Introduction 

Essential oils are volatile compounds found in aromatic plants. These are the compounds that give flowers, herbs, leaves, rhizomes and resins their distinctive fragrance. They act as a secondary metabolite by plants which act as a preservation mechanism rather than one that is essential for their lives.  

Secondary metabolites in plants:

• protection against other bacteria, fungi, other plants, insects, and large animals.

• for attracting pollination

• agents of symbiosis "living together" between microbes and plants, nematodes (round worms), insects, and higher animals.

• sexual hormones and as molecular basis of lineage (origin, identification)

• sporulation refers to the formation of spores from vegetative cells during unfavourable environmental conditions.

As such, it may be described as an adaptive response that allows the organism to survive given adverse conditions (radiation, extreme heat or cold, lack of nutrition etc). Although antibiotics are not obligatory for sporulation, some secondary metabolites (including antibiotics) stimulate spore formation and inhibit or stimulate germination. 

• Formation of secondary metabolites and spores are regulated by similar factors. This similarity could insure secondary metabolite production during sporulation.

• favourable conditions for growth exist. 

Absence of secondary metabolites does not result in immediate death of a plant, but rather in a long-term impairment of the organism's ability to survive and to produce an abundance of offspring or new growth, or aesthetics, or perhaps in no significant change at all. 

Essential oils are found in all parts of aromatic plants 

• Leaves

• Petals

• Twigs

• Rhizomes

• Roots 

• Wood