Cymbopogon citratus

Culinary uses

Cymbopogon citratus is abundant in the Philippines and Indonesia where it is known as tanglad or sereh. Its fragrant leaves are traditionally used in cooking, particularly for lechon and roasted chicken.

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.

Medicinal uses

The leaves of Cymbopogon citratus have been used in traditional medicine and are often found in herbal supplements and teas. Many effects have been attributed to both their oral consumption and topical use, with modern research supporting many of their alleged benefits.

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 | doi=10.1016/j.fct.2010.07.027}} (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.

Pharmacology

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. diazepam) 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.

Effect on insects

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.