Siam Villa Garden: Holy Basil

Ocimum tenuiflorum, commonly known as holy basil, tulsi or tulasi, is an aromatic perennial plant in the family Lamiaceae. It is native to the Indian subcontinent and widespread as a cultivated plant throughout the Southeast Asian tropics.

Tulsi is cultivated for religious and traditional medicine purposes, and also for its essential oil. It is widely used as a herbal tea, commonly used in Ayurveda, and has a place within the Vaishnava 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: กะเพรา kaphrao) and is the key herb in phat kaphrao, a stir-fry dish; it is not the same as Thai basil, which is a variety of Ocimum basilicum. In Cambodia, it is known as mreah-prov (Khmer: ម្រះព្រៅ).

Holy basil is an erect, many-branched subshrub, 30–60 cm (12–24 in) tall with hairy stems. Leaves are green or purple; they are simple, petioled, with an ovate blade up to 5 cm (2 in) long, which usually has a slightly toothed margin; they are strongly scented and have a decussate phyllotaxy. The purplish flowers are placed in close whorls on elongated racemes.

The three main morphotypes cultivated in India and Nepal are Ram tulsi (the most common type, with broad bright green leaves that are slightly sweet), the less common purplish green-leaved (Krishna or Shyam tulsi) and the common wild vana tulsi (e.g., Ocimum gratissimum).

Tulsi (Sanskrit: Surasa) has been used in Ayurvedic and Siddha practices for its supposed treatment of diseases.

Insect repellent

For centuries, the dried leaves have been mixed with stored grains to repel insects.

Nematicidal

The essential oil may have nematicidal properties against Tylenchulus semipenetrans, Meloidogyne javanica, Anguina tritici, and Heterodera cajani.

Disinfection

Water disinfection using O. tenuiflorum extracts was tested by Bhattacharjee et al 2013 and Sadul et al 2009. Both found an alcoholic extract to be more effective than aqueous or leaf juice. Sundaramurthi et al 2012 finds the result to be safe to drink, and additionally to be antimicrobial. A constituent analysis by Sadul found alkaloids, steroids, and tannins in the aqueous, and alkaloids and steroids only in the alcoholic extract.