Serai makan leaf sheath and stem
Cymbopogon citratus (DC.) Stapf
Poaceae
Figure 1 : C. citratus. (a) Whole Plant; (b) stem and leaves; (c) stem. (Photos courtesy of Centre for Herbal Standardization (CHEST), USM, 2015)
DEFINITION
Serai makan leaf sheath and stem consists of the dried leaf sheath and stem of Cymbopogon citratus (DC.) Stapf (Poaceae).
SYNONYM
Andropogon roxburghii Nees ex Steud. , Andropogon ceriferus Hack., Andropogon fragrans C. Cordem., Andropogon citratus DC [ 1 ].
VERNACULAR NAMES
Lemon grass (English); serai (Malay); xiang mao cao (Chinese); sera, verveine (Tamil) [ 2 ].
CHARACTER
| Colour | Light brown (powder) |
| Odour | Aromatic |
| Taste | Characteristic |
IDENTIFICATION
Plant Morphology
C. citratus is a perennial, aromatic, tufted, or clustered with numerous erect stems arising from an oblique, ring-shaped, sparingly branched and short rhizome. Stem up to 2(-3) m tall, farinose below the nodes, smooth and glabrous. Leaves sheathing, blade and sheath differentiated; sheath coriaceous, terete, glabrous, greenish inside, basal ones persistent; ligule rounded or truncate, less than 2 mm long, chartaceous; blades linear, 50-100 cm x 0.5-2 cm, long-attenuate at both ends, apex acuminate, base gradually narrowed, drooping, glabrous, glaucous-green, midrib prominent below and white above, smooth on both surfaces but top part and margins often scabrid. Inflorescence large, loose, terminal, compound nodding panicle, up to 60 cm long, 4-9-nodes; raceme 1.5-2.5 cm long; rachis villous with hairs, 2-3 mm long, bearing 4-7 pairs of spikelets, 1 of each pair sessile; pedicellate spikelet, 4.5 mm long, male or reduced to empty glumes; lower glume 7-9-veined, upper glume 3-veined; upper glume boat-shaped, 1-keeled on the back; lower floret reduced to an empty lemma; upper floret bisexual, awnless, 2-lobed lemma; palea mostly absent; lodicules 2, cuneate or truncate; stamens 3; styles 2 with plumose stigmas. Seed a cylindrical to subglobose caryopsis with basal hilum [ 3 ].
Microscopy
Powdered material consists of fragments of adaxial epidermis in surface view showing long cells with wavy anticlinal walls associated with small, thin-walled of short cells and silica bodies; paracytic type of stomata occurs on the abaxial epidermis with rectangular, conspicuously elongated long cells and associated with long pitted vessel; fragments of parenchyma cells; fragments of fibre; unicellular and multicellular covering trichomes; calcium oxalate crystals in solitary and raphide form [ 1 , 2 , 4 , 5 ].
Figure 2 : Microscopic characters of C. citratus leaf sheath and stem powder. (a) Fragments of adaxial epidermis cells with wavy anticlinal walls; (b) fragments of parenchyma cells; (c) fragments of fibre; (d) pitted vessel; (e) simple multicellular trichome; (f) simple unicellular trichome; (g) fragments of epidermis cells containing silica body (arrow); (h) fragments of abaxial epidermis with long cells and stomata; (i) solitary crystal; (j) raphide crystals. [Scale bars: g = 10 µm; a, b, d-f, h, i = 20 µm; c, j = 50 µm]
Colour Tests
Observed colour of solution after treatment with various reagents:
| HCI | Brown |
| NaOH (5%) | Yellow |
| FeCl3 (5%) | Green |
Thin Layer Chromatography (TLC)
Figure 3 : TLC profiles of citral (S) and water extract of C. citratus dried leaves sheath and stem powder (L) observed under (a) UV at 254 nm and (b) UV at 366 nm before derivatization.
Figure 4 : TLC profiles of citral (S) and water extract of C. citratus dried leaves sheath and stem powder (L) observed under (a) UV at visible light (b) UV at 366 nm after derivatization with vanillin-sulphuric acid.
| Test Solutions | Weigh about 5.0 g of C. citratus dried leaves sheath and stem powder in round flask and add 50 mL of water. Distilled for 4 hr using Clevenger apparatus. Discard the water in Clevenger and collect the oil in 5 mL of volumetric flask. Rinse the Clevenger with 5 mL of methanol and collect in a same volumetric flask. Use the solution as test solution. |
| Standard solution | Dissolve citral standard [CAS no.: 5392-40-5] in 60 mL methanol to produce a standard concentration 0.33 µL/mL solution. |
| Stationary Phase | HPTLC Glass silica gel 60 F254, 10 x 10 cm. Pre-heat the plate at 105°C for 20 min. |
| Mobile phase | Toluene : ethyl acetate : formic acid (9 : 1 : 0.1) (v/v/v) |
| Application |
|
| Development distance | 8 cm |
| Drying | Air drying |
| Detection |
|
High Performance Liquid Chromatography (HPLC)
| Test solution | Weigh about 5.0 g of C. citratus dried leaves sheath and stem powder in a round flask and add 50 mL of water. Distilled for 4 hr using Clevenger apparatus. Discard the water in Clevenger apparatus and collect the oil in 10 mL volumetric flask. Rinse the Clevenger with methanol and collect in a same volumetric flask. Top up to 10 mL with methanol. Filter through a 0.45 µm syringe filter and inject the filtrate into the HPLC column. | ||||||||||||||||||||||||
| Standard solution | Dissolve citral standard [CAS no.: 5392-40-5] methanol to produce 1.1764 µL/mL solution. Dilute 5 mL in 10 mL methanol to produce a standard concentration 0.588 µL/mL solution. | ||||||||||||||||||||||||
| Chromatographic system |
Detector: UV 240 nm Column: C18 column (3.5 µm, 4.6 mm I.D x 150 mm) (Zorbax SB- C18 unless necessary) Column oven temperature: 25°C Flow rate: 1.2 mL/min Injection volume: 10 µL |
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| Mobile Phase (gradient mode) |
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| System suitability requirement |
Perform at least five replicate injections of citral (0.5 µL/mL). The requirements of the system suitability parameters are as follow:
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| Acceptance criteria |
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(a)
(b)
Figure 5 : HPLC chromatogram of citral standard solution (0.5 µL/mL) (a) full and (b) zoom at tr =16.850 min (neral) and tr = 19.006 min (geranial).
Figure 6 : UV spectrum of citral solution (neral) (0.5 µL/mL).
Figure 7 : UV spectrum of citral solution (geranial) (0.5 µL/mL).
(a)
(b)
Figure 8 : HPLC chromatogram water extract of C. citratus dried leaves sheath and stem powder solution (a) full and (b) zoom at tr =16.850 min (neral) and tr = 19.006 min (geranial).
Figure 9 : UV spectrum of citral standard solution (neral) (0.5 µL/mL) and water extract of C. citratus dried leaves sheath and stem powder.
Figure 10 : UV spectrum of citral standard solution (geranial) (0.5 µL/mL) and water extract of C. citratus dried leaves sheath and stem powder.
PURITY TESTS
| Foreign Matter |
| Not more than 2% |
| Ash Contents | |
| Total ash | Not more than 7% |
| Acid-insoluble ash | Not more than 2% |
| Loss on Drying |
| Not more than 10% |
| Extractive Values | |
| Water-soluble extracts | |
| Hot method | Not less than 25% |
| Cold method | Not less than 13% |
| Ethanol-soluble extracts | |
| Hot method | Not less than 13% |
| Cold method | Not less than 7% |
SAFETY TEST
| Heavy Metals | |
| Arsenic | Not more than 5.0 mg/kg |
| Mercury | Not more than 0.5 mg/kg |
| Lead | Not more than 10.0 mg/kg |
| Cadmium | Not more than 0.3 mg/kg |
| Microbial Limits | |
| Total bacterial count | Not more than 105 cfu/g |
| Total yeast and mould count | Not more than 104 cfu/g |
| Bile-tolerant gram negative | Not more than 104 cfu/g |
| Specific Pathogens | |
| Salmonella spp. | Absent in 25 g |
| Escherichia coli | Absent in 1 g |
| Staphylococcus aureus | Absent in 1 g |
| Pseudomonas aeruginosa | Absent in 1 g |
CHEMICAL CONSTITUENTS
Essential oil of C. citratus dried leaf sheath and stem have been reported to contain monoterpenes [e.g. myrcene, (Z)-β-ocimene, (E)-β-ocimene, 6,7-epoxymyrcene, nerol, hydrogenated monoterpenes, oxygenated monoterpenes]; terpene (e.g. linalool); monoterpenoids (e.g. citronellal, geraniol); terpenoids (e.g. neral, geranial,); bicyclic sesquiterpene (e.g. β-caryophyllene); sesquiterpenes, oxygenated sesquiterpenes [ 6 ].
MEDICINAL USES
Uses described in folk medicine, not supported by experimental or clinical data
Traditionally used in tonics and for after childbirth. Its preparation is used for kidney problems [ 7 ].
Biological and pharmacological activities supported by experimental data
Antidiabetic activity
Essential oil of leaf sheath of C. citratus (400 and 800 mg/kg) administered subcutaneously to poloxamer-407 (non-ionic detergent) induced type 2 diabetic male albino Wistar rats (150-160 g) for a duration of 12 weeks significantly (p < 0.001) showed a reduction in glucose levels (400 mg/kg: 432.55 ± 15.49 mg/dL; 800 mg/kg: 323.96 ± 4.89 mg/dL), when compared to the diabetic control rats (614.85 ± 3.84 mg/dL). The same treatment in diabetic rats significantly (p < 0.001) reduced the insulin levels (400 mg/kg: 162.66 ± 0.83 pmol/L; 800 mg/kg: 158.98 ± 1.76 pmol/L) compared to the diabetic control rats (184.85 ± 1.28 pmol/L) [ 6 ].
Antidiarrheal activity
Aqueous extract of C. citratus stalk (800 mg/kg) administered orally to mice (20-30 g; 6-8 weeks old) 1 hr before induction of diarrhea using castor oil showed significant (p < 0.001) reduction in faecal output (53.44%) during 12 h post treatment compared to the standard drug loperamide HCI (57.01%) [ 8 ].
Aqueous extract of C. citratus stalk (800 mg/kg) orally administrated to mice (20-30 g; 6-8 weeks old) 1 hr before induction of diarrhea using castor oil. At the end of 4 hr of post induction, the extract showed significant (p < 0.001) reduction in number of diarrheal episodes (1.50 ± 0.96) and the percentage of protection of diarrhea (50.0%) compared to loperamide (no. of diarrheal episodes: 0.50 ± 0.22; percentage of protection of diarrhea: 50.0%) [ 8 ].
Aqueous extract of C. citratus stalk (800 mg/kg) orally administrated to mice (20-30 g; 6-8 weeks old) 1 hr before inducing diarrhea using magnesium sulfate (MgSO4) exhibited significant (p < 0.01) reduction in diarrhoeal fluid accumulation in intestines (22.82%) after 30 min of induction when compared to loperamide (26.51%) using enteropooling assay (test the diarrheogenic property of prostaglandins) [ 8 ].
Antitumour promoting activity
Ethanol (80%) extract of C. citratus stem (dietary concentrations of 1.8%) administered intraperitoneally to diethylnitrosamine (100 mg/kg) initiated hepatocarcinoma (induced 4 weeks earlier before treatment) in 344 male Fischer rats (5 weeks old) for a duration of 10 weeks significantly (p < 0.05) decreased the number of putatively preneoplastic, glutathione S-transferase placental form-positive lesions (9 ± 3 number/cm3) and the level of oxidative hepatocyte nuclear DNA injury (1.08 ± 0.27/106 dG) in dose dependent manner compared to vehicle treated group (0 number/cm3 and 0.52 ± 0.06 /106 dG) [ 9 ].
Anticholinesterase activity
Essential oil of C. citratus overground part showed significant (p < 0.05) dose-dependent inhibition of acetylcholinesterase (IC50 = 2.14 ± 0.18 μL/mL) and butyrylcholinesterase activity (IC50 = 0.34 ± 0.07 μL/mL) using Ellman’s colorimetric assay [ 10 ].
Vasodilatory activity
Methanol extract of C. citratus stalk (2.5-37.0 µg/ml) showed significant (p < 0.05) vasorelaxation activity (widening of blood vessels) by 55% on isolated perfused mesenteric artery of Wistar Kyoto rats (4 months old) compared to vasoactive drugs control acetylcholine (65%) and histamine (60%) [ 11 ].
Mosquito repellent activity
Essential oil of C. citratus stem diluted with olive oil (0.33 μL/cm2) significantly (p < 0.05) increase the protection time (170.0 ± 9.0 min) from the bites of C. quinquefasciatus on the forearm of volunteers compared to standard repellent Sketolene Shield (182.0 ± 12.2 min). Lemon grass oil in coconut oil provided protection time for 155.5 ± 10.4 min while lemon grass oil in soya bean oil provided protection for 84.0 ± 25.1 min [ 12 ].
Clinical studies
Information and data have not been established.
SAFETY INFORMATION
Preclinical studies (Toxicology studies)
Acute toxicity
Aqueous extract of C. citratus stalk (100-3200 mg/kg) administered orally to mice (20-30 g; 6-8 weeks old) did not show any mortality or any adverse reactions in the animals in term of body weight, body temperature, food and water intake during 72 hr period of observation [ 8 ].
Others (Adverse reaction, contraindication, side effect, warning, precaution)
Information and data have not been established.
DOSAGE
In Ayurvedic practice, the recommended dosage is 3-6 g [ 13 ].
STORAGE
Store below 30°C. Protect from light and moisture.
REFERENCES
- The Plant List. [Internet] Cymbopogon citratus. Version 1.1; [cited on 15th October 2015]. Available from: http://www.theplantlist.org/tpl1.1/record/kew-406132.
- Negrelle RRB, Gomes EC. Cymbopogon citratus (DC.) Stapf: Chemical composition and biological activities. Revista Brasileira De Plantas Medicinais Botucatu. 2007; 9(1):80-92.
- Plant Resources of South-East Asia. [Internet] Cymbopogon citratus [cited on 15th October 2015]. Available from: http://proseanet.org/prosea/eprosea_detail.php?frt=&id=659.
- Eltahir AS, AbuEReish BI. Leaf and stem anatomy of Cymbopogon citratus and Cymbopogon schoenanthus in Sudan. Journal of Chemical and Pharmaceutical Research. 2010; 2(4):766-771.
- Folorunso AE, Oyetunji OA. Comparative foliar epidermal studies in Cymbopogon citratus (Stapf.) and Cymbopogon giganteus (Hochst.) Chiov. in Nigeria. Notulae Botanicae Horti Agrobotanici Cluj-Napoca. 2007; 2(35):7-14.
- Bharti SK, Kumar A, Prakash O, Krishnan S, Gupta AK. Essential oil of Cymbopogon citratus against diabetes: Validation by in vivo experiments and computational studies. Journal of Bioanalysis and Biomedicine. 2013; 5(5):194-203.
- Burkill IH. A dictionary of the economic products of the Malay peninsula. Vol. 2. London; Published on behalf of the governments of the Straits settlements and Federated Malay states by the Crown agents for the colonies. 1935; p.2303-2304.
- Tangpu V, Yadav AK. Antidiarrhoeal activity of Cymbopogon citratus and its main constituent, citral. Pharmacologyonline. 2006;2:290-298.
- Puatanachokchai R, Kishida H, Denda A, Murata N, Konishi Y, Vinitketkumnuen U, Nakae D. Inhibitory effects of lemon grass (Cymbopogon citratus Stapf) extract on the early phase of hepatocarcinogenesis after initiation with diethylnitrosamine in male Fischer 344 rats. Cancer Letters. 2002;183(1):9-15.
- Chaiyana W, Saeio K, Hennink EW, Okonogi S. Characterization of potent anticholinesterase plant oil based microemulsion. International Journal of Pharmaceutics. 2010;401(1-2):32-40.
- Runnie I, Salleh MN, Mohamed S, Head RJ, Abeywardena MY. Vasorelaxation induced by common edible tropical plant extracts in isolated rat aorta and mesenteric vascular bed. Journal of Ethnopharmacology. 2004; 92(2-3):311-316.
- Soonwera M, Phasomkusolsil S. Efficacy of Thai herbal essential oils as green repellent against mosquito vectors. ActaTropica. 2015;142:127-130.
- Department of Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy, Ministry of Health and Family Welfare, Government of India. The Ayurvedic Pharmacopoeia of India Part 1. Volume V. New Delhi, India: Controller of Publications. 2006; pg. 71-73.
