Citrus limon, commonly known as the lemon, is a small evergreen tree or shrub native to Asia, particularly the Indian subcontinent and China. It is widely cultivated for its fruit, which is valued for its tart flavor and high vitamin C content. The lemon tree is known for its aromatic leaves and bright yellow fruit, which are used in culinary, medicinal, and cosmetic applications.

Botanical Classification:

• Kingdom: Plantae
• Order: Sapindales
• Family: Rutaceae
• Genus: Citrus
• Species: Citrus limon

Plant Characteristics:

• Growth Form: The lemon tree typically grows to a height of 3-6 meters (10-20 feet) and has a spreading canopy. It is evergreen and retains its foliage throughout the year.
• Leaves: The leaves are glossy, dark green, and have a distinctive, aromatic scent. They are ovate to elliptical, with a smooth margin and a pointed tip. The leaves are about 5-10 cm (2-4 inches) long.
• Flowers: Lemon trees produce fragrant white to pale pink flowers with a five-petaled structure. The flowers are usually solitary or in small clusters, blooming from spring to summer.
• Fruit: The fruit is a bright yellow, round to oval citrus, measuring about 6-8 cm (2.5-3 inches) in diameter. The lemon has a thick, textured rind and a sour, acidic pulp with a high vitamin C content.

Chemical Composition and Structure:

• Essential Oils: Lemon essential oil is extracted from the rind and contains compounds such as limonene, citronellol, and gamma-terpinene. These compounds contribute to the fruit's characteristic aroma and have various therapeutic properties.
• Citric Acid: The fruit is rich in citric acid, which contributes to its tart flavor and is used as a natural preservative and acidulant in food and beverages.
• Flavonoids: Lemons contain flavonoids like hesperidin and eriocitrin, which have antioxidant properties.
• Vitamins and Minerals: The fruit is an excellent source of vitamin C (ascorbic acid), as well as small amounts of B vitamins, potassium, calcium, and magnesium.

How to Cultivate It:

• Soil: Lemon trees prefer well-drained, sandy loam soils with a slightly acidic to neutral pH. They can tolerate a range of soil types as long as drainage is adequate.
• Climate: The lemon tree thrives in subtropical and tropical climates with warm temperatures and plenty of sunlight. It requires frost-free conditions and can be grown in USDA hardiness zones 9-11.
• Watering: Regular watering is essential, especially during dry periods. The soil should be kept consistently moist but not waterlogged. Drip irrigation is often used in commercial cultivation.
• Fertilization: Lemon trees benefit from balanced fertilizers with high potassium content. They should be fed during the growing season to promote healthy growth and fruit production.
• Propagation: Lemon trees are commonly propagated from seeds, grafting, or cuttings. Grafting is often used to ensure that the plant has desirable fruit characteristics and disease resistance.

Uses and Benefits:

• Culinary: Lemons are widely used in cooking and baking to add flavor and acidity. The juice, zest, and pulp are used in a variety of dishes, beverages, and desserts.
• Health Benefits: The high vitamin C content of lemons supports immune function, skin health, and antioxidant protection. Lemon juice is also used as a home remedy for digestive issues and detoxification.
• Cosmetic: Lemon essential oil is used in skincare products for its astringent and brightening properties. It is also used in hair care products to help with dandruff and shine.

Applications:

• Food and Beverage: Lemons are used in a wide range of culinary applications, including dressings, marinades, beverages (like lemonade), and as a garnish. Lemon zest and juice are also used in baking and confectionery.
• Cosmetics and Personal Care: Lemon essential oil is included in products such as cleansers, toners, shampoos, and body scrubs. Its natural astringent and antimicrobial properties are beneficial for skin and hair care.
• Household: Lemon juice and essential oil are used as natural cleaning agents due to their antibacterial and deodorizing properties.

Environmental and Safety Considerations:

• Environmental Impact: Lemon cultivation can have environmental impacts such as water usage and pesticide application. Sustainable practices and integrated pest management can help mitigate negative effects.
• Safety: Lemons are generally safe for consumption. However, lemon juice can be acidic and may cause irritation to sensitive skin or exacerbate certain conditions like acid reflux. It is advisable to use lemon products in moderation and consult with a healthcare provider if needed.

Most common species:

• Citrus Aurantifolia
• Citrus Limon
• Citrus Limon
• Medical Citrus

Studies

The chemical composition of the lemon includes mainly citric acid and limonene.
It contains flavonoids, which are extremely useful components for the immune defense of the human body and therefore to combat degenerative diseases such as cancer. In particular, Rutin, Quercetin, Neoeriocitrin (1).

It also contains a large amount of vitamin C, one of the most important antioxidants found in nature and an element of contrast to free radicals that are the cause of aging and many diseases related to the oxidation process of cells. However, the fruit that contains the highest amount of vitamin C is the kiwi.

A lemon juice, you know is a remedy against colds and flu and cooling diseases.

It also acts as a protector against rheumatoid arthritis.

Thin-skinned lemons are preferable as they have more juice.

The lemon have been recognized by scientific studies antimicrobial activity both in the form of nanoemulsions in essential oil and in the form of pure essential oil juice (2).

Among the various phenolic components present in lemon peel, Eriocitrin, for its anti-aging properties, has been the subject of specific studies in rats (3).

Lemon extract has also demonstrated antimicrobial activity against bacteria such as Pseudomonas aeruginosa and Klebsiella pneumoniae (4).

Lemon studies

References_________________________________________________________________

(1) Aliberti L, Caputo L, De Feo V, De Martino L, Nazzaro F, Souza LF. Chemical Composition and in Vitro Antimicrobial, Cytotoxic, and Central Nervous System Activities of the Essential Oils of Citrus medica L. cv. 'Liscia' and C. medica cv. 'Rugosa' Cultivated in Southern Italy. Molecules. 2016 Sep 18;21(9):1244. doi: 10.3390/molecules21091244. 

(2)  Ledesma-Escobar CA, Priego-Capote F, Luque de Castro MD. Comparative Study of the Effect of Sample Pretreatment and Extraction on the Determination of Flavonoids from Lemon (Citrus limon). PLoS One. 2016 Jan 25;11(1):e0148056. doi: 10.1371/journal.pone.0148056.

(3) Yazgan H, Ozogul Y, Kuley E. Antimicrobial influence of nanoemulsified lemon essential oil and pure lemon essential oil on food-borne pathogens and fish spoilage bacteria. Int J Food Microbiol. 2019 Oct 2;306:108266. doi: 10.1016/j.ijfoodmicro.2019.108266.

(4) Shimizu C, Wakita Y, Inoue T, Hiramitsu M, Okada M, Mitani Y, Segawa S, Tsuchiya Y, Nabeshima T. Effects of lifelong intake of lemon polyphenols on aging and intestinal microbiome in the senescence-accelerated mouse prone 1 (SAMP1). Sci Rep. 2019 Mar 6;9(1):3671. doi: 10.1038/s41598-019-40253-x.

(5) Liya SJ, Siddique R. Determination of Antimicrobial Activity of Some Commercial Fruit (Apple, Papaya, Lemon and Strawberry) Against Bacteria Causing Urinary Tract Infection. Eur J Microbiol Immunol (Bp). 2018 Aug 16;8(3):95-99. doi: 10.1556/1886.2018.00014.