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PubMed2003

Induction of reversible antifertility with a crude ethanol extract of Citrullus colocynthis Schrad fruit in male rats.

A crude 50% ethanol extract of Citrullus Colocynthis Schrad was administered orally to male albino rats for evaluation of antifertility effects. The animals were divided into five groups: group A was a vehicle-treated control group; treatment groups B, C, and D received 100 mg/kg/day C. Colocynthis extract for periods of 20, 40, and 60 days, respectively, and group E animals received the extract at 100 mg/kg/day for 60 days followed by 60 days of recovery. For androgenicity evaluation of the extract, the animals were divided into four groups: group F animals were castrated 30 days before the experiment to serve as controls, and group G, H, and I were subjected to castration 30 days before the experiments, followed by administration of fruit extract (100 mg/kg/day p.o.), testosterone propionate (0.01 mg/rat/alternate day s.c.), and fruit extract along with testosterone propionate, respectively, for 30 days. Significantly reduced cauda epididymis sperm motility and density, number of pups, fertility, and circulatory levels of testosterone were observed in all treatment groups. The weights of testes, epididymis, seminal vesicle, and prostate were significantly decreased in groups B, C, and D. The weights of all organs in the different groups of the androgenicity study were markedly decreased in group F when compared with group A, in group G when compared with group F, and in group I when compared with group H, and increased in group H when compared with group F. The serum testosterone levels also showed a similar pattern. The concentration of testicular cholesterol was significantly elevated, while protein, sialic acid, acid and alkaline phosphatase concentrations were decreased. The histoarchitecture of the testes showed degenerative changes in the seminiferous epithelium, arrest of spermatogenesis at the secondary spermatocyte stage, cytolysis, and the lumen filled with eosinophilic material. Histometric parameters except Sertoli cell nuclear area and number of round spermatids showed marked alterations. All altered parameters restored to normal in group E. No changes were observed in body weight, litter size, hematology, and serum biochemistry. In conclusion, a 50% ethanol extract of C. Colocynthis showed an antiandrogenic nature, thereby reduced reversible infertility in male albino rats.

Animals↗

PubMed1994

Molecular cloning of a cysteine synthase cDNA from Citrullus vulgaris (watermelon) by genetic complementation in an Escherichia coli Cys- auxotroph.

We have isolated cDNA clones encoding cysteine synthase (CSase, EC 4.2.99.8), which catalyzes the terminal step in cysteine biosynthesis, by direct genetic complementation of a Cys- mutation in Escherichia coli with an expression library of Citrullus vulgaris (watermelon) cDNA. The library was constructed from 8-day-old etiolated seedlings of C. vulgaris in the lambda ZAPII vector, converted to a plasmid library by in vivo excision, and then used for transformation of cysteine auxotroph E. coli NK3, which lacks the cysK and cysM loci. The complementing cDNA containing a 560 bp 5'-untranslated region encodes a polypeptide of 325 amino acids of M(r) 34342. The translational product reacted with an antibody raised against CSase A of Spinacia oleracea. CSase and beta-pyrazolealanine synthase activities were demonstrated in vitro in extracts from E. coli cells expressing the cDNA. Genomic DNA blot analysis indicated the presence of a single copy of the gene, designated cysA, in the C. vulgaris genome. RNA blot hybridization indicated constitutive expression of cysA in cotyledons, hypocotyls and radicles of green and etiolated seedlings. These data suggested that this cDNA clone encodes CSase A the homolog of which in spinach is localized in the cytoplasm. The molecular phylogenetic tree of the amino acid sequences of CSases from plants and bacteria suggested that there are three families in the CSase superfamily; the plant CSase A family, the plant CSase B family and the bacterial CSase family. The proteins in the plant CSase A family are the most conserved relative to the ancestral CSase protein.

Amino Acid Sequence↗

PubMed1984

Carcinogenic activity of condensate from coloquint seeds (Citrullus colocynthis) after chronic epicutaneous administration to mice.

In the Sahelian countries coloquint seed tar is used in traditional medicine. A condensate from the seed of Citrullus colocynthis was obtained in a camel nomad settlement. It contained a large number of polycyclic aromatic hydrocarbons, including known carcinogens [e.g., benzo(a)pyrene, benz(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene]. The dose-related carcinogenic activity of this condensate was established after chronic epicutaneous application to mouse skin. We conclude that the manufacture and use of coloquint tar and related compounds may involve a health hazard and could lead to the development of cancer.

Africa↗

PubMed1993

Physiological effects of ozone on cultivars of watermelon (Citrullus lanatus) and muskmelon (Cucumis melo) widely grown in Spain.

Two cultivars of watermelon (Citrullus lanatus) and muskmelon (Cucumis melo), which are widely grown in Spain, were exposed to ozone (70 nl litre(-1), 6 h d(-1)) for 21 days. Ozone sensitivity was assessed by recording the extent of visible injury, changes in fast-fluorescence kinetics, the relative-growth rate (R) of root (RR) and shoot (RS), and effects on the number of flowers produced per plant. Leaf gas exchange was measured in order to provide some indication of the factors underlying differential response to ozone. After 9-10 days of fumigation, all the cultivars developed typical visible symptoms of zone injury on the older leaves. However, significant (P < 0.05) changes in fast-fluorescence kinetics were detected prior to the development of visible foliar injury, indicating that detectable effects of ozone on primary photochemical processes supersede the appearance of visible symptoms. In both muskmelon and watermelon, there was a marked reduction in the rate of CO(2) assimilation as a result of exposure to ozone, and this was accompanied by a parallel decrease in stomatal conductance. Mean plant-relative-growth rate (R) was markedly (P < 0.01) suppressed by ozone in the two cultivars of watermelon, but there were no significant effects on R in muskmelon. Ozone reduced root growth relative to the shoot in three out of four cultivars-an effect that may be of considerable ecological significance. Moreover, exposure to ozone reduced flower production in both muskmelon and watermelon, which indicated effects on yield. There was no correlation between a variety of methods used to assess ozone sensitivity and visible injury, and reasons for this are discussed. This observation draws clear attention to the dangers in ranking plants for ozone sensitivity purely on the basis of visible symptoms. It is concluded from this study that ozone-insensitive genotypes should be identified and considered for planting in the major areas of melon production concentrated on the Mediterranean coast of Spain.

Journal Article↗

PubMed2000

Preliminary toxicity study on the individual and combined effects of Citrullus colocynthis and Nerium oleander in rats.

The toxicity of diet containing 10% of Citrullus colocynthis fruits or 10% of Nerium oleander leaves or their 1:1 mixture (5%+5%) for rats treated for 6 weeks was determined. Dullness, ruffled hair, decreased body weight gains and feed efficiency, and enterohepatonephropathy characterised treatment with C. colocynthis and N. oleander given alone. Diarrhoea was a prominent sign of C. colocynthis poisoning. Organ lesions were accompanied by leucopenia, anaemia and alterations in serum AST, ALT and ALP activities and concentrations of total protein, albumin, urea, bilirubin and other serum constituents. Feeding the mixture of C. colocynthis and N. oleander caused more marked effects and death of rats.

Animals↗

PubMed1997

Genomic structure and expression analyses of serine acetyltransferase gene in Citrullus vulgaris (watermelon).

The genomic clones of Sat gene encoding serine acetyltransferase (SATase), a key enzyme in cysteine biosynthesis in plants, were isolated from the genomic library of Citrullus vulgaris (watermelon). The determination of nucleotide sequence of 5.7 kilobase pair (kbp) length revealed the presence of two introns of 1939 basepair (bp) and 515 bp length in the gene. The transcription start point was determined by primer extension experiments. Southern blot analysis indicated the presence of a single copy of the Sat gene and a couple of additional related sequences in the genome of C. vulgaris. The expression of Sat was analyzed in watermelon plants growth under sulfur- and/or nitrogen-starved conditions and in the presence of pyrazole, O-acetylserine and N-acetylserine. Only slight increment (ca. 1.5-2-fold) of Sat gene expression was observed upon sulfur starvation for 48 h. Interestingly, the addition of pyrazole, which is a precursor of beta-pyrazolealanine (beta-PA) synthesized by SATase and cysteine/beta-PA synthase, enhanced the expression of Sat by ca. 2-fold.

Acetyltransferases↗

PubMed2000

The hypoglycaemic and antihyperglycaemic effect of citrullus colocynthis fruit aqueous extract in normal and alloxan diabetic rabbits.

Effects of the aqueous, glycosidic, alkaloidal and saponin extracts of the rind of Citrullus colocynthis on the plasma glucose levels were investigated in normal rabbits, while the effects of saponin extract on the fasting plasma glucose levels were studied in alloxan induced diabetic rabbits. 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. Phytochemical screening revealed that the rind of C. colocynthis and its aqueous extract contains tertiary and quaternary alkaloids, glycoside and saponin components. The hypoglycaemic effects of these components given orally at a dose (50 mg/kg) were studied in normoglycaemic rabbits. Result showed that the alkaloidal extract did not significantly lower the blood glucose levels from 132 mg/100 ml at 0 h to 120 mg/100 ml after 6 h, 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 highly significant (P<0.001) after 3 and 6 h. Graded doses (10, 15 and 20 mg/kg) of saponin extract, when given orally to alloxan diabetic rabbits, produced a significant reduction of plasma glucose concentration. These results suggest that the aqueous extract of the rind of C. colocynthis possesses a hypoglycaemic effect and its hypoglycaemic action could be attributed for more extent to the presence of saponin in addition to the presence of glycosidic components.

Alkaloids↗

PubMed2001

Response of Najdi sheep to oral administration of Citrullus colocynthis fruits, Nerium oleander leaves or their mixture.

Susceptibility of sheep to oral administration of Citrullus colocynthis fruits, Nerium oleander leaves or their mixture is described in 12 sheep assigned as untreated controls, C. colocynthis-treated at 0.25g/kg/day, N. oleander-treated at 0.25g/kg and plant mixture-treated at 0.25g of C. colocynthis/kg plus 0.25g of N. oleander/kg. The daily use of 0.25g of C. colocynthis/kg for 42 days was not fatal to sheep and caused slight diarrhoea, catarrhal enteritis, centrilobular hepatocellular fatty change and degeneration of the renal tubular cells. Single oral doses of 0.25g of N. oleander/kg were lethal to sheep within 18-24h and caused uneasiness, grinding of the teeth, dyspnoea, anorexia, frequent urination, ruminal bloat, ataxia and recumbency before death. The main lesions were widespread congestion and haemorrhage, pulmonary cyanosis and emphysema and severe hepatonephropathy. Rapid death was also observed in sheep receiving single doses of the mixture of the two plants. Effects were correlated with changes in the activities of serum lactic dehydrogenase (LDH) and aspartate transaminase (AST) and concentrations of cholesterol, bilirubin, total protein, albumin, globulin and urea and haematological parameters.

Journal Article↗

PubMed1998

Microbial populations associated with the retting of melon pods (Colocynthis citrullus L.) during seed recovery.

The traditional process for the retting of melon pulp and microbiological characteristics in the recovery of melon seeds (Colocynthis citrullus L.) were investigated. Melon pods were sliced open and exposed for seven days. The pulp underwent a natural fermentation that was characterized by the growth of microorganisms to 10(8)-10(10) cfu/g. The pH fluctuated between 4.8 and 5.1 with a lactic acid content of 0.72%. Bacillus subtilis, B. polymyxa, Lactobacillus fermentum, L. brevis and Streptococcusfaecalis were the predominant microorganisms but, significant contributions were made by Staphylococcus saprophyticus and Enterobacter cloacae. Penicillium, Aspergillus and Rhizopus species including the yeasts, Saccharomyces cerevisiae, Candida krusei and Deboromyces hansenii were isolated from the fermentation. Growth of microorganisms was completely inhibited in antibiotic-treated samples indicating that the melon pods were the main source of microorganisms for the fermentation.

Cucurbitaceae↗

PubMed1993

Induction of Pyrophosphate-Dependent Phosphofructokinase in Watermelon (Citrullus lanatus) Cotyledons Coincides with Insufficient Cytosolic D-Fructose-1,6-Bisphosphate 1-Phosphohydrolase to Sustain Gluconeogenesis.

During germination of Citrullus lanatus, pyrophosphate-dependent phosphofructokinase (PFP) activity is induced. The peak of PFP activity coincides with the maximum gluconeogenic flux and high fructose-2,6-bisphosphate (Fru-2,6-P2) concentrations. Determination of cytosolic fructose-1,6 bisphosphatase (FBPase) activity in crude extracts is unreliable because of the high PFP activity. The FBPase activity, after correction for the contaminating PFP, is only one-third of the PFP activity. Purified cytosolic FBPase is inhibited by Fru-2,6-P2. The low cytosolic FBPase activity and high Fru-2,6-P2 most probably result in inadequate in vivo activity to catalyze the observed gluconeogenic flux. The total PFP activity is sufficient to catalyze the required carbon flux.

Journal Article↗

PubMed1985

Effect of Water Stress on the Carbohydrate Metabolism of Citrullus lanatus Seeds during Germination.

Gluconeogenesis in Citrullus lanatus seeds is a post germinative event. Increases in isocitrate lyase activity and incorporation of radioactivity from [2-(14)C]acetate into sugars occur only after radicle emergence. During germination, the seeds appear to rely on carbohydrate as the respiratory substrate. At this time, glycolysis, the pentose phosphate pathway, and the tricarbocyclic acid cycle seem to be functional. Utilization of raffinose during germination appears to be important.Water stress, which completely inhibits germination, has a marked effect on carbohydrate metabolism. The rate of (14)CO(2) release from [2-(14)C]acetate, [1-(14)C]glucose, and [6-(14)C]glucose is lower in the stressed seeds than the control seeds during the respiratory lag phase. However, in the stressed seeds neither glycolysis, the pentose phosphate pathway, nor the tricarboxylic acid cycle is completely inhibited. In contrast to the control seeds in which raffinose content sharply declines after 12 h of incubation, raffinose content in the stressed seeds remains fairly constant.The respiratory lag phase of the control seeds coincides with a lower reducing substance content, glucose content, and fructose content than in the stressed seeds during the corresponding incubation period.

Journal Article↗

PubMed1990

Control of Pyrophosphated-Fructose-6-Phosphate 1-Phosphotransferase Activity in the Cotyledons of Citrullus lanatus.

After initiation of radicle elongation, the pyrophosphate:d-fructose-6-phosphate 1-phosphotransferase (PFP) activity sharply increases in the cotyledons of Citrullus lanatus. Removal of the radicle early during incubation prevents the increase in PFP activity in the cotyledons evident in the control. Removal of the radicle at any stage after germination results in a decrease in PFP activity in the cotyledons. Application of kinetin (0.5 micromolar) or 2-chlorophosphonic acid (0.1 micromolar) to isolated cotyledons replaces the effect of the radicle. Gibberellic acid (0.09 micromolar GA(3)) also partially mimics the presence of the radicle. Anaerobic conditions, as well as cycloheximide application (0.18 micromolar) to intact embryos or to kinetin and ethrel treated isolated cotyledons prevent the increase in PFP activity evident in the control.

Journal Article↗

PubMed1992

Purification and Properties of Glyoxysomal Cuprozinc Superoxide Dismutase from Watermelon Cotyledons (Citrullus vulgaris Schrad).

A glyoxysomal copper,zinc-containing superoxide dismutase (EC 1.15.1.1) was purified to homogeneity, for the first time, from watermelon cotyledons (Citrullus vulgaris Schrad.). The stepwise purification procedure consisted of acetone precipitation, batch anion-exchange chromatography, anion-exchange Fast Protein Liquid Chromatography and gel-filtration column chromatography. Pure copper,zinc-superoxide dismutase (Cu,Zn-SOD II) had a specific activity of 1211 units per milligram protein and was purified 400-fold, with a yield of 8 micrograms enzyme per gram cotyledon. The glyoxysomal Cu,Zn-SOD had a relative molecular weight of about 33,000 and was composed of two equal subunits of 16,500 Daltons. Metal analysis showed that the enzyme, unlike other Cu,Zn-SODs, contained 1 gram-atom Cu and 1 gram-atom Zn per mole dimer. No iron and manganese were detected. Ultraviolet and visible absorption spectra were reminiscent of other copper,zinc-superoxide dismutases.

Journal Article↗

PubMed2000

Effect of combined Citrullus colocynthis and Rhazya stricta use in Najdi sheep.

The effect of oral administration of 0.25 g/kg/day of Citrullus colocynthis fruits, 0.25 g/kg/day of Rhazya stricta leaves or mixture of the two plants at 0.25 g/kg/day of C. colocynthis fruits plus 0.25 g/kg/day of R. stricta leaves in Najdi sheep was examined. Oral administration of 0.25 g/kg/day of C. colocynthis fruits or 0.25 g/kg/day of R. stricta leaves for 42 days proved not fatal but that of the mixture of the two plants (0.25 g + 0.25 g/kg/day) proved fatal within 26 days with profuse diarrhea, dehydration, loss in condition, ataxia and recumbency, prior to death. These manifestations accompanied by enterohepatonephrotoxicity, gelatinization of the renal and epicardial fat and transudate in serous cavities were correlated with alterations in serum LDH and AST activities and concentrations of total protein, albumin, globulin, bilirubin, cholesterol and urea and hematology.

Animals↗

PubMed1998

Characterization of cDNAs encoding small and large subunits of ADP-glucose pyrophosphorylases from watermelon (Citrullus vulgaris S.).

Three cDNA clones encoding ADP-glucose pyrophosphorylases were isolated from a full red fruit cDNA library of watermelon (Citrullus vulgaris S.). Sequence analyses indicated that one clone, wms1, corresponds to the small subunit, and two clones, wml1 and wml2 (a partial gene), are the large subunits of AGPase. The presumed AGPase proteins encoded by wms1, wml1, and wml2 have 526, 526, and 481 amino acids, respectively. The protein sequences have the conserved amino acids important for the substrate or regulator binding site, with some variation. Developmental changes in the amounts of wms1, wml1, and wml2 transcripts in fruits were measured by northern blot analysis. Their expression levels decreased from the small green to medium green stages, then increased in accordance with fruit ripening, which was different from those of tomato and oriental melon.

Base Sequence↗

PubMed1987

Amino-acid sequences of trypsin inhibitors from watermelon (Citrullus vulgaris) and red bryony (Bryonia dioica) seeds.

The amino-acid sequences of two trypsin inhibitors isolated from red bryony (Bryonia dioica) and watermelon (Citrullus vulgaris) seeds are reported. Both species represent different genera of the Cucurbitaceae family, which have not been previously investigated as a source of proteinase inhibitors. The sequences are unique but are very similar to those of other proteinase inhibitors which have been isolated from squash seeds. Based on structural homology we assume that the Arg5-Ile6 peptide bond represents the reactive site bond of both inhibitors.

Amino Acid Sequence↗

PubMed1997

Purification and properties of cytosolic copper, zinc superoxide dismutase from watermelon (Citrullus vulgaris Schrad.) cotyledons.

Cytosolic copperzinc-superoxide dismutase (CuZn-SOD I; EC 1.15.1.1) was purified to homogeneity from watermelon (Citrullus vulgaris Schrad.) cotyledons. The stepwise purification procedure consisted of acetone precipitation, batch anion-exchange chromatography, anion-exchange Fast Protein Liquid Chromatography, gel-filtration column chromatography, and affinity chromatography on concanavalin A-Sepharose. CuZn-SOD I was purified 310-fold with a yield of 12.6 micrograms enzyme per gram cotyledons, and had a specific activity of 3,450 units per milligram protein. The relative molecular mass for cytosolic CuZn-SOD was 34000, and it was composed by two equal subunits of 16.3 kDa. CuZn-SOD I did not contain neutral carbohydrates in its molecule, and its ultraviolet and visible absorption spectra showed two absorption maxima at 254 nm and 580 nm. Metal analysis showed that the enzyme contained 1 gram-atom Cu and 1 gram-atom Zn per mole dimer. Cytosolic CuZn-SOD was recognized by the antibody against peroxisomal CuZn-SOD from watermelon cotyledons, and its enzymatic activity was inhibited by this antibody. By IEF (pH 4.2-4.9), using a new method for vertical slab gels set up in our laboratory, purified cytosolic CuZn-SOD was resolved into two equal isoforms with isoelectric point of 4.63 and 4.66.

Cotyledon↗

PubMed1976

[Studies on urease from the seeds of Citrullus vulgaris: action of chemical agents and ionizing radiations].

Urease obtained from seeds of Citrullus vulgaris fruits has been studied under three points of view: a) the effect of the urea analogs acetamide and hydroxi-urea on the enzyme kinetic b) the action of the sulfhydryl reagents and the reactivation agents on the enzyme c) the effect of X-rays and the protective action of the cysteamine. The Berthelot reaction for the determination of the liberated NH3 was used enzyme activity. Acetamide has no effect on urease kinetic. Hidroxy-urea which produces a typical green color when it is mixed with the Berthelot reagents at high concentrations, when properly diluted acts a aompetitive inhibitor of urease. Spectrophotometric experiments suggest that the studied urease decomposes hydroxi-urea with liberation of hydroxilamine. The sulphydril reagent, p-hydroxi-mercuribenzoate inhibits the enzime. Cysteine and dithiotreitol reactivate the enzyme activity in no more then 50% even when excess of the substances is used. Probably only in the first step of the urea hydrolysis, the enzyme behaves as a typical SH-enzyme. Urease is very sensitive to X-rays. Cysteamine acts as a protective agent of the enzyme. Dithiotreitol reinforces this protective action. This effect is clearly observed when the Fisbein catalytic method for urease is employed.

Chemical Phenomena↗