Lavender (Lavandula angustifolia Mill.)

The lavender plant belongs to the Lavandula L. genus of the Lamiaceae family. In our country, there are three taxa known and represented as lavender: L. angustifolia Mill. subsp. angustifolia, L. pedunculata (Mill.) subsp. cariensis (Boiss.), and L. stoechas L. subsp. cariensis (Boiss.). Locally, L. angustifolia is known as 'lavender', L. pedunculata subsp. cariensis is known as 'karan', and L. stoechas subsp. stoechas is known as 'blackhead'. 

Lavender is a valuable plant used in medicine, cosmetics, and perfumery worldwide due to its high-quality essential oil. The Romans are believed to have added lavender to their bathwater, and the plant's name comes from the Latin word 'lavare,' meaning 'to wash.' In North Africa, tribal women used Lavandula vera, also known as 'el khazma' in Morocco, to protect themselves from spousal abuse. Lavender oil was used in ancient Egypt for embalming and in perfumes, as it is still used today. In traditional Uighur medicine, it is used to treat stroke-like neurological disorders. Lavender tincture has been used for over 200 years in the British Pharmacopoeia to treat headaches and muscle spasms. Dioscorides mentioned the medicinal benefits of lavender in early Greek medicine. During the Middle Ages, it was used as an aphrodisiac to attract the opposite sex. Lavender has spiritual uses, representing love, protection and purification, and is burned in birth rituals to bring peace and tranquillity, and in midsummer rituals dedicated to gods and goddesses. Lavender is also mentioned in Ibn Sina's El-Kanun fi't-Tıb (Canon) and Razi's El-Hevi (Liber Continens).

Lavender is a species that grows up to 40-100 cm in height, forming compact and regular clumps. The stem is woody at the base and herbaceous and green at the top. Lavender has short-petiolate, straight or lanceolate leaves with curled margins and a highly branched root system. The silver-green leaves are covered with tomentum, which protects them from strong sunlight, wind and excessive water loss. Lavender flowers grow in circular spikes, with 3 to 5 clusters of 5-15 flowers each, on the upper part of the stem. The spikes are located at the end of 15-20 cm long stems. While the flowers are typically pale purple, there are also cultivated varieties with white or pink flowers (Rosea). The flower clusters are shielded by two opposing leaves. The lavender flowers have very short stalks and are surrounded by smooth and shiny 5mm sepals. The sepals are grey-blue inside and hairy outside, wrapping the petals in a tubular shape and ending with four small pointed teeth at the tip. The blue-violet petals have four male stamens in their centre, and there is a nectar gland at the bottom of the corolla tube. Small and numerous glandular hairs surround the sepals, and the stems of these hairs are unicellular and store the plant's essential oil. Lavender seeds are elongated su-oval in shape, measuring 2 mm in length and 1 mm in width. They are glossy and dark brown in colour, weighing less than 1 gram per 1000 grains. Plants can be propagated generatively from seeds, by tissue culture, or vegetatively from cuttings of soft and hard wood. Lavender bushes require regular pruning to stimulate plant growth and encourage flowering. The flowering period varies between regions but typically occurs between July and August. Harvest lavender on dry and sunny days. Collect the flowers before they open and dry them in shady, well-ventilated areas. The plant parts used for herbal purposes are flowers (Flos Lavandulae) or flowering parts (Herba Lavandulae). The material used for essential oil production consists of fresh or dried parts of flowering plants.

The lavender plant has various applications in the health and cosmetics industries due to its potent essential oil. It can be used for treating skin diseases and promoting wound healing. Lavender essential oil can also aid in falling asleep faster and prolonging sleep duration. Moreover, it possesses antimicrobial, anti-inflammatory, fungicidal, insecticidal, and acaricidal properties.

L. angustifolia Mill. subsp. angustifolia, also known as 'Medicinal Lavender', is a species that naturally grows in Turkey. In recent years, there has been an increase in cultivating lavender species, including other varieties, in our country. The Lavandula genus is significant due to its numerous endemic, medicinal, and aromatic species. However, it is a challenging genus known for its high hybridisation among species and taxonomic complexities.

The essential oil yield of fresh lavender flowers varies between 1-3%. According to the Codex, flowers should contain at least 1% essential oil. Lavandula angustifolia, commonly known as English lavender, produces the highest quality lavender oil. Lavandin, also known as hybrid lavender, has a higher yield of essential oil but lower quality compared to lavender. The essential oil yield of lavandin varieties is 3-5 times higher than that of lavender varieties. It is important to note that the addition of further aspects must be avoided at all costs. Lavender essential oil (Aetheroleum Lavandulae) is a crucial active ingredient extracted from the flowers (Flores Lavandulae) of lavender. It is widely used for medicinal and commercial purposes. This slightly yellow or colourless oil is among the 15 most produced essential oils globally. Commercially used lavender essential oils contain over 100 terpenoid components, with the most important ones being linalool, linalyl acetate, cineole and camphor. Lavender essential oil contains a high proportion of linalyl acetate, while lavandin and spike lavender oils have a higher proportion of linalool. The quality and commercial value of lavender oil are related to its essential oil content. The International Organisation for Standardisation (ISO) has established quality standards for lavender essential oil composition. To meet the standards for lavender oil in the perfume industry, it is recommended that the concentration of linalool and linalyl acetate, both important components of essential oils that affect the quality of lavender oil, should be at least 25%, while camphor should not exceed 0.5%. Camphor is also a crucial factor in determining the quality and market value of lavender oils. Lavender contains various phenolic compounds such as chlorogenic acid, gallic acid, umbelliferone, luteolin 7-O-glucoside, vitexin, and isoquercitroside.

Lavender essential oil has a stimulating effect on the nervous system. It possesses sleep-inducing, soothing, calming, and antistress properties, making it useful against skin burns and redness.  Additionally, lavender oil has strong antiseptic and antibiotic properties, making it highly valued in aromatherapy applications.  It is often formulated with neroli, bergamot, geranium, and rose essences. Teas made with lavender buds can be beneficial for the body due to the strong narcotic effect of linalyl acetate and the sedative effect of linalool, which are the two most important components of lavender essential oil. Lavender pillows can also aid in achieving restful sleep. Additionally, a blend of lavender oil, juniper oil, basil oil, and sweet thyme oil can be used to promote easy sleep.

Lavender is a highly effective ingredient in aromatherapy. Lavender oil is a commonly used treatment for anxiety, neurological conditions, infections, and pain. It is recognised as safe for consumption by the US Food and Drug Administration. However, there is no data on the excretion of its components into breast milk or on its safety and efficacy for nursing mothers or infants. It is important to avoid applying lavender oil topically around the breast due to its estrogenic and antiandrogenic activity.  Various studies have demonstrated the antibacterial and anti-inflammatory properties of Lavandula angustifolia (Mill.) essential oil in diabetic patients.

Lavender is not only used for health and cosmetic purposes but also for culinary purposes in the Mediterranean region. It is used to produce ice cream, tea, coffee, honey, jam, pancakes, lemonade, and Turkish delight.  Additionally, it can be used to add flavour to meat dishes, sauces, and as a spice. Lavender is considered one of the most widely used edible flowers for nutrition and health worldwide. The dishes that include lavender are lavender cream, lavender-flavoured candies, lavender powdered sugar, frozen lavender with sticks, lavender chicken, and lavender gel.