Isolation of Cucurbitacin E Glucoside and Cucurbitacin I Glucoside

Introduction:

Ethnomedicinal studies play a significant role in highlighting the indigenous plant species particularly for the discovery of new crude drugs. Documentation of indigenous medicinal knowledge of traditional plant species has resulted in development of a number of new drugs(Mahmood et al. 2013).

Medicinal plants are spread through varied habitats and landscapes. Rajasthan state is known for a rich floral diversity with 1911 wild species belonging to 780 genera and 154 families. The most common herbal medicines used by tribes of Rajasthan are plants of Fabaceae, Euphorbiaceae, Asteraceae, Apiiaceae, Cucurbitaceae, Acantheceae, papaveraceae, Capparidaceae and Solanaceae families. (bhuvaneshwar upadhayay) (Upadhyay et al. 2010)

Chemical constituents of plants are of utmost importance for the discovery of therapeutic agents and in establishing the medicinal value of traditional plants. (C.Uma)(Uma & Sekar 2014)

Citrullus colocynthis (L.) is a member of Cucurbitaceae family, a desert plant with immense medicinal importance and a good source of valuable oil. It is widely distributed throughout Asia including India. It is commonly known as bitter apple, or colosynth is used as an abortifacient, cathartic, purgative and vermifuse, and for the treatment of fever, cancer, amenorrhea, jaundice, leukemia, rheumatism, tumour and as an insect repellant. It also act as a traditional medicines for arthritis, diabetes, inflammatory disorders, and stomachache (Taslimahemad Khatri)

Citrullus colocynthis is annual or perennial (in wild), herbaceous, flowers monoecious, fruit pepo & seed numerous. Its fruits are used as strong laxative. (Arshad Iqbal Dar)(Dar et al. 2012)

Citrullus colocynthis produces fruits called as colocynth apples which are similar to the common watermelon vine and tastes bitter. This plant bears solitary sterile flowers and a large, fleshy perennial root, which sends out slender, tough, angular, vine-like stems and branched tendrils. (Salah Ali Idan)(Idan et al. 2015)

Citrullus colocynthis fruits aqueous pulp extract is used for kidney, liver functions treatment. Isolated phenolic compounds have antioxidative and anticarcinogenic properties by absorbtion and neutralization of free radicals. (Hediat M.H. Salama)(Salama 2012)

The main medicinal part of this plant is the fruit pulp, and it so far different biological activities have been reported from it. Fruits of Citrullus colocynthis showed analgesic, purgative, anti-inflammatory, antioxidant, antidiabetic, and hypolipidemic activities. Cucurbitacins have been reported as the main chemical constituents of Citrullus colocynthis fruits.(Saeed Mehrazadi)(Mehrzadi et al. 2015)

Infusion prepared from the fruit and seeds of this plant from the cucurbitaceae family are indeed recommended to diabetic patients[5]. The chemical compounds identified in antidiabetic plants are often alkaloids and polyphenols, but also polysaccharides, gums and glycans. (Alaa M. Shawkey)(Shawkey et al. 2014)

This literature survey involves the documentation of data from 1950 to 2017 from authenticated sources like google scholar, sciencedirect and pubmed regarding phytochemical studies and pharmacological activities of various parts of Citrullus colocynthis plant.

Phytochemical Studies

Isolated compounds ursolic acid and cucurbitacin E 2-O-β-D-glucopyranoside from the methanolic fruit extract of Citrullus colocynthis showed antimicrobial activity. In an experimentation isolated compounds, cucurbitacin and colocynthin from the ethanolic root extract of this species proved to be hepatoprotective against carbon tetra chloride induced toxicity in experimental animals. (Jamuna S, Karthik)

In a study related to Citrullus colocynthis leaf extract two new tetracyclic cucurbitane-type triterpene glycosides were isolated from an ethyl acetate extract of Citrullus colocynthis leaves and four known cucurbitacins. Chemical structures were designed through spectroscopic data (mainly NMR and mass spectrometry). Two new cucurbitacins isolated were- 6′-acetyl-2-O-β-D-glucocucurbitacin E and 25-p-coumaroyl-3′- acetyl-2-O-β-D-glucocucurbitacin I. The later coumaroyl cucurbitacin derivative showed significant specific cytotoxic activity towards colorectal cell lines. (Rachid Chawech)(Chawech et al. 2015)

In an experimental study the methanolic extract of the whole plant of citrullus colocynthis was divided into fractions soluble in hexane, chloroform, ethylacetate, butanol, and water. Column chromatography of the ethylacetate soluble fraction showed three new bitter principles named as colocynthins A, B & C along with β-sitosterol, 3-O-β-D-glucopyranoside, elaterinide, and bryoamaride, respectively. New compounds were glycosides gave, positive Molisch test result, as well as Salkowski and Liebermann – Burchard color reactions for triterpenes. Colocynthin A was obtained as an off-white amorphous solid and Infra Red spectrum showed bands for OH (3400 cm ^-1), C¼O (1715 cm ^-1 ), conjugated C¼O (1680 cm ^-1 ),and olefinic (1610 – 1650 cm ^-1) functionalities. The HR-FAB-MS (positive-ion mode) provided an [M+H]⁺ peak at m/z 659.3422, indicating the molecular formula C₃₆H₅₀O₁₁, as well as a fragment ion [M-162+H] ⁺ at m/z 497.2832 due to the loss of the glucose moiety. Colocynthin B also obtained as an off-white amorphous solid. The HR-FAB-MS of Colocynthin B gave signal at 691.3681 [M+H]⁺, and in conjunction with the ¹³C-NMR data, the molecular formula determined as C₃₇H₅₄O_12. Colocynthin C was isolated as an off-white amorphous solid. The molecular formula obtained as C₃₇H₅₄ O₁₁ by HR-FAB-MS in the positive-ion mode, which gave an [M+H]⁺ peak at m/z 675.3732 (C₃₇H₅₅O⁺₁₁ ; calc. 675.3744). (Durey Nayab)(Taylor et al. n.d.)

In a study conducted in the chloroform fraction of the methanol extract of C. colocynthis fruits, active constituent was isolated by silica gel column chromatography and preparative HPLC. Structural analysis was done using spectroscopy including EI/MS, ¹H NMR, ¹³C NMR, COSY, DEPT, and HMQC NMR and then by direct comparison with an authentic reference compound. The active compound isolated was 4-methylquinoline. Spectroscopy reported about 4- methylquinoline(C₁₀H₉N); EI/MS (70 eV) m/z M⁺ 143 (100, base peak), 135 (40), 105 (39), 107 (40), 79 (46), 51 (13); ¹H NMR (CD₃ OD, 600 MHz) δ 2.61 (s), 7.26−7.27 (d, J = 6.7 Hz), 7.42−7.43 (t, J = 6.9 Hz), 7.63−7.75 (t, J = 83.1 Hz), 8.00−8.05 (d, J = 35.7 Hz), 8.09−8.11 (d, J = 7.3 Hz), 8.42− 8.43 (d, J = 1.6 Hz); ¹³C NMR (CD₃OD, 150 MHz) δ 150.6, 148.2, 135.5, 130.0, 128.5, 128.1, 126.5, 124.4, 122.9, 19.6. (Ju-Hyun Jeon)(Jeon & Lee 2014)

During the investigation of citrullus colocynthis in-vivo (leaf, stem, fruit and root)and in-vitro callus a flavonoid quercetin was obtained. Rf value (0.82) of quercetin isolated from the extract samples resembles the Rf value of standard quercetin as well as characteristic Infra Red spectral peaks were superimposable with respective standard reference compounds of quercetin. HPLC parameter showed retention time of 3.475 min which coincided with that of standard quercetin. Quercetin was present in vivo (leaf, stem, fruit and root) and in vitro callus samples of Citrullus colocynthis. (Mahesh Chand Meena)(Meena & Patni 2008)

In an investigation the reversed-phase preparative HPLC analysis of the butanol fraction of the methanol extract of C. colocynthis fruits gave three flavonoid glycosides, isosaponarin, isovitexin and isoorientin 3’-O-methyl ether and two cucurbitacin glucosides, 2-O-β-D-gluco-pyranosylcucurbitacin I and 2-O-β-D-glucopyranosylcucurbitacin L. An ESIMS mass spectrum of isosaponarin showed [M+H]+ (positive ion mode) ion peak at m/z 595, M_r = 594 and obtained molecular formula as C₂₇H₃₀O₁₅. An ESIMS mass spectrum of isovitexin obtained as [M+H]⁺ ion peak at m/z 433, M_r= 432 and C₂₁H₂₀O₁₀. An ESIMS mass spectrum of isoorientin 3’-O-methyl ether gave [M+H]⁺ ion peak at m/z 463, M_r= 462 and C₂₂H₂₂O₁₁. While ESIMS mass spectrum of 2-O-β-D-gluco-pyranosylcucurbitacin Igave [M+H]⁺ (positive ion mode) ion peak at m/z 677, suggesting M_r = 676 and solving for C₃₆H₅₂O₁₂ and ESIMS mass spectrum of 2-O-β-D-glucopyranosylcucurbitacin L showed [M+H]⁺ (positive ion mode) ion peak at m/z 679,Mr = 678 and C₃₆H₅₄O₁₂. (Abbas Delazar)(Delazar et al. 2006)

The chloroform extract of the defatted Citrullus colocynthis plant was fractionated to obtain four glycosides as 2-O- β-D-glucopyranosyl-cucurbitacin I, 2-O- β -D-glucopyranosyl-cucurbitacin E as the major product, 2-O- β -D- glucopyranosyl-cucurbitacin L and a novel glycoside 2-O- β -D-glucopyranosyl-(22 -27)-hexanorcucurbitacin I. Structural studies of cucurbitacins were done using ¹H and ¹³CNMR spectra. The NMR spectra of first three compounds resemble with free aglycones while EIMS spectra for same compounds did not produce observable parent ions. But FABMS showed observable parent ions either: as [M +1]⁺ or [M + Na] ⁺ ions. The spectral evidence lead to the structural assignment of 2-O-B-D-glucopyranosyl-(22-27)-hexanorcucurbitacin I, which was the only degraded cucurbitacin glycoside reported till 1988. This compound was isolated as an amorphous powder, and analysis showed a molecular ion peak at m/z 585 [M (C₃₀H₄₂O₁₀) + Na]⁺ in the FAB mass spectrum, and ketonic carbonyl absorption (1690 cm^-1) in the IR spectrum. (Natiq A.R. Hatam)(Hatam et al. 1984)

In this study alcoholic extract of citrullus colocynthis was extracted with chloroform and the product of this extraction after maintaining the pH 5.2-5.4 and addition of elaterase enzyme showed the formation of elaterin in the sediment. Further experimental studies isolated a white crystalline substance identified as elatericin B (II) (cucurbitacin I). Thereafter two more compounds were isolated as dihydroelatericin B (III) and tetrahydroelatericin B (IV) with petroleum ether and ether. A yellow substance crystallized out of from ether solution identified as the glycoside elaterinide ll. (D lavie)(Lavie & Will 1963)

During the gas chromatography-mass spectrometry (GC-MS) spectral analysis of methanolic extract of Citrullus colocynthis 33 bioactive phytochemical compounds were identified by studying the peak area, retention time molecular weight and molecular formula. Spectral analysis of C. colocynthis revealed the existence of the methyl 6-oxoheptanoate, hexanoic acid, 2-isopropyl-2-methyl-5-oxo-, methyl ester, dodecanoic acid, 3-hydroxy, benzofuran,2,3-dihydro, 1,1-Cyclopropanedimethanol, 2-methyl-α-phenyl, 1,1-cyclopropanedimethanol, 2-methyl-α-phenyl, 12,15-octadecadiynoic acid, methyl ester, (5ß)pregnane-3,20ß-diol, 14α,18α-[4-methyl-3-oxo-(1-oxa-4-azabutan, 3-N,Ndimethyllaurylammonio) propanesulfonate, 2H-1-benzopyran-3,4-diol,2-(3,4-dimethoxyphenyl)-3,4dihydro-6-met, 11,13-dihydroxy-tetradec-5-ynoic acid, methyl ester, Cyclopenta[1,3]cyclopropa[1,2]cycloheptan-3(3aH)-one,1,2,3b,6,7, 4-(2,4,4-trimethyl-cyclohexa-1,5-dienyl)-but-3-en-2-one, 1-tetradecanamine,N,N-dimethyl, α-D-glucopyranoside, O-α-D-glucopyranosyl-(1,fwdarw.3)-ß-D-fructo, acetamide, N-methyl-N-[4-(3-hydroxypyrrolidinyl)-2-butynyl]-, 9-octadecenamide,(z)-, butyrophenone,2´,3,4´,6´-tetramethyl-, ethyl 5,8,11,14,-eicosatetraenoate, 9,12,15-octadecatrienoic acid, 2,3,-dihydroxypropyl ester, (Z,Z,Z)-, 1H-cyclopropa[3,4]benz[1,2-e]ezulene -5,7b,9,9a 476.241018tetrol,1a,1b,4,4a, 9,12,15-octadecatrienoic acid, 9,10-Secocholesta -5,7,10(19)-triene-3,24,25,-triol,(3ß,5Z,7E)-,9,12,15-Octadecatrienoicacid,2,3-dihydroxypropylester,(Z,Z,Z)-,triazido-(1,2,3,4,5-pentamethylcyclopenta-2,4-dienyl)-german, ethyl iso-allocholate, α-N-Normethadol, Octadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester, phthalic acid , decyl oct-3-yl ester, 1,2-Benzenedicarboxylic acid , bis(8-methylnonyl)ester, phthalic acid, di(6-ethyl-3-octyl)ester, y-tocopherol, 1,4-ethanonaphthalene -6,9(4H)-dione,1,4a,5,8a-tetrahydro-4,5,7,10 and vitamin E. (Salah Ali Idan)(Idan et al. 2015)

In this study the chromatographic purification obtained from C. colocynthis fruits extract resulted in the isolation of cucurbitacin E glucoside and cucurbitacin I glucoside. These compounds showed promising results against in vitro cytotoxic activity against Hepatoma Cell Line (HepG2) and mice-bearing tumor of Ehrlich’s ascites carcinoma (EAC). The in vivo study showed the tendency of both compounds prolonging the survival time, life span and normalize the biochemical parameters of the infected mice with EAC. Both compounds had potent inhibitory activity on HepG2 with IC50 3.5 and 2.8 nmol/mL respectively.  (S.Ayyad)(Ayyad et al. 2012)

During investigation of Citrullus colocynthis fruits using different solvents (n-hexane, methylene chloride, Chloroform and ethanol) showed presence of six compounds, and the most abundant of them had retention time (Rt.) 4.8 min. (69.3%). This compound was purified by using florisil column stepwise eluted with different mixtures of methanol: chloroform. Mass analysis of the compound showed the molecular ion peak at m/z 719. The elemental analysis (C, H and N) showed molecular formula to be C₃₈ H₅₅ O₁₃ and I.R., proton and ¹³C NMR analys identified the compound as 2-O-β-D-glucopyranosylcucurbitacin E. (A .Torkey)(Torkey HM, Azeiz 2009)

Pharmacological activities,

Traditional uses:

Citrullus colocynthis (Linn.) Schrad (CCT) is an important medicinal plant belonging to the family of Cucurbitaceae. It is a well recognized plant in the traditional medicine and was used by people in rural areas as a purgative, antidiabetic and insecticide. Citrullus colocynthis has a beneficial effect in sciatica and gout. It is useful as enema during colic, sciatica, backache, and paralysis discomforts. C. colocynthis oil obtained by boiling pulp with sesame or olive oil is externally used for ear pains, tinnitus, toothache, and hair loss. Administration of nearly 3.5 g of this oil is phlegmatic purgative and vermifuge. The leaf of C. colocynthis has purgative effect and also used in epilepsy. External application of its leaf is useful in inflammation and bleeding. The root acts as a potent antidote for scorpion and snail bites. The most popular traditional use of C. colocynthis seeds and fruits is in diabetes treatment. (Roja Rahimi)(Rahimi et al. 2012)

Antioxidant activity:

Antioxidant activity of Citrullus colocynthis (L.) Schrad. methanolic fruit extract showed the total phenolic content as 0.74% of gallic acid equivalents of phenolic compounds while the total flavonoid content was 0.13% of catechin equivalent of fresh mass of C. colocynthis fruit extract. DPPH radical was used as a substrate to evaluate the free radical scavenging activity of CCF extract. The scavenging effect of CCF extract on the DPPH radical was 88.0 ± 2.7% (p < 0.005), at a concentration of 2500 mg mL^-1 compared to the scavenging effects of ascorbic acid, BHA and a-tocopherol at 50 mg mL^-1 of 89.5 ± 1.1, 83.2 ± 1.1 and 67.5 ± 0.8% (p < 0.05) respectively. The percentage of H₂O₂ scavenging activity of CCF was found to be 62.7 ± 3.5 (p < 0.001) at 2500 mg mL^-1, and antioxidant activity of BHA and a-tocopherol was 89.3 ± 3.1 % (p < 0.05) and and 94.5 ± 2.5 % (p < 0.05), respectively at a concentration of 50 mg mL^-1. The highest antioxidant and free radical scavenging ability of the fruit extract was ob- served at a concentration of 2500 mg mL^-1. Free radical scavenging effect of CCF increases with increasing concentration and maximum antioxidant activity was observed at 2500 mg mL^-1 (Sunil Kumar)(Kumar et al. 2008)

Anti-hyperlipidemic effect

The pulp and the seeds of Citrullus colocynthis were investigated for the anti-hyperlipidemic effects on New Zealand rabbits. The hypercholesterolemic regimen of Citrullus colocynthis significantly increased the amount of blood cholesterol, LDL-C, HDL-C, triglyceride and blood sugar (p<0.05). The reduction of LDL-C in the groups receiving the pulp extracts and 100 mg/kg seed extract were significant (p<0.05). HDL-C reduction was also significant in the groups receiving a diet containing the standard regimen, plus cholesterol (0.5%) and 100 mg/kg of Citrullus pulp extract; diet containing the standard regimen, plus cholesterol (0.5%) and 100 mg/kg of Citrullus seed extract. The effect of C. colocynthis on the blood lipid profile in rabbits may be due to high amounts of saponins in C. colocynthis which decreased cholesterol levels by reducing the absorption of cholesterol, increasing the repel of fecesic estrol, and diarrhea due to increased peristalsis. In this trial, the use of C. colocynthis resulted significant reduction of total serum cholesterol and LDL-C in groups receiving the extracts. (Marzyieh Zamani)(Zamani et al. 2007)

Anti-hyperglycaemic effect

In normal rabbits, oral administration of aqueous extract (300 mg/kg) produced significant reduction in plasma glucose after 1 h and highly significant after 2,3 and 6 h. The hypoglycaemic effects of tertiary and quaternary alkaloids, glycoside and saponin components present in this plant at a dose (50 mg/kg p.o) were studied in normoglycaemic rabbits. The alkaloidal extract did not significantly lower the blood glucose levels while the glycosidic extract significantly lowered the fasting glucose levels after 2 and 3 h and highly significant after 6 h. The effect was more pronounced with saponin extract, the saponin significantly lowered the fasting glucose levels after 1 and 2 h and higly significant (P<0.001) after 3 and 6 h. Plasma glucose concentration was significantly reduced by administration of different doses (10, 15 and 20 mg/kg) of saponin extract given to alloxan diabetic rabbits.(Issa Abed Abdel-Hassan)(Abdel-hassan & Abdel-barry 2000)

Anti-fertility effects:

The present study showed that C. colocynthis (50% EtOH) extracts suppresses sperm density and motility and fertility of rats. However, the administration of the fruit extract exhibited a severe and reversible inhibition of sperm density and fertility. The sperm density approached to around 10 million/mm³ in all treatment groups as compared to 46.5 million/mm3 in the vehicle-treated group. The weights of testes, epididymis, seminal vesicles, and ventral prostate markedly reduced after C. colocynthis treatment in the various groups due to the antiandrogenic nature of the drug suggesting androgen imbalance and inhibition of the androgen production by the testes. Hence 50% ethanol extract of C. colocynthis fruit induced reversible antifertility activity in male rats due to its antiandrogenic nature. (M. Chaturvedi)(Chaturvedi et al. 2003)

Anti-ulcer activity:

The present study investigated the antiulcer potential of aqueous and ethanolic extracts of Citrullus colocynthis. Aqueous and ethanolic extracts of fruits Citrullus colocynthis at  200 mg/kg and 400 mg/kg using pylorus ligation ulcer model, considered the following parameters- viz. gastric volume, pH, total acidity, free acidity, ulcer index and percentage inhibition of ulceration was determined. Pretreatment of aqueous and ethanolic extracts 400 mg/kg of Citrullus colocynthis fruits showed significant (P<0.001) decrease in the gastric volume, total acidity and free acidity. However, pH of the gastric juice was significantly (P<0.001) increased at the dose, 400 mg/kg. It showed also significant (P<0.001) decrease in number of ulcers and ulcer score index in pylorus ligation ulceration model. Fruit extracts of Citrullus colocynthis (CCT) exhibited a significant anti-ulcer activity in experimental male wistar rats. Ethanolic extract showed better anti-ulcer activity than aqueous extract. (V. PRASANTH REDDY)(Reddy 2012)

Antifungal activity:

The study evaluated the antifungal activity of hydroalcoholic extract of Citrullus colocynthis fruits against different Candida and Aspergillus strains. Activity was determined using disc diffusion and broth of macrodilution methods. All tested fungal strains showed sensitivity to the extract. The growth inhibition value of the extract showed high antifungal activity against A.fumigatus and A. niger and a lesser effect against C. guilliermondii and C. kreusei. The minimal inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values ranged from 1.56 to 12.5 mg/ml and 3.125 to 25 mg/ml, respectively. The results justified the use of  Citrullus colocynthis in the treatment of some fungal infections. (Samaneh Eidi)(Eidi et al. 2015)

Antibacterial activity:

In the present investigation antibacterial properties of Citrullus colocynthis were studied. The antibacterial activity of Citrullus colocynthis leaves and fruits extracts (water and ethanolic) against standard (ATCC 25923) and hospital isolated strains of Staphylococcus aureus from novobiocin treatment patients were evaluated using disc diffusion method. The inhibitory effects of this extracts were compared with standard antibiotic, novobiocin. The ethanolic extract showed inhibitory activity more than the water extract against S. aureus in a dose dependent manner. 5 mg/mL fruits ethanolic extract showed similar inhibitory effect with novobiocin against standard strain. The present research suggested that one of the chemical components in ethanolic extract such as alkaloids, flavonoides and glycosides had a powerful antibacterial effect even more than novobiocin, especially against hospital isolated strains.( Shahla Najafi) (Najafi et al. 2010)

Anticonvulsant Activity:

This study investigated the anticonvulsant activity of Citrullus colocynthis fruit extract in the treatment of convulsion. Pentylenetetrazole induced convulsions were made in albino mice pretreated with fruits extract (10, 25, 50, and 100 mg/kg dose). Hydroalcoholic extract at doses 25 and 50 mg/kg prolonged the onset of seizures and decreased the duration compared with control group. Citrullus colocynthis pulp extract showed a statistically significant reduction in the seizures duration and increase in latency period of seizures induced by pentylenetetrazole in mice. This effect increased dose dependently at doses of 10, 25, and 50mg/kg. The main action of the pentylenetetrazole-induced seizure is reducing Ƴ-aminobutyric acid (GABA) level in the cortex. (Saeed Mehrzadi)(Mehrzadi et al. 2015)

Hypoglycaemic activity:

A study showed presence of saponin glycosides, triterpenoids, alkaloids, flavanoids and resins in aqueous extract of roots of Citrullus colocynthis which significantly reduced the blood sugar level (58.70%) when compared with chloroform (34.72%) and ethanol extracts (36.60%) (P< 0.01). Assumed mechanism behind the decrease in the blood glucose levels of diabetic rats treated with the extracts is due to stimulation of residual pancreatic mechanism or by increase in peripheral utilization of glucose. The aqueous extracts of Citrullus colocynthis improved the parameters like body weight, serum creatinine, serum urea and serum protein as well as lipid profile and also restored the serum level of bilirubin total, conjugated bilirubin, serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transminase (SGPT) and alkaline phosphatase (ALP). VIPIN AGARWAL

Antimicrobial effect:

Antimicrobial effect of aqueous extract of the Citrulllus colocynthis showed high antibacterial activity against E.coli and Staphylococcus aureus, and considerably less effect against Klebseilla pneumoniae and Bacillus subtilis . While, methanolic extracts of this plant showed high antibacterial activity against Bacillus subtilis, Streptococcus pyogenes, Salmonella typhi, considerably less activity against Streptococcus faecalis and there was no effect against Proteus mirabilis, Proteus vulgaris and Vibrio cholerae. The methanolic extract also showed high antifungal activity against Aspergillus fumigatus, Mucor sp., and Aspergillus flavus, Candida albicans, Penicillium sp., and Rhizopus sp. did not show any antifungal activity. The results obtained in the study suggest the antimicrobial role of Citrullus colocynthis in treating infections caused by the test organisms.   Gurudeeban

Insecticidal activity:

A glycoside Cucurbitacin E isolated from Citrullus colocynthis was investigated for insecticidal activity against Aphis craccivora with extraction obtained from different solvents like n-hexane, methylene chloride, chloroform 50 and ethanol. The ethanolic extract showed the highest insecticidal effect (LC 11003 ppm) against A. craccivora. After further extraction of the residue remaining after evaporation of ethanolic extract with nine solvents, the butanol fraction showed the highest insecticidal effect (LC3123.10 ppm).This insecticidal potency of C. colocynthis extract is due to the presence of specific extracted active ingredients of the tested plant such as saponin, alkaloids and glycosides. Overall analysis, conclude that this compound showed an insecticidal effect against Aphis craccivora. Torkey(Torkey HM, Azeiz 2009)

Anti-diabetic activity:

Antidiabetic Effect of Citrullus colocynthis on liver hexokinase and gluconeogenic enzymes like glucose-6 phosphatase and fructose 1,6-biphosphatase in Alloxan Induced Diabetic Rats was evaluated. Leaf suspension of Citrullus colocynthis at dose of 250mg and 500mg /kg body weight administered for 60 days reduced the blood glucose level (from 381 ± 34 to 105 ± 35), glycosylated hemoglobin, and decrease in the activities of glucose-6 phosphatase and fructose 1, 6-bisphosphatase, while increasing the activity of liver hexokinase. Hence the results showed positive therapeutic efficacy in terms of antidiabetic activity of Citrullus colocynthis. Gurudeeban S and Ramanathan

Antibacterial and anticandidal activity:

Tunisian Citrullus colocynthis extracts both aqueous and diluted acetone extracts (roots, stems, leaves and three maturation stages of its fruit and seeds) showed activity against all microbial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis —and various Candida spp. – Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei. The highest MICs and MBCs/MFCs were obtained from the fruit aqueous extracts(MIC0.10mg/ml against Candida albicans and Candida glabrata ,0.20mg/ml against Escherichia coli and Pseudomonas aeruginosa), and obtained lowest activity from the plant root extracts. Antibacterial and anticandidal properties of Citrullus colocynthis, makes it a broad spectrum antimicrobial agent. Belsem Marzouk(Marzouk et al. 2009)

Anti-diabetic activity: 

Antidiabetic activity of petroleun ether extract of Citrullus colocynthis fruits against Streptozotocin induced hyperglycemic rats was evaluated after oral administration of two different doses (300&500 mg/kg) of Citrullus colocynthis fruit extract exhibiting a significant reduction in blood glucose level in diabetic rats resulting in an acute effect. Also subacute effect i.e. antihyperglycemic effect was observed on 7^th as well as 14^th day of the experiment. Administration of petroleun ether extract of Citrullus colocynthis significantly improved body weight of diabetic animals in a dose dependent and time dependent manner. Petroleum ether extract of colocynthis to diabetic rats restored the total haemoglobin and glycosylated haemoglobin levels (P < 0.01). The investigation reported that petroleum ether extract of Citrullus colocynthis showed significant pharmacological activity towards lowering blood glucose in diabetes. R. JAYARAMAN