CHUKWUMA MUANYA in this report examines why lemon grass is widely used in most Nigerian communities as the main ingredient in herbal remedies for malaria and typhoid fevers, colds and rheumatism among other ailments; and even as an insect repellant. LEMON Grass has to many Nigerians been a household name over the years and even though many have left the countrysides, observers say it remains popular. Commonly called lemon grass, Cymbopogon citratus belongs to the plant family Graminae. To the French it is citronelle, Potuguese citronela. But in Nigeria the Edos call it eti; Efik ikon eti; Hausa tsauri; Ibibio myoyaka makara; Igbo (Owerri) achara ehi; and Yoruba kooko oba. The botanical genus name Cymbopogon is derived from Greek kymbe (k?mbh) "boat" and pogon (1?gwn) "beard"; it refers to the boat-shaped spathes and the many-awned inflorescences which remind to a beard. The species name citratus obviously relates to the prominent lemon fragrance of the plant. Similarly, most European names of lemon grass are either adapted from local names of lemon (citronella) or are compounds meaning "lemon herb" (Finnish sitruunaruoho, Portuguese erva-cidreira, Turkish limon otu) or particularly often "lemon-grass" (Danish citrongr¾s, Lithuanian citrinzÿoleú, Czech citr—nov‡ tr‡va, Estonian sidrunhein, Hungarian citromfuy´). Similar compounds are Russian limmonoe sorgo "lemon-sorghum" and Spanish te de lim—n "lemon tea". Native to Asia and grown in India, Lemongrass is cultivated in many hot humid areas such as West Indies, Guatemala, Brazil, Sri Lanka and parts of Central Africa. It can also be found in large quantities in Nigeria. Lemon grass could be described as a fast growing tall aromatic perennial grass that grows up to 1.5 metres high. It produces a thick network of roots that rapidly exhausts the soil. Fresh grassy-citrus scent with earthy undertones. Ranges in colour from yellow, amber to a reddish-brown. According to a botanists at the Department of Botany and Microbiology, University of Lagos, Akoka, Associate Professor Oluwatoyin Ogundipe, there are two distinct types of plants and many chemotypes within each variety. The two main types are : Cymbopogon citratus: It is also known as West Indian Lemongrass, Madagascar Lemongrass and Guatemala Lemongrass. It is likely native to Sri Lanka. Cymbopogon flexuosus: This plant is also known as East Indian Lemongrass and is native to East India. It varies slightly from the previous lemongrass in chemical composition. Lemon grass oil, according to Ogundipe is produced from finely chopped grass by distillation. He cautioned that lemon grass oil should be used with care on children under two years of age, and it may irritate sensitive skin. He said: "Lemon grass has general benefits. It calms nervous exhaustion, stress related conditions. It is also good for acne, athlete's foot, colitis, excessive perspiration, fevers, gastro-enteritis, headaches, indigestion, infectious disease, insect repellent (fleas, lice, ticks), muscle tone, muscular pain, open pores, pediculosis, poor circulation, scabies, slack tissue, tissue toner. Phyto-chemical analysis of lemon grass shows that it contains hydrocarbons: myrcene (12-25 per cent), limonene, dipentene (monoterpenes) -- Alcohol: linalol, geraniol, nerol, citronellol (monoterpenols) (5 percent) - farnesol (12.8 per cent) (sesquiterpenols) - Ketones: methylheptenone - Aldehydes (60-80 per cent): citral, citronella, farmesal. The most active constituent is citral, which accounts for 70 per cent - 85 per cent of the oil's volume. Indeed, lemon grass oil has been known to be a very powerful antiseptic and bactericide, and laboratory trials have provided scientific confirmation of its benefits. To a homeopath, Dr Osmond Onyeka of the National Association of Natural Physicians (NAPNM), "it is a powerful tonic and has a stimulating effect on the body. Lemon grass has been found to have a soothing effect on headaches. If treating a headache, lemon grass should be diluted in carrier oil before gently massaging the temples and the forehead. Neat oil would be damaging to the skin. In a bath, lemon grass is refreshing, anti-septic and deodorising. Due to possible skin irritation, you must be careful when applying it. Like all lemon scented oils, this oil is a good insect repellant. "The safety data indicates that the essential oil may irritate the skin over long use or with very sensitive clients. It should be used cautiously on children. It is a possible concern due to its citral content for prostate hyperplasia. Although not listed, it is a concern orally for glaucoma." A study on the effect of lemon grass on fifteen fungi and ten bacteria by Agarwal et al showed that the oil posses a high degree of anti-fungal activity, a moderate activity toward the bacteria. In another study by Wannisron et al, the leaf oil of lemon grass was tested against four dermatophytes (35 clinical isolates). It exhibited antifungal activity towards all strains. It was found that citral was the major fungicidal constituent; however the complete oil was more effective than the constituent alone. Creams were then evaluated in vitro and their antifungal effect was found to be dose -dependent. A cream base containing 2.5 per cent oil was more efficacious than four commercial creams. Indeed, further research by Syed et al showed that there was no general correlation between antibacterial activity and age. In the study, the oil was tested in vitro for activity against several bacteria. The oil was kept at room temperature for at two, seven and twelve years and re-tested. An insulin-like material, according to Encyclopaedia of Medicinal Plants of West African has been isolated from the plant value of 440 units orally, or 880 units subcutaneously, per gm. Leaf-wax has been shown to contain a ketone named cymbopogone and an alcohol cymbogonol. A trace of alkaloid is detected in the leaves, and an unnamed one in the rhizome. The report reads: "Leaf and root contain traces of hydrogen cyanide. Miscellaneous other principles have been reported. The whole plant has a strong fragrant smell. It is often burnt in houses, either green or dry, to dispel mosquitoes. In the early days of the rubber plantation industry in Malaysia it was commonly planted near to labourers' quarters in the belief that it would keep away anopheles (malaria-carrying) mosquitoes, a hope not borne out. It has been planted in West Africa in tsetse fly areas as a control to discourage flies breeding. "In most areas in Nigeria the leaves are used in infusion to make a tea-form beverage. This infusion is taken as a febrifuge, sudorfic and dyspeptic, and put into hot baths for fumigation. Leaves boiled with guava leaves are taken in Nigeria for cough. Leaf and rhizome infusions are considered pectoral and good for colds, flu, pneumonia, cough and consumption, as well as for fever. It is also applied to the forehead to relieve headache. The rhizomes are used as toothpicks, chew-sticks and to rub on teeth for cleansing in West Africa. Their use as chew-sticks is said to assuage toothache. A tisane of the root is given to children to relieve cough, and a decoction is considered febrifugal". To a naturopath, Dr Chinyere Ogbonna of Ugo Herbal Home Festac Town, Lagos, lemon grass is very effective in treating common medical conditions. She recommends: "For Fevers: Use with ginger, sugar, cinnamon. You can also use a tea or decoction made from the leaves as a diaphoretic in fever. "For disordered menstruation, for congestive and neuralgic forms of dysmnorrhoea, for dropsical conditions caused by chronic malaria: Use herb with black pepper. "For vomiting and diarrhoea: It is carminative and tonic to the intestinal mucous membrane. "For colic, flatulence, fever, catarrh: Use an infusion of leaves with pudina, black pepper, dried ginger and sugar-candy."Ogbonna continued: "The lemon grass oil is useful as a carminative in flatulent and spasmodic affections of the bowels, colic, and gastric irritability. It is also used in treating cholera with obstinate vomiting, by controlling vomiting and aiding the process of reaction. Use three to six drops of lemon grass oil on a piece of sugar cube or in emulsion. For painful affections - lumbago, chronic rheumatism, neuralgia, sprains, etc.: Mix lemongrass oil with an equal quantity of pure coconut oil. Use it externally as an embrocation or liniment."According to a study titled Formulation of an effective mosquito-repellent topical product from lemon grass oil published recently by the Department of Pharmaceutics, Obafemi Awolowo University, Ile-Ife, Nigeria, extracts of lemon grass can not only bring relief in malaria fever, but can repel mosquitoes. The team of researchers :Oyedele A.O, Gbolade A.A, Sosan M.B, Adewoyin F.B, Soyelu O.L, and Orafidiya O.O evaluated ointment and cream formulations of lemon grass oil in different classes of base and the oil in liquid paraffin solution for mosquito repelling property in a topical application. Mosquito repelling property was tested by determining the bite-deterrence of product samples applied on an experimental bird's skin against a two-day starved culture of Aedes aegypti L. mosquitoes. The one per cent v/v solution and 15 per cent v/w cream and ointment preparations of the oil exhibited > or =50 per cent repelling lasting 2-3 hours, which may be attributed to citral, a major oil constituent. According to the authors, this activity was comparable to that of a commercial mosquito repellent. Base properties of the lemon grass oil formulations influenced their effectiveness. The oil demonstrated efficacy from the different bases in the order of hydrophilic base, emulsion base and oleaginous base.