Essential oil is any concentrated, hydrophobic (immiscible with
water), typically lipophilic (oil or fat soluble) liquid of
plants that contains highly volatile aroma compounds and carries
a distinctive scent, flavor, or essence of the plant. This large
and diverse class of oils also are referred to as volatile oils
or ethereal oils. They usually are named for the plants from
which they are extracted, such as oil of clove or peppermint
oil. Essential oils do not as a group need to have any specific
chemical properties in common, beyond conveying characteristic
fragrances. Essential oils are found in diverse parts of plants,
including leaves, seeds, flowers, roots, and bark. They are
extracted by a variety of techniques, including distillation,
expression, and solvent extraction. Essential oils can be very
complex chemically, with some essential oils with more than 200
identified chemical substances (Dupler and Odle 2005). For the
plant, essential oils are thought to be vital for the life of
the plant, contain