Editor’s Note: Each month, HerbalEGram highlights a conventional food and
briefly explores its history, traditional uses, nutritional profile, and modern
medicinal research. We also feature a nutritious recipe for an easy-to-prepare
dish with each article to encourage readers to experience the extensive
benefits of these whole foods. With this series, we hope our readers will gain
a new appreciation for the foods they see at the supermarket and frequently
include in their diets.
The basic materials for this series were compiled
by dietetic interns from Texas State University (TSU) in San Marcos and the
University of Texas at Austin (UT) through the American Botanical Council’s
(ABC’s) Dietetic Internship Program, led by ABC Education Coordinator Jenny
Perez. We would like to acknowledge Perez,
ABC Special Projects Director Gayle Engels, and ABC Chief Science Officer
Stefan Gafner, PhD, for their contributions to this project.
By Hannah
Baumana and Monica Silvab
a HerbalGram Associate Editor
b ABC Dietetics
Intern (TSU, 2017)
Overview
The caper (Capparis
spinosa, Capparaceae) bush is a small, salt-tolerant shrub with trailing,
thorny branches and thick, fleshy leaves. Caper has a deep root system and
trailing vines that grow seven to 10 feet tall.1 The semi-prostrate
branches have ovate, petiolate leaves arranged opposite of each other. The
flowers are pink or white with three petals and numerous stamens. Caper is a
deciduous, dicotyledonous plant that produces distinctive flower buds, which have
a life span of 24 to 36 hours after opening.1,2
Caper’s
edible shoots are considered a vegetable, and its processed buds are considered
a culinary herb.1 The tender shoots emerge in the spring, while the
flower buds are harvested from mid-May to mid-August. Each plant produces hundreds of flowers each
season. When pickled in vinegar or brine, the immature flower buds form capric
acid, which is responsible for caper’s unique, salty-sour flavor.2,3
Once the flower blooms and is pollinated, it produces a
fruit two to three inches in length and one-half to three-quarters of an inch
in diameter. Caper fruits start out green, but turn purple when ripe. Each
fruit contains 200 to 300 seeds.1 The fruit of the caper bush is also harvested, but
not commonly used.2
Currently, capers are cultivated commercially in northern
Africa, Spain, and Italy. Caper plants in Cyprus, Greece, and Turkey are grown
for domestic use and not for export. The United States imports more than $20
million of processed capers annually.1 Caper plants that are two to
three years old produce about two pounds of buds in a year, while plants older
than four years may produce more than 20 pounds of buds annually.1
Phytochemicals and Constituents
Macronutrients are found in capers in very small
amounts. One tablespoon (8.6 grams) of pickled capers has two calories, half a gram
of carbohydrates, and minute amounts of protein and fat. An important
micronutrient to consider when eating capers is sodium. One tablespoon of
capers contains 202 milligrams of sodium, which is 8.5% of the recommended
daily intake for a healthy adult.4,5 The flower bud also contains
trace amounts of vitamins C and E. The concentration of vitamins can vary from
plant to plant. The vitamin C content in capers cultivated in different regions
in Tunisia, for example, ranged from 0.3 to 0.5 milligrams per 100 grams of
capers.6
A number of bioactive compounds have been isolated
from the flower buds of the caper bush. The pickling process has varying
effects on the bioavailability of compounds due to different fermentation
methods.7 Among the most
investigated of these phytochemicals are flavonoids and antioxidants.
Flavonoids from capers reportedly have cytotoxic, anti-inflammatory,
antidiabetic, and antiparasitic properties.7,8 Rutin (quercetin-3-O-rutinoside) is the most abundant
flavonoid in fresh and pickled caper buds.7 Simple water extractions
high in rutin have been shown to reduce inflammation and arrest cell growth in
cancer cells, as well as kill intestinal parasites in animals.8,9 Caper
flower buds also contain quercetin-3-O-rhamnosylrutinoside,
a derivative of quercetin.6
Quercetin, another well-studied flavonoid, is
formed from rutin during the pickling process.7 Quercetin can
inhibit inflammation and cancer cell growth in the same way as rutin.9
Quercetin has also shown immune-health benefits. Kaempferol 3-O-rhamnosylrutinoside, another flavonoid
identified in an aqueous extract, has proven antiparasitic properties.8
The flower bud of the caper bush also contains
antioxidants such as carotenoids, tocopherols, ascorbic acid, and a newly
identified antioxidant, cappariside, a small organic acid.6,10
Antioxidants eliminate free radicals that cause damage to body tissues and DNA,
and have been implicated in the prevention of cancer, kidney damage, and heart
disease, as well as protection against prescription drug-induced toxicity.11
The antioxidant effects of flower bud preparations have been shown to be more
potent than those of the antioxidants in isolation.8
Historical and Commercial Uses
The unopened
flower buds of the caper bush are commercially known as capers.2
Capers are used as a condiment in salads and sauces, or with meat or fish. They
are also used in cosmetics and medicines.
Archeological evidence for the historical use of capers
as a food and medicine exists among many ancient cultures.12 The earliest known evidence of caper consumption
was found in the Mesolithic soil layer of an excavation site in Syria,
potentially dating back to 9000 BCE. Nearby ancient peoples may have been using
capers in 7500 BCE as evidenced by mineralized seeds found in the Franchthi cave,
a Stone Age cave in the Greek Peloponnesian peninsula. Dried seeds found in the
Nahal Hemar cave in Israel may have been used as early as 6000 BCE. In China,
fresh clumps of capers and plant parts were preserved in entombed containers that
are almost 3,000 years old. There is also evidence of Egyptian consumption of
capers from 275 BCE to 600 CE.
Historical medicinal uses of capers ranged from
expelling bad odor spirits in ancient Arabic cultures to treating paralysis in
ancient Xinjiang, China.12 In addition to the buds, the root bark,
fruit, and aerial parts of the caper bush were used in traditional remedies.
Countries in the native range of caper, including Iran, Iraq, and Syria, used
every part of the caper bush for a variety of ailments. As the cultivation and
use of capers spread, the Greeks, Egyptians, and Chinese incorporated the caper
bush into their traditional medicine practices.
Capers contain phytochemicals that can inhibit
inflammation, which supports caper’s usages as a cleanser and pain reliever.9,12
In ancient Chinese, Greek, and Arabic cultures, the root bark was mixed with
vinegar or honey and applied topically to treat skin conditions such as ulcers
and white spots associated with vitiligo.12 Similarly, the root was
consumed as a treatment for inflammation and lacerations of the mouth, spleen,
stomach, and intestines. In ancient Egypt, the root was used to reduce the pain
of a scorpion sting.
In ancient Greece and China, the caper bush was
regarded for its drying properties and was used as an expectorant in treating
wet cough and asthma.12 Ancient Romans boiled caper root and root
bark in oil and used it as an anthelmintic (digestive tract parasitic worm
expeller). Likewise, in the 12th century, the Egyptians used the root to cleanse
and dry the stomach.
Current medicinal usages are a testament to caper’s
efficacy for treating different ailments. In the Middle East, indigenous groups
still use capers as a so-called “blood purifier” and diuretic, to relieve
stomach discomfort, treat kidney stones, improve liver function, and treat eczema.13
In Ayurveda, one of the traditional medicine systems of India, caper is used to
treat paralysis and tremors, as well as edema, gout, and rheumatism.14
The root bark is still used to stimulate the menstrual cycle, as an
expectorant, and to treat paralysis, rheumatism, spleen conditions, and
toothaches.15
Modern Research
Commercial capers are not frequently studied for their
medicinal properties. However, some research has been conducted on the
bioactive compounds in the flower buds.
A recent study investigated the antiparasitic
effect of a caper bud extract against Haemonchus
contortus, a common parasite in cows and sheep. The large number of eggs
and short life span of H. contortus
allows the parasite to adapt quickly to its environment.16 Parasite
infestations can result in large economic losses in the animal production
industry, and current treatments include chemotherapy and vaccinations, which
pose a safety concern.17 Researchers compared the caper extract to a
commonly prescribed antiparasitic drug albendazole. The flower bud extract (50 mg/mL)
was almost twice as effective as albendazole (1 mg/mL) at killing parasites in
sheep and inhibited the hatching of
parasitic eggs more than the leaf extract.8
The caper bud has also been studied for its
anti-inflammatory and cytotoxic properties. A recent study investigated the
potential of capers to inhibit nuclear factor-kappa B (NF-κB), a transcription
factor that controls inflammation and cell growth. Mutations that impact its
activation may lead to uncontrolled cell growth, one of the conditions that can
cause a proliferation of cancer cells.18 For this reason, NF-κB is a
therapeutic target for pancreatic, renal, and thyroid cancer treatments.18-20
In one in vitro study, researchers tested an aqueous extract of the flower bud
and leaves, which were selected for their high levels of phenolic compounds, on
human adenocarcinoma cells. The caper extract successfully inhibited the
inflammation mechanism, and arrested cell growth in a dose-dependent manner.9
Additionally, a caper flower bud extract has been
studied for its ability to treat liver toxicity in animals. Rats were exposed
to two different liver toxins: carbon tetrachloride, a known carcinogen that
has been used as a commercial refrigerant, propellant, and solvent; and
paracetamol, also known as acetaminophen, a pain-relieving drug that can induce
liver failure in sufficiently high doses.21 Compared to control, the
caper extract resulted in a significant reductions in carbon tetrachloride-induced
and paracetamol-induced liver toxicity.
Nutrient Profile4
Macronutrient Profile: (Per 1 tablespoon
pickled capers, drained)
2 calories
0.2 g
protein
0.4 g
carbohydrate
0.1 g
fat
Secondary Metabolites: (Per 1 tablespoon
pickled capers, drained)
Provides small amounts of:
Vitamin
K: 2.1 mcg (2.6% DV)
Dietary
Fiber: 0.3 g (1.2% DV)
Provides trace amounts of:
Magnesium:
3 mg (0.8% DV)
Vitamin
C: 0.4 mg (0.7% DV)
Iron:
0.1 mg (0.6% DV)
Riboflavin:
0.01 mg (0.6% DV)
Folate:
2 mcg (0.5% DV)
Vitamin
E: 0.1 mg (0.5% DV)
Manganese:
0.007 mg (0.4% DV)
Calcium:
3 mg (0.3% DV)
Niacin:
0.06 mg (0.3% DV)
Vitamin
A: 12 IU (0.2% DV)
Phosphorus:
1 mg (0.1% DV)
Potassium:
3 mg (0.1% DV)
Thiamin:
0.002 mg (0.1% DV)
Vitamin
B6: 0.002 mg (0.1% DV)
DV =
Daily Value as established by the US Food and Drug Administration, based on a
2,000-calorie diet.
Recipe: Lemon
Capellini with Capers
Adapted from Ina
Garten22
Ingredients:
- 1
pound dried capellini pasta
- 1/3
cup of extra virgin olive oil
- Zest
and juice of two lemons
- 1/4
cup capers, drained
- Salt
and pepper to taste
Directions:
- Cook
pasta according to package directions. Before draining, reserve 1/4 cup of
pasta cooking water. Drain pasta and return to pot off the heat.
- Toss
the cooked pasta with olive oil, lemon juice, salt, and pepper, adding pasta
water a tablespoon at a time until a thin sauce forms. Discard any remaining
pasta water.
- Add
capers and lemon zest and toss once more to combine. Serve immediately.
References
- Kontaxis
DG. Specialty Crop: Capers. Davis, CA: University of California Cooperative
Extension; 2012. Available at: http://sfp.ucdavis.edu/pubs/SFNews/DecJan97-98/capers_148/.
Accessed April 17, 2017.
- Van
Wyk, BE. Food Plants of the World: An
Illustrated Guide. Portland, OR: Timber Press; 2005.
- National
Geographic Society. Edible: An
Illustrated Reference to the World’s Food Plants. Washington DC: National
Geographic Society; 2008.
- Basic
Report: 02054, Capers, canned. United States
Department of Agriculture Agricultural Research Service website. Available at: https://ndb.nal.usda.gov/ndb/foods/show/303. Accessed April 6, 2017.
- Appendix 7. Nutritional Goals for Age-Sex Groups Based on
Dietary Reference Intakes and Dietary
Guidelines Recommendations. In: Dietary
Guidelines for Americans 2015-2020. 8th ed. Washington DC: US
Department of Health and Human Services and US Department of Agriculture; 2015.
- Tlili N, Khaldi A, Triki S, Munné-Bosch S. Phenolic compounds
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spinosa). Plant Foods Hum Nutr.
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- Nabavi SF, Maggi F, Daglia M, Habtemariam S, Rastrelli L,
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spinosa L. Phyother Res.
2016;30:1733-1744.
- Akkari H, B’chir F, Hajaji S, et al. Potential anthelmintic
effect of Capparis spinosa
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activity. Veterinární Medicína.
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- Kulisic-Bilusic T, Schmöller I, Schnäbele K, Siracusa L,
Ruberto G. The anticarcinogenic potential of essential oil and aqueous infusion
from caper (Capparis spinosa L.). Food Chem. 2012;132(1):261-267.
- Yang T, Wang C, Liu H, Chou G, Cheng X, Wang Z. A new
antioxidant compound from Capparis
spinosa. Pharm Biol.
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- Kaur CK, Kapoor HC. Antioxidants in fruits and vegetables —
the millennium’s health. International
Journal of Food Science and Technology. 2001;36(7):703-725.
- Jiang HE, Li X, Ferguson DK, Wang YF, Liu CJ, Li CS. The
discovery of Capparis spinosa L.
(Capparidaceae) in the Yanghai tombs (2800 years b.p.), NW China, and its
medicinal implications. J Ethnopharmacol.
2007;113(3):409-420.
- Sher H, AlMutairi K, Mansoor M. Study on the
ethnopharmaceutical values and traditional uses of Capparis spinosa L. African
Journal of Pharmacy and Pharmacology. 2012;6(16):1255-1259.
- Nadkarni K. Indian
Materia Medica. Vol 1. Bombay, India: Bombay Popular Prakashan; 1976.
- Duke J. Duke’s Handbook
of Medicinal Plants of the Bible. Boca Raton, FL: CRC Press; 2008.
- Emery DL, Hunt PW, Le Jambre LF. Haemonchus contortus: the then and now, and where to from here? Int J Parasitol. 2016;46(12):755-769.
- Kebede B, Sori T, Kumssa B. Review on current status of
vaccines against parasitic diseases of animals. J Veterinar Sci Techno. 2015;7(3):27.
- Tunçel D. Role of NF-kappa b in the approach to pancreatic
ductal adenocarcinoma. Archives Medical
Review Journal. 2015;24(4):565-577.
- Li X, Abdel-Mageed AB, Mondal D, Kandil E. The nuclear factor
kappa-B signaling pathway as a therapeutic target against thyroid cancers. Thyroid. 2013;23(2):209-218.
- Peri S, Devarajan K, Yang DH, Knudson AG, Balachandran S.
Meta-analysis identifies NF-kappaB as a therapeutic target in renal cancer. PLoS One. 2013;8(10):e76746.
- Chhaya G, Mishra SH. Antihepatotoxic activity of p-methoxy benzoic avid from Capparis spinosa. J Ethnopharmacol. 1999;66:187-192.
- Garten
I. Lemon capellini with caviar. Food Network
Magazine. Available at: www.foodnetwork.com/recipes/ina-garten/lemon-capellini-with-caviar.
Accessed April 6, 2017.
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