyl or alkenyl is unsubstituted or substituted; and R.sub.4 and R.sub.5 are each independently one to three H, halogen, OH, NH.sub.2, NO.sub.2, C.sub.1-10alkyl, C.sub.2-6alkenyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl; or a pharmaceutically acceptable salt thereof.

2. The method of claim 1, wherein R.sub.1 is phosphate; R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl; and R.sub.4 and R.sub.5 are each independently H; or a pharmaceutically acceptable salt thereof.

3. The method of claim 1, wherein R.sub.2 and R.sub.3 are each independently ethenyl; or a pharmaceutically acceptable salt thereof.

4. The method of claim 1, wherein the pharmaceutically acceptable salt is a sodium salt.

5. The method of claim 1, wherein the compound is 3,5-diallyl-[1,1-biphenyl]-2,4-diyl bis(phosphate), or a pharmaceutically acceptable salt thereof.

6. The method of claim 1, wherein the compound is sodium 3,5-diallyl-[1,1-biphenyl]-2,4-diylbis(phosphate).

7. The method of claim 1, wherein platelet aggregation can be inhibited in the subject.

8. A method of providing antioxidant and neuroprotective effects in a subject, comprising administering a therapeutically effective amount of a compound of Formula (I) to a subject: ##STR00006## wherein X is (CH.sub.2).sub.1-6; R.sub.1 is phosphate or carbonate; R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl, C.sub.1-10alkyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl, wherein the alkyl or alkenyl is unsubstituted or substituted; and R.sub.4 and R.sub.5 are each independently one to three H, halogen, OH, NH.sub.2, NO.sub.2, C.sub.1-10alkyl, C.sub.2-6alkenyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl; or a pharmaceutically acceptable salt thereof.

9. The method of claim 8, wherein R.sub.1 is phosphate; R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl; and R.sub.4 and R.sub.5 are each independently H; or a pharmaceutically acceptable salt thereof.

10. The method of claim 8, wherein R.sub.2 and R.sub.3 are each independently ethenyl; or a pharmaceutically acceptable salt thereof.

11. The method of claim 8, wherein the pharmaceutically acceptable salt is a sodium salt; and/or wherein the compound is 3,5-diallyl-[1,1-biphenyl]-2,4-diyl bis(phosphate), or a pharmaceutically acceptable salt thereof.

12. The method of claim 8, which is sodium 3,5-diallyl-[1,1-biphenyl]-2,4-diyl bis(phosphate).

13. The method of claim 8, wherein the method does not cause hemorrhage.

14. The method of claim 8, wherein the method reduces edema.

15. The method of claim 8, wherein the compound has a prolonged half-life compared to honokiol.

16. The method of claim 8 wherein the compound converts to honokiol in plasma.

17. The method of claim 8, wherein the neuroprotective effect diminishes brain damage in the subject.

18. The method of claim 17, wherein the brain damage is ischemic stroke.

19. The method of claim 8, wherein the administration is parenteral administration.

20. The method of claim 19, wherein the parenteral administration is intravenous, intramuscular or intracranial administration.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0010] FIG. 1A shows coronal sections of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brains after middle cerebral artery occlusion (MCAO) in the vehicle group treated with an isovolumetric solvent (normal saline, intravenous [i.v.]), and groups treated with HP-TMU (0.25, 0.5 and 1 mg/kg, i.v.) or honokiol (0.129, 0.258 and 0.516 mg/kg, i.v.; the doses of honokiol were adjusted by the ratio of the molecular weight of honokiol to HP-TMU (266.33/514.22)) after 30 min-embolic occlusion. The densitometric analyses for the measurement of infarct volume and brain edema after treatment with HP-TMU or honokiol against embolic stroke in mice were shown in FIG. 1B & FIG. 1C, respectively. Data are presented as the meansSEM (n=8). *P<0.05 compared with the vehicle group.

[0011] FIG. 2 shows bleeding time measured at 10 min after the i.v. administration of normal saline (isovolumetric control) or HP-TMU (0.5 and 1 mg/kg, i.v.) for 30 min. Data are presented as the meansSEM (n=6). Each symbol represents the bleeding time of an individual mouse.

[0012] FIG. 3A and FIG. 3B show assays of neurobehavioral functions including A. neurological severity scoring and B. the rotarod test, evaluations were performed before and 24 and 48 h after surgery. All data are presented as the meansSEM (n=8). * P<0.05, compared with the vehicle group.

[0013] FIG. 4A and FIG. 4B show the A. mean plasma concentrations of honokiol vs. time profile in five rats after intravenous injection of HP-TMU(.circle-solid.) or honokiol(); and B. pharmacokinetic parameters of HP-TMU in rat plasma.

[0014] FIG. 5 shows that mice were subjected to middle cerebral artery occlusion (MCAO) surgery for 30 min, and then treated with the isovolumetric vehicle control (normal saline, intravenous [i.v.]) or HP-TMU (1 mg/kg, i.v.) or edaravone (3 mg/kg, i.v.). The therapeutic effects of HP-TMU on long-term recovery were evaluated by neurological severity scoring before or 1, 2, 7, 14, and 28 days after surgery. All data are presented as the meansSEM (n=3). *P<0.05, compared with the vehicle control group.

DETAILED DESCRIPTION OF THE INVENTION

[0015] In accordance with the present disclosure and as used herein, the following terms are defined with the following meanings, unless explicitly stated otherwise. It is to be understood that both the foregoing general description and the following detailed description are examples and explanatory only and are not restrictive of the subject matter claimed. In this application, the use of the singular includes the plural unless specifically stated otherwise. In this application, the use of or means and/or unless stated otherwise. Furthermore, use of the term including as well as other forms, such as includes, and included is not limiting.

[0016] As used herein, the singular forms a, an and the include plural referents unless the context clearly dictates otherwise.

[0017] As used herein, the term prodrug refers to a compound (e.g., a drug precursor) that is transformed in vivo to yield a parent compound or a pharmaceutically acceptable salt, hydrate or solvate of the parent compound.

[0018] As used herein, the term alkyl refers to a saturated straight or branched hydrocarbon, such as a straight or branched group of 1-6, 1-4, or 1-3 carbon atoms, referred to herein as C.sub.1-C.sub.6alkyl, C.sub.1-C.sub.4alkyl, and C.sub.1-C.sub.3 alkyl, respectively. Exemplary alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, 2-methyl-1-propyl, 2-methyl-2-propyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 3-methyl-2-butyl, 2,2-dimethyl-1-propyl, 2-methyl-1-pentyl, 3-methyl-1-pentyl, 4-methyl-1-pentyl, 2-methyl-2-pentyl, 3-methyl-2-pentyl, 4-methyl-2-pentyl, 2,2-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-ethyl-1-butyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, neopentyl, hexyl, etc.

[0019] As used herein, the terms halo or halogen as used herein refer to F, Cl, Br, or I.

[0020] As used herein, the term alkenyl refers to an aliphatic hydrocarbon group containing at least one carbon-carbon double bond and which may be straight or branched and having the indicated number of carbon atoms. Preferably alkenyl contains one carbon to carbon double bond, and up to four nonaromatic carbon-carbon double bonds may be present. Examples of alkenyl groups include ethenyl, propenyl, n-butenyl, 2-methyl-1-butenyl, 3-methylbut-2-enyl, n-pentenyl, octenyl and decenyl.

[0021] As used herein, the term pharmaceutically acceptable means approved or approvable by a regulatory agency of the Federal government of the United States of America or the corresponding agency in countries other than the United States of America (such as the EMA, the European Medicines Agency), or that is listed in the United States Pharmacopeia or European Pharmacopoeia (Ph. Eur.).

[0022] As used herein, the term bioavailable is art-recognized and refers to a form of the subject disclosure that allows for it, or a portion of the amount administered, to be absorbed by, incorporated to, or otherwise physiologically available to a subject or patient to whom it is administered.

[0023] As used herein, the terms treating or treatment of a disease includes inhibiting the disease (slowing or arresting or partially arresting its development), preventing the disease, providing relief from the symptoms or side effects of the disease (including palliative treatment), and/or relieving the disease (causing regression of the disease.

[0024] As used herein, a patient, subject or host to be treated by the subject method may mean either a human or non-human animal. Non-human animals include companion animals (e.g. cats, dogs) and animals raised for consumption (i.e. food animals), such as cows, pigs, chickens.

[0025] As used herein, the term neuroprotection refers to the prevention or inhibition of degenerative effects of injury or disease in the NS, including protection from the secondary neurodegenerative effects which persist even when the primary risk factor is removed or attenuated.

[0026] The present disclosure provides a novel honokiol derivative with enhanced stability and surprisingly good bioavailability. Particularly, the compound of the present invention can be used to prepare parenteral or injectable drug delivery.

[0027] In one aspect, the present disclosure provides a compound having the following formula:

##STR00001##

wherein
X is (CH.sub.2).sub.1-6;
R.sub.1 is phosphate or carbonate;
R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl, C.sub.1-10alkyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl, wherein the alkyl or alkenyl is unsubstituted or substituted;
R.sub.4 and R.sub.5 are each independently one to three H, halogen, OH, NH.sub.2, NO.sub.2, C.sub.1-10alkyl, C.sub.2-6alkenyl, OC.sub.1-10alkyl or NHC.sub.1-10alkyl;
or a pharmaceutically acceptable salt thereof.

[0028] In one embodiment, R.sub.1 is phosphate; R.sub.2 and R.sub.3 are each independently C.sub.2-6alkenyl; and R.sub.4 and R.sub.5 are each independently H. In a further embodiment, R.sub.2 and R.sub.3 are each independently ethenyl.

[0029] The pharmaceutically acceptable salts as used herein refer to salts prepared from pharmaceutically acceptable non-toxic bases including inorganic bases and organic bases. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines, and basic ion exchange resins, such as arginine, betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethyl-morpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like. In one embodiment, the pharmaceutically acceptable salt is a sodium salt.

[0030] In one embodiment, the compound of the present invention is 3,5-diallyl-[1,1-biphenyl]-2,4-diylbis(phosphate) or sodium 3,5-diallyl-[1,1-biphenyl]-2,4-diylbis(phosphate).

[0031] The present disclosure provides a preparation method of a honokiol derivative represented by formula (I). The synthetic procedure for honokiol phosphate (3) is illustrated in the following scheme 1. Honokiol (Compound 1) as a starting substance was reacted with dibenzyl phosphite in the presence of N-chlorosuccinimide to afford compound 2. The benzyl groups of the resulting product were removed using bromotrimethylsilane followed by basification by sodium methoxide to obtain the corresponding phosphate 3.

##STR00002##

[0032] Reagents and conditions: (a) N-chlorosuccinimide, dibenzyl phosphite, DMAP, DIEA, acetonitrile; (b) i. bromotrimethylsilane, CH.sub.2Cl.sub.2; ii. sodium methoxide, EtOH.

[0033] In order to use the compound of Formula (I) in therapy, it will normally be formulated into a pharmaceutical composition in accordance with standard pharmaceutical practice.

[0034] The present disclosure therefore provides a pharmaceutical composition, which comprises a therapeutically effective amount of a compound of Formula (I) and optionally one or more pharmaceutically acceptable carriers and/or excipients.

[0035] The present disclosure also provides a dosage form comprising the pharmaceutical composition of the invention. In one embodiment, the dosage form is an injection dosage form.

[0036] A pharmaceutical composition of the invention, which may be prepared by admixture, suitably at ambient temperature and atmospheric pressure, is usually adapted for oral administration and, as such, may be in the form of tablets, capsules, oral liquid preparations, powders, granules, or lozenges.

[0037] Compositions containing the active ingredient may be in any form suitable for the intended method of administration. In some embodiments, the compounds of a method and/or composition described herein can be provided via oral administration, rectal administration, transmucosal administration, intestinal administration, enteral administration, topical administration, transdermal administration, intrathecal administration, intraventricular administration, intraperitoneal administration, intranasal administration, intraocular administration and/or parenteral administration.

[0038] The terms parenteral administration and administered parenterally are art-recognized and refer to modes of administration other than enteral and topical administration, usually by injection, and includes, without limitation, intravenous, intramuscular, intracranial, intraarterial, intrathecal, intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal, transtracheal, subcutaneous, subcuticular, intra-articular, subcapsular, subarachnoid, intraspinal, and intrasternal injection and infusion. For example, Formulations suitable for parenteral administration include aqueous and non-aqueous isotonic sterile injection solutions which may contain, for example, antioxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents. The formulations may be presented in unit-dose or multi-dose sealed containers, for example, ampoules and vials, and may be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example water for injections, immediately prior to use. Injection solutions and suspensions may be prepared from sterile powders, granules and tablets of the kind previously described.

[0039] When the compounds are administered via oral administration, for example, tablets, troches, lozenges, aqueous or oil suspensions, dispersible powders or granules, emulsions, hard or soft capsules, syrups or elixirs may be prepared. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents including sweetening agents, flavoring agents, coloring agents and preserving agents, in order to provide a palatable preparation. Tablets containing the active ingredient in admixture with non-toxic pharmaceutically acceptable excipient which are suitable for manufacture of tablets are acceptable. These excipients may be, for example, inert diluents, such as calcium or sodium carbonate, lactose, calcium or sodium phosphate; granulating and disintegrating agents, such as maize starch, or alginic acid; binding agents, such as starch, gelatin or acacia; and lubricating agents, such as magnesium stearate, stearic acid or talc. Tablets may be uncoated or may be coated by known techniques including microencapsulation to delay disintegration and adsorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate alone or with a wax may be employed.

[0040] In some embodiments unit dosage formulations contain a daily dose or unit, daily sub-dose, or an appropriate fraction thereof, of a drug. In one embodiment, the unit dosage formulation is an injection dosage form. It will be understood, however, that the specific dose level for any particular patient will depend on a variety of factors including the activity of the specific compound employed; the age, body weight, general health, sex and diet of the individual being treated; the time and route of administration; the rate of excretion; other drugs which have previously been administered; and the severity of the particular disease undergoing therapy, as is well understood by those skilled in the art.

[0041] In a further aspect there is provided a method of antagonizing glycoprotein VI receptor, comprising administration of a therapeutically effective amount of the compound of Formula (I) to the subject. In one embodiment, the compound can inhibit platelet aggregation.

[0042] Glycoprotein (GP) VI is a platelet membrane protein with a molecular weight of 62 kDa that was identified as a physiological collagen receptor from studies of patients deficient in this protein. GPVI-deficient platelets lacked specifically collagen-induced aggregation and the ability to form thrombi on a collagen surface under flow conditions, suggesting that GPVI makes an indispensable contribution to collagen-induced platelet activation.

[0043] The present invention also provides a method of providing antioxidant and neuroprotective effects in a subject, comprising administering a therapeutically effective amount of the compound of Formula (I) to the subject.

[0044] The present disclosure also provides a method of improving brain damage in a subject, which comprises administration of a therapeutically effective amount of the compound of Formula (I) to the subject. In one embodiment, the brain damage is ischemic stroke.

[0045] In one embodiment, the methods described herein do not cause hemorrhage.

[0046] In one embodiment, the methods described herein reduces edema.

[0047] In the methods described herein, the compound of the present disclosure has a prolonged half-life compared to honokiol.

[0048] In the methods described herein, the compound of the present disclosure converts to honokiol in plasma.

[0049] The dose range of the compounds of general formula (I) applicable per day is usually from about 0.01 to about 1.0 mg per kg body weight, preferably from about 0.025 to about 1.0, about 0.05 to about 1.0, about 0.075 to about 1.0, about 0.025 to about 0.1, about 0.05 to about 0.1, about 0.75 to about 0.1, about 0.1 to about 1.0, about 0.25 to about 1.0, about 0.5 to about 1.0 or about 0.75 to about 1.0 mg per kg body weight of the patient.

[0050] The examples which follow are intended in no way to limit the scope of the disclosure but are provided to illustrate how to prepare and use compounds disclosed herein. Many other embodiments of this disclosure will be apparent to one skilled in the art.

EXAMPLE

Example 1 Preparation of Tetrabenzyl (3,5-diallyl-[1,1-biphenyl]-2,4-diyl) bis(phosphate) (2) (HP-TMU)

[0051] ##STR00003##

[0052] A solution of N-chlorosuccinimide (5.0 equiv) in CH.sub.3CN was heated at 40 C. for 5 min. A solution of dibenzyl phosphite (5.0 equiv) in CH.sub.3CN was added to this prepared solution and stirred at room temperature for 4 hours. Meanwhile, a solution of honokiol (1, 1 equiv), N,N-diisopropylethylamine (DIPEA, 5.0 equiv), and 4-dimethylaminopyridine (DMAP, 0.2 equiv) in CH.sub.3CN was prepared and added to the stirring mixture at room temperature. The resulting mixture was stirred at room temperature for 1 hour. The reaction mixture was quenched by H.sub.2O and extracted with toluene. The organic layer was collected and dried to afford tetrabenzyl (3,5-diallyl-[1,1-biphenyl]-2,4-diyl) bis(phosphate) (referred as compound 2).

Example 2 Preparation of Sodium 3,5-diallyl-[1,1-biphenyl]-2,4-diyl bis(phosphate) (3)

[0053] ##STR00004##

[0054] Bromotrimethylsilane was added to a solution of compound 2 (1 equiv) in CH.sub.2Cl.sub.2 was added bromotrimethylsilane under ice bath and stirred at room temperature for 3 hours. The reaction mixture was quenched by H.sub.2O and extracted with ethyl acetate. The aqueous layer was collected and dried to afford a crude product. The resulting residue was dissolved in EtOH and then sodium methoxide (4.4 equiv) was added. After stirring at room temperature for 18 hours, the organic solvent was removed in vacuum. The resulting residue was dissolved in H.sub.2O and extracted with ethyl acetate. The aqueous layer was collected and dried to afford sodium 3,5-diallyl-[1,1-biphenyl]-2,4-diyl bis(phosphate) (referred to as compound 3).

Example 3 HP-TMU Exerts (1) Superior Neuroprotective Effects Against Embolic Stroke as Compared to Honokiol (2) without Causing the Risk of Hemorrhagic Incidence in Mice

[0055] Coronal sections of 2,3,5-triphenyltetrazolium chloride (TTC)-stained brains were taken after middle cerebral artery occlusion (MCAO) in the vehicle group treated with an isovolumetric solvent (normal saline, intravenous [i.v.]), and groups treated with HP-TMU (0.25, 0.5 and 1 mg/kg, i.v.) or honokiol (0.129, 0.258 and 0.516 mg/kg, i.v.; the doses of honokiol were adjusted by the ratio of the molecular weight of honokiol to HP-TMU (266.33/514.22)) after 30 min-embolic occlusion. The densitometric analyses for the measurement of infarct volume and brain edema were performed after treatment with HP-TMU or honokiol against embolic stroke in mice. Bleeding time was measured 10 min after the i.v. administration of normal saline (isovolumetric control) or HP-TMU (0.5 and 1 mg/kg, i.v.) for 30 min.

[0056] As shown in FIG. 1A, the red region in the TTC-stained sections indicates the nonischemic portion of the brain, whereas the pale region indicates the ischemic portion. Treatment with HP-TMU (0.5 and 1 mg/kg) significantly reduced the infarct volume compared with that in the solvent control group (P<0.05) (FIG. 1B). In addition, MCAO-induced cerebral edema in the ischemic hemisphere was reduced by the treatment of 1 mg/kg HP-TMU (FIG. 1C). Furthermore, the administration of HP-TMU reveals more potent neuroprotective effects than honokiol in mice subjected to MCAO (FIGS. 1A-1C). On the other hand, increased risk of hemorrhage is a major side effect of anti-stroke treatments. To evaluate HP-TMU in this aspect, we used the mouse tail transection model as an index of hemostasis. As shown in FIG. 2, HP-TMU (0.5 and 1 mg/kg) did not alter the bleeding time substantially, illustrating that HP-TMU treatment for embolic stroke is harmless, eliciting no side effects of bleeding.

Example 4 HP-TMU Improves Neurobehavioral Functions in Mice after MCAO

[0057] Mice were subjected to middle cerebral artery occlusion (MCAO) surgery for 30 min, and then treated with the isovolumetric vehicle control (normal saline, intravenous [i.v.]) or HP-TMU (0.25, 0.5 and 1 mg/kg, i.v.) or honokiol (0.129, 0.258 and 0.516 mg/kg, i.v.). Assays of neurobehavioral functions include neurological severity scoring and the rotarod test. Evaluations were performed before and 24 and 48 h after surgery.

[0058] Neurological deficit was examined and scored on an 18-point scale before and 24 and 48 h after MCAO reperfusion injury. The changes in neurological deficit scores of different groups are illustrated in FIG. 3A. At 24 and 48 h after MCAO, neurobehavioral deficit scores significantly increased compared with those before MCAO; nevertheless, 0.5 and 1 mg/kg HP-TMU significantly ameliorated these increased scores (Post-24 h groups: P<0.05; Post-48 h groups: P<0.05). In addition, the performance of the MCAO group mice in the rotarod test at 24 and 48 h after MCAO was also impaired, and the decrease of rotarod duration was significant reversed in the HP-TMU (0.5 and 1 mg/kg)-treated mice compared with the vehicle control group (Post-24 h groups: P<0.05; Post-48 h groups: P<0.05) (FIG. 3B). Mean plasma concentrations of honokiol vs. time profile in five rats were measured after intravenous injection of HP-TMU or honokiol.

[0059] The plasma concentrations of honokiol at different points are expressed as meanSD, and the mean concentration-time curve is shown in FIG. 4A. The calculated pharmacokinetic parameters of HP-TMU are summarized in FIG. 4B. The results revealed that intravenous administration of honokiol (0.258 mg/kg) rapidly distributed and could not be detected in plasma. However, the same dosage of HP-TMU (0.5 mg/kg) could be hydrolyzed to honokiol and be detected in rat plasma. HP-TMU has prolonged half-life compared to honokiol, and it was indeed converted to honokiol in plasma.

Example 5 Comparison of the Neuroprotective Effect of HP-TMU and Edaravone in Mice Subjected to MCAO

[0060] Mice were subjected to middle cerebral artery occlusion (MCAO) surgery for 30 min, and then treated with the isovolumetric vehicle control (normal saline, intravenous [i.v.]) or HP-TMU (1 mg/kg, i.v.) or edaravone (3 mg/kg, i.v.). The therapeutic effects of HP-TMU on long-term recovery were evaluated by neurological severity scoring before or 1, 2, 7, 14, and 28 days after surgery.

[0061] The long-term recovery of neurological deficit of MCAO mice were significantly improved by the treatment of HP-TMU (1 mg/kg) at 1, 2, and 7 days after surgery (FIG. 5). In addition, the administration of HP-TMU (1 mg/kg) reveals similar therapeutic effects compared with edaravone (3 mg/kg), an approved drug in Japan to treat acute ischemic stroke (FIG. 5).