Plant extract compositions for forming protective coatings

A method of preparing cutin-containing monomers, oligomers, esters thereof or combinations thereof derived from cutin-containing plant material, comprising: obtaining cutin from cutin-containing plant material; adding the cutin to a solvent to form a first mixture, the solvent having a boiling point at a first temperature at a pressure of one atmosphere; wherein the solvent comprises water, glycerol, methanol, ethanol, liquid CO2 or supercritical CO2; and heating the first mixture to a second temperature and second pressure, the second temperature being higher than the first temperature and the second pressure being higher than one atmosphere, to form a second mixture comprising the monomers, oligomers, esters thereof. or combinations thereof derivatives of cutin.