Cymbopogon citratus, commonly known as West Indian lemon grass[2] or simply lemon grass,[3] is a tropical plant native to South Asia and Maritime Southeast Asia and introduced to many tropical regions.[1]
Cymbopogon citratus is often sold in stem form. While it can be grown in warmer temperate regions, such as the UK, it is not hardy to frost.
Morphology
Cymbopogon citratus is part of the grass family, Poaceae. They contain simple, bluish-green leaves with entire margins and are linear in shape. The blades tend to be 18–36 inches long. Like other grasses, the leaves also have parallel venation.[4]
In its native range, Cymbopogon citratus is known as sereh, serai, or serai dapur in Indonesia and Malaysia; and tanglad (from Proto-Austronesian *Caŋelaj originally referring to Themeda gigantea, a type of elephant grass[6]), salai, or balioko in the Philippines.[5] In the language of the Hmong people, who are a diasporic people spread across Southeast Asia including Laos and Thailand, it's called tauj dub.[7]
Culinary uses
Knots of C. citratus leaves sold at a supermarket in the PhilippinesReady-to-use bundles of lemon grass, galangal, kaffir lime leaves, and, for chicken tom yam, also turmeric, are sold at Thai markets.
Cymbopogon citratus is abundant in the Philippines and Indonesia where it is known as tanglad or sereh, respectively. Its fragrant leaves are traditionally used in cooking, particularly for lechon and roasted chicken.[8]
The dried leaves can also be brewed into a tea, either alone or as a flavoring in other teas, imparting a flavor reminiscent of lemon juice but with a mild sweetness without significant sourness or tartness.
In Sri Lanka, lemongrass is known as sera (සේර). It is used as a herb in cooking, in addition to its use for the essential oils.[9]
Lemongrass in Thailand is called takhrai (ตะไคร้). It is the essential ingredient of tom yam and tom kha kai. Fresh thin slices of lemongrass stem are also used in the snack food miangpla.
The leaves of Cymbopogon citratus have been used in traditional medicine and are often found in herbal supplements and teas. Evidence of effective Cymbopogon citratus essential oil anti-protozoa activity against Leishmania amazonensis.[10]
Chemical composition
Lemon grass oil contains 65–85% citral in addition to myrcene, citronellal, citronellol, linalool and geraniol.[11][12] Hydrosteam distillation, condensation, and cooling can be used to separate the oil from the water. The hydrosol, as a by-product of the distillation process, is used for the production of skin care products such as lotions, creams, and facial cleansers. The main ingredients in these products are lemon grass oil and "negros oil" (mixture of lemon grass oil with virgin coconut oil) used in aromatherapy.[13]
Citronellol is an essential oil constituent from Cymbopogon citratus, Cymbopogon winterianus, and Lippia alba. Citronellol has been shown to lower blood pressure in rats by a direct effect on the vascular smooth muscle leading to vasodilation.[14] In a small, randomized, controlled trial, an infusion made from C. citratus was used as an inexpensive remedy for the treatment of oral thrush in HIV/AIDS patients.[15]
Laboratory studies have shown cytoprotective, antioxidant, and anti-inflammatory properties in vitro.[16][17][18]
Traditional medicinal use
In the folk medicine of the Krahô people of Brazil, it is believed to have anxiolytic, hypnotic, and anticonvulsant properties.[19][20]
Video tracking of a stable fly, demonstrating repellency of lemongrass oil [21]
Beekeepers sometimes use lemon grass oil in swarm traps to attract swarms. Lemon grass oil has also been tested for its ability to repel the pestilent stable fly,[21] which bite domestic animals.
Growing conditions
Light and Climate
Lemongrass (Cymbopogon citratus) thrives in full sun conditions, requiring at least 6 to 8 hours of sunlight per day. Exposure to supplemental ultraviolet-B (sUV-B) radiation has been shown to enhance both the yield and quality of essential oils.[22] The optimal temperature range for cultivation is between 25 °C and 30 °C. The species is sensitive to low temperatures, and prolonged exposure to temperatures below 10 °C may result in plant mortality. The ideal annual rainfall ranges between 2,500 and 3,000 mm.[23]
Soil condition
Well-drained sandy loam soil with a pH range of approximately 5.5 to 7.5 is considered optimal. Moderate soil fertility is sufficient, and the application of organic fertilizers during the early growth stage can promote tillering.[24]
Propagation method
Division or Tillering
Lemongrass (Cymbopogon citratus) is primarily propagated through division or tillering, as seed propagation is inefficient due to its rare flowering and fruiting. Mature lemongrass clumps typically consist of 50 to 200 tillers. Propagation involves cutting the upper leaves and separating rooted divisions approximately 10 to 15 cm in length from the mother plant, which can then be directly planted in the field.[25]
Tissue culture
It have been developed an efficient in vitro mass propagation system for Cymbopogon citratus using both organogenesis and somatic embryogenesis. The study optimized conditions such as liquid culture media, plant growth regulators, and temporary immersion systems (TIS) to achieve high multiplication and rooting rates[26]. This method offers a scalable and cost-effective approach for producing lemongrass plantlets, especially useful in medicinal and essential oil production industries.
^Shaikh, Mosma; Suryawanshi, Yogesh; Digambar, Mokat (2019). "Volatile Profiling and Essential Oil Yield of Cymbopogon citratus (DC.) Stapf Treated with Rhizosphere Fungi and Some Important Fertilizers". Journal of Essential Oil Bearing Plants. 22 (2): 477–483. doi:10.1080/0972060X.2019.1613933. S2CID191177588.
^Baby P. Skaria; P.P. Joy; Samuel Mathew; Gracy Mathew; Ancy Joseph; Ragina Joseph (2007). Aromatic Plants. Vol. 1. New Delhi, India: New India Publishing Agency. p. 103. ISBN9788189422455.
^Wright SC. Maree JE. Sibanyoni M. (2009). "Treatment of oral thrush in HIV/AIDS patients with lemon juice and lemon grass (Cymbopogon citratus) and gentian violet". Phytomedicine. 16 (2–3): 118–124. doi:10.1016/j.phymed.2008.07.015. PMID19109001.
^Figueirinha A. Cruz MT. Francisco V. Lopes MC. Batista MT. (2010). "Anti-inflammatory activity of Cymbopogon citratus leaf infusion in lipopolysaccharide-stimulated dendritic cells: contribution of the polyphenols". Journal of Medicinal Food. 13 (3): 681–690. doi:10.1089/jmf.2009.0115. PMID20438326.
^Lee HJ. Jeong HS. Kim DJ. Noh YH. Yuk DY. Hong JT. (2008). "Inhibitory effect of citral on NO production by suppression of iNOS expression and NF-kappa B activation in RAW264.7 cells". Archives of Pharmacal Research. 31 (3): 342–349. doi:10.1007/s12272-001-1162-0. PMID18409048. S2CID20909743.
^Tiwari M, Dwivedi UN, Kakkar P (2010). "Suppression of oxidative stress and pro-inflammatory mediators by Cymbopogon citratus D. Stapf extract in lipopolysaccharide stimulated murine alveolar macrophages". Food Chem. Toxicol. 48 (10): 2913–2919. doi:10.1016/j.fct.2010.07.027. PMID20655974. S2CID9395057.
^Blanco MM, Costa CA, Freire AO, Santos JG, Costa M (March 2009). "Neurobehavioral effect of essential oil of Cymbopogon citratus in mice". Phytomedicine. 16 (2–3): 265–70. doi:10.1016/j.phymed.2007.04.007. PMID17561386.
^Rodrigues, Eliana & Carlini, E.A. (2006): Plants with possible psychoactive effects used by the Krahô Indians, Brazil. Revista Brasileira de Psiquiatria28(4): 277–282. PDF fulltextArchived 2020-08-01 at the Wayback Machine
