FIELD OF THE INVENTION
The present invention relates to a pharmaceutical composition useful as acetylcholinesterase inhibitor (AChE). The present invention particularly relates to the use of natural compounds selected from (±) Marmesin, Columbianetin, Dihydroxanthyletin and substituted coumarin derivatives for the preparation of composition useful as acetylcholinesterase inhibitors.
BACKGROUND OF THE INVENTION
Alzheimer's disease (AD) (J. Med. Chem. 46, 2279, 2003) is a chronic neuro degenerative disorder, which finds severe behavioral abnormalities and loss of cognitive ability. Alzheimer's disease is associated with cerebral cholinergic hypo function and characterized by plaques of the amyloid β-peptide, neurofibrillary tangles and degeneration or atrophy of the basal forebrain cholinergic neurons. The loss of forebrain cholinergic cells results reduction in acetylcholine, which plays an important role in the cognitive impairment associated with Alzheimer's disease. One of the most promising approaches for the treatment of Alzheimer's disease is to increase in the levels of acetyl choline by inhibition of acetycholinesterase.
Several approaches have been developed for the treatment of Alzheimer's disease by inhibiting the AChE. The most used AChE inhibitors are Galanthamine, donepezil, rivastigmine, tacrine and 2H-3,4-tetrahydroquinazoline-2-one & 2H-3,4-tetrahydro quinazoline-2,4-dione (U.S. Pat. No. 5,504,088, 1996) were also reported.
Pyrano coumarins, furo coumarins and substituted coumarins are natural compounds possessing biological activities like purgative (J. Indian. Chem. Soc. Vol 66, 66, 1989), insecticidal (Jpn. Appl. 7 973 12, 1977; Chem. Abstr Vol 91, p152771u, 1977), antimicrobial (Chem. Abstr. Vol 56, 1835b, 1962), anti feedant (J. Agric. Food. Chem. Vol 37, 1435, 1989), antiulcer (Fitoterapia Vol 68, 410, 1997; Chem. Abstr Vol 128, 268242j, 1998), anti cancer (J. Nat. Prod. Vol 57, 518, 1994) and anti HIV (U.S. Pat. No. 5,637,589; Chem. Abstr. Vol 127, 104326t, 1997). Coumarin derivatives were also exhibited monoamine oxidase (MAO-A& B) inhibitory properties (J. Med. Chem. 43, 4747, 2000, J. Med. Chem. 44, 3195, 2001, Arkivoc, 272, 2004).
The present invention relates to the compounds of natural sources (±) Marmesin, Columbianetin (Phytochemistry, Vol 39(6), 1347, 1995) Dihydroxanthyletin (Phytochemistry, Vol 34(3), 819, 1993), coumarin derivatives of 7-allyloxy coumarin, 7-benzyloxy coumarin, 7-methoxy coumarin, 7-acetyloxy coumarin, 4-methyl-7-hydroxy coumarin and 4-methyl-7-acetyloxy coumarin are potent highly selective towards the AChE in vitro and in vivo. These compounds are highly effective for the treatment and prevention of AChE.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1a: Effect of AP 20am Samples (100 mg/Kg, Po×3 Days) on Scopolamine induced Deficit in Passive Avoidance Test in Mice (p**<0.001, *<0.01 Significant difference from 1st Trial, p value determined by student's t Paired test).
FIG. 1b: Effect of Ap 20am14.15 & 16. Samples (50 mg/Kg, po×3 Days) on Scopolamine induced Deficit in Passive Avoidance Test in Mice (p**<0.001, *<0.01 Significant difference from 1st Trial, p value determined by student's t Paired test).
OBJECTIVE OF THE INVENTION
The main objective of the present invention is to provide a pharmaceutical composition useful as acetylcholinesterase inhibitor.
Another object of the present invention is to provide the composition wherein the composition exhibit more percent memory retention than standard drug Donepezil, in scopolamine induced memory deficit mice.
One of the objectives of the present invention is to use the naturally occurring compounds for the preparation of (±) Marmesin and Columbianetin.
It is another objective of the present invention is to provide composition using dihydroxanthyletin, useful as AChE inhibitor.
It is further objective of the present invention is to provide composition using compounds 7-allyloxy coumarin, 7-benzyloxy coumarin and 4-methyl-7-acetyloxy coumarins, useful as AChE inhibitor.
It is yet further objective of the present invention is to provide composition using compounds selected from 7-methoxy coumarin, 7-acetyloxy coumarin and 4-methyl-7-hydroxy coumarins, useful as AChE inhibitor.
SUMMARY OF THE INVENTION
Accordingly the present invention provides a pharmaceutical composition comprising an effective amount of compound of formula 1, analogs and pharmaceutically acceptable salts thereof;
(i) wherein R1 and R2 is linked with each other via the following moiety and collectively makes fused system, and R3 is H;
(ii) wherein R1 and R3 is linked with each other via following moiety and collectively makes fused system, and R1 is H;
(iii) wherein R1 and R2 is linked with each other via following moiety and collectively makes fused system, and R3 is H;
(vi) wherein the value of R, R1, R2, and R3 is selected from the group consisting of
1. R=R2=R3=H; R1=OH.
2. R=R2=R3=H; R1=Prenyl
3. R=R2=R3=H; R1=Allyl
4. R=R2=R3=H; R1=2,2-dimethyl alkyne
5. R=R2=R3=H; R1=2,2-dimethyl alkene
6. R=R2=R3=H; R1=Benzyl
7. R=R2=R3=H; R1=Acetyl
8. R=R2=R3=H; R1=Methyl
9. R=R1=R3=H; R2=Prenyl
10. R=R3=H; R1=R2=Prenyl
11. R=R1=R2=H; R3=Prenyl
12. R=Methyl; R1=R2=R3=H
13. R=R1=Methyl; R2=R3=H
14. R=R1=Acetyl; R2=R3=H
15. R=Methyl; R1=R3=H; R2=OH
16. R=Methyl; R1=Benzyl, R2=Benzyloxy, R3=H
17. R=Methyl; R1=Methyl, R2=Methyloxy, R3=H
18. R=Methyl; R1=Acetyl, R2=Acetyloxy, R3=H
optionally along with the pharmaceutically acceptable carrier, or diluent, wherein the effective dose of composition is ranging between 50 to 100 mg/kg body weight.
In an embodiment of the present invention, wherein the compound of general formula 1 further comprising:
In an embodiment of the invention, wherein the compound of general formula 1 further comprising: