Name currently accepted: Cymbopogon citratus
Authority: (DC.) Stapf
Taxonomic serial no.: 41613 (ITIS, 2016)
Synonyms: Andropogon citratus DC. ex Nees., Andropogon cerifier Hack., Andropogon citriodorum hort. ex Desf., Andropogon roxburghii Nees ex Steud., Andropogon nardus ssp. ceriferus (Hack.) Hack., Cymbopogon nardus subvar. citratus (DC.) Roberty (Anon., 2010a).
Family: Poaceae (Gramineae) (Kingdom: Plantae, Subkingdom: Viridiplantae; Infrakingdom: Streptophyta; Superdivision: Embryophyta; Division: Tracheophyta; Subdivision: Spermatophytina; Class: Magnoliopsida; Superorder: Lilianae; Order: Poales; Family: Poaceae; Subfamily: Panicoideae; Tribe: Andropogoneae; Genus: Cymbopogon; Species: citratus; Binomial: Cymbopogon citratus (DC.) Stapf).
Common names: Lemongrass, West Indian lemongrass, citronella grass, fever grass, lemon-scented grass.
Regional/vernacular names: Arabic: hashisha al-limun; Bulgarian: limonova treva; Chinese: ning meng cao, xiang mao, xiang mao cao; Czech: citrónová tráva; Danish: citrongræs; Dutch: citroengras; French: verveine des indes, citronnelle; German: lemongras, zitronengras; Hindi: aghin ghas, gandhatrina, gauti chai, khawi, sera; Hungarian: ázsiai citromfű, citromfű, indiai citromfű; Japanese: remon gurasu, remonsou; Korean: remon gurasu; Polish: palczatka cytrynowa; Portuguese: capim-santo, capim-cidrão, erva-cidreira (Brazil); Russian: chelnoborodnik limonnyj, lemongrass, limonnaya trava, limonnyĭ zlak, limonnoe sorgo; Spanish: caña de limón, hierba de limón, limonaria (Argentina), malojillo, te de limon (Honduras), pasto cedrón (Argentina), pasto-limón (Argentina), zacate de limón, zacate-limón (El Salvador), zacate-dete; Swedish: citrongräs; Thai: dta krai gaeng, (dtôn-jà-krai), horwor dta bpai, ja khai (Northern Thailand), khrai (Southern Thailand); Turkish: limon out; Urdu: agan ghas; aghin ghas; Vietnamese: sà (Katzer, 2007; Porcher, 2012). (See Katzer, 2007, for a detailed list.)
Cymbopogon includes many species of aromatic grasses that are distributed in tropical and subtropical regions in all continents, from sea level to the mountains to the grasslands and deserts. Some of the species are commercially very valuable because they yield essential oils that have found varied uses in industry. Five Cymbopogon species yield three commercially important oils that are traded internationally. They are: lemongrass oil from Cymbopogon citratus (Indian or West Indian lemongrass) and Cymbopogon flexuosus (East Indian lemongrass from Sri Lanka, India, Thailand and Myanmar); palmarosa oil from Cymbopogon martini; and citronella oil from Cymbopogon nardus (Sri Lanka) and Cymbopogon winterianus (Java) (Bertia and Maffei, 2010). Lemongrass is also used widely as a spice because it imparts a very pleasing aroma and flavour to many dishes. Owing to the commercial importance, the above species are cultivated in many parts of the world. Lemongrass grows well in the tropics and subtropics from sea level to an elevation of up to 900 m; a warm humid climate with high rainfall and good sunshine is ideal for the growth of lemongrass (Nambiar and Matela, 2012; also see chapter 64 on citronella).
The following species description is based on the Flora of China (Chen and Phillips, 2006) and the PROSEA database (Oyen, 1999); a more detailed description is available in the grasses database (GrassBase – The Online World Grass Flora) (Clayton et al., 2016).
Lemongrass is a perennial grass, growing as large clumps that have many culms (stems) arising from the basal rhizomatous stem base. The culms are tall, 2–3 m, solid, with nodes and internodes, smooth and glabrous. Leaves arise from the nodes, the leaf sheath tightly covering the internodal portion above. Leaf sheaths are coriaceous, glabrous and smooth; the ligule is rounded or truncate. The leaf blade is long, linear, up to 100 cm long and 2 cm wide. Leaves are long, attenuate at both ends and the apex is acuminate; the leaf apical portion is drooping, glabrous on both sides, and the margins scabrid. The inflorescence is a large panicle, loose and decompound, up to 60 cm long and 4–9 noded. The panicle branches repeatedly, each division arising from a spathe-like sheath and the ultimate branch arising from a spatheole carrying a pair of racemes. Each such raceme is 1.5–2.5 cm long bearing 4–7 spikelet pairs, rachis hairy. In each spikelet pair one is sessile and the other pedicellate; each raceme ends in a single sessile and two pedicellate spikelets. The pedicellate spikelets are sterile, either male or reduced to empty glumes. Each sessile spikelet has two florets; the upper floret is hermaphrodite and fertile, and the lower one reduced and sterile. The lower glume of the upper floret is flat or has a shallow, concave shape, two-keeled and glabrous; the upper glume is boat-shaped and one-keeled. This floret is awnless with hyaline, two-lobed lemma; the palea is often absent, lodicules two, stamens three, styles two, and ovary superior, monocarpellary and with plumose stigma. The seed is a caryopsis with basal hilum. The chromosome number is 2n = 60 (Oyen, 1999; Chen and Phillips, 2006; IPCN, 2016).
Like many other members of the grass family, lemongrass too is a C4 plant; its leaf anatomy shows the typical features of C4 plants (showing Kranz structural syndrome). Bertia and Maffei (2010) provide a detailed review of the anatomical and physiological aspects of lemongrass.
The value of lemongrass is due to the essential oil contained in the leaves. The essential oil from the shade-dried leaf is extracted, employing conventional steam distillation. The yield of oil varies greatly, ranging from 0.28% to 3.0%. The highest registered yield was 3.0% obtained by hydro-distillation of the dry leaves (Chisowa et al., 1998). Lemongrass oil contains a large number of compounds that include monoterpenoids, diterpenoids, sesquiterpenoids, triterpenoids, ketones and aldehydes. The various compounds present in the oil are listed by Ross (2003), Akhila (2010) and Duke (2016).
- Major terpenes: Citral-A (geranial) (10–48%), citral-B (neral) (3–43%), borneol (5%), geraniol (2.6–40%), geranyl acetate (0.1–3.0%), linalool (1.2–3.4%) and nerol (0.8–4.5%).
- Minor / trace compounds: A large number of minor and trace compounds are reported in lemongrass oil. They include: α-pinene, β-pinene, camphene, camphor, α-camphorene, 1,8-cineole, citronellal, citronellol, n-decylaldehyde, Δ-3-carene, caryophyllene, caryophyllene oxide, limonene, linalyl acetate and many others. A detailed listing can be found in Duke (2016) and Akhila (2010).
Lemongrass is an important crop in Ethiopia; the oil produced there contains geraniol (40%), geranial and neral (13–15%) and α-oxobisabolene (12%) as the major components, the composition being different from the usual West Indian lemongrass oil (Abegaz et al., 1983). The oil produced in Zambia contains trans-citral (39.0%), cis-citral (29.4%) and myrcene (18.0%) as the major compounds (Chisowa et al., 1998). The oil distilled from lemongrass from Lagos, Nigeria, gave geranial (33.7%), neral (26.5%) and myrcene (25.3%) and small amounts of neomenthol (3.3%), linalyl acetate (2.3%), (Z)-β-ocimene (1.0%) and (E)-β-ocimene were also detected (Adeleke et al., 2001). In one of the reports, citral (69.39%) has been cited as a major component along with other minor components, such as caryophyllene, citronellol, geraniol, α- and β-pinene, ethyl laurate, 1,8-cineole, limonene, phellandrene methyl heptenone, linalool, menthol, myrcene, terpineol and citronellol. Thirty four constituents were identified in Moroccan lemongrass oil, the important ones being geraniol (39.8%) and neral (32%) (Baruah et al., 1995). The plant extract yielded triterpenic compounds cymbopogone, cymbopogonol, triacontanol, saponin and alkaloid (Ansari et al., 1996). In an analysis of the functional phytochemicals of lemongrass of Nigerian origin, Uraku (2015) reported the major constituents as: hexadecanoic acid (8.11%), hepta-9,10,11-trienioc acid (17.43%), octadecenoic acid (8.41%), 2-ethenyltradecan-1-ol (13.28%), eicosane aldehyde (37.56%) and 1-ethoxyoctadecane (15.20%) as the most important chemical constituents.
Lemongrass and its oil are credited with many biological properties. Duke (2003) and DerMarderosian and Beutler (2005) list the biological properties of lemongrass, lemongrass oil and its major constituents. Ross (2003) gives an extensive listing of the pharmacological properties reported in the literature and lists the important ones. Avoseh et al. (2015) reviewed recently the pharmacological properties of lemongrass. The more important of such properties are described below.
- Analgesic effect: Lemongrass oil, extract and one of the components myrcene, showed significant analgesic action, inhibiting the acetic-acid-induced writhing in mice. Oil and extract produced a dose-dependent analgesic effect on carrageenan and prostaglandin-E-induced hypersensitivity to pain, but did not inhibit the cyclic AMP-induced hyperalgesia, thereby indicating that the oil/ extract is peripheral in action (Lorenzetti et al., 1991).
- Antimicrobial activity: Lemongrass oil has significant antimicrobial activity against bacteria, fungi and protozoans. Geranil and nerol (α- and β-citrals) are the active agents present in the oil, both acting independently on Gram-negative and Gram-positive bacteria. The oil is also very active against the amoebiasis-causing Entamoeba histolytica (Onawunmia, 1984; Syed et al., 1990; Blasi et al., 1990; Orafidiva, 1993). Lemongrass oil is also effective against many dermatophytic fungi, ringworm fungi and food-spoiling fungi. The oil has herbicidal and insecticidal actions too (Kishore et al., 1993; Mishra and Dubey, 1994; Wannissorm, et al., 1996; Abe et al., 2003). The oil was reported to exhibit action against the malarial parasite Plasmodium berghei, showing 86.6% inhibition compared to 100% in the control drug choloroquinone (Tchoumbougnang et al., 2005).
- Anti-mutagenicity: An alcoholic extract of lemongrass showed anti-mutagenic activity, exhibiting growth inhibition of fibroblastoma cells transplanted in mice; the oil also prevented lung metastasis. The extract prevented DNA-adduct formation and aberrant crypt formation by azoxymethane in the rat colon. Lemongrass extract showed inhibitory action on the early phase of diethylnitrosamine-induced hepatocarcinogenesis (Suaeyun et al., 1997; Puatanachokchai et al., 2002; Shah et al., 2011).
- Hypoglycaemic, hypolipidaemic and hypocholesterolaemic effects: Lemongrass leaf extract reduced dose-dependently the fasting plasma glucose and total cholesterol, triglycerides, low-density lipoproteins and very low-density lipoprotein. In the same way there was a concomitant dose-related elevation of high-density cholesterol; the triglyceride level remained unaffected (Adeneye and Agbaje, 2007; Agbafor and Akubugwo, 2007).
- Neurobehavioural effect: Research reports showed that lemongrass oil had a sedative/hypnotic activity, anxiolytic activity and anti-convulsant activity. The oil increased sleeping time and significantly delayed pentylenetetrazole-induced seizures (Blanco et al., 2007; Shah et al., 2011).
- Cardiac effects: Lemongrass aqueous extract reduced cardiac rate but did not affect the contractile force in isolated rat hearts. The oil significantly increased the functional refractory period in isolated guinea pig papillary muscles and atrium, suggesting the anti-arrythmic action of the oil. The oil, as well as the extract, exhibited vaso-relaxation on an isolated, perfused mesenteric artery preparation; the effect was probably mediated by nitric-oxide-independent and non-prostanoid mechanisms. Intravenous administration produced a hypotensive effect (Gazola et al., 2004; Runnie et al., 2004; Anon., 2010b).
- Other effects: A free radical scavenging action and anti-nociceptive actions were also reported for lemongrass oil and extract (Viana et al., 2000; Cheel et al., 2005).
The medicinal uses of lemongrass and its oil are listed in detail by Duke (2003) and Ross (2003). Lemongrass is used in traditional medicine in many countries, mainly in Asia and Africa. The leaf is a stimulant, is sudorific, anti-periodic and anti-catarrhal; the essential oil is carminative, anti-choleric, depressant, analgesic, anti-pyretic, antibacterial and antifungal (Khare, 2007). Nadkarni (1976) in the Indian Materia Medica provides details on the traditional medicinal uses of lemongrass. In traditional medicine it is generally used as an infusion or decoction. Its commonest use is as a stomachic to children. Mixed with ginger, cinnamon and sugar it is administered for reducing temperature in high fever. A decoction mixed with black pepper powder is prescribed for disordered menstruation and in the congestive and neuralgic forms of dysmenorrhoea. The extract, infusion, decoction and oil are all very effective carminatives and are rural remedies for diarrhoea and severe stomach-ache. The oil mixed with coconut oil is used as very effective massage oil for the treatment of lumbago, chronic rheumatism, neuralgia, sprains and other painful affections. A lemongrass oil–coconut oil mixture (2:3) is indicated as a cure for ringworm infestation and for removing dandruff, acne and pimples. This mixture is also recommended as a massage oil to tone up muscles and tissues (Nadkarni, 1976). In the Ayurvedic system of India, lemongrass is considered acrid, thermogenic, anthelmintic, a laxative, appetizer, alexipharmic (antidote to poisons) and an aphrodisiac. It is prescribed for helminthiasis, flatulence, gastric irritations, lack of appetite, poisonous bites, bronchitis, epilepsy, leprosy, skin diseases, cholera, neuralgia, sprains, fever and vitiated conditions of vata and kapha (Warrier et al., 1995).
In the Far East and Pacific Ocean countries a lemongrass decoction and infusion are used in alleviating diarrhoea and for the ritual ‘suob’ (a ritual post-partum cleansing bath given after childbirth). A leaf paste is applied on the forehead for curing headaches; a leaf decoction is gargled for toothache. The oil is used in wound cleansing (Anon., 2016). In South America (Cuba, Brazil, etc.), lemongrass is widely used as herbal medicine for low blood pressure, as an anti-inflammatory, as a sedative and for all gastrointestinal maladies. Leaf tea is used as an anxiolytic and sedative. Lemongrass is used for similar ailments in Indonesia, China and most African countries, wherever the plant grows naturally (Anon., 2016). As a home remedy and ‘grandma's remedy’, lemongrass extract/infusion/oil is used in treating fever, flatulent colic, persistent vomiting, gastric irritability, neuralgia, rheumatism, sprains and painful afflictions (Sairam, 2002).
Leaves and the basal portion of the stem with the overlapping sheaths are used as a spice in the cuisines of most Asian countries and in the Far East, Oceania and Africa. However, cooking with lemongrass is most popular in the cuisines of Thailand, Cambodia, Laos, Vietnam, Indonesia and Sri Lanka. Lemongrass is used as a stuffing ingredient while spit-roasting a pig, in order to enhance the flavour and reduce the greasiness of the meat. Lemongrass is very popularly used in Thai cuisine in fish preparations. Two purposes are achieved with the use of lemongrass. It much improves the flavour and taste and suppresses the undesirable smell and flavour of fish, adding a fresh aroma to the dish. For such purposes the young shoots after the removal of the external leaves are used. Young leaves are chopped finely and added to rice preparations and to curries. Lemongrass is used in flavouring wines, sauces, stews and soft drinks. Sherbets are flavoured with lemongrass (Katzer, 2007; Anon., 2016).
According to Katzer (2007), in Vietnamese cooking lemongrass is used in several ways. It is used lavishly while cooking the main meal bo nhung dam, which is beef slices in vinegar broth and with plenty of lemongrass. In Indonesia, lemongrass is an essential ingredient in a fresh spice mix (bumbu), which is employed in fish and meat preparations. It is added to most curries for giving a deep spicy taste.
Lemongrass essential oil is distilled mainly in Sri Lanka; it is used widely for flavouring numerous food products such as frozen desserts, candies, baked goods, gelatins, puddings, breakfast cereals and beverages (both alcoholic and non-alcoholic). The highest average maximum use level reported is about 0.005% in candy and baked goods (45.9 and 47.6 ppm, respectively) (Khan and Abourashed, 2010). There are very many recipes in which lemongrass oil is used as a spice and many can be found online (e.g. Anon, 2015a–c; Dalal, 2016).
Lemongrass oil is used widely as a mosquito and house-fly repellent. It is added to floor cleaners to help give both aroma and an insect-repellency effect. Another major use of lemongrass oil is in the manufacture of soaps, disinfectants, brilliantines and perfumes. The highest use levels reported for the lemongrass oil from Sri Lanka in soaps is 0.6% and in perfumes 0.8% (Khan and Abourashed, 2010). Yet another use of lemongrass oil is for calming barking dogs (Anon., 2012).
Lemongrass has been in use for centuries both as a medicinal herb and as a spice and no adverse effect has ever been reported from such uses. Lemongrass tea is a very common item of regular consumption and no toxic or adverse effects have been recorded from the use. In fact it has been suggested as a healthier alternative to caffeine-containing products (tea and coffee). However, caution should be exercised against the consumption in excess and for prolonged time periods. Citral present in the oil can interact with cytochrome P450 and also could interact with drugs that are metabolized by this enzyme. Although not confirmed, the general guidelines provided are that the lemongrass extract and oil should be used with caution by individuals suffering from kidney damage, liver disease, by pregnant or lactating women, and children under the age of six. A high dose and prolonged use of lemongrass tea or decoction should be discouraged. The use of lemongrass as a food additive and spice is perfectly safe because the chances of any overdose are simply impossible without making the dish unusable (Dilberto et al., 1988, 1990; Blanco et al., 2009; Shah et al., 2011; Ekpenyong et al., 2014).
If the lemongrass is intended to be eaten in a soup or salad, discard the top end of the stalk and slice the rest into fine rings, starting...
Source: Cymbopogon citratus (DC.) Stapf (syn. Andropogon citratus DC.) and C. flexuosus (Nees ex Steud.) W. Wats. (syn. A. flexuosus ...
pronunciation (1801) : a grass (Cymbopogon citratus) of robust habit native to southern India and Ceylon that is grown in tropical regions for its l