Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
2001-07-20
2003-02-18
Trinh, Ba K. (Department: 1625)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
C514S467000, C549S357000, C549S430000
Reexamination Certificate
active
06521661
ABSTRACT:
BACKGROUND OF THE INVENTION
Of great importance to man is the control of fungi which can cause human, animal and plant diseases as well as food spoilage. Considerable research and resources have been devoted to identifying antifungal agents. While certain methods and chemical compositions have been developed which aid in inhibiting or controlling the growth of fungi, new methods and antifungal compositions are needed.
Only about 100 of the thousands of known species of yeasts and molds cause disease in humans or animals. Only the dermatophytes and Candida are commonly transmitted from one human to another.
Human mycotic infections may be grouped into superficial, subcutaneous, and deep (or systemic) mycoses. Superficial fungal infections of skin, hair, and nails may be chronic and resistant to treatment but rarely affect the general health of the patient. Deep mycoses, on the other hand, may produce systemic involvement and are sometimes fatal.
The deep mycoses are caused by organisms that live free in nature in soil or on decaying organic material and are frequently limited to certain geographic areas. In such areas, many people acquire the fungal infection. A majority develop only minor symptoms or none at all, and only a small minority of infections progress to full-blown serious or fatal disease. The host's cell-mediated immune reactions are of paramount importance in determining the outcome of such infections.
Pathogenic fungi generally produce no toxins. In the host, they regularly induce hypersensitivity to their chemical constituents. In systemic mycoses, the typical tissue reaction is a chronic granuloma with varying degrees of necrosis and abscess formation.
Fungal infections are common to a large number of animal species. Common agents of fungal infections include various species of the genii Candida and Aspergillus, and types thereof, as well as others. While external fungus infections can be relatively minor, systemic fungal infections can give rise to serious medical consequences. The incidence of fungal infections has undergone a significant increase, particularly in humans. This increase is, at least in part, attributable to an ever increasing number of patients having impaired immune systems, both as a result of medical therapy for other conditions, and as a result of diseases such as AIDS which compromise the immune system. Fungal disease, particularly when systemic, can be life threatening to patients having an impaired immune system. See, for example, U.S. Pat. No. 5,891,861.
A number of prior art pharmaceutical agents have been developed for the treatment of fungal diseases. These materials include compounds such as amphotericin B (AMB), triazoles and flucytosin. AMB is the drug of choice for many systemic fungal infections due to its broad range of activity; however, it is harmful to the kidneys and must be administered intravenously. Many of the triazoles exhibit broad ranging activity and can be administered orally; however, many strains of fungi have become resistant to these materials. Consequently, there is a need for a new group of agents which are effective in elminating fungus disease.
Food spoilage is typically caused by bacteria and fungi. Foods such as low-fat spreads, cheese, tea-based beverages, fruit- and tomato-based products are among the vulnerable food products. See, for example, U.S. Pat. No. 5,888,504. Although fungi can sometimes be controlled through heat treatment, an inactivating heat treatment is not always desirable or possible. Furthermore fungal spores present in factories can cause problems at the packing stage. Combating bacteria is relatively easy; fungi, however, can survive under very adverse conditions. Therefore, new compounds for preserving and protecting food are needed.
Post-harvest losses during storage of plant produce are caused, inter alia, by fungal and bacterial pathogens. Fungicidal compounds have long been used to increase yields and extend agricultural production capabilities into new areas. They have also been extremely important tools for ameliorating season-to-season differences in yield and quality caused by weather-driven variations in disease pressure.
Chemical fungicides have provided an effective method of control; however, the public has become concerned about the amount of residual chemicals which might be found in food, ground water and the environment. Stringent new restrictions on the use of chemicals and the elimination of some effective pesticides from the market place could limit economical and effective options for controlling fungi.
One example of the need to control post-harvest spoilage of agriculture products pertains to green and blue molds of citrus fruits caused by
Penicillium digitatum
and
P. italicum
. These molds cause severe damage during storage and shipping. The existing fresh-market industry relies completely on a combination of several chemical treatments to deliver sound fruit to distant markets over substantial periods of time without excessive damage caused by these molds. Unfortunately, there are increasing concerns about the safety of the chemicals currently used to control these fungal pathogens. Also, there are increasing problems with fungal strains with resistance to the most effective compounds.
In another example, powdery mildew of grapes caused by
Uncinula necator
can cause severe damage even in dry areas such as California. Traditionally this disease was controlled with applications of elemental sulfur, but this necessitates frequent, high volume applications of an irritating material. The introduction of egosterol biosynthesis inhibiting fungicides (primarily triazoles) greatly simplifies control, but also selects for tolerant strains. Some of these compounds are also known to have potential teratogenic effects and very long soil residuals. In these and other examples, alternative control methods are in great demand—particularly methods which are safer or more environmentally benign.
To prevent fungal spoilage it is common practice in many countries to spray produce with systemic fungicides in the field and to dip harvested produce in fungicide solutions prior to storage. Since the oncogenic nature of many of the most commonly used fungicides is increasingly recognized and because the persistence of most fungicides is increased by the low storage temperatures the postharvest use of fungicides is of growing concern.
Additionally, resistance to the fungicides, used has been reported and suppression of the main spoilage organism
B. cinera
by fungicides such as BENOMYL fungicide has been shown to result in increased population of
A. brassicicola
which causes a more penetrating rot of produce than
B. cinera
. See, for example, U.S. Pat. No. 5,869,038.
The future role of fungicides in agriculture is increasingly threatened by several factors including; the development of pest resistance, increasing concerns about food safety, and environmental accumulation of toxic compounds. As older fungicides are removed from the market due to regulatory changes there is an increasing need to find new effective fungicidal compounds.
In searching for new biologically active compounds, it has been found that some natural products and organisms are potential sources for chemical molecules having useful biological activity of great diversity. For example, the diterpene commonly known as taxol, isolated from several species of yew trees, is a mitotic spindle poison that stabilizes microtubules and inhibits their depolymerization to free tubulin (Fuchs, D. A., R. K. Johnson [1978
] Cancer Treat. Rep
. 62:1219-1222; Schiff, P. B., J. Fant, S. B. Horwitz [1979
] Nature
(London) 22:665-667). Taxol is also known to have antitumor activity and has undergone a number of clinical trials which have shown it to be effective in the treatment of a wide range of cancers (Rowinski, E. K. R. C. Donehower [1995
] N. Engl. J. Med
. 332:1004-1014). See also, e.g., U.S. Pat. Nos. 5,157,049; 4,960,790; and 4,206,221.
Marine sponges have also proven to be a sourc
Chen Ying
Chilson Katherine
Harmody Dedra
Killday Keith Brian
McCarthy Peter J.
Harbor Branch Oceanographic Institution Inc.
Saliwanchik Lloyd & Saliwanchik
Trinh Ba K.
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