At least three particular species in the Ocimum family have been associated with a wide array of health benefits. This column will briefly discuss the as an “adaptogen” to counter life’s stresses. It is called “holy basil” because it is sacred to the Hindus who plant it around shrines.
O. sanctum (O. tenuiflorum)
Dr. Leslie S. Baumann
Known popularly as holy basil in English and Tulsi in Sanskrit (in which the translation is “the incomparable one”), O. tenuiflorum is used for multiple indications in traditional medical practices in Southeast Asia, including Ayurveda, Siddha, and Unani.1,2
In Ayurvedic medicine, the leaves, stem, flower, root, seeds, and whole plant of O. sanctum have been used to treat various ailments, including skin diseases. Eugenol (1-hydroxy-2-methoxy-4-allylbenzene) is its primary constituent and the wide variety of biological activities associated with the plant (including antifertility, anticancer, antidiabetic, antifungal, antimicrobial, hepatoprotective, cardioprotective, antiemetic, antispasmodic, analgesic, adaptogenic, and diaphoretic) are ascribed to it.3
O. sanctum and its water-soluble flavonoids, orientin, and vicenin – as well as eugenol, its main nonpolar component – have been shown in animal studies and a few small clinical trials to act against various radiation-induced illnesses. Antioxidant, anti-inflammatory, and metal-chelating activity have been linked to these benefits.4 Indeed, multiple studies have demonstrated that O. sanctum exerts anti-inflammatory, analgesic, and immunomodulatory activities, among other beneficial functions, with phytochemical constituents such as eugenol, rosmarinic acid, apigenin, myrtenal, luteolin, beta-sitosterol, and carnosic acid playing critical roles.2
Several animal studies have also demonstrated that O. sanctum imparts wound-healing activity, such as increasing the rates of epithelialization and wound contraction and augmenting granulation tissue and hydroxyproline levels, with some evidence of benefits for also healing keloids and hypertrophic scars.1,5
Yamani et al. studied the antimicrobial activity of the flower spikes, leaves, and essential oil of O. sanctum grown in Australia in 2016. They found that, at concentrations of 4.5% and 2.25%, the oils prevented the growth of Staphylococcus aureus (including methicillin-resistant S. aureus) and Escherichia coli, and partly hindered the growth of Pseudomonas aeruginosa. Further, the investigators identified camphor, eucalyptol, and eugenol as the primary ingredients, among 54 observed, accountable for the antimicrobial activity. They concluded that O. sanctum essential oil has potential as a topical antimicrobial agent.6
A 2015 investigation into the antioxidant activities of 10 essential oils and 10 absolutes extracted from Thai aromatic plants revealed that O. sanctum was among four of the essential oils to display robust antioxidant activity in the 2,2-diphenyl-1-1-picrylhydrazyl and thiobarbituric acid reactive species tests. The study by Leelapornpisid et al. suggested that holy basil oil, along with ginger oil, Wan-sao-long leaf oil, and lemongrass oil, appear to have potential for use as natural antioxidants in cosmetic formulations aimed at preventing or treating cutaneous aging.7
O. gratissimum
O. gratissimum has been used in traditional medicine to treat a range of conditions, including skin and gastrointestinal infections and wounds.8