Citrullus lanatus (Thunb.) Matsum. & Nakai

Last updated: 6 Jun 2016

Scientific Name

Citrullus lanatus (Thunb.) Matsum. & Nakai

Synonyms

Anguria citrullus Mill., Citrullus amarus Schrad., Citrullus anguria (Duchesne) H.Hara, Citrullus aquosus Schur, Citrullus battich Forssk., Citrullus caffer Schrad., Citrullus caffrorum Schrad., Citrullus chodospermus Falc. & Dunal, Citrullus citrullus H.Karst., Citrullus citrullus Small, Citrullus edulis Spach, Citrullus edulis Pangalo [Illegitimate], Citrullus mucosospermus (Fursa) Fursa, Citrullus pasteca Sageret, Citrullus vulgaris Schrad., Colocynthis amarissima Schrad. [Invalid], Colocynthis amarissima Schltdl., Colocynthis citrullus (L.) Kuntze, Colocynthis citrullus Fritsch, Cucumis amarissimus Schrad., Cucumis citrullus (L.) Ser., Cucumis dissectus Decne., Cucumis edulis Steud. [Invalid], Cucumis laciniosus Eckl. ex Steud., Cucumis laciniosus Eckl. ex Schrad., Cucumis vulgaris (Schrad.) E.H.L.Krause, Cucurbita anguria Duchesne, Cucurbita caffra Eckl. & Zeyh., Cucurbita citrullus L., Cucurbita gigantea Salisb., Cucurbita pinnatifida Schrank, Momordica lanata Thunb. [1]

Vernacular Name

Malaysia Tembikai, mendikai [2]
English Watermelon [2]
China Xi gua [3], si yong xi gua [4]
India Alpapramanaka, bachchangaayi, brihadgold, Chaya-pula, chelana, chhanho, chitra, chitraphala, chitravalika, darbooji, darbuje, dasamekke, dharbusini, hindano, jamuka, kaalenga, hannu, kaalengu, kalinda, kalinga, kalingad, karigo, karigu, karing, karubooja, komardu, krishnabijartula, kuttowombi, latapanasa, madhuraphala, mandeki-patak, mansala, mansaphala, matira, matiro, meho, meta, mutrala, natamra, pilchagnadi, rajatinisha, seta, shirnavrinta, tandur, tarambuja, tarbooj, tarbooz, tarbuj, tindisa, vrittaphala [5]
Indonesia Semangka, cimangko (Minahasa) [2]
Thailand Taeng-mo (Central); taeng-chin (Peninsular); matao (Northern) [2]
Laos Moo, teeng moo [2]
Philippines Pakwan (Tagalog); sandiya (Bicol); dagita (Marinduque) [2]
Cambodia öö’w llök [2]
Vietnam D[uw]a h[aa] [us], d[uw]a d[or] [2]
Papa New Guinea Melon [2]
France Pasteque [2].

Geographical Distributions

Citrullus lanatus originated from the drier, open areas of tropical and subtropical Africa. Its cultivation became widespread in the Mediterranean region at least 3000 years ago. Introduction into India must also have occurred in ancient times and there a strong secondary centre of genetic diversity developed. Watermelon reached China around the 10th Century and Japan in the 16th Century. From India and China, it spread to Southeast Asia in the 15th Century. It was introduced to the Americas in post-Columbian times. C. lanatus is now widespread in all tropical and subtropical regions of the world. [2]

Botanical Description

C. lanatus is a member of the Cucurbitaceae family. It is a monoecious, occasionally andromonoecious, spreading and annual vine. The root system is extensive but shallow, consisting of taproot and many lateral roots growing in the top 50-60 cm of the soil. The stem is thin, angular and grooved, measures 1.5-5 m long, with soft, long and white hairs. [2]

The leaves are simple, alternately arranged, oblong-ovate in outline, heart-shaped at base, measuring 5-20 cm x 2-19 cm and palmately deeply 3-5(-7)-lobed. The lobes are elongated-ovate in outline, pinnately sinuate-lobulate, shallowly sinuate-toothed, rarely subentire and largest at the central lobe. The petiole is 2-14 cm long. The tendrils are simple to 2(-4)-fid. [2]

The flowers are solitary, axillary, with long hairy pedicels, pale yellow in colour, measure 2-3 cm in diametre and usually in cycles of 6 staminate flowers followed by 1 pistillate flower. There are 5-lobed sepal and 5-partite petal. The male flowers are with 3 free anthers on short filaments. The female flowers are with an inferior, ovoid, hairy ovary and a short style terminated by a 3-lobed stigma. The nectaries are present in male and female flowers. The fruit is an indehiscent pepo, globular to oblongoid or ellipsoid, measuring up to 60-70 cm in length and weighing 1.5-30 kg. [2]

The fruit wall is hairless to hairy, thin to thick, brittle to tough and flexible while the color varies from creamy, golden-yellow, light green to dark green and uniform or mottled or striped. The flesh is derived from the placenta, mostly red or yellow but also pink, orange or white. The flesh texture is from finely grained and 'melting' to firm, coarse and fibrous. [2]

The seeds are scattered throughout the flesh, numerous (200-900 per fruit), smooth, flattened, measuring 6-15 mm x 5-7 mm x 2.5 mm, black, brown, red, yellow, rarely white and without endosperm. [2]

Cultivation

C. lanatus is day length neutral. A warm (day temperatures 25-30°C, night temperatures > 18°C), sunny and relatively dry climate is required for rapid growth and fruiting. Excessive rainfall and high humidity give excessive vegetative growth, affect flowering, induce leaf diseases and fruit rot. Market garden production is usually concentrated in the dry season, with furrow or drip irrigation. It prefers well-drained, fertile loamy sands with high organic matter content and pH 6-7. At lower pH values, soilborne diseases (Fusarium) may become a serious problem. [2]

Chemical Constituent

C. lanatus fruits have been reported to contain carotenoid, prolycopene, lutein, β-carotene, and lycopene. [6][7]

C. lanatus roots has been reported to contain pentacyclic triterpene (e.g. bryonolic acid (3 β-hydroxy-D:C-friedoolean-8-en-29-oic acid)). [8]

C. lanatus seeds have been reported to contain 25-46% fat and 30-35% protein [9][10]. The seeds protein is a good quality with predominant amounts of arginine, glumatic acid, aspartic acid and leucine [11]. The fatty acid composition of the seed oil were, for saturated acids: C16, 11%; C18, 6.6%; for unsaturated acids: C18:1, 24.8% and C18:2, 57.6% [10]. The seeds contain a high proportion of A5-sterols, with codisterol present as a trace component (e.g. 25(27)-dehydroporiferasterol, clerosterol, isofucosterol, stigmasterol, campesterol, and sitosterol) [12].

The compositions of melon seeds and kernel which were obtained from mature fruits [9], and presented on a moisture-free basis were as follows: The crude fat content of the seed and kernel were 28.28 ± 0.85 and 49.95 ± 0.50%, respectively.  The crude protein content of the seed and kernel ranged from 23 to 27% and 38 to 40 %, respectively [9][11].  The crude fibre content of the seed and kernel were 32.99 ± 1.78 and 1.79 ± 0.06%, respectively while the carbohydrate content of the seed and kernel were 12.76 ± 1.76 5.53 ± 0.17, respectively.  The ash content of the seed and kernel were 2.84 ± 0.19 and 2.71 ± 0.02. The melon oil is pale yellow in colour (colour value of 16.0) with a refractive index of 1.482 and a specific gravity of 0.908.  The iodine value (a measure of its degree of unsaturation) was 145.7 [9].

The raw seed kernels contain phytic acid, 5±0.1 mg/g; oxalate, 12±0.4%; total phenols, 2±0.3 mg catechin/g; hydrocyanic acid, 15±0.2 mg/100 g; saponin, 4±0.1% while the kernel/seed ratio was 0.6±0.1 g.  None of the vales were altered when the kernels were toasted to 100 or 125oC, except for the saponin level which was significantly raised at 125oC. The boiling significantly reduced the total oxalates and the hydrocyanic acid content of the kernels. [2]

Plant Part Used

Fruit, seed kernel, kernel oil, rind. [9][11][12][13]

Traditional Use

The ripe fruit was used as a febrifuge, a diuretic and in the treatment of dropsy and renal stones [13]. The flesh of the ripe fruit is eaten or used as animal feed while the seed is roasted for use as roasted or salted foods. The immature fruits are consumed as vegetables while the seed oil is used as cooking oil in some countries in Africa and the Middle East. The kernel is used as a garnish or condiment in traditional Indian cooking [9]. The melon kernel is generally used as a soup thickener in Nigeria while the kernels are eaten as snacks [12]. The fruit rind was used in alcoholic poisoning and diabetes [13]. The rind is also used to make pickles and preserves and is extracted for pectin [11] and is traditionally used for making jam [12].

The seed was used as a demulcent, pectoral, tonic, vermifuge, diuretic and to treat bed wetting. The seed also has hypotensive effect. [13]

The root is used as purgative while large dose can be used as emetic. [13]

Preclinical Data

Pharmacology

Antioxidant activity

The molecular mechanisms of drought/oxidative stress-tolerance in wild C. lanatus was elucidated by subjecting plants that were grown in a growth chamber with a light intensity of 700μmol photons/m2/s, 16 hours daily light period, day/night temperatures of 35/25oC and a relative humidity of 50/60% to water deprivation. [14]

A mRNA differential display technique was used to follow changes in the gene expression patterns in the leaves. The up-regulated genes (designated ‘‘wadi’’ for C. lanatus drought-induced genes) were cloned into plasmid vectors and the sequences compared with those in public databases.  The cDNAs that were identified encoded a broad spectrum of proteins, some of which were induced by abiotic stresses in other plants.  One of the isolated genes exhibited significant homology to plant type-2 metallothionein.  This gene was shown by Northern blotting to be induced in wild C. lanatus leaves under drought/high light stress conditions.  The metallothionein has established roles in Cd-detoxification and Cu/Zn-homeostasis and protected fungal and vertebrate cells from oxidative injuries.  The protein product of this gene was named CLMT2 (C. lanatus metallothionein type-2).  The CLMT2 protein (10-40 μM) dose-dependently suppressed the reaction between salicylate (200 μM) and hydroxyl radicals, thus was a potent scavenger of hydroxyl radicals.  In contrast, an order higher concentration of citrulline (a compatible solute in wild C. lanatus ) was required for effective competition with salicylate for the radicals.  The rate constant for CLMT2 was estimated to be 1.2 x 1011 /M/s, which was one- or two orders higher than those reported for antioxidants  such as ascorbate and glutathione (7.2 and 8.8 x 109/M/s, respectively) or citrulline (3.9x109 /M/s).  The degradation of DNA by hydroxyl radicals generated by the iron/H2O2 system was dose-dependently suppressed by CLMT2 with almost complete suppression elicited by 12 μM CLMT2. [14]

The wild C. lanatus plants that grow in the Kalahari desert, Botswana, exhibit exceedingly high drought tolerance.  Their leaves showed massive accumulation of the free amino acid citrulline.  To determine whether citrulline has hydroxyl radical scavenging property, its reactivity in vitro against hydroxyl radicals was determined.  The citrulline competed with salicylate for hydroxyl radicals produced by iron/H2O2 in a concentration-dependent manner with an ID50 of 6.6±1.2 mM and a rate constant of (3.9 ± 0.82)x109/M/s.  The citrulline (50-200 mM) also effectively protected DNA from attacks by reactive oxygen species.  The citrulline (200 or 400 mM) protected pyruvate kinase from oxidative damage without much effect on other metabolic enzymes. [15]

The lycopene is a red pigment that occurs naturally in C. lanatus.  It is a highly effective antioxidant with free radical scavenging activity and has the highest singlet oxygen quenching rate of all carotenoids [7][16]. The use of lycopene as a dietary supplement has shown potential in reducing the risk of coronary heart disease [17] and to decrease the susceptibility of low density lipoprotein (LDL) to oxidation [18] besides protection from other cellular oxidative damage.  Its other benefits include relief of oral leukoplakia [19] and prostate cancer [20] and the suppression of human papilloma virus (HPV) [21]. The treatment of rats with lycopene (10 or 50 mg/kg per os for 2 weeks) resulted in the accumulation of lycopene in the liver, liver microsomes, and blood plasma and an increase in total plasma antioxidant activity.  The lipid peroxidation in the liver was inhibited while solubilization of lysosomal enzymes was reduced [22].

Antiallergy activity

The bryonolic acid or its derivatives, was active against at least three types of allergies. The synthetic derivatives, in particular a potassium salt of its succinate ester has significantly greater activities than the natural compound. [8]

Toxicity

No documentation

Clinical Data

Clinical findings

No documentation

Adverse reaction

C. lanatus allergy has been described, especially in patients with pollinosis. [23]

Interaction & Depletion

No documentation

Contraindications

No documentation

Case Report

A series of case reports of patients with ragweed (Ambrosia artemisiifolia) allergy who also experienced oral symptoms after eating various members of the Cucurbitaceae family (C. lanatus , cantaloupe, honeydew melon, zucchini, and cucumber) was described. The fifty percent of the patients with ragweed allergy also had IgE directed against these fruits while crossreactivity between watermelon (C. lanatus) and ragweed pollen was shown in enzyme-linked immunosorbent assay (ELISA)-based IgE inhibition experiments.  The mellon allergy mostly occurred in patients with pollinosis.  The melon allergens were identified by IgE immunoblotting experiments using sera from patients who displayed oral allergy symptoms following melon ingestion.  The melon profilin, a 13-kDa component was identified as a major allergen.  It is stable in human saliva, probably due to the lack digestive proteases such as pepsin in saliva, but it is digested within a few seconds by simulated gastric fluid.  This lead to the speculation that melon profiling may be responsible for the local oral symptoms of melon allergy.  The ten percent of patients with melon allergy may display severe anaphylactic reactions. [23]

Dosage

No documentation

Poisonous Management

No documentation

Line drawing

 

118

Figure 1: Line drawing of C. lanatus [2]

References

  1. The Plant List. Ver1.1. Citrullus lanatus (Thunb.) Matsum. & Nakai.[homepage on the Internet]. c2013 [updated 2012 Mar 23; cited 2016 Jun 6] Available from: http://www.theplantlist.org/tpl1.1/record/kew-2723908
  2. Siemonsma JS, Piluek K, editors. Plant Resources of South-East Asia No 8. Vegetables. Wageningen, Netherlands: Pudoc Scientific Publishers; 1993.
  3. Schmidt MW. The HSK guide to vocabulary, Chinese characters and grammar points: For all the six levels of the Chinese language proficiency exam. Hamburg: disserta Verlag, 2015; p. 41.
  4. Hong DY, Blackmore S, editors. Plants of China: A companion to the flora of China. Beijing: Science Press, 2015; p. 373.
  5. Quattrocchi U. CRC world dictionary of medicinal and poisonous plants: Common names, scientific names, eponyms, synonyms and etymology. Volume II C-D. Boca Raton, Florida: CRC Press, 2012; p. 979.
  6. Davis AR, Collins J, Fish WW.  Rapid method for total carotenoid detection in canary yellow-fleshedwatermelon.  J Food Sci. 2007;72(5):S319- S323.
  7. Perkins-Veazie P, Collins JK, Pair SD.  Lycopene content differs among red-fleshed watermelon cultivars.  J Sci Food Agric. 2001;81(10):983-987.
  8. Tabata M, Tanaka S, Cho HJ.  Production of an anti-allergic triterpene bryonolic acid, by plant cell cultures.  J Nat Prod. 1993;56(2):165-174.
  9. Das M, Das SK, Suthar SH.  Composition of seed and characteristics of oil from karingda [Citrullus lanatus (Thumb) Mansf].  Int J Food Sci Technol. 2002;37(8):893–896.
  10. Girgis P, Turner TD.  Lesser known Nigerian edible oils and fats.  III. Fatty acid compositions as determined by gas-liquid chromatography.  J Sci Food Agric. 1972;23(2):259-262.
  11. Wani AA, Sogi DS, Grover L.  Effect of temperature, alkali concentration, mixing time and meal/solvent ratio on the extraction of watermelon seed proteins-a response surface approach.  Biosyst Eng. 2006;94(1):67-73.
  12. Badifu GIO.  Effect of processing on proximate composition, antinutritional and toxic contents of kernels from Cucurbitaceae species grown in Nigeria.  J Food Compost Anal. 2001;14(2):153-161.
  13. Plants for a Future. Citrullus lanatus - (Thunb.)Matsum.&Nakai. [homepage on the Internet] c1996-2012 [cited 2016 Jun 06 09]. Available from: http://www.pfaf.org/user/Plant.aspx?LatinName=Citrullus+lanatus
  14. Akashi K, Nishimura N, Ishida Y, Yokota A. Potent hydroxyl radical-scavenging activity of drought-induced type-2 metallothionein in wild watermelon.  Biochem Biophys Res Commun. 2004;323(1):72-78.
  15. Akashi K, Miyake C, Yokota A.  Citrulline, a novel compatible solute in drought-tolerant wild watermelon leaves, is an e¤cient hydroxyl radical scavenger.  FEBS Lett. 2001;508(3):438-442.
  16. Xu Y, Leo MA, Lieber CS.  Lycopene attenuates arachidonic acid toxicity in HepG2 cells overexpressing CYP2E1.  Biochem Biophys Res Commun. 2003;11:303(3):745-50.
  17. Sesso HD, Liu S, Gaziano JM.  Dietary lycopene, tomato-based food products and cardiovascular disease in women.  J Nutr. 2003;133(7):2336-2341.
  18. Chopra M, O'Neill M. E, Keogh N.  Influence of increased fruit and vegetable intake on plasma and lipoprotein carotenoids and LDL oxidation in smokers and nonsmokers.  Clin Chem. 2000;46(11):1818-1829.
  19. Singh M, Krishanappa R, Bagewadi A. Efficacy of oral lycopene in the treatment of oral leukoplakia. Oral Oncol. 2004;40(6):591-596.
  20. Clinton SK, Emenhiser C, Schwartz SJ. Cis-trans Lycopene isomers, carotenoids, and retinol in the human prostate.  Cancer Epidemiol Biomarkers Prev. 1996;5(10):823-383.
  21. Sedjo RL, Roe D. J, Abrahamsen M, et al. Vitamin A, carotenoids, and risk of persistent oncogenic human papillomavirus infection. Cancer Epidemiol Biomarkers Prev. 2002;11(9):876-884.
  22. Kravchenko LV, Morozov SV, Beketova NA, Deryagina VP, Avren'eva LI, Tutel'yan VA. Antioxidant status of rats receiving lycopene in different doses.  Bulletin of Experimental Biology and Medicine. 2003;135(4):353-357.
  23. Egger M, Mutschlechner S, Wopfner N, Gadermaier G, Briza P, Ferreira F. Review.  Pollen-food syndromes associated with weed pollinosis: an update from the molecular point of view.  Allergy. 2006;61(4):461-476.