Plant extracts and compositions comprising extracellular protease inhibitors

Abstract

The present invention provides a plant derived extract comprising inhibitory activity against one or more extracellular proteases which degrade human tissue matrix. Moreover, the amount of inhibitory activity in an extract can be increased by stressing the plant prior to forming an extract. These extracts are each prepared by a standard process and demonstrate the ability to inhibit one or more extracellular proteases which degrade human tissue matrix. Libraries of extracts can be prepared from stressed and non-stressed plants, wherein each of the extracts demonstrate inhibitory activity against one or more extracellular protease inhibitors. Alternatively, semi-purified and purified inhibitory compounds can be isolated from the extracts following standard procedures. In one aspect, these extracts with inhibitory activity can be used during protein purification to minimize the degradation due to extracellular proteases.

We claim:  
     
         1 . An extract from a plant, comprising non-proteinaceous molecules having protease inhibitor activity, which inhibits the activity of one or more extracellular proteases, wherein the extract has been prepared by the steps of harvesting plant material, treating plant material with a solvent, separating the resulting extract from the solid material, testing an aliquot of the extract against a panel of extracellular proteases, and retaining the extract if it inhibits the activity of one or more extracellular proteges.  
     
     
         2 . A library of plant extracts, comprising non-proteinaceous molecules having protease inhibitor activity, wherein each extract inhibits the activity of one or more extracellular proteases.  
     
     
         3 . A library of plant extracts, comprising non-proteinaceous molecules having protease inhibitor activity, formed by a process comprising: 
 (a) contacting plant material with either an aqueous, ethanolic, or an organic solvent;    (b) isolating an extract from said plant material;    (c) analysing said extract for the presence of one or more inhibitory activities against an extracellular protease;    (d) and collected two or more extracts together, so as to form a library of plant extracts wherein each extract inhibits one or sore extracellular proteases.    
     
     
         4 . A plant extract, comprising non-proteinaceous molecules having protease inhibitor activity, which inhibits the activity of one or more extracellular proteases, wherein said plant has been stressed prior to generating the extract.  
     
     
         5 . A library of plant extracts, comprising non-proteinaceous molecules having protease inhibitor activity, wherein each extract inhibits the activity of one or more extracellular proteases and wherein said plants have been stressed prior to generating the extract.  
     
     
         6 . A non-proteinaceous extracellular protease inhibitor derived from a plant comprising the steps of: 
 (a) contacting plant material with either an aqueous, ethanolic, or an organic solvent;    (b) isolating an extract from said plant material;    (c) analysing said extract for the presence of one or more inhibitory activities against a panel of extracellular proteases;    (d) further purifying a compound from said extract if said extract demonstrates the inhibition of one or more extracellular proteases greater than about 20%.    
     
     
         7 . A method for increasing the levels of non-proeteinaceous extracellular protease inhibitors in plants comprising he step of stressing the plant prior to forming a plant extract.