Basil

Basil
Scientific classification
Kingdom:	Plantae
(unranked):	Asterids
Order:	Lamiales
Family:	Lamiaceae
Genus:	Ocimum
Species:	O. basilicum
Binomial name
Ocimum basilicum L.

Basil, Thai basil, or sweet basil, is a common name for the culinary herb Ocimum basilicum (UK /ˈbæzəl/;^[1] US /ˈbeɪzəl/^[2]) of the family Lamiaceae (mints), sometimes known as Saint Joseph's Wort in some English speaking countries.

Basil is possibly native to India,^[3] and has been cultivated there for more than 5,000 years.^[4] It was thoroughly familiar to the Greek authors Theophrastus^[5] and Dioscorides. It is a half-hardy annual plant, best known as a culinary herb prominently featured in Italian cuisine, and also plays a major role in Southeast Asian cuisines of Indonesia, Thailand, Malaysia, Vietnam, Cambodia, Laos, and Taiwan. Depending on the species and cultivar, the leaves may taste somewhat like anise, with a strong, pungent, often sweet smell.

There are many varieties of Ocimum basilicum, as well as several related species or species hybrids also called basil. The type used in Italian food is typically called sweet basil, as opposed to Thai basil (O. basilicum var. thyrsiflora), lemon basil (O. X citriodorum) and holy basil (Ocimum tenuiflorum), which are used in Asia. While most common varieties of basil are treated as annuals, some are perennial in warm, tropical climates, including holy basil and a cultivar known as 'African Blue'.

Etymology

The word basil comes from the Greek βασιλεύς (basileus), meaning "king",^[6] as it has come to be associated with the Feast of the Cross commemorating the finding of the True Cross by St. Helena, mother of the emperor Constantine I.^[7] The herbalist John Gerard noted that those stung by scorpions would feel no pain if they ate of basil,^[8] and Nicholas Culpeper noted of basil that it was "an herb of Mars and under the Scorpion, and therefore called Basilicon",^[9] relating it to basilisk. The Oxford English Dictionary quotes speculations that basil may have been used in "some royal unguent, bath, or medicine". Basil is still considered the "king of herbs" by many cookery authors.^[10]

Nomenclature and taxonomy

Most commercially available basils are cultivars of sweet basil. There are over 160 named cultivars available, with new ones appearing every year. There are also a number of species sold. Here are some basils commonly sold in the US.^[4]

For a more complete list, see List of basil cultivars

• African blue basil (Ocimum basilicum X O. kilimandscharicum)
• Anise basil or Persian basil (Licorice basil || O. basilicum 'Licorice'||)
• Camphor basil, African basil (O. kilimandscharicum)
• Cinnamon basil (Ocimum basilicum 'Cinnamon')
• Dark opal basil (Ocimum basilicum 'Dark Opal')
• Globe basil, dwarf basil, French basil (Ocimum basilicum 'Minimum'^[11])
• Hoary basil (Ocimum americanum formerly known as O. canum)
• Holy basil (Ocimum tenuiflorum, formerly known as O. sanctum)
• Spice basil (a cultivar of Ocimum americanum, which is sometimes sold as holy basil)
• Lemon basil (Ocimum americanum)
• Lettuce leaf basil (Ocimum basilicum 'Crispum')
• Purple basil (Ocimum basilicum 'Purpurescens')
• Queen of Siam basil (Ocimum basilicum citriodorum)
• Rubin basil (Ocimum basilicum 'Rubin')

Similar species

• Ocimum gratissimum^[12][13]

Culinary use

Dried basil leaves

Basil is most commonly used fresh in cooked recipes. In general, it is added at the last moment, as cooking quickly destroys the flavor. The fresh herb can be kept for a short time in plastic bags in the refrigerator, or for a longer period in the freezer, after being blanched quickly in boiling water. The dried herb also loses most of its flavor, and what little flavor remains tastes very different, with a weak coumarin flavor, like hay.

Basil is one of the main ingredients in pesto—a green Italian oil-and-herb sauce.

The most commonly used Mediterranean basil cultivars are "Genovese", "Purple Ruffles", "Mammoth", "Cinnamon", "Lemon", "Globe", and "African Blue". The Chinese also use fresh or dried basils in soups and other foods. In Taiwan, people add fresh basil leaves to thick soups (Chinese: 羹湯; pinyin: gēngtāng). They also eat fried chicken with deep-fried basil leaves. Basil (most commonly Thai basil) is commonly steeped in cream or milk to create an interesting flavor in ice cream or chocolates (such as truffles). The leaves are not the only part of basil used in culinary applications, the flower buds have a more subtle flavor and they are edible.

Thai basil is also a condiment in the Vietnamese noodle soup, phở.

Seeds

When soaked in water, the seeds of several basil varieties become gelatinous, and are used in Asian drinks and desserts such as faluda, sherbet or hột é.

Folk use

Basil is used for its medicinal properties in Ayurveda, the traditional medicinal system of India and Siddha medicine, a traditional Tamil system of medicine.

Other cultivars

Several other basils, including some other Ocimum species, are grown in many regions of Asia. Most of the Asian basils have a clove-like flavor that is, in general, stronger than the Mediterranean basils. The most notable is the holy basil or tulsi, a revered home-grown plant in India and Nepal. In China, the local cultivar is called (Chinese: 九層塔; pinyin: jiǔ céng tǎ; literally: "nine-level pagoda"), while the imported varieties are called (Chinese: 羅勒; pinyin: luó lè) or (Chinese: 巴西里; pinyin: bā xī lǐ), although [巴西里] often refers to a different plant—parsley.

Lemon basil has a strong lemony smell and flavor very different from those of other varieties because it contains a chemical called citral. It is widely used in Indonesia, where it is called kemangi and served raw, together with raw cabbage, green beans, and cucumber, as an accompaniment to fried fish or duck. Its flowers, when broken up, are a zesty salad condiment.

Chemical components

The various basils have such different scents because the herb has a number of different essential oils that come together in different proportions for various breeds. The strong clove scent of sweet basil is derived from eugenol, the same chemical as actual cloves.^[14] The citrus scent of lemon basil and lime basil reflects their higher portion of citral, which causes this effect in several plants including lemon mint, and of limonene, which gives actual lemon peel its scent. African blue basil has a strong camphor smell because it contains camphor and camphene in higher proportions. Licorice basil contains anethole, the same chemical that makes anise smell like licorice, and in fact is sometimes called "anise basil."

Other chemicals that help to produce the distinctive scents of many basils, depending on their proportion in each specific breed, include:

• citronellol (scented geraniums, roses, and citronella)^[15]
• linalool^[16] (a flowery scent also in coriander)
• myrcene (bay leaf, myrcia)^[17]
• pinene (which is, as the name implies, the chemical that gives pine oil its scent)
• ocimene^[17]
• terpineol
• linalyl acetate
• fenchyl acetate
• trans-ocimene
• 1,8-cineole
• camphor octanane
• methyl eugenol
• methyl chavicol^[15]
• eugenol^[15]
• beta-caryophyllene

Based on chemical content, basils can be divided into four groups:

1. French; Ocimum basilicum, contains lower amounts of phenols
2. exotic; contains methyl chavicol (40–80%)
3. methyl cinnamate – ether 90%
4. eugenol

Aroma profiles

• 1,8-cineole^[18][19]
• Bergamotene^[20]
• Eugenol^[18][20]
• Linalool^[18][20]
• Methyl chavicol^[19][20]
• Methyl cinnamate^[20][21]
• Methyl eugenol^[18][22]
• Phenylpropanoids^[18]
• trans-β-Ocimene^[18]

Cultivation

Timelapse of growing basil

Basil growing in the sun

Basil sprout at an early stage

Desiccated basil showing seed dispersal

Most culinary and ornamental basils are cultivars of the species Ocimum basilicum, but other species are also grown and there are many hybrids between species. Traditionally a green plant, some varieties, such as 'Purple Delight' have leaves that appear purple.^[23]

Basil grows between 30–130 cm (12–51 in) tall, with opposite, light green, silky leaves 3–11 cm (1.2–4.3 in) long and 1–6 cm (0.39–2.36 in) broad. The flowers are small, white in color and arranged in a terminal spike. Unusual among Lamiaceae, the four stamens and the pistil are not pushed under the upper lip of the corolla, but lie over the inferior lip. After entomophilous pollination, the corolla falls off and four round achenes develop inside the bilabiate calyx.

Basil is very sensitive to cold, with best growth in hot, dry conditions. It behaves as an annual if there is any chance of a frost. In Northern Europe, Canada, the northern states of the U.S., and the South Island of New Zealand it will grow best if sown under glass in a peat pot, then planted out in late spring/early summer (when there is little chance of a frost).^[24] Additionally, it may be sown in soil once chance of frost is past. It fares best in a well-drained sunny spot.

Although basil grows best outdoors, it can be grown indoors in a pot and, like most herbs, will do best on an equator-facing windowsill. It should be kept away from extremely cold drafts, and grows best in strong sunlight, therefore a greenhouse or row cover is ideal if available. It can, however, be grown even in a basement, under fluorescent lights.

If its leaves have wilted from lack of water, it will recover if watered thoroughly and placed in a sunny location. Yellow leaves towards the bottom of the plant are an indication that the plant has been stressed; usually this means that it needs less water, or less or more fertilizer.

In sunnier climates such as Southern Europe, the southern states of the U.S., the North Island of New Zealand, and Australia, basil will thrive when planted outside. It also thrives over the summertime in the central and northern United States, but dies out when temperatures reach freezing point. It will grow back the next year if allowed to go to seed. It will need regular watering, but not as much attention as is needed in other climates.

Basil can also be propagated very reliably from cuttings with the stems of short cuttings suspended for two weeks or so in water until roots develop.

Once a stem produces flowers, foliage production stops on that stem, the stem becomes woody, and essential oil production declines. To prevent this, a basil-grower may pinch off any flower stems before they are fully mature. Because only the blooming stem is so affected, some stems can be pinched for leaf production, while others are left to bloom for decoration or seeds.

Once the plant is allowed to flower, it may produce seed pods containing small black seeds, which can be saved and planted the following year. Picking the leaves off the plant helps promote growth, largely because the plant responds by converting pairs of leaflets next to the topmost leaves into new stems.

Companion planting

In double-blind taste tests, basil has been found not to significantly affect the taste of tomatoes when planted adjacent to them.^[25]

Diseases

Basil suffers from several plant pathogens that can ruin the crop and reduce yield. Fusarium wilt is a soil-borne fungal disease that will quickly kill younger basil plants. Seedlings may also be killed by Pythium damping off.

A common foliar disease of basil is gray mold caused by Botrytis cinerea; it can also cause infections post-harvest and is capable of killing the entire plant. Black spot can also be seen on basil foliage and is caused by the fungi genus Colletotrichum.

More recently, downy mildew of basil caused by Peronospora belbahrii has been a huge problem for both commercial producers and home growers. The disease was first reported in Italy in 2004,^[26] and was also reported in the U.S. in 2007 and 2008^[27][28] and has been steadily increasing in prevalence, distribution, and economic importance since then.

Potential health effects

Recently, there has been much research into the health benefits conferred by the essential oils found in basil. Scientific studies in vitro have established that compounds in basil oil have potent antioxidant, antiviral, and antimicrobial properties, and potential for use in treating cancer.^{[29][30][31][32]} In addition, basil has been shown to decrease the occurrence of platelet aggregation and experimental thrombus in mice.^[33] It is traditionally used for supplementary treatment of stress, asthma and diabetes mellitus in India.^[34]

Basil, like other aromatic plants such as fennel and tarragon, contains estragole, a known carcinogen and teratogen in rats and mice. While human effects are currently unstudied, extrapolation using body weight from the rodent experiments indicates that 100–1000 times the normal anticipated exposure still probably produces a minimal cancer risk.^[35]

Cultural aspects

A female carpenter bee foraging on basil

There are many rituals and beliefs associated with basil. The French sometimes call basil "l'herbe royale" ("royal herb"),^[36] while in Welsh it has the synonymous name "brenhinllys".^[37][38] Jewish folklore suggests it adds strength while fasting.^[39] In Portugal, dwarf bush basil is traditionally presented in a pot, together with a poem and a pom-pom, to a sweetheart, on the religious holidays of Saint John and Saint Anthony. However, basil represented hatred in ancient Greece, and European lore sometimes claims that basil is a symbol of Satan.^[40] African legend claims that basil protects against scorpions, while the English botanist Culpeper cites one "Hilarius, a French physician" as affirming it as common knowledge that smelling basil too much would breed scorpions in the brain.

Holy basil, also called tulsi, is highly revered in Hinduism. It is believed that the herb was found growing on the original cross of Christ when it was discovered by the Empress Helena, and hence basil has religious significance in the Greek Orthodox Church, where it is used to sprinkle holy water.^[41] The Bulgarian Orthodox Church, Serbian Orthodox Church, Macedonian Orthodox Church and Romanian Orthodox Church use basil (Bulgarian and Macedonian: босилек; Romanian: busuioc, Serbian: босиљак) to prepare holy water and pots of basil are often placed below church altars.^[42]

In Europe, basil is placed in the hands of the dead to ensure a safe journey.^[43] In India, they place it in the mouth of the dying to ensure they reach God.^[44] The ancient Egyptians and ancient Greeks believed it would open the gates of heaven for a person passing on.^[45]

In Boccaccio's Decameron a memorably morbid tale (novella V) tells of Lisabetta, whose brothers slay her lover. He appears to her in a dream and shows her where he is buried. She secretly disinters the head, and sets it in a pot of basil, which she waters with her daily tears. The pot being taken from her by her brothers, she dies of her grief not long after. Boccaccio's tale is the source of John Keats' poem Isabella or The Pot of Basil – which in turn inspired the paintings Isabella (Millais painting) and Isabella and the Pot of Basil. A similar story is told of the Longobard queen, Rosalind.

In certain central regions of Mexico, basil is used to draw fortune by hanging a bunch of the plant in the door or window of the shop. The plant's growth reflects the wealth of the business, showing how dutifully the owner cares for his shop and the herb.

Toxicity studies

A study of the essential oil showed antifungal and insect-repelling properties.^[46] A similar study reported in 2009 has confirmed that extracts from the plant are very toxic to mosquitos.^[47] However, the plant is not toxic to rats.^[12] Little information is available about any potential toxicity in humans.

List of the cultivars and their nomenclature

• African blue
• Dark opal
• Genovese^[47][48]
• Genovese Gigante^[22]

Gallery

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  Flowering basil stalk and leaves

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  Fresh basil leaves

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  Basil seeds

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  Basil plant

• 

  Flowering basil stalk

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  Basil leaves

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  Ocimum basilicum

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  sweet basil

See also

• Insect repellent

References

External links

Wikimedia Commons has media related to Basil.

• Diseases of Basil and Their Management
• Basil: Knowing and Growing from the New York Botanical Garden