Plant-derived powder and an extract of the same

Details Plant-derived powder and an extract of the same Plant-derived powder and an extract of the same

1997-10-16

2001-07-31

Tate, Christopher R. (Department: 1633)

Drug, bio-affecting and body treating compositions

Plant material or plant extract of undetermined constitution...

Containing or obtained from a tree having matured height of...

C424S774000, C424S778000

Reexamination Certificate

active

06267993

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to an antiviral powder obtained from a medicinal plant having an antiviral action, an antiviral extract obtained from the powder, and a preparation comprising the powder and/or extract.
BACKGROUND OF THE INVENTION
In the history of human beings who have suffered with various bacterial and viral infections from old, the discovery of antibiotics and the development of vaccines against viruses have brought about a great development in the medical care of this century. However, many chronic and infectious diseases have still presented a serious social problem.
More particularly, the greatest problem which confronts us today includes prophylaxis of infection with viruses such as human immunodeficiency virus (abbreviated as HIV; Barre-Sinoussi et al., 1983; Gallo et.al., 1984) which causes human adult T-cell leukemia (abbreviated as HALT) and human T-cell lymphotropic virus (abbreviated as HTLV; Yoshida et al., 1984) which causes acquired immunological deficiency syndrome (abbreviated as AIDS) and the treatments of theses diseases.
Some of herb medicines and crude drugs constituting the herb medicines have been hitherto believed as having the antiviral action. In recent years, a number of studies and reports have been made on crude drugs having the antiviral action. The antiviral activity itself has been elucidated on about half of the crude drugs, thus leaving many crude drugs to be unclear with respect to the activity. The mechanism of the antiviral action has now been under detailed study. Some reports have been already made on the antiviral action through an immunological regulation activity system.
On the other hand, there is the possibility of developing antiviral agents along the line of the central dogma of the molecular biology, i.e. the flow of deoxyribose nuleic acid (abbreviated as DNA)→messenger ribonucleic acid (abbreviated as mRNA)→protein.
Additionally, transcription that takes place in the direction opposite the central dogma, i.e. from RNA to DNA (in contrast to the central dogma's flow of DNA to mRNA) also occurs in nature. This has been backed up with the discovery of a reverse transcriptase (abbreviated as RT) made by Temin and Baltimore in 1970 (Baltimore, 1970; Temin and Mizutani, 1970).
Retroiviruses (reverse transcriptase contains oncovirus) are those having reverse transcriptases as is suggested by the name. Specific attention has been paid to the virus since the retroviruses were recognized in 1980's as causing human adult T-cell leukemia and AIDS, whose spread has been viewed with anxiety.
Since then, extensive studies have been made on retroviruses. At present, detailed information has been reported at a gene level and the life cycles of the viruses are now being made clear (Meek et al., 1990a).
The target in the development of antiviral agents is considered to reside in a method of suppressing the attachment of viruses to cells and suppressing the reverse transcription of viral ribonucleic acid toward deoxyribonucleic acid. Typical compounds reported as having the activity of inhibiting reverse transcription include nucleotides, antibiotics, natural products and the like.
Of these, nucleotide derivatives are greatest in number and have been synthesized for the purpose of the competitive inhibiting action of the reverse transcriptase substrate (Nhtsuya and Broder, 1987)
Azidothymidine, 2′,3′-dideoxycytidine and 2′,3′-dideoxyinosin are typical of these reverse transcriptase inhibitors and are a few medicines authorized as agents for treating for AIDS.
SUMMARY OF THE INVENTION
An object of the invention is to provide an antiviral powder capable of inhibiting the enzymatic activity of reverse transcriptases and derived from medicinal plants, and an antiviral extract extracting an inhibiting component from the powder.
Another object of the invention is to provide an antiviral powder which has an inhibiting action on HIV-I reverse transcriptase, which is a pathogen of AIDS, and also on a reverse transcriptase derived from mouse leukemia virus.
A further object of the invention is to provide an antiviral preparation which comprises the powder and/or extract set out above.
DETAILED DESCRIPTION OF THE INVENTION
The antiviral powder of the invention derived from a medicinal plant is one obtained according to the following procedure. Immediately after collection of a medicinal plant starting material having the antiviral action, the starting material is quickly heated under conditions sufficient to de-activate the enzymatic activity of the starting material, followed by drying the quickly heated plant at a low temperature of from −5° C. to +10° C. to an extent that a moisture content is not higher than 10% to obtain a powder of the medicinal plant. For obtaining a powder, the medicinal plant is milled or powdered at a stage after the quick heating or after the low temperature drying.
In order to obtain an antiviral extract, the powder of the medicinal plant is subjected to extraction with hot water or a lower alcohol. If necessary, the extract may be appropriately concentrated.
In the practice of the invention, a preparation comprising the powder and/or extract as an effective component is also provided. The preparation may be formulated as an emulsion, oil, wettable powder, powder or the like. Preferably, a powder is used.
The present invention is described in detail.
The starting medicinal plants used to obtain the antiviral powder or extract of the invention and having the antiviral action may be any medicinal plants provided that they have the antiviral activity. All sites or portions of the medicinal plant containing an antiviral component may be usable including leaf, stem, root, flower and the like. Especially, the leaves and, preferably, young leaves of Japanese lacquer (
Rhus verniciflua
) and the flower portion of
Ulmus davidiana var.japonica
are preferably used as having a remarkable reverse transcriptase inhibiting action. It will be noted that the term “young leaves” used herein means ones which are in a soft condition and which generally are not older than 8 weeks in age, preferably not older than 4 weeks. The above definition concerning the young leaves should not be construed as limitative because the Japanese lacquer greatly differs in the rate of growth depending on the growing district.
In order to obtain the antiviral powder, the certain portions of the medicinal plant are collected. Immediately after the collection, the portions are subjected to quick heating. The term “immediately after collection” is intended to mean that the portions collected are subjected to quick heating within 3 minutes to about 30 minutes after the collection. The immediate quick heating can, to an extent, prevent an effective component form being decomposed by enzymes. The terms “quick heating under conditions sufficient to de-activate enzymatic activity” means that when using, for example, a pressure drum heater, the starting material is thermally treated at a temperature ranging from 80 to 140° C. within 2 minutes, preferably for approximately one minute, and more preferably for 40~50 seconds. Alternatively, a heater such as a microwave oven may also be used. In the case, with an output power of 600 W, the active enzymes can be de-activated by heating for 20 to 50 seconds although depending on the amount of starting material. The quick heating should be carried out under conditions of de-activating a lytic enzyme or enzymes in the starting material but not decomposing other components of the medicinal plant. Since the lytic enzyme is de-activated or broken down, the decomposition of the other components with the lytic enzyme can be prevented, thereby preventing a lowering in amount of effective components.
The thus quickly heated starting material is subsequently subjected to low temperature drying. The low temperature drying is performed within a range of −5 to 10° C. The drying at low temperatures can prevent decomposition in the drying step of the medicin

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