LEMON GRASS: A Culinary and Medicinal Herb

 Lemongrass is an important aromatic herb that has been cultivated for centuries in many Asian countries due to its culinary and medicinal properties. It is an integral part of many popular cuisines in Thailand. Scientifically known as Cymbopogon citratus, it belongs to the Grass family (Poaceae, erstwhile Graminae). Although it is native to India and Sri Lanka, it has been introduced to many other countries of the world due to its culinary and medicinal value. Lemongrass tea is relished all over the globe for its unique lemony aroma and health benefits. It is colloquially known as Cochin grass as 90% of its global export is from Cochin port in India.

Names in India

Hindi: गंधत्रिण Gandhatrina • Sanskrit: Bhustrina • Bengali: Gandhabena • Gujarati: Lilicha • Marathi: Olecha • Konkani: Oli-cha • Kannada: Majjigehullu • Tamil: Karppurappul • Malayalam: Vasana Pullu • Telugu: Nimmagaddi

 

MORPHOLOGY

Lemongrass is a perennial rhizomatous grass that usually grows in clumps. The culms are robust and can attain a height of approximately 1.5 meters. Leaves are made up of two parts: leaf sheath and blade. Leaf blades can be up to 90 cm long, 2 cm wide, rough in texture and have sharp edges. Inflorescence is a large, lax, spathate, panicle (compound raceme), up to 50 cm long. Spikelets in panicle (compound raceme) are sessile, linear-lanceolate. Most of the cultivars of lemongrass do not bear flowers. 

CHEMICAAL CONSTITIENTS

Lemongrass essential oil contains a large number of bioactive compounds such as citral (mixture of geranial and neral), isoneral, isogeranial, geraniol, geranyl acetate, citronellal, citronellol, germacrene-D, elemol, etc. In addition to essential oils, it also contains phytosterols, anthocyanin, amino acids, organic acid, phenolic compounds, volatile components, fatty acids, fumesol, flavonoids, isovaleranic aldehyde, methylheptenone, valeric esters, L-linanool, furfurol, isopulegol and  p-coumaric acid.

MEDICINAL USES

1.   Anti-Hypertensive Effect

Essential oils especially citral present in lemongrass have been reported to have anti-hypertensive activity expressed through endothelium-independent vaso-relaxation by blockaging of Ca²⁺ influx and prostacyclins channel.

2.   Anti-Diabetic Activity

Lemon grass has been considered to maintain healthy blood glucose levels through the regulation of insulin. It also regulates the glycosylated haemoglobin (HbA1C) levels.

3.   Anti-Obesity Activity

Lemon grass has traditionally been used to control obesity in many herbal systems of medicines.

4.   Antioxidant Activity

Lemon grass is rich in many natural antioxidants, such as flavonoids, chlorogenic acids, phenolic acids, etc., which reduce the oxidation of lipids in the membranes. Oxidative stress and free radicals are responsible for many diseases (cancer, cardiovascular diseases, arthritis, etc.) and premature ageing in human beings.

5.   Anti-Inflammatory Activity

Chronic inflammation is linked with many diseases, such as cancer. Citral present in lemongrass is reported to inhibit the secretion of inflammatory mediators (prostaglandins, nitric oxide, cytokines, etc.) responsible for inflammation.

6.   Good Analgesic

Essential oils present in lemongrass are reported to suppress the cramps and pains by lowering the expression of pain mediators.

7.   Anti-Bacterial Activity

Lemongrass has found its prominent role in folk medicine for combating bacterial infections such as meningitis, pneumonia, cellulitis and food poisoning. This activity is attributed to the presence of essential oils such as α-citral (geranial) and β-citral (neral) present in this plant.

8.   Anti-Fungal Activity

Lemongrass essential oils have been reported to have anti-fungal activity against ringworm, jock itch, yeast infections and athlete's foot.

9.   Antimalarial Activity

Experimental studies have shown that citral, myrcene and citronellal have considerable antimalarial activity against Plasmodium species.

10.  Cardioprotective Activity

Experimental studies on various animal models have reported that lemongrass is useful in maintaining a healthy lipid profile. Dyslipidaemia is a known risk factor for coronary heart disease. Lemongrass phytochemicals were reported to decrease the serum levels of total cholesterol, LDL, VLDL, and HMG-CoA reductase, while simultaneously increasing HDL levels in a dose-dependent manner.

11.  Protection of Kidney

Some antimicrobial drugs are toxic to the kidneys. Scientific studies on rabbit models have shown that when these antibiotics were administered along with lemongrass phytochemicals, kidney damage was negated considerably.

12.  Antitussive Activity

Experimental studies on animal models have reported that lemongrass phytochemicals reduce violent coughing in a dose-dependent manner.

13.  Anticancer Activity

Lemongrass essential oils are reported to initiate cancer cell death by increasing intracellular ROS, altering mitochondrial membranes and initiating apoptosis in human cervical adenocarcinoma (HeLa), human lung carcinoma (A549) cell line and squamous (ME-180) cell lines in laboratory culture conditions.

14.  Hepatoprotective Activity

Lemongrass essential oils are found to be useful in protecting the liver by reducing the levels of hepatotoxicity-induced serum liver markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and gamma-glutamyl transferase (γGT) considerably in mice with paracetamol-induced acute liver injury.

15.  Healing of Gastric Ulcers

Geraniol and citral present in lemongrass are reported to prevent gastric injury and heal gastric ulcers.

CAUTION

Citronella (Cymbopogon nardus) is a similar-looking grass, which can be confused with lemongrass. Citronella oil finds its use in mosquito repellent creams. Citronella oil is reported to be toxic and causes lung damage. 

Experimental studies on healthy human beings using lemongrass for two weeks have shown it to be safe in moderate quantities. Lemongrass oil, where alfa and beta citral are major components, was reported to be safe in a recent experimental study recent experimental study even at dose of 2000 mg/kg body weight after a single dose of oral administration to female Sprague Dawley rats. It is not advised to use lemongrass essential oils during pregnancy since they may stimulate the uterus and menstrual flow, increasing the risk of miscarriage.

REFERENCES

• Ekpenyong, C.E., Akpan, E.E. and Daniel, N.E. 2014. Phytochemical Constituents, Therapeutic Applications and Toxicological Profile of Cymbopogon citratus Stapf (DC) Leaf Extract. J Pharmacogn Phytochem. 3(1):133–41.
• Medical News Today. 2024. What are the health benefits of lemongrass tea?. Retrieved from: https://www.medicalnewstoday.com/articles/321969
• Oladeji, O.S., Adelowo, F.E., Ayodele, D.T. and Odelade, K.A. 2019. Phytochemistry and pharmacological activities of Cymbopogon citratus: A review. Scientific African 6: e00137
• Shah, G., Shri, R.,  Panchal, V., Sharma, N., Singh, B. and Mann, A.A. 2011. Scientific basis for the therapeutic use of Cymbopogon citratus, stapf (Lemon grass). J. Adv. Pharm. Technol. Res. 2(1): 3–8.
• Sinha, S., Jothiramajayam, M., Ghosh, M. and Mukherjee, A. 2014. Evaluation of toxicity of essential oils palmarosa, citronella, lemongrass and vetiver in human lymphocytes. Food and Chemical Toxicology: 68: 71-77.
• University of Wisconsin-Stevens Point. Lemongrass. Retrieved from: https://www.uwsp.edu/sbcb/tropical-conservatory/lemongrass/
• WebMD. 2024. Lemongrass - Uses, Side Effects, and More. Retrieved from: https://www.webmd.com/vitamins/ai/ingredientmono-719/lemongrass

• Xavier, A., Rani, S.S., Shankar, R., Nisha, A.R., Sujith, S. and Uma, R. 2022. Evaluation of acute oral toxicity of lemon grass oil and citral in albino rats. J. Phytopharmacology 11(4):281-285.