Capers
Scientific Name(s): Capparis spinosa L.
Common Name(s): Alcaparro (Spanish, Portugese), Alcappara (Spanish, Portugese), Caper, Caperberry, Caperbush, Cappero (Italian), Fabagelle (French), Himsra (India), Kabarra (Punjabi), Kapernstrauch (German), Kapersy (Russian), Kapper (German), Kappertjes (Dutch), Kapricserje (Hungarian), Kapris (Finnish, Swedish), Kiari (Hindi), Kobra (Hindi), Lussef (Egyptian), Tapana (French, Spanish), Torkav (Estonian)
Medically reviewed by Drugs.com. Last updated on Dec 18, 2023.
Clinical Overview
Use
Pickled flower buds are used as a condiment. Limited clinical trials are lacking to support various traditional uses. Antioxidant, hepatoprotective, hypolipidemic, hypoglycemic, and immune actions are being investigated.
Dosing
Limited adequate clinical evidence exists to guide dosage. Diabetes mellitus type 2: 1,200 mg (400 mg 3 times daily) of caper fruit extract given over 2 months was used in a small clinical trial. Ethnobotanical medicinal use for diabetes includes doses of 2 to 8 g of caper fruit eaten per day.
Contraindications
Avoid use in patients hypersensitive to the plant species.
Pregnancy/Lactation
Generally recognized as safe when used as food. Capers have been used in traditional Arabian medicine for diabetes as well as an emmenagogue and should be avoided in pregnancy.
Interactions
None well documented.
Adverse Reactions
Topical use of capers may cause contact dermatitis. Food allergy has also been reported.
Toxicology
Information is limited.
Scientific Family
- Capparaceae
- Capparidaceae
Botany
C. spinosa L. is a member of the Capparidaceae family and is also known as C. rupestris and C. ovata Desf.Alkire 2017 C. spinosa is a dicotyledonous perennial shrub found throughout the Mediterranean countries of Europe, Asia, and North Africa where it prefers the dry heat and intense sunlight. The plant has been used for erosion control because the roots grow up to 3 m into the soil. It is also salt-tolerant and grows readily along shores within sea-spray zones. From mid-April to the end of September, capers may grow 1 to 1.5 m in height, spread 2 to 3 m, and bud white flowers up to 7.6 cm across. If unpicked, the caper bud will flower and produce a round berry fruit (caperberry). Two forms of the caper can be found, a spiny and a nonspiny variety. The genus has been reported to include 350 species.Alkire 2017, Andrade 1997, Inocencio 2002, Kelly 1991, USDA 2008
History
The caper has a long history of use as a culinary spice and remains widely used as a spice today. Archaeological findings in China indicate a medicinal use for the caper. In ancient Greece, the caper was used as a carminative (relieving flatulence) whereas records of ayurvedeic medicine include its use to improve liver function. Capers have also been used for arteriosclerosis, diuresis, kidney disinfectant, and as vermifuges and tonics.Alkire 2017, Jiang 2007, Simon 1984
In commercial operations, the unopened flower buds are collected by hand and pickled to produce the characteristic pungent taste and smell. Immature small leaves are also eaten as a vegetable or picked and used in salads and fish dishes. The fruits (ie, caperberry, capperone, taperone) are used in sauces or pickled and eaten similar to small gherkins. The strong flavor of caper comes from mustard oil; methyl isothiocyanate. Seeds of the caper have been traditionally used to preserve wine and relieve toothache, while infusions and decoctions from the root bark has been used for cough, asthma, arthritis, gout, dropsy (edema), paralysis, anemia, spleen and skin disorders, as well as for rheumatism. Caper roots have been burned and the ash used as a source of salt.Alkire 2017, Jiang 2007, Simon 1984
Chemistry
Extracts of the dried whole plant contain the flavonoids rutin, kaempferol-3-glucoside, kaempferol-3-rutinoside, and kaempferol-3-rhamnorutinoside.Rodrigo 1992 Other components include quercetin 3-O-glucoside, quercetin 3-O-glucoside-7-O-rhamnoside, a new flavonoid quercetin 3-O-(6-alpha-L-rhamnosyl-6-beta-D-glucosyl)-beta-D-glucosideSharaf 2000 and 2 novel (6S)-hydroxy-3-oxo-alpha-ionol glucosides.Calis 2002 One article reports on the anti-inflammatory activity of the polyprenol cappaprenol-13.al-Said 1988 Other identified compounds include ursolic acid, coumaric acid, nicotinamide, sitosterol, cadabicine, and stachydrine.Khanfar 2003 Many of these compounds are also found in the floral buds.Tesoriere 2007
Mature fruits contain an indole acetonitrile and various glucosides.Calis 2002
Seed oil contains the fatty acids linoleic and oleic acids, sterols, and tocopherols.Matthäus 2005
Uses and Pharmacology
Few high-quality clinical trials exist.
Antimicrobial
A butanolic caper extract exerted antimicrobial effects greater than those of aqueous extracts in in vitro experiments. Clinical importance was not evaluated and no comparison was made with standard antimicrobial agents.(Ali-Shtayeh 1999, Mahasneh 2002)
Antioxidant
Methanol extracts of the flower buds have been evaluated for antioxidant effect. Inhibition of lipid oxidation has been demonstrated in vitro; the mechanism is attributed to a cooperative interaction(Tesoriere 2007) between the tocopherol, flavonoid, and isothiocyanate chemical constituents.(Germano 2002, Tesoriere 2007)
Hepatoprotective
Animal data
In rats, p-Methoxy benzoic acid, from an aqueous C. spinosa extract, protected against induced hepatotoxicity,(Gadgoli 1999) while the fruit extract significantly attenuated liver injury, improved liver inflammation, and decreased elevated liver enzymes in a non-alcoholic steatohepatitis model.(Akbari 2020)
Clinical data
A clinical trial investigating the efficacy of a mixed preparation containing caper extract combined with other extracts found an improvement in liver function laboratory values.(Huseini 2005)
Diabetes and metabolic syndrome
Animal data
Experiments in diabetic rats have reported a hypoglycemic effect.(Eddouks 2004)
Clinical data
A double-blind, randomized, placebo-controlled trial in 60 Iranian adults investigated the antihyperglycemic effect of caper fruit extract (1,200 mg/day, equivalent to 5 g/day caper fruit on average). Participants were type 2 diabetic patients who were stabilized for 2 months on a diabetic food regimen and antidiabetic medications prior to study initiation. After 2 months of treatment, consumption of the caper extract led to a significant improvement in fasting blood glucose (FBG; mean change, −20.2 mg/dL; P=0.037) and HgA1c (mean change, −0.4%; P=0.043) compared to controls; no significant changes were observed in any lipid parameters, liver enzymes, or other lab values. Compared to baseline, FBG and triglycerides improved significantly in the caper group (P=0.005 and P=0.29, respectively). No adverse effects were seen in either group.(Huseini 2013) In a triple-blind, randomized, placebo-controlled trial (N=30) that enrolled patients with poorly controlled type 2 diabetes, administration of a 10% hydroalcoholic fruit extract of C. spinosa oxymel (standardized to rutin content and mixed in a grape vinegar and lactulose syrup) for 3 months did not significantly glucose or lipid parameters compared to controls. Mean body weight was the only significant parameter improved with caper fruit oxymel (−2.8 kg; P=0.01).(Vahid 2019)
Hypolipidemic
In normal and diabetic (induced) rats fed aqueous extracts of the powdered caper fruits for a 2-week period, a reduction in plasma cholesterol and triglycerides was demonstrated.(Eddouks 2005)
Immune
A 2% methanol caper extract in aqueous gel inhibited histamine-induced erythema in human volunteers.(Trombetta 2005) A protective effect on chondrocyte cells was shown in vitro and may be due to activation of an immune response.(Panico 2005)
Other uses
Caper leaf extract, which was found to exhibit antioxidant properties approximately 6 times that of the fruit extract, significantly improved sperm motility and viability (P<0.05 for each) in sperm collected from 20 to 45-year-old males.(Khojesteh 2021) In a an ischemic stroke rat model, pre-treatment with caper extract once daily for 7 days prior to occlusion significantly improved neurological deficit, infarction volume, and cerebral histopathological changes.(Rakhshandeh 2021)
Dosing
A 2% aqueous gel has been used for antihistaminic effects.Trombetta 2005 Approximately 600 mg of dried whole plant extract per day has been used in a mixed preparation in experiments investigating hepatoprotective effects.Huseini 2005
Diabetes
Average doses recommended by herbalists in Iranian ethnobotanic medicine are 2 to 8 g/day of dry pickled caper fruits. A dose of hydro-alcoholic caper fruit extract 400 mg taken 3 times daily was used in a clinical trial in type 2 diabetics patients.Eddouks 2005
Pregnancy / Lactation
Generally recognized as safe when used as food. Capers have been used in traditional Arabian medicine as an emmenagogue and should be avoided during pregnancy.Khanfar 2003
Interactions
None well documented.
Adverse Reactions
The topical application of wet compresses soaked in fluid containing capers has been associated with the development of contact dermatitis.Angelini 1991 A food allergy to caper fruit and bud was confirmed with skin prick tests in a 22-year-old man after he presented to the emergency department with angioedema of the face and hands, redness, and aphonia.Alcántara 2013
Toxicology
Information is limited. No reduction of cell viability was demonstrated by a methanol extract of capers.Panico 2005 Related species may be poisonous.Simon 1984
Index Terms
- Capparis rupestris
- Capparis rupestris Desf
References
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