Pumpkin

Scientific Name(s): Cucurbita pepo L. Family: Cucurbitaceae.

Common Name(s): Chilacayote , acorn squash , butternut squash , field pumpkin , fig-leaf gourd , pepo , pumpkin , squash , yellow summer squash , zucchini

Uses

Pumpkin seeds, seed oil, and pumpkin pulp have been evaluated in limited clinical trials for medicinal actions, including anthelmintic, hypotensive, and hypoglycemic activity. The extracts may also be useful for managing symptoms of benign prostatic hyperplasia and anxiety-related disorders, although limited clinical trial information is available.

Dosing

Limited high-quality clinical trials exist to support therapeutic dosing. Pumpkin seed 30 g daily has been used as a source of supplemental iron in nonpregnant adults.

Contraindications

Contraindications have not been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Antinutrients (eg, oxalates, cyanide, tannin) have been identified in pumpkin seeds and leaves.

Interactions

An increased anticoagulant effect of warfarin has been reported during concurrent ingestion of a combination preparation of cucurbita, saw palmetto, and vitamin E. Causality of cucurbita was not proven.

Adverse Reactions

Clinical trials report few adverse reactions. Methemoglobinemia caused by high nitrate content has been reported in infants given zucchini soup for constipation. IgE-related allergy to zucchini has been reported, as well as oral allergy syndrome, nausea, diarrhea, and pruritus. Cross-reactivity to watermelon, cucumber, and pumpkin was demonstrated.

Toxicology

There have been no reports of severe toxicity with the use of cucurbita extracts. Antinutrients have been described in the seeds and leaves, including oxalates, tannins, and cyanide.

Botany

Pumpkin is a dicotyledonous vegetable that develops long vine-like stems with trifoliate leaves and edible large, fleshy fruits. The rapid-growing plant can climb to 5 m. The large, yellow flowers are eaten in some Mediterranean and Mexican cultures, and the fruits are eaten worldwide. Many cultivated varieties can be found throughout the world. 1 , 2 , 3 Other members of the genus include Cucurbita digitata , Cucurbita ficifolia , and Cucurbita maxima species.

History

The seeds of several species of pumpkin have been used in traditional medicine for centuries. Traditionally, the seeds of the Cucurbita species are ingested as a tea or after grinding. They have been used to immobilize and aid in the expulsion of intestinal worms and parasites. In some cultures, small amounts of the seeds are eaten on a daily basis as a prophylactic against worm infections. The seeds also have been used in the treatment of prostate disorders. Pumpkin flowers are sometimes added to tacos or soup as a source of protein. 2 , 3 , 4

Chemistry

The fleshy pulp of Cucurbita is primarily consumed as a vegetable. Investigational interest centers on polysaccharide and pectin content, as well as the presence of triterpenoids, cucurbitan glycosides, carotenoids, including lutein and beta-carotene, and cucurmosin, a ribosome-inactivating protein. 3 , 5 , 6 , 7 , 8 , 9 , 10 , 11

The pumpkin flower is a source of protein. Glutamic and aspartic acid, leucine, valine, phenylalanine, and tryptophan are among the amino acids identified. Phytosterols, such as spinasterol, have been identified, as well as trypsin-inhibitors. 4 , 12 , 13

Lipids comprise up to 50% of the seed and around 30% is protein. Pumpkin seeds can be a nutritional source of iron and potassium. Phytosterols (eg, beta-sitosterol, stigmasterol), antioxidant tocopherols, antihelminthic cucurbitin, squalene, and cardioprotective fatty acids have been isolated from the seeds and seed oil. The presence of squash inhibitors (serine protease inhibitors) is thought to confer a protective effect to the plant against pests and pathogens. 3 , 14 , 15 , 16 , 17 , 18 , 19 , 20

Uses and Pharmacology

Anthelmintic activity
Animal data

In vitro experiments and animal studies have demonstrated anthelmintic action of dried seeds and extracts against some Schistosoma japonicum and malarial parasites, but not all parasites (eg, tapeworm). 21 , 22 , 23

Clinical data

A preclinical study demonstrated an anthelmintic effect with pumpkin seed 23 g in 100 mL water; however, cucurbitin has been generally supplanted by more effective single-dose vermifuges. 3

Benign prostatic hyperplasia (BPH)

Pumpkin seed extract may have antiandrogenic and anti-inflammatory activity. 24

Animal data

A protective effect on testosterone-induced prostatic hyperplasia was seen in rats fed pumpkin seed oil. 25

Clinical data

Trials are limited and the results conflict. A large clinical trial (N = 476) found an improvement in symptoms associated with BPH as determined by the International Prostate Symptom Score, but no change in objective measures, such as p-vol or post-void residual urine. 24 Another clinical trial found that a preparation of C. pepo (curbicin) improved certain parameters of BPH, including urinary flow, micturition time, residual urine, and urinary frequency versus placebo. 26

Cancer

Limited in vitro and animal experiments have shown antimutagenic and inhibitory actions of pumpkin seed extract and boiled, but not fresh, pumpkin juice. 3 , 27 , 28

Cardiovascular effects

In rats, pumpkin seed oil improved the plasma lipid profile 3 , 29 and exhibited antioxidant activity in the heart and liver. 30 In these experiments, a hypotensive action was demonstrated by the oil alone, and in combination with captopril and felodipine. 29 , 30

CNS

Defatted squash seed is rich in tryptophan. 31 , 32 Limited clinical trials have been conducted comparing plant-based tryptophan with the pharmaceutical grade chemical. Modest improvements were demonstrated in social anxiety disorder (social phobia) and insomnia when squash-derived tryptophan was administered with glucose to improve CNS blood levels. 31 , 32

Diabetes
Animal data

The pulp and seeds of C. ficifolia have been evaluated for hypoglycemic action in alloxan-induced diabetic rabbits. 3 , 33

Clinical data

Multiple open-label clinical studies report reduced postprandial serum and fasting glucose levels in patients with type 2 diabetes given pumpkin juice or pumpkin powder, but quality clinical trials are lacking. 3 A small clinical trial (N = 10) demonstrated decreases in fasting blood glucose levels 3 to 5 hours after consumption of the juice of fresh immature C. ficifolia fruit; 4 mL/kg of body weight of the juice was administered (100 g crushed fruit was equivalent to 75 mL of juice). 34

Dosage

Limited high-quality clinical trials exist to support therapeutic dosing. Fresh pumpkin juice 4 mL/kg of body weight was administered in a study conducted among patients with type 2 diabetes. 34 However, it would take 100 g of crushed fruit to equal 75 mL of juice. 35 Pumpkin seed 30 g provide approximately 4 mg of iron. When administered to nonpregnant adults for 4 weeks, iron status improved. 14 Pumpkin seed 23 g per 100 mL was used in a study of anthelmintic action. 3

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking. Anti-nutrients (eg, oxalates, cyanide, tannin) have been identified in pumpkin seeds and leaves, with detrimental effects on growing rats and chickens. 3 , 19

Interactions

In an experiment conducted in rats, pumpkin seed oil potentiated the hypotensive effect of captopril and felodipine. 30 Two men stabilized on warfarin experienced an increase in the international normalized ratio (INR) after taking an herbal combination containing Cucurbita , saw palmetto, and vitamin E. 36 In both patients, the INR returned to previous values when the herbal product was discontinued. Although neither Cucurbita nor saw palmetto can be ruled out as the cause of the INR increase, it is more likely that vitamin E interfered with vitamin K-dependent clotting factors, adding to the anticoagulant effects of warfarin. 36

Adverse Reactions

Clinical trials report few adverse reactions. 3 , 26

Methemoglobinemia has been reported in infants 2 months of age or younger who were given zucchini soup for constipation. The adverse reaction was attributed to the high nitrate content of the vegetable. 37

Vitamin A toxicity, with abnormal liver function tests, has been reported with prolonged and excessive pumpkin consumption. 38

IgE-related allergy to zucchini has been reported. Oral allergy syndrome, nausea, diarrhea, and pruritus have also been described in a number of patients. Cross-reactivity to watermelon, cucumber, and pumpkin has occurred. 39 , 40 , 41

A number of pathogenic fungi causing the deterioration of carved pumpkins have been identified. These fungi could cause severe infection in immunocompromised individuals. 42

Toxicology

Severe toxicity has not been reported with the use of Cucurbita extracts. Ingestion of C. maxima seeds by rats and pigs during a 4-week period resulted in no changes in most laboratory parameters. 43 The median lethal dose of freeze-dried C. ficifolia juice in mice was 650 mg/kg. 35

Antinutrients (eg, oxalates, cyanide, tannin) have been found in pumpkin seeds and leaves, having detrimental effects on rats and chickens. 3 , 19 Trypsin inhibitors have been described in flowers of pumpkin varieties, but were not considered antinutritional. 4

Bibliography

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5. Wang DC, Xiang H, Li D, et al. Purine-containing cucurbitane triterpenoids from Cucurbita pepo cv dayangua. Phytochemistry . 2008;69(6):1434-1438.
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13. Itokawa H, et al. Studies on the constituents of the male flowers of Cucurbita pepo L [in Japanese]. Yakugaku Zasshi J Pharm Soc Japan . 1982;102(4):318-321.
14. Naghii MR, Mofid M. Impact of daily consumption of iron fortified ready-to-eat cereal and pumpkin seed kernels ( Cucurbita pepo ) on serum iron in adult women. Biofactors . 2007;30(1):19-26.
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16. Stevenson DG, Eller FJ, Wang L, Jane JL, Wang T, Inglett GE. Oil and tocopherol content and composition of pumpkin seed oil in 12 cultivars. J Agric Food Chem . 2007;55(10):4005-4013.
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18. Chiche L, Heitz A, Gelly JC, et al. Squash inhibitors: from structural motifs to macrocyclic knottins. Curr Protein Pept Sci . 2004;5(5):341-349.
19. Akwaowo EU, Ndon BA, Etuk EU. Minerals and antinutrients in fluted pumpkin ( Telfairia occidentalis Hook f .). Food Chem . 2000;70(2):235-240.
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21. De Amorim A, et al. Anthelmintic action of plants. Part 6. Influence of pumpkin seeds in the removal of Vampirolepis nana from mice. Rev Bras Farmacogn . 1992;73:81-82.
22. Elisha E, et al. Anthelmintic activity of some Iraqi plants of the Cucurbitaceae. Pharm Biol . 1987;25(3):153-157.
23. Amorim CZ, Marques AD, Cordeiro RS. Screening of the antimalarial activity of plants of the Cucurbitaceae family. Mem Inst Oswaldo Cruz . 1991;86(suppl 2):177-180.
24. Dreikorn K. The role of phytotherapy in treating lower urinary tract symptoms and benign prostatic hyperplasia. World J Urol . 2002;19(6):426-435.
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29. Gossell-Williams M, Lyttle K, Clarke T, Gardner M, Simon O. Supplementation with pumpkin seed oil improves plasma lipid profile and cardiovascular outcomes of female non-ovariectomized and ovariectomized Sprague-Dawley rats. Phytother Res . 2008;22(7):873-877.
30. Zuhair HA, Abd El-Fattah AA, El-Sayed MI. Pumpkin-seed oil modulates the effect of felodipine and captopril in spontaneously hypertensive rats. Pharmacol Res . 2000;41(5):555-563.
31. Hudson C, Hudson S, MacKenzie J. Protein-source tryptophan as an efficacious treatment for social anxiety disorder: a pilot study. Can J Physiol Pharmacol . 2007;85(9):928-932.
32. Hudson C, Hudson SP, Hecht T, MacKenzie J. Protein source tryptophan versus pharmaceutical grade tryptophan as an efficacious treatment for chronic insomnia. Nutr Neurosci . 2005;8(2):121-127.
33. Roman-Ramos R, Flores-Saenz JL, Alarcon-Aguilar FJ. Anti-hyperglycemic effect of some edible plants. J Ethnopharmacol . 1995;48(1):25-32.
34. Acosta-Patiño JL, Jiménez-Balderas E, Juárez-Oropeza MA, Díaz-Zagoya JC. Hypoglycemic action of Cucurbita ficifolia on Type 2 diabetic patients with moderately high blood glucose levels. J Ethnopharmacol . 2001;77(1):99-101.
35. Andrade-Cetto A, Heinrich M. Mexican plants with hypoglycaemic effect used in the treatment of diabetes. J Ethnopharmacol . 2005;99(3):325-348.
36. Yue QY, Jansson K. Herbal drug curbicin and anticoagulant effect with and without warfarin: possibly related to the vitamin E component. J Am Geriatr Soc . 2001;49(6):838.
37. Savino F, Maccario S, Guidi C, Castagno E, Farinasso D, Cresi F, Silvestro L, Mussa GC. Methemoglobinemia caused by the ingestion of courgette soup given in order to resolve constipation in two formula-fed infants. Ann Nutr Metab . 2006;50(4):368-371.
38. Nagai K, Hosaka H, Kubo S, Nakabayashi T, Amagasaki Y, Nakamura N. Vitamin A toxicity secondary to excessive intake of yellow-green vegetables, liver and laver. J Hepatol . 1999;31(1):142-148.
39. Reindl J, Anliker MD, Karamloo F, Vieths S, Wüthrich B. Allergy caused by ingestion of zucchini ( Cucurbita pepo ): characterization of allergens and cross-reactivity to pollen and other foods. J Allergy Clin Immunol . 2000;106(2):379-385.
40. Figueredo E, Cuesta-Herranz J, Minguez A, et al. Allergy to pumpkin and cross-reactivity to other Cucurbitaceae fruits. J Allergy Clin Immunol . 2000;106(2):402-403.
41. Potter T, Hashimoto K. Butternut squash ( Cucurbita moschata ) dermatitis. Contact Dermatitis . 1994;30(2):123.
42. Nagano Y, Millar BC, Loughrey A, Goldsmith CE, Rooney PJ, Moore JE, Elborn JS. Jack o'Lantern–scarier than you think! Am J Infect Control . 2006;34(10):680-681.
43. de Queiroz-Neto A, Mataqueiro MI, Santana AE, Alessi AC. Toxicologic evaluation of acute and subacute oral administration of Cucurbita maxima seed extracts to rats and swine. J Ethnopharmacol . 1994;43(1):45-51.

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