*6.3.1 Bergamot*

The essential oil of bergamot obtained from the peel of the fruits of the *Citrus bergamia* is known as the bitter orange tree. The extract of the bergamot is used in flavoring

**Figure 4.** *Applications of essential oils in daily life.*

in Earl Grey tea and essential oil of this is used also for the same purpose. It is applicable for the treatment of skin diseases, and it improves the mood, relieves pain, reduces fever, treats the digestive system problems, and breaks up chest congestion [26].

### *6.3.2 Clove*

It is extracted from the aromatic flower buds of *Syzygium aromaticum* tree that is native to Maluku, Indonesia. The essential oil of Clove provides the strong fragrance, used in cooking spice foods; medically, it is used as pain relief, used for the treatment of dental disorders, for nausea treatment, to reduce inflammation, for the treatment of the digestive ailment, and to clear up acne [26].

#### *6.3.3 Eucalyptus*

It is extracted from the different species of genus *Eucalyptus*. Every type of species contains different and unique usage in every field. The most familiar essential oil obtained from the *Eucalyptus globulus* has a mint-like fragrance. It is used for decongestant chest rub, as pain relievers, as an antimicrobial agent, immunostimulant, and for the treatment of the flu and cold cough. It is used in aromatherapy and it provides mental clarity; it also boosts up energy and used as a natural insect repellent [26].

### *6.3.4 Frankincense*

The earliest known and the most useful essential oil is Frankincense and it is obtained from the resin of the four species of the generous Bowwellia and the most known from this genus is the Bowsellia carterii hard tree which grow in the arid land of Arabian Peninsula and north eastern. The old African people used the essential oil of Frankincense in the religious and spiritual ceremonies. The Frankincense essential oil is unique from all other obtained essential oils because of the perfect combination of wood, balsam, earth, and citrus. It is used as the mood enhancer, antimicrobial, stress reducer, for faster wound healing, aid in digestion, anti-inflammatory, fades scars, reduces swelling of insect bites, for the treatment of skin diseases, and eases itching [26].

### *6.3.5 Lavender*

The most effective essential oil obtained from the *Lavandula angustifolia* is the most popular garden herb English lavender. Its odor is same as the flowers from which they are obtained having the sweet smell, floral, and green, and the health benefits are greater as compared to their fragrance. The best purpose of essential oil of lavender is their sleep-inducing properties and calmness. It showed good antioxidant, anti-inflammatory, antibacterial, and antifungal properties, and it is also used for the treatment of various sorts of skin diseases including eczema or ringworm and acne. Lavender essential oil is used to enhance the digestive system, to reduce the swelling of sore muscles, and to relieve pain. Due to its attractive smell, it attracts butterflies, bees, and some pollinators, and it also acts as a natural repellent for many flying six-legged pests [26].

#### *6.3.6 Lemon*

Essential oils obtained from the lemon are mostly used. The essential oil obtained from the *Citrus limon* is used worldwide. The essential oil of lemon is used as antimicrobial agents, in household items including soaps, polishes, furniture, fresheners, and

**45**

*Biological Importance of Essential Oils*

*6.3.7 Oregano*

*6.3.8 Peppermint*

*6.3.9 Rosemary*

*6.3.10 Tea tree*

*DOI: http://dx.doi.org/10.5772/intechopen.87198*

and helps to control the flu and cold infections [26].

improving the digestive system processes [26].

is also the best natural insecticide and the bug repellent [26].

*6.3.11 Some plant species essential oils and their usage*

in most of the cleaning products. Some other uses of these essential oils are that they are the pain relievers, show antifungal activity, help for the loss of weight, and alleviate the severe nausea; the essential oil of lemon is used in aromatherapy to reduce the anxiety and stress and simultaneously enhances the concentration and mood. It is also

The essential oil of Oregano was obtained from the kitchen spice *Origanum vulgare*. It is the perfect combination of the earth, spice, and warmth. When the bottle of essential oil is opened, their fragrance has an effect on the senses. The usage of the essential oil of Oregano is increasing day by day and it is mostly used for the skin care treatment like eczema, rosacea, and psoriasis. It is used to alleviate the menstrual problems or painful menstrual cramp, used to cure stomach problems,

The essential oil of peppermint is used worldwide and it is obtained from the *Mentha piperita*. This mint hybrid is the most favorite between the essential oil and gardeners. It is the most famous type of essential oil because of its unique applications, and it is mostly used in preventing flu and cold, alleviating headache, relieving pain in muscles and joints, clearing the skin conditions, relieving nausea, and

The essential oil of rosemary is obtained from the evergreen shrub of *Rosmarinus officinalis* and is famous albeit common kitchen herb has the extraordinary healing potential in its natural oil. Just like the rosemary, the essential oil of this herb has the crisp woody, herbal, and somewhat balsamic odor just like the camphor. Due to its unique fragrance of rosemary oil, it is used for cleaning the inside and outside of the body. It is further used for the treatment of various diseases, especially skin care, dandruff treatment, to improve the scalp health, to boost up the immune system, flu infections, and ward off cold. Although this oil is used to alleviate the pain, swelling in joints and muscles, for treatment of the digestive tissues, soothe tension headaches, to promote the mental clarity, to enhance the memory, and improve mood, it

The essential oil of the tea tree is obtained from the leaves and stem of *Melaleuca alternifolia* and shrub of *Camellia sinensis.* The oil is toxic if ingested directly and it is used mostly for the external purposes and has the herbal, fresh, and slightly camphorates aroma. Melaleuca claims that essential oil of tea tree act as an antimicrobial agent, treating antifungal infections, and cleansing wounds. It is used in cosmetics products including the shampoo to clear some scalp conditions and dandruff and used for the treatment of insect bite to reduce itching and inflammation [26].

Some plant species essential oils and their usage are shown in **Table 1**.

used for cleaning the hair and enhancing the natural growth of hairs [26].

#### *Biological Importance of Essential Oils DOI: http://dx.doi.org/10.5772/intechopen.87198*

in most of the cleaning products. Some other uses of these essential oils are that they are the pain relievers, show antifungal activity, help for the loss of weight, and alleviate the severe nausea; the essential oil of lemon is used in aromatherapy to reduce the anxiety and stress and simultaneously enhances the concentration and mood. It is also used for cleaning the hair and enhancing the natural growth of hairs [26].
