Ocimum tenuiflorum, also known as Holy Basil, tulsi, or tulasī, is an aromatic plant in the family Lamiaceae which is native throughout the Eastern World tropics and widespread as a cultivated plant. It is an erect, much branched subshrub, 30–60 cm tall with hairy stems and simple, opposite, green leaves that are strongly scented. Leaves have petioles, and are ovate, up to 5 cm long, usually slightly toothed. The flowers are purplish in elongate racemes in close whorls. The two main morphotypes cultivated in India and Nepal are green-leaved (Sri or Lakshmi tulsi) and purple-leaved (Krishna tulsi).
Tulsi is cultivated for religious and medicinal purposes, and for its essential oil. It is widely known across South Asia as a medicinal plant and an herbal tea, commonly used in Ayurveda, and has an important role within the Vaishnavite tradition of Hinduism, in which devotees perform worship involving holy basil plants or leaves.
The variety of Ocimum tenuiflorum used in Thai cuisine is referred to as Thai holy basil (Thai language: กะเพรา kaphrao); it is not to be confused with Thai basil, which is a variety of Ocimum basilicum.
In Hinduism 
Tulsi or tulasi is a sacred plant for Hindus and is worshipped by Hindus as the avatar of goddess Lakshmi. Water mixed with the petals is given to the dying to raise their departing souls to heaven. Tulsi, which is Sanskrit for "the incomparable one", is most often regarded as a consort of Krishna in the form of Lakshmi. According to the Brahma Vaivarta Purana, tulsi is an expression of Sita.[full citation needed] There are two types of tulsi worshipped in Hinduism: "Rama tulsi" has light green leaves and is larger in size; "Shyama tulsi" has dark green leaves and is important for the worship of Hanuman. Many Hindus have tulsi plants growing in front of or near their home, often in special pots. Traditionally, tulsi is planted in the center of the central courtyard of Hindu houses. It is also frequently grown next to Hanuman temples, especially in Varanasi.[full citation needed]
According to Vaishnavas, it is believed in Puranas that during Samudra Manthana when the gods win the ocean-churning against asuras, Dhanvantari comes up from the ocean with Amrita in hand for the gods. Dhanvantari (the divine medico) sheds happy tears and when the first drop falls in Amrita it forms Tulasi. In the ceremony of Tulsi Vivah, tulsi is ceremonially married to Krishna annually on the eleventh day of the waxing moon or twelfth of the month of Kartika in the lunar calendar. This day also marks the end of the four-month Cāturmāsya period, which is considered inauspicious for weddings and other rituals, so the day inaugurates the annual marriage season in India. The ritual lighting of lamps each evening during Kartika includes the worship of the tulsi plant, which is held to be auspicious for the home. Vaishnavas especially follow the daily worship of tulsi during Kartika.
Vaishnavs traditionally use japa malas made from tulsi stems or roots, which are an important symbol of initiation. Tulsi malas are considered to be auspicious for the wearer, and believed to put them under the protection of Hanuman. They have such a strong association with Vaishnavas, that followers of Hanuman are known as "those who bear the tulasi round the neck".
Thai cuisine 
The leaves of holy basil, known as kraphao in the Thai language (Thai: กะเพรา), are commonly used in Thai cuisine. Kraphao should not be confused with horapha (Thai: โหระพา), which is normally known as Thai basil, or with Thai lemon basil (maenglak; Thai: แมงลัก).
The best-known dish made with this herb is phat kraphao (Thai: ผัดกะเพรา) — beef, pork or chicken, stir-fried with Thai holy basil.
Insect repellent 
For centuries, the dried leaves have been mixed with stored grains to repel insects.
Tulsi has been used for thousands of years in Ayurveda for its diverse healing properties. It is mentioned in the Charaka Samhita, an ancient Ayurvedic text. Tulsi is considered to be an adaptogen, balancing different processes in the body, and helpful for adapting to stress. Marked by its strong aroma and astringent taste, it is regarded in Ayurveda as a kind of "elixir of life" and believed to promote longevity.
Tulsi extracts are used in ayurvedic remedies for a variety of ailments. Traditionally, tulsi is taken in many forms: as herbal tea, dried powder, fresh leaf or mixed with ghee. Essential oil extracted from Karpoora tulsi is mostly used for medicinal purposes and in herbal cosmetics, and is widely used in skin preparations.
Pharmacological study 
||This article needs more medical references for verification or relies too heavily on primary sources. (October 2012)|
Some of the main chemical constituents of tulsi are: oleanolic acid, ursolic acid, rosmarinic acid, eugenol, carvacrol, linalool, β-caryophyllene (about 8%), β-elemene (c.11.0%), and germacrene D (about 2%).
A variety of in vitro studies and animal studies have indicated some potential pharmacological properties of Ocimum tenuiflorum or its extracts. Recent studies suggest tulasi may be a COX-2 inhibitor, like many modern painkillers, due to its high concentration of eugenol. One small study showed it to reduce blood glucose levels in type 2 diabetics when combined with hypoglycemic drugs. The same study showed significant reduction in total cholesterol levels with tulsi. Another study showed its beneficial effect on blood glucose levels is due to its antioxidant properties. Tulasi also shows some promise for protection from radiation poisoning and cataracts. It has anti-oxidant properties and can repair cells damaged by exposure to radiation.[medical citation needed] The fixed oil has demonstrated antihyperlipidemic and cardioprotective effects in rats fed a high fat diet. A double-blind trial conducted in 2011 suggested that an alcoholic extract of tulsi modulates immunity, thus promoting immune system function.
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