Lemongrass

Citral (geranial plus neral) constitutes up to 90 percent. Clear skin sensitization potential if used above the dermal limit.

Dermal reaction rate: 25 of 1,606 contact dermatitis patients (1.6 percent) reacted to 2 percent lemongrass oil. In 100 patients, no reactions occurred at 1 percent.

Drug interactions through CYP2B6 inhibition by citral and geraniol. Use orally with caution alongside drugs metabolized by this enzyme, particularly antidiabetic drugs (citral has cardiovascular effects).

Teratogenicity: citral carries a risk of birth defects at high doses. Maximum daily oral dose in pregnancy is only 46 mg.

Children under 2 years: avoid dermal use. Hypersensitive or damaged skin: use with caution.

Lemongrass oil is not phototoxic. In a 21-day mouse trial at 1, 10, and 100 mg/kg there were no significant changes in gross pathology, biochemistry, or organ weights.

Lemongrass comes in two main species. East Indian (Cymbopogon flexuosus) grows in India, Sri Lanka, and Southeast Asia. West Indian (Cymbopogon citratus) grows in the Caribbean, Brazil, Africa, and parts of Southeast Asia.

East Indian typically has higher citral and less β-myrcene. West Indian has more complex chemistry with significant β-myrcene.

A tropical grass that grows in dense clumps with long, sharp leaves. The oil is distilled from fresh or dried leaves. Oil yield is around 0.2-0.4 percent by leaf weight.

In Vietnam, lemongrass is a common culinary herb, known locally as 'sa'. Belongs to genus Cymbopogon, which includes related species with different chemistry (citronella, palmarosa, gingergrass).

Family Poaceae (Gramineae), same family as rice, corn, and sugarcane.

Lemongrass oil is commonly adulterated with synthetic citral. Distinguished by chiral GC-MS analysis.

East Indian and West Indian differ in aroma and chemistry. Sometimes the label 'lemongrass' does not specify the species.

Fresh lemongrass produces a different aromatic profile from dried, distillation immediately after cutting preserves a richer character.

Notable anticarcinogenic activity in vitro. East Indian lemongrass oil is cytotoxic to 12 human cancer cell lines (cervix, lung, liver, colon, prostate, mouth, neuroblastoma) with IC50 values of 4.2-79.0 μg/mL.

In mice at 200 mg/kg ip, lemongrass oil inhibited Ehrlich and Sarcoma-180 tumors by 37-97 percent.

Also has antigenotoxic activity, reduces MNU-induced DNA damage in mouse leukocytes.

In cosmetic applications, lemongrass is common in soaps, massage oils, and mosquito-repellent products. Fresh, sharp, stimulating aroma.

Cultural role in Vietnam: lemongrass is among the foundational seasonings, from grilled meats and noodle soups to sweet broths. Dried leaves brewed as tea, a centuries-long tradition.