Lemongrass (Cymbopogon citratus) is a plant in the grass family. It and several others from the same family are used as an herb in cooking and also as a medicinal herb. Lemongrass is generally used fresh because it loses quite a bit of flavor when dried. The fresh leaves are a favorite for making tea. Although its name and taste are reminiscent of lemons, lemongrass is not botanically related to this citrus fruit.
The tender part of the lemongrass stems (usually the bottom third) and the base of the leaves are the only parts of the plant that are used for culinary purposes.
Lemongrass has a flavor reminiscent of lemons and smells a bit like roses. This aroma develops when the thin, cane-like stems are grated or sliced. Dried lemongrass is less flavorful.
Traditionally, lemongrass is used in a number of Vietnamese and Indonesian dishes and drinks. In Thailand, chefs “bruise” the stems before pouring water over them and brewing a type of tea that is very good for quenching your thirst. The process of bruising allows the lemongrass to release its essential oils. Lemongrass gives tea mixtures an exotic flavor.
Fresh stems and leaves can be used to add zest to salads, and it is also a favorite for seasoning sauces and vegetables. The upper two-thirds of the stem can be cooked with the food to add flavor, but should then be removed before serving as this part is not edible.
Lemongrass is an ingredient in Thai curry paste and in bambu, a paste-like spice blend found in Indonesia. Bambu is traditionally stone-ground with a mortar and pestle and contains a wide variety of fresh spices such as garlic, chili peppers, galangal, turmeric, ginger, and lemongrass. In Indonesia, vegetables are often cooked with only water, broth, coconut milk, and bambu.
You can purchase fresh lemongrass in well-stocked supermarkets or Asian shops. The smaller the stems are, the more tender they will be. Large, older plants tend to be a bit tough. You can sometimes find frozen or dried, ground lemongrass under the name “Sereh.”
Lemongrass can be stored for several days in the refrigerator. Whole fresh lemongrass stems can be frozen and stored in the freezer for up to six months.
From Wikipedia: The leaves of Cymbopogon citratus have been used in traditional medicine and are often found in herbal supplements and teas. In the folk medicine of Brazil, it is believed to have anxiolytic, hypnotic, and anticonvulsant properties. In traditional medicine of India the leaves of the plant are used as stimulant, sudorific, antiperiodic, and anticatarrhal, while the essential oil is used as carminative, depressant, analgesic, antipyretic, antibacterial, and antifungal agent.
Laboratory studies have shown cytoprotective, antioxidant, and anti-inflammatory properties in vitro, as well as antifungal properties (though Cymbopogon martinii was found to be more effective in that study). 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. 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.
Lemon grass oil contains 65-85% citral in addition to myrcene, citronella, citronellol, and geraniol. 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.1
One low-dose study found no effect of Cymbopogon citratus essential oils on humans. However, subsequent research has demonstrated that the plants essential oil enhances GABA-ergic neurotranssmision at sufficient doses (with an anxiolytic threshold dose of 10 mg/kg) via positive allosteric agonism in the same manner as benzodiazepines (ex. "diazep..") which are used clinically as anxiolytics, sedative/hypnotics, muscle relaxants, and anticonvulsants. Despite the observed pharmacological activity, the average adult male would require 600–800 mg of the pure essential oil to achieve a clinically significant reduction in anxiety. Most commercial supplements contain doses far below the threshold dose which suggests that the majority of lemongrass supplements exert their anxiolytic benefits either primarily or entirely through the induction of the placebo effect. As the essential oil was demonstrated to act synergistically with other GABA-ergics (even in sub-therapeutic doses) and likely also potentiates anxiolytics of other mechanisms (as predicted by the mechanics of benzodiazepines), the possibility of pharmacologically-induced anxiolysis cannot be eliminated when formulations containing a sub-therapeutic lemongrass dosage also contain other anxiolytic herbs/chemicals.1
Cymbopogon citratus, commonly known as lemon grass or oil grass, is a tropical plant from South Asia and Southeast Asia.v 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.1
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, which bite domestic animals.1