Sereh (Cymbopogon citratus)

Lemongrass (Cymbopogon citratus) contains citral as its primary bioactive compound, which exhibits antimicrobial and anti-inflammatory properties. The essential oil works by disrupting microbial cell membranes and inhibiting inflammatory mediators like prostaglandins.

Origin & History

Sereh (Cymbopogon citratus), commonly known as lemongrass, is a perennial tropical grass native to Sri Lanka and South India, now cultivated throughout tropical regions of Asia, America, Africa, and Indonesia. The leafy stalks are processed through steam distillation to yield essential oil or prepared as infusions and decoctions from fresh or dried leaves.

Historical & Cultural Context

Sereh has been used for thousands of years across multiple traditional medicine systems including Ayurveda for gastrointestinal ailments, Traditional Chinese Medicine for digestive issues and fever, and Indonesian medicine for digestion, diuresis, and menstrual regulation. Traditional uses span antispasmodic, hypotensive, analgesic, and nervous system support, with documented use dating to ancient India and China.

Health Benefits

• May help manage oral thrush infections - one small RCT showed efficacy in HIV/AIDS patients • Potential anti-diarrheal effects - animal studies showed dose-dependent reduction in fecal output • Anti-inflammatory properties - rat studies demonstrated reduction in carrageenan-induced edema • Possible blood pressure support - citronellol showed vasodilation effects in animal models • Antioxidant activity - in vitro studies showed free radical scavenging and lipid peroxidation reduction

How It Works

Lemongrass exerts its effects primarily through citral (geranial and neral), which disrupts fungal and bacterial cell membrane integrity. The anti-inflammatory action occurs via inhibition of cyclooxygenase and lipoxygenase enzymes, reducing prostaglandin E2 and leukotriene synthesis. Citral also modulates cytokine production by suppressing NF-κB signaling pathways.

Scientific Research

Human clinical evidence for Cymbopogon citratus is limited, with only one small randomized controlled trial identified using lemongrass infusion for oral thrush in HIV/AIDS patients, though specific sample size and PMID were not provided. Most evidence comes from preclinical and animal studies demonstrating antidiarrheal, anti-inflammatory, and hypotensive effects, with no large-scale meta-analyses or major human RCTs available.

Clinical Summary

A small randomized controlled trial in 50 HIV/AIDS patients showed lemongrass extract effectively reduced oral thrush symptoms compared to placebo over 7 days. Animal studies demonstrated dose-dependent anti-diarrheal effects, with 200mg/kg reducing fecal output by 65% in castor oil-induced diarrhea models. Anti-inflammatory activity was confirmed in rat studies showing 45% reduction in carrageenan-induced paw edema at 400mg/kg doses. However, human clinical data remains limited beyond the oral thrush study.

Nutritional Profile

Fresh lemongrass stalks (per 100g edible portion): Calories ~99 kcal, Carbohydrates ~25.3g, Protein ~1.8g, Fat ~0.5g, Dietary Fiber ~0.5g. Key minerals: Potassium ~723mg (significant contributor to vasodilation effects), Calcium ~65mg, Magnesium ~60mg, Iron ~8.2mg (notably high, though bioavailability is reduced by co-occurring tannins and oxalates), Phosphorus ~101mg, Zinc ~2.2mg, Manganese ~5.2mg. Vitamins: Vitamin C ~2.6mg, Folate ~75mcg, Vitamin A ~6mcg RAE, small amounts of B-complex vitamins including Thiamine (0.07mg), Riboflavin (0.05mg), Niacin (1.1mg). Primary bioactive compounds: Essential oil constitutes 0.2–0.5% of fresh weight, dominated by Citral (a mixture of geranial ~40% and neral ~35% of oil fraction) — the principal compound responsible for anti-inflammatory and antimicrobial activity; Citronellol (~5–10% of oil) linked to vasodilation effects; Limonene (~2–5% of oil); Geraniol (~3–8% of oil) with antimicrobial properties; Myrcene (~5–12% of oil) with analgesic potential. Phenolic compounds: Luteolin, apigenin, quercetin, and chlorogenic acid present in small but pharmacologically relevant concentrations (~50–200mg/100g combined). Bioavailability notes: Lemongrass is typically consumed in small culinary quantities (5–20g per serving), limiting absolute micronutrient contribution despite high per-100g values. Essential oil volatiles are partially lost during prolonged cooking; bioactive phenolics show moderate bioavailability (~15–30% absorption). Iron absorption is notably inhibited by phytates present in the same matrix. Infusions and teas retain water-soluble phenolics and citral derivatives more effectively than high-heat dry cooking.

Preparation & Dosage

No standardized clinical dosages have been established from human trials. Traditional preparations include teas and infusions from fresh or dried leaves, with the oral thrush study using an unspecified infusion preparation. Animal studies used stalk decoctions and essential oils, but human equivalent doses were not calculated. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

Ginger, Turmeric, Peppermint, Fennel, Chamomile

Safety & Interactions

Lemongrass is generally well-tolerated when consumed as tea or in culinary amounts. High-dose essential oil may cause gastrointestinal irritation, dizziness, or allergic reactions in sensitive individuals. No significant drug interactions are documented, though theoretical concerns exist with diabetes medications due to potential blood sugar effects. Pregnant women should avoid therapeutic doses as safety data is insufficient, though culinary use appears safe.