Drug – bio-affecting and body treating compositions – Plant material or plant extract of undetermined constitution... – Containing or obtained from a leaf
Reexamination Certificate
2002-08-20
2004-04-06
Moran, Marjorie (Department: 1631)
Drug, bio-affecting and body treating compositions
Plant material or plant extract of undetermined constitution...
Containing or obtained from a leaf
C514S693000, C514S763000, C536S001110
Reexamination Certificate
active
06716459
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition for inhibiting an increase of a blood sugar level or lowering a blood sugar level. More specifically, it relates to a composition for inhibiting an increase of a blood sugar level or lowering a blood sugar level, which composition contains extract components from
Lagerstroemia Speciosa
, Linn. or Pers. as a main component and has a specific content of corosolic acid.
2. Prior Art of the Invention
Lagerstroemia Speciosa
, Linn. or Pers. comes under the loosestrife family of Myrtales and is generally called “queen's crape myrtle” as well, and it occurs widely in south east Asian areas including the Philippines, India, Malaysia, southern China and Australia. In the Philippines in particular, dry leaves and flowers of
Lagerstroemia Speciosa
, Linn. or Pers. are decoted and taken as a drink. This drink is also well known as a folk medicine against diabetes.
Leaves of
Lagerstroemia Speciosa
, Linn. or Pers. have received attention and an extract thereof has been analyzed for obtaining some components. It has been accordingly reported that corosolic acid is contained as one of the components and that the corosolic acid has been studied for its activity by using Ehrlich Ascites Tumour Cells to show that it is a substance which activates the mobility of grape sugar [Chem. Pharm. Bull. 41(12) 2129-2131 (1993)].
The above report is concerned with results of in vitro experiments and merely suggests results of first-stage discrimination test of anti-diabetes activities of corosolic acid.
JP-A-5-310587 discloses an anti-diabetes preparation containing, as an ingredient, a concentrated dry substance (
Lagerstroemia Speciosa
, Linn. or Pres. powder extract) obtained by extracting leaves of
Lagerstroemia Speciosa
, Linn. or Pers. in hot water or an organic solvent. The above preparation is an easily prepared and high-safety anti-diabetes preparation produced by taking out a water-soluble fraction and a lipid-soluble fraction from an extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pers. and adjusting it to a dry extract. The above publication discloses a preferred embodiment in which the powder extract is diluted, e.g., in a concentration of 2% and taken as a drink, and the anti-diabetes activity thereof is confirmed by an animal experiment using mice diseased with diabetes.
As already described, dry leaves of
Lagerstroemia Speciosa
, Linn. or Pers. have been used as having an effect on the therapy of diabetes in folk medicine. However, it is not clearly known what component(s) of the leaves of
Lagerstroemia Speciosa
, Linn. or Pers. has/have human anti-diabetes activity. It is known that corosolic acid is contained as one component, while the activity thereof is a mere result of a study of the function to activate the mobility of grape sugar in an in vitro experiment using cells.
Further, there has been no specific clinical knowledge of component(s) of the extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pers. which has/have activity in the therapy of human diabetes. Moreover, there has been found no knowledge obtained by studying a relationship between component(s) of the extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pers. and an increase in a human blood sugar level.
The present inventor has therefore studied a relationship between component(s) of an extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pers. and an increase or inhibition of an increase in human blood sugar level on the basis of clinical tests. When a composition which was a concentrated extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pers. and which had a specific content of corosolic acid was administered to mild-case diabetes patients who had a fasting blood sugar level of slightly higher than approximately 110 mg/dl and who were insulin-non-dependent, it was found that an increase in blood sugar level was inhibited and that the blood sugar levels decreased on average.
According to studies by the present inventors, it has been also found that the composition which had a specific content of corosolic acid can be obtained by extracting, concentration and drying leaves of
Lagerstroemia Speciosa
, Linn. or Pers., under a specific condition.
MEANS TO SOLVE THE PROBLEMS
According to the present invention, therefore, there is provided a composition for inhibiting an increase blood sugar level, which comprises, as a main component, a concentrate of a hot water or alcohol extract of leaves of
Lagerstroemia Speciosa
, Linn. or Pres. and has a corosolic acid content of 0.01 to 15 mg per 100 mg of the concentrate.
According to the present invention, further, there is provided a method of inhibiting an increase in a blood sugar level, which comprises orally administering the above composition to a patient who is expected to suffer an increase in blood sugar level from a normal blood sugar level.
Further, according to the present invention, there is provided a method of lowering a blood sugar level to a normal level, which comprises orally administering the above composition to a mild-case diabetes patient having a blood sugar level higher than a normal level to some extent or a serious diabetes patient having a high blood sugar level.
The present invention will be explained more specifically hereinafter.
Corosolic acid is one of triterpenoids having the following structural formula.
It is considered that the activity of the composition of the present invention in inhibiting an increase in, or lowering, a human blood sugar level is caused by the interaction of a specific content of corosolic acid in the concentrate and extracted components of leaves of
Lagerstroemia Speciosa
, Linn. or Pers.
Leaves of
Lagerstroemia Speciosa
, Linn. or Pers. used as a raw material for the composition of the present invention refer to green leaves of
Lagerstroemia Speciosa
, Linn. or Pers. which occurs in the Philippines or some other areas or a dry product prepared by drying the same. The green leaves may be dried by leaving it in atmosphere, by air-drying or by forcible drying. Preferably, the drying is carried out by so-called toasted-drying until the leaves have a water content of 20% by weight or less, preferably 10% by weight or less, for preventing the growth of microorganisms and attaining storage stability.
Green leaves of
Lagerstroemia Speciosa
, Linn. or Pers. may be extracted as they are, while it is desirable to pulverize the dry leaves or cut them into pieces before the extraction.
The method and condition of extracting leaves of
Lagerstroemia Speciosa
, Linn. or Pers. in hot water or an alcohol and concentrating the extract are not specially limited, while there should be employed a method and a condition under which a resultant concentrate has a specific content of corosolic acid. That is, the concentrate preferably has a corosolic acid content of 0.01 to 15 mg per 100 mg of the concentrate (dry solid substance). The corosolic acid content per 100 mg of the concentrate is preferably 0.1 to 15 mg, more preferably 0.2 to 12 mg, particularly preferably 0.5 to 10 mg.
In the composition of the present invention, those components of the leaves of
Lagerstroemia Speciosa
, Linn. or Pers. which are other than corosolic acid also have an effect on the activity, and it is required to take account of components to be extracted and a concentrating method and condition with regard to other components. A preferred embodiment of a proper method and a proper condition will be apparent from an explanation to be given later.
Method 1
In this method, a pulverization product of dry leaves of
Lagerstroemia Speciosa
, Linn. or Pers. (raw material) added to ethanol or an ethanol aqueous solution (ethanol content 50 to 80% by weight) in an amount 5 to 20 times, preferably 8 to 10 times the weight of the raw material, and the mixture is refluxed under heat at a temperature between room temperature and 90° C., preferably approximately between 50° C. and 80° C., for 30 minutes to 2 hours. Th
Moran Marjorie
Morgan & Lewis & Bockius, LLP
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