Serai (Cymbopogon citratus)

Lemongrass (Cymbopogon citratus) contains citral as its primary bioactive compound, comprising 65-85% of the essential oil. Clinical studies demonstrate its ability to reduce blood pressure and anxiety through GABA receptor modulation and inhibition of inflammatory mediators like nitric oxide.

Origin & History

Serai (Cymbopogon citratus), commonly known as lemongrass, is a tropical perennial grass native to Sri Lanka and southern India, now widely cultivated across Southeast Asia, Africa, and South America. The aromatic leaves and stems are processed through hot water infusion, aqueous extraction, hydroethanolic extraction, or steam distillation to produce therapeutic extracts and essential oils rich in monoterpenes and flavonoids.

Historical & Cultural Context

Lemongrass has been used for centuries in Brazilian herbal medicine as a CNS-depressant, digestive aid, and treatment for diarrhea, fever, and inflammation. It features prominently in Ayurvedic, African, and Southeast Asian traditional medicine systems for antidiarrheal, antifungal, antimalarial, and hypoglycemic applications, with historical use dating back millennia in tropical regions.

Health Benefits

• Reduces anxiety and blood pressure: RCT (n=66) showed lemongrass aromatherapy significantly lowered systolic/diastolic BP and anxiety scores in surgical patients (p<0.05)
• Anti-inflammatory effects: Inhibits LPS-induced NO production and iNOS protein expression in dendritic cells through polyphenolic fractions
• Potential anticancer activity: In vitro studies demonstrated antiproliferative effects against HT-29 colon cancer cells (IC50 23.11 µg/mL)
• Hormonal balance support: Animal studies showed up to 37.10% reduction in testosterone and 56.15% increase in estradiol in PCOS models
• Oral health benefits: Clinical studies suggest efficacy for periodontitis, gingivitis, and oral malodor (limited detail available)

How It Works

Lemongrass essential oil rich in citral (geranial and neral) modulates GABA neurotransmitter activity to reduce anxiety and lower blood pressure. The polyphenolic compounds inhibit lipopolysaccharide-induced nitric oxide production by suppressing inducible nitric oxide synthase (iNOS) protein expression in immune cells. Citral also demonstrates anti-inflammatory activity by blocking nuclear factor-kappa B (NF-κB) signaling pathways.

Scientific Research

Human clinical evidence remains limited, with one RCT (n=66 surgical patients) demonstrating aromatherapy benefits for anxiety and cardiovascular parameters. Most research consists of preclinical animal models, particularly a PCOS rat study (n=54) showing hormonal modulation, and in vitro anticancer assays. No PMIDs were provided in the research dossier for the identified studies.

Clinical Summary

A randomized controlled trial with 66 surgical patients showed lemongrass aromatherapy significantly reduced both systolic and diastolic blood pressure while lowering anxiety scores (p<0.05). In vitro studies demonstrate potent anti-inflammatory effects through inhibition of nitric oxide production in dendritic cells. The evidence base remains limited with small sample sizes, requiring larger clinical trials to establish therapeutic dosing and long-term safety. Most research focuses on aromatherapy applications rather than oral supplementation.

Nutritional Profile

Serai (lemongrass) is a low-calorie herb (~99 kcal/100g dry weight) primarily used in small culinary quantities. Macronutrients per 100g fresh: carbohydrates ~25g, protein ~1.8g, fat ~0.5g, dietary fiber ~0.5g. Key micronutrients: potassium ~723mg/100g (significant contributor), magnesium ~60mg/100g, calcium ~65mg/100g, iron ~8.2mg/100g (notable but non-heme form with limited bioavailability ~5-12% without vitamin C co-consumption), zinc ~2.2mg/100g, manganese ~5.2mg/100g. Vitamins: folate ~75mcg/100g, vitamin C ~2.6mg/100g, vitamin A ~6mcg RAE/100g, niacin ~1.1mg/100g. Primary bioactive compounds: essential oil fraction (0.2–0.5% fresh weight) dominated by citral (geranial + neral, comprising 65–85% of essential oil), myrcene (~12%), limonene (~3%), linalool (~1%), and geraniol (~3%). Polyphenolic fraction includes chlorogenic acid, isoorientin, swertiajaponin, and luteolin glycosides at ~15–30mg/100g fresh weight total. Citral is the principal bioactive compound responsible for antimicrobial, anti-inflammatory, and anxiolytic effects; bioavailability of citral via dietary route is moderate (~40–60% absorption) but significantly enhanced via aromatherapy inhalation route due to direct mucosal absorption. Fiber content is primarily insoluble cellulose from fibrous stalks; typically the outer stalks are discarded, so actual nutrient intake per culinary serving (~5–10g fresh) is modest. Mineral bioavailability is reduced by moderate oxalate content (~50mg/100g).

Preparation & Dosage

Human aromatherapy: Essential oil via inhalation (concentration not specified). Animal studies: Aqueous extract 100-400 mg/kg/day or hydroethanolic extract 100-200 mg/kg/day orally for 28 days. In vitro anticancer: 23-100 µg/mL essential oil. No standardized human oral dosages established. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Ginger, Turmeric, Peppermint, Chamomile, Green Tea

Safety & Interactions

Lemongrass is generally recognized as safe when used as a culinary herb or short-term aromatherapy. Topical application may cause contact dermatitis in sensitive individuals due to citral content. No significant drug interactions are documented, though theoretical concerns exist with blood pressure medications due to hypotensive effects. Pregnancy and breastfeeding safety data is insufficient, warranting caution during these periods.