Medicine Chemistry
AgriculturalAndFoodSciences,1970-2015-Agricultural And Food Sciences-2011.jsonl.gz.gz
Agricultural And Food Sciences
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Scienti ﬁ c basis for the therapeutic use of Cymbopogon citratus , Stapf (Lemon grass)

Cymbopogon citratus, Stapf (Lemon grass ) is a widely used herb in tropical countries, especially in Southeast Asia. The essential oil of the plant is used in aromatherapy. The compounds identified in Cymbopogon citratus are mainly terpenes, alcohols, ketones, aldehyde and esters. Some of the reported phytoconstituents are essential oils that contain Citral  , Citral  , Nerol Geraniol, Citronellal, Terpinolene, Geranyl acetate, Myrecene and Terpinol Methylheptenone. The plant also contains reported phytoconstituents such as flavonoids and phenolic compounds, which consist of luteolin, isoorientin 2'-O-rhamnoside, quercetin, kaempferol and apiginin. Studies indicate that Cymbopogon citratus possesses various pharmacological activities such as anti-amoebic, antibacterial, antidiarrheal, antifilarial, antifungal and anti-inflammatory properties. Various other effects like antimalarial, antimutagenicity, antimycobacterial, antioxidants, hypoglycemic and neurobehaviorial have also been studied. These results are very encouraging and indicate that this herb should be studied more extensively to confirm these results and reveal other potential therapeutic effects.


PARTS USED
Leaves and whole plant.

BOTANICAL DESCRIPTION
Lemongrass is equally versatile in the garden. This tropical grass grows in dense clumps that can grow to 6 (1.8 m) in height and about 4 (1.2 m) in width, with a short rhizome. [18] Table 2 shows the morphological description of Cymbopogon citratus.

Country Uses References
Argentina Decoction of leaf is taken orally with "mate" tea for sore throat, empacho and as an emetic [4] Brazil The tea made from its leaves is popularly used as antispasmodic, analgesic anti-inflammatory, antipyretic, diuretic and sedative [5][6] Cuba Hot water extract of the dried leaves is taken orally as a hypotensive for catarrh and rheumatism [7] Egypt Hot water extract of the dried leaves and stem is taken orally as a renal antispasmodic and diuretic [8] India Fresh entire plant is said to repel snakes. Two to three drops of essential oil in hot water are taken orally for gastric troubles. For cholera, a few drops of oil with lemon juice are taken orally. Hot water extract of the dried leaves is used for bathing in cases of severe headache and fever. A tea prepared from lemon grass is used as a sedative for the central nervous system [9][10][11] Indonesia Hot water extract of the entire plant is taken orally as an emmenagogue [12] Malaysia Hot water extract of the entire plant is taken orally as an emmenagogue [13] Thailand Fresh entire plant is inhaled as a fragrance and eaten as a condiment. [14] Hot water extract of the dried entire plant is taken orally as a stomachic. [15] Hot water extract of the dried root is taken orally for diabetes [14][15][16] USA Hot water extract of the entire plant is used externally by Laotian Hmong in Minnesota for healing wounds and bone fractures [17]

Flavonoids and Phenolic Compounds
Lemongrass consists of luteolin and its 6-C and 7-Oglycosides, [31] isoorientin 2'-O-rhamnoside [32] and isolation of the fl avonoids quercetin, kaempferol and apiginin [33] from the aerial parts. The phenolic compounds elimicin, catecol, chlorogenic acid, caff eic acid and hydroquinone are also isolated from the plant. [34] PHARMACOLOGY Although a lot of pharmacological investigations have been carried out based on the ingredients present, but a lot more can still be explored, exploited and utilized. A summary of the fi ndings of these studies is presented below.

Anti-amebic Eff ect
The essential oil in broth culture was active on Entamoeba histolytica. [35] Antibacterial Activity The chromatographic fraction of the essential oil in agar plate was active on Bacillus subtilis, Escherichia coli, Staphylococus aureus [36][37] and Salmonella paratyphi and Shigella fl exneri. [38] These activities are shown in two of the three main components of the oil identifi ed through chromatographic and mass spectrometric methods. While the α-citral (geranial) and β-citral (neral) components individually elicit an antibacterial action on gram-negative and gram-positive organisms, the third component, myrcene, did not show any observable antibacterial activity on its own. [36] The extract was also active when the volatile oil extract was oxidized via the active oxygen method. [39][40][41][42]

Antidiarrheal Activity
Cymbopogon citratus stalk decoction reduced the fecal output in a dose-dependent manner. [43] Antifi larial Activity Fresh leaves were active on Setaria digitata. [44] Antifungal Activity Lemon grass oil is active against such dermatophytes such as Trichophyton mentagrophytes, T. rubrum, Epidermophyton fl occosum and Microsporum gypseum, [45] and is among the most active agents against human dermatophytes. Other studies reported that lemon grass oil is active against keratinophilic fungi, 32 ringworm fungi [46][47] and food storage fungi. [48] Lemongrass oil is also effective as a herbicide and as an insecticide because of these naturally occurring antimicrobial eff ects.

Anti-infl ammatory Activity
The hot water extract of the dried leaves administered intragastrically to rats was active when compared with carrageenin-induced pedal edema. [7] Antimalarial Activity The essential oils of Cymbopogon citratus were found to produce 86.6% suppression in the growth of Plsmodium  berghei when compared with chloroquine (taking inhibition by chloroquine as 100%). [49] Antimutagenicity The ethanolic extract of lemon grass extract exhibits an antimutagenic activity in various models [50][51][52] and retards the growth of fi brosarcoma cells transplanted in mice in association with the prevention of lung metastasis. [53] The plant extract is known to show inhibition on the formation of azoxymethane-induced DNA adducts and aberrant crypt foci in the rat colon. [54] Inhibitory eff ects of the plant extract on the early phase of hepatocarcinogenesis a er initiation with diethylnitrosamine were seen in 344 male Fischer rats. [55] Antimycobacterial Activity The essential oil in agar plate was active on Mycobacterium smegaris. [56]

Antinociceptive Eff ect
The essential oil of Cymbopogon citratus possesses a signifi cant antinociceptive activity. Comparing the results obtained with three different experimental models of nociception (hot-plate, acetic acid-induced writhings and formalin test), we can speculate that the essential oil acts both at the peripheral and at the central levels. [57] Antiprotozoan Activity A dose-dependent antiprotozoan eff ect of the essential oil of Cymbopogon citratus could be observed on two strains of Crithida deanei. [58]

Ascaricidal Activity
The fresh leaf essential oil has an ascaricidal activity. [59]

Free Radical Scavengers and Antioxidant Eff ects
Methanol, MeOH/water extracts, infusion and decoction of Cymbopogon citratus were shown to have free radical scavenging eff ects by measuring the bleaching of the 1, 1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion and inhibition of the enzyme xanthine oxidase and lipid peroxidation in human erythrocytes. [60]

Hypocholesterolemic Eff ect
The elevated cholesterol concentration was signifi cantly lowered in the animals given the plant extract. This reduction was found to be dose dependent. This result shows that the extract possesses a hypocholestecolemic potential. [61] Hypoglycemic and Hypolipidemic Eff ects A fresh leaf aqueous extract of Cymbopogon citratus administered in normal rats lowered the fasting plasma glucose and total cholesterol, triglycerides, low-density lipoproteins and very low-density lipoprotein dose dependently while raising the plasma high-density lipoprotein level in the same dose-related fashion, but with no eff ect on the plasma triglyceride levels. [62] Larvicidal Activity The fresh leaf essential oil has a larvicidal activity. [63] Neurobehavioral Eff ect The essential oil was evaluated for sedative/hypnotic activity through pentobarbital sleeping time, anxiolytic activity by elevated plus maze and light/dark box procedures and anticonvulsant activity through seizures induced by pentylenetetrazole and maximal electroshock. The essential oil was eff ective in increasing the sleeping time, the percentage of entries and time spent in the open arms of the elevated plus maze as well as the time spent in the light compartment of the light/dark box. In addition, the essential oil delayed clonic seizures induced by pentylenetetrazole and blocked the tonic extensions induced by maximal electroshock, indicating the elevation of the seizure threshold and/or blockage of the seizure spread. [64]

MARKETED FORMULATION OF THE HERB Lemongrass Essential Oil
As a vaporizer, the oil works as an eff ective panacea against bacteria, fl u and colds. It has stimulating agent, tonics, aromas, diuretic and antispasmodic, and so on. People suff ering from urine problems can apply lemon grass oils. In hot weather, this is the best oil to cool down the body temperature and to revive the mind and soul. In other health benefi ts, this is used to improve digestion, nausea and menstruation problems and ailments like headaches, muscle cramps, spasms and rheumatisms.

CONCLUDING REMARKS AND FUTURE PO-TENTIAL
Cymbopogon citratus is native to Sri Lanka and South India, and is now widely cultivated in the tropical areas of America and Asia. The plant is used as a fragrance and fl avoring agent and in folk medicine as an antispasmodic, hypotensive, anticonvulsant, analgesic, antiemetic, antitussive, antirheumatic, antiseptic and treatment for nervous and gastrointestinal disorders and fevers. The plant is also used as an antibacterial, antidiarrheal and antioxidant, but the mode of action for the diff erent bioactivities has not been studied in detail. Cymbopogon citratus contains various phytoconstituents such as fl avonoids and phenolic compounds, terpenoids and essential oils, which may be responsible for the diff erent biological activities. Hence, we can isolate some pure phytopharmaceuticals, which in turn can be used as lead molecules for synthesizing the novel agents having good therapeutic activity. With regard to the development of quality herbal medicine standardization of the extracts, phytopharmacology of diff erent extracts, isolation and characterization of active phytopharmaceuticals, elucidation of the mechanism of action of the isolated compounds and clinical trials of the compounds are much needed. In the changing global scenario, the interest toward plants with medicinal value is increasing substantially in the primary healthcare system both in the developed and in the developing countries. Therefore, the information will help scientists and researchers to screen the compounds responsible for diff erent bioactivities and to elucidate the molecular mechanism of action.