Abstract:
Disclosed is the cosmeceutical potential of 3,5-dimethoxy-4′-hydroxystilbene in terms of its melanogenesis inhibitory and photo protective activities. Also disclosed does a topical melanogenesis inhibitory composition comprising 0.01 to 50% by weight of 3,5-dimethoxy-4′-hydroxystilbene.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention in general relates to 3,5-dimethoxy-4′-hydroxystilbene. More specifically, the invention discloses the cosmeceutical potential of 3,5-dimethoxy-4′-hydroxystilbene (pterostilbene) in terms of its melanogenesis inhibitory and photo protective activities and compositions thereof. 
         [0003]    2. Description of Prior Art 
         [0004]    Pterostilbene is a stilbenoid belonging to a group of compounds called phytoalexins which are produced by plants in response to stress It is thought to be the key compound found predominantly in blueberries and grapes known to exhibit anti-cancer, anti-hypercholesterolemia, anti-hypertriglyceridemia, anti-diabetic and anti-fungal potential. 
         [0005]    It is the primary objective of the present invention to disclose novel melanogenesis inhibitory activity of pterostilbene. 
         [0006]    It is another objective of the present invention to disclose a melanogenesis inhibitory composition comprising 3,5-dimethoxy-4′-hydroxystilbene, wherein said composition by weight from about 0.01% to about 50% 3,5-dimethoxy-4′-hydroxystilbene. 
         [0007]    It is yet another objective of the present invention to disclose the use of 3,5-dimethoxy-4′-hydroxystilbene in the manufacture of a medicament to treat skin-hyper pigmentation. 
         [0008]    Further, the present invention also discloses a method of treating skin hyper-pigmentation. 
         [0009]    The present invention fulfills the aforementioned objectives and provides further related advantages. 
       SUMMARY OF THE INVENTION 
       [0010]    The invention relates to the cosmeceutical potential of 3,5-dimethoxy-4′-hydroxystilbene in terms of its melanogenesis inhibitory and photo protective activities. Also disclosed does a topical melanogenesis-inhibitory composition comprising 0.01 to 50% by weight of 3,5-dimethoxy-4′-hydroxystilbene. 
         [0011]    Other features and advantages of the present invention will become apparent from the following more detailed description which illustrates by way of example, the principle of the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0012]    In another most preferred embodiment the present invention relates to a melanogenesis inhibitory composition comprising 3,5-dimethoxy-4′-hydroxystilbene represented by STR#1, wherein said composition by weight from about 0.01% to about 50% 3,5-dimethoxy-4′-hydroxystilbene. 
         [0013]    In yet another most preferred embodiment, the present invention relates to the use of 3,5-dimethoxy-4′-hydroxystilbene represented by STR#1, in the manufacture of a medicament to treat skin-hyper pigmentation. 
         [0014]    In yet another most preferred embodiment, the present invention relates to a method of treating skin hyper-pigmentation, said method comprising the topical application on affected areas of the skin in need of such treatment, a composition comprising by weight from about 0.01% to about 50% 3,5-dimethoxy-4′-hydroxystilbene represented by STR#1. 
         [0015]    In yet another most preferred embodiment, the present invention relates to a method of treating skin hyper-pigmentation, said method comprising the topical application on affected areas of the skin in need of such treatment, a composition comprising by weight from about 0.01% to about 50% 3,5-dimethoxy-4′-hydroxystilbene represented by STR#1, the said stilbene being obtained from  Pterocarpus marsupium  extract in commercially significant purity of at least 90%. The stilbene 3,5-dimethoxy-4′-hydroxystilbene was obtained by solvent extraction of  Pterocarpus marsupium.  The solvents used were ethyl acetate and hexane. Other solvents of similar polarity can be used. Supercritical carbon di-oxide, scCO2, can also be used for removal of non-polar constituents from  Pterocarpus marsupium.  Alternatively, pterostilbene can be obtained by synthesis as exemplified in U.S. Pat. No. 7,253,324 
         [0000]    
       
                 
         
             
             
         
       
     
       EXAMPLE I 
       [0016]    The mushroom tyrosinase inhibitory activity of 3,5-dimethoxy-4′-hydroxystilbene was studied in a micro plate by incubating varying concentrations of the sample with 400 U/ml of mushroom tyrosinase and then by the addition of 3.53 mM of L-tyrosine substrate. The absorbance at the 10th minute of the reaction was read in a Fluostar Optima micro plate reader at 492 nm. 3,5-dimethoxy-4′-hydroxystilbene showed a significant inhibition of mushroom tyrosinase with an IC50 value of 7 μg/ml. 
       EXAMPLE II  
       [0017]    3,5-dimethoxy-4′-hydroxystilbene was studied for melanogenesis inhibition in B16F1 mouse melanoma cell line. B16F1 cells were induced with 0.5 nM MSH (Melanocyte stimulating hormone) and then treated with varying concentrations of the sample. Sample treatment was given thrice after every 72 hrs. On the 9th day of treatment, the melanin from the cells was extracted with 1N NaOH and the absorbance was read at 405 nm in a Fluostar Optima micro plate reader. 3,5-dimethoxy-4′-hydroxystilbene showed a significant inhibition of melanogenesis with an IC50 value of 0.5 μg/ml. 3,5-dimethoxy-4′-hydroxystilbene surprisingly showed about 6 times higher potential than Glabridin. 
       EXAMPLE III 
       [0018]    3,5-dimethoxy-4′-hydroxystilbene was studied for UV protection in Swiss 3T3 mouse fibroblast cells. Swiss 3T3 fibroblast cell monolayers were exposed to UV A (0.5 J/cm2) and UV B (0.05 J/cm2) in the presence and absence of sample treatment at varying concentrations. After UV exposure, the cells were incubated in CO2 incubator for 72 hours and the cell viability was determined by SRB (Sulphorhodomine B) dye staining. The UV protection is determined as the enhanced percentage of viable sample treated cells as compared to the untreated cells after UV exposure. 3,5-dimethoxy-4′-hydroxystilbene showed a significant UV protection of 32% as compared to the untreated cells. 
       EXAMPLE IV 
       [0019]    Pterostilbene Compositions of the Present Invention (Illustrative Examples) 
       Prototype Formula for Depigmentation Cream 
       [0020]      
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Ingredients 
                 % w/w 
                 Function 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 A 
                 Glyceryl mono stearate 
                 qs 
                 Emulsifying agent 
               
               
                   
                 Isopropyl palmitate 
                 qs 
                 Emollinet 
               
               
                   
                 PEG 100 stearate 
                 qs 
                 Emolllient 
               
               
                   
                 Stearic acid 
                 qs 
                 Emulsifying agent 
               
               
                   
                 Capric Caprylic Triglyceride 
                 qs 
                 Emollient 
               
               
                   
                 Propyl Paraben 
                   
                 Preservative 
               
               
                 B 
                 Propylene glycol 
                 qs 
                 Humectant 
               
               
                   
                 Tetrasdium EDTA 
                 qs 
                 Chelating agent 
               
               
                   
                 Imidurea 
                 qs 
                 Preservative 
               
               
                   
                 Methyl Paraben 
                 qs 
                 Preservative 
               
               
                   
                 Demineralised water 
                 up to 100 
                 Solvent 
               
               
                 C 
                 Pterostillbene 
                 0.1 
                 Active 
               
               
                   
                 Arbutin 
                 1.0 
                 Active 
               
               
                   
                 Licorice 40% CA 
                 0.1 
                 Active 
               
               
                   
                 Ethanol 
                 qa 
                 Solubilizer 
               
               
                 D 
                 20% Sodium Hydroxide Solution 
                 qs 
                 Neutralizer 
               
               
                   
                 (if required to adjust the pH) 
               
               
                   
                 DC 3021 
                 qs 
                 Silicon 
               
               
                   
                 Salcare SC 91 
                 qs 
                 Viscosity modifier 
               
               
                 E 
                 Fragrance 
                 qs 
                 Fragrance 
               
               
                   
               
             
          
         
       
     
       Properties: 
       [0000]    
       
         Appearance: Light brown colored emulsion 
         pH: 5.5-7.5 
       
     
         [0023]    Alternative formulation
   Ceteareth-25-2.0%   Glyceryl Stearate-4.0%   Stearyl Alcohol-2.0%   Ethyl hexyl Stearate-8.5%   Caprylic/Capric triglyceride-5.5%   Water-75.0%   Kathon CG-2-3 Tr   Pterostilbene (90%)-1%   
 
         [0032]    While the invention has been described with reference to a preferred embodiment, it is to be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention is to be interpreted only in conjunction with the appended claims.