|Lycium barbarum fruits|
Wolfberry, commercially called goji berry, is the common name for the fruit of two very closely related species: Lycium barbarum (Chinese: 寧夏枸杞; pinyin: Níngxià gǒuqǐ) and L. chinense (Chinese: 枸杞; pinyin: gǒuqǐ), two species of boxthorn in the family Solanaceae (which also includes the potato, tomato, eggplant, deadly nightshade, chili pepper, and tobacco). It is native to southeastern Europe and Asia.
It is also known as Chinese wolfberry, mede berry, barbary matrimony vine, bocksdorn, Duke of Argyll’s tea tree, Murali (in India), red medlar, or matrimony vine. Unrelated to the plant’s geographic origin, the names Tibetan goji and Himalayan goji are in common use in the health food market for products from this plant.
Wolfberry species are deciduous woody perennial plants, growing 1–3 m high. L. chinense is grown in the south of China and tends to be somewhat shorter, while L. barbarum is grown in the north, primarily in the Ningxia Hui Autonomous Region, and tends to be somewhat taller.
Leaves and flower
Wolfberry leaves form on the shoot either in an alternating arrangement or in bundles of up to three, each having a shape that is either lanceolate (shaped like a spearhead longer than it is wide) or ovate (egg-like). Leaf dimensions are 7-cm wide by 3.5-cm broad with blunted or round tips.
The flowers grow in groups of one to three in the leaf axils. The calyx (eventually ruptured by the growing berry) consists of bell-shaped or tubular sepals forming short, triangular lobes. The corolla are lavender or light purple, 9–14 mm wide with five or six lobes shorter than the tube. The stamens are structured with filaments longer than the anthers. The anthers are longitudinally dehiscent.
In the northern hemisphere, flowering occurs from June through September and berry maturation from August to October, depending on the latitude, altitude, and climate.
These species produce a bright orange-red, ellipsoid berry 1–2-cm deep. The number of seeds in each berry varies widely based on cultivar and fruit size, containing anywhere between 10–60 tiny yellow seeds that are compressed with a curved embryo. The berries ripen from July to October in the northern hemisphere.
“Wolfberry” is the most commonly used English name, while gǒuqǐ (枸杞) is the Chinese name for the berry producing plant. In Chinese, the berries themselves are called gǒuqǐzi (枸杞子), with zi meaning “seed” or specifically “berry”. Other common names are “the Duke of Argyll’s Tea Tree”
and “matrimony vine”.
Rarely, wolfberry is also known in pharmacological references as Lycii fructus, meaning “Lycium fruit” in Latin.
The origin of the common name “wolfberry” is unknown, perhaps resulting from confusion over the genus name, which resembles “lycos”, the Greek word for wolf. In the English-speaking world, “goji berry” has been used since the early 21st century as a synonym for “wolfberry”. The word “goji” is an approximation of the pronunciation of gǒuqǐ in several Chinese dialects, including Hokkien and Shanghainese.
L. chinense was first described by the Scottish botanist Philip Miller in the eighth edition of his The Gardener’s Dictionary, published in 1768.
In Japan the plant is known as kuko (クコ) and the fruits are called kuko no mi (クコ の 実) or kuko no kajitsu (クコ の 果 実); in Korea the berries are known as gugija (hangul: 구기자; hanja: 枸杞子); in Vietnam the fruit is called “kỷ tử” (杞子), “cẩu kỷ” (枸杞), “cẩu kỷ tử”(枸杞子) but the plant and its leaves are known more popularly as “củ khởi”; and in Thailand the plant is called găo gèe (เก๋ากี้). In Tibetan the plant is called dretsherma (), with dre meaning “ghost” and tsherma meaning “thorn”; and the name of the fruit is dretshermǟ dräwu (), with dräwu meaning “fruit”.
Since the early 21st century there has been rapidly growing attention for wolfberries for their nutrient value and antioxidant content. They have been termed a superfruit, which has led to a profusion of consumer products.
The majority of commercially produced wolfberries come from the Ningxia Hui Autonomous Region of north-central China and the Xinjiang Uyghur Autonomous Region of western China, where they are grown on plantations. In Zhongning County, Ningxia, wolfberry plantations typically range between 100 and 1000 acres (or 500–6000 mu) in area. As of 2005, over 10 million mu have been planted with wolfberries in Ningxia .
Cultivated along the fertile aggradational floodplains of the Yellow River for more than 600 years, Ningxia wolfberries have earned a reputation throughout Asia for premium quality sometimes described commercially as “red diamonds”.Government releases of annual wolfberry production, premium fruit grades, and export are based on yields from Ningxia, the region recognized with
- The largest annual harvest in China, accounting for 42% (13 million kg, 2001) of the nation’s total yield of wolfberries, estimated at approximately 33 million kg (72 million lb) in 2001.
- Formation of an industrial association of growers, processors, marketers, and scholars of wolfberry cultivation to promote the berry’s commercial and export potential.
- The nation’s only source of therapeutic grade (“superior-grade”) wolfberries used by practitioners of traditional Chinese medicine.
In addition, commercial volumes of wolfberries grow in the Chinese regions of Inner Mongolia, Qinghai, Gansu, Shaanxi, Shanxi, and Hebei. When ripe, the oblong, red berries are tender and must be picked carefully or shaken from the vine into trays to avoid spoiling. The fruits are preserved by drying them in full sun on open trays or by mechanical dehydration employing a progressively increasing series of heat exposure over 48 hours.
Wolfberries are celebrated each August in Ningxia with an annual festival coinciding with the berry harvest.Originally held in Ningxia’s capital, Yinchuan, the festival has been based since 2000 in Zhongning County, an important center of wolfberry cultivation for the region. As Ningxia’s borders merge with three deserts, wolfberries are also planted to control erosion and reclaim irrigable soils from desertification.
China, the main supplier of wolfberry products in the world, had total exports generating US$120 million in 2004. This production derived from 82,000 hectares farmed nationwide, yielding 95,000 tons of wolfberries.
Pesticide and fungicide use
Organochlorine pesticides are conventionally used in commercial wolfberry cultivation to mitigate destruction of the delicate berries by insects. Since the early 21st century, high levels of insecticide residues (including fenvalerate, cypermethrin, and acetamiprid) and fungicide residues (such as triadimenol and isoprothiolane), have been detected by the United States Food and Drug Administration in some imported wolfberries and wolfberry products of Chinese origin, leading to the seizure of these products.
China’s Green Food Standard, administered by the Chinese Ministry of Agriculture’s China Green Food Development Center, does permit some amount of pesticide and herbicide use. Agriculture in the Tibetan plateau (where many “Himalayan” or “Tibetan”-branded berries originate) conventionally uses fertilizers and pesticides, making organic claims for berries originating here dubious.
The Duke of Argyll introduced Lycium barbarum into the United Kingdom in the 1730s where it is known as Duke of Argyll’s Tea Tree.It was and still is used for hedging, especially in coastal districts. Its red berries are attractive to a wide variety of British birds.
The plant continues to grow wild in UK hedgerows. On 15 January 2003, the Department for Environment, Food and Rural Affairs launched a project to improve the regulations protecting traditional countryside hedgerows, and specifically mentioned Duke of Argyll’s Tea Tree as one of the species to be found growing in hedges located in Suffolk Sandlings, Hadleigh, Bawdsey, near Ipswich, and Walberswick.
On June 18, 2007, the FSA (UK Food Standards Agency) stated that there was a significant history of the fruit being consumed in Europe before 1997, and has removed it from the Novel Foods list. It is now legal to sell the wolfberry in the UK as a food as reported by the British Food Standards Agency, but see section below: Marketing claims under scrutiny in Europe.
Importation of mature plants
Importation of wolfberry plants into the United Kingdom from most countries outside Europe is illegal, due to the possibility they could be vectors of diseases attacking Solanaceae crops, such as potato or tomato.
Wolfberries are usually sold in open boxes and small packages in dried form.
As a food, dried wolfberries are traditionally cooked before consumption. Dried wolfberries are often added to rice congee and almond jelly, as well as used in Chinese tonic soups, in combination with chicken or pork, vegetables, and other herbs such as wild yam, Astragalus membranaceus, Codonopsis pilosula, and licorice root. The berries are also boiled as an herbal tea, often along with chrysanthemum flowers and/or red jujubes, or with tea, particularly pu-erh tea, and packaged teas are also available.
At least one Chinese company also produces wolfberry beer, and New Belgium Brewery makes their seasonal Springboard ale with wolfberries used as flavoring. Since the early 21st century, an instant coffee product containing wolfberry extract has been produced in China.
Preliminary medical research
Marketing literature for wolfberry products including several “goji juices” suggest that wolfberry polysaccharides have biological effects and possible health benefits, although no such claims have been supported by peer-reviewed research or approved by any regulatory agency.
A 2008 pilot study indicated that parametric data did not show significant differences between subjects receiving Lycium barbarum berry juice and subjects receiving a placebo; the authors, nevertheless, concluded that subjective measures had been affected. This study was subject to various criticisms concerning its experimental design and interpretations.
Published studies have also reported biological effects of Lycium barbarum in animal models, and inferred from this basic research that there may be potential benefits against cardiovascular and inflammatory diseases,vision-related diseases (such as age-related macular degeneration and glaucoma) or from neuroprotective,anticanceror immunomodulatory activity.
In Traditional Chinese Medicine, Lycium leaves may be used in a tea, together with the root bark (called dìgǔpí; 地 骨 皮). A glucopyranoside (namely (+)-Lyoniresinol-3α-O-β-d-glucopyranoside) and phenolic amides (dihydro-N-caffeoyltyramine, trans-N-feruloyloctopamine, trans-N-caffeoyltyramine and cis-N-caffeoyltyramine) isolated from wolfberry root bark have inhibitory activity in vitro against human pathogenic bacteria and fungi.
Two published case reports described elderly women who experienced increased bleeding, expressed as an elevated INR, after drinking quantities of wolfberry tea.Further in vitro testing revealed that the tea inhibited warfarin metabolism, providing evidence for possible interaction between warfarin and undefined wolfberry phytochemicals.
Atropine, a toxic alkaloid found in other members of the Solanaceae family, occurs naturally in wolfberry fruit. The atropine concentrations of berries from China and Thailand are variable, with a maximum content of 19 ppb, below the likely toxic amount.
Micronutrients and phytochemicals
Wolfberries contain many nutrients and phytochemicals including
- 11 essential and 22 trace dietary minerals
- 18 amino acids
- 6 essential vitamins
- 8 polysaccharides and 6 monosaccharides
- 5 unsaturated fatty acids, including the essential fatty acids, linoleic acid and alpha-linolenic acid
- beta-sitosterol and other phytosterols
- 5 carotenoids, including beta-carotene and zeaxanthin (below), lutein, lycopene and cryptoxanthin, a xanthophyll
- numerous phenolic pigments (phenols) associated with antioxidant properties
Select examples given below are for 100 grams of dried berries.
- Calcium. Wolfberries contain 112 mg per 100 gram serving, providing about 8-10% of the Dietary Reference Intake (DRI).
- Potassium. Wolfberries contain 1,132 mg per 100 grams dried fruit, giving about 24% of the DRI.
- Iron. Wolfberries have 9 mg iron per 100 grams (100% DRI).
- Zinc. 2 mg per 100 grams dried fruit (18% DRI).
- Selenium. 100 grams of dried wolfberries contain 50 micrograms (91% DRI)
- Riboflavin (vitamin B2). At 1.3 mg, 100 grams of dried wolfberries provide 100% of DRI.
- Vitamin C. Vitamin C content in dried wolfberries has a wide range (from different sources) from 29 mg per 100 grams to as high as 148 mg per 100 grams (respectively, 32% and 163% DRI).
Wolfberries also contain numerous phytochemicals for which there are no established DRI values. Examples:
- Beta-carotene: 7 mg per 100 grams dried fruit.
- Zeaxanthin. Reported values for zeaxanthin content in dried wolfberries vary considerably, from 2.4 mg per 100 grams to 82.4 mg per 100 grams to 200 mg per 100 grams. The higher values would make wolfberry one of the richest edible plant sources known for zeaxanthin content Up to 77% of total carotenoids present in wolfberry exist as zeaxanthin.
- Polysaccharides. Polysaccharides are a major constituent of wolfberries, representing up to 31% of pulp weight.
One study published in the Journal of Ethnopharmacology found that:
- Endogenous lipid peroxidation, and decreased antioxidant activities, as assessed by superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (TAOC), and immune function were observed in aged mice and restored to normal levels in Lycium polysaccharide-treated groups. Antioxidant activities of Lycium barbarum polysaccharides were found to be comparable with normal antioxidant, vitamin C. Furthemore, adding vitamin C to the polysaccharide treatment further increased in vivo antioxidant activity of the polysaccharides.
Marketers of some wolfberry products claim that polysaccharides have specific physiological roles mediated by specialized cell receptors “master” control properties over other bioactive chemicals and cells. Characteristic spectral peaks are claimed to define one berry’s geographic origin from another.
These assertions are an important marketing message for wolfberry products branded as Tibetan Goji Berries or Himalayan Goji Juice. Such statements, however, have no scientific evidence published under peer-reviewand are not compliant with regulatory guidelines for marketing natural food products (see below, Marketing claims under scrutiny in Europe, Canada and the United States).
Functional food and beverage applications
It is often cultivated for a variety of food and beverage applications within China, but increasingly today for export as dried berries, juice, and pulp or grounds. Wolfberries are prized for their versatility of color and nut-like taste in common meals, snacks, beverages, and medicinal applications. A major effort is underway in Ningxia, China to process wolfberries for “functional” wine.
Since the early 21st century, the dried fruit has been marketed in the West as a health food (typically under the name “Tibetan goji berry”), often accompanied by scientifically-unsupported claims regarding its purported health benefits.
Its most claimed nutritional attribute is an exceptional level of vitamin C, to be among the highest in natural plants.However, it was demonstrated by independent assays on dried berries to be quite variable, in a range of 29–148 mg per 100 grams of fruit. This level is comparable to many citrus fruits and strawberries as well as numerous other fruits and berries.
Companies marketing the berries often also include the unsupported myth that a Chinese man named Li Qing Yuen, who was said to have consumed wolfberries daily, lived to the age of 252 years (1678–1930).
Commercial products marketed outside Asia
Typical of many exotic fruits being introduced into western food and beverage commerce, wolfberry is best known as a juice marketed over the Internet since 2002, often via multi-level marketing that asserts its health benefits. There is an increasing presence of wolfberry in health food stores and grocery markets in many countries.
While juice prepared entirely from fresh wolfberries is rare,blends containing several other berry and fruit juices are used for nearly all “wolfberry” juice products, many of which are nevertheless labeled as “goji juice”. The percentage of wolfberry contained in these juices is generally not stated on the labels of such products.
Other wolfberry consumer applications are
- Dried berries (pictured above)
- Berry pieces in granola barsand
- Skin soap (made from seed oils)
- Yogurt products
Commercial suppliers have processed wolfberry as
- An additive for manufacturing
- Juice concentrate
- Whole fruit purée
- Powders from juice or juice concentrate made from spray drying
- Pulp powders
- Whole or ground seeds
- Seed oils (as with grape seed oil), and essential oils derived from seeds)
Marketing claims under scrutiny in Europe
In February 2007, the Food Standards Agency (FSA) of the United Kingdom, an advisor for food safety to the European Food Safety Authority of the European Union (EU), published an inquiry to retailers and health food stores requesting evidence of significant use of wolfberries in Europe before 1997. This period would document a safety history and evaluate how “novel” the berries are in the EU, affecting their authorization status for sale.
Proponents hoped this review would provide important safeguards for consumers by checking whether new foods are suitable for the whole population, including people with food allergies. Opponents on the other hand feared it would limit consumer choice and protect monopolistic interests rather than the public. Food safety in the EU relies importantly on a scientific basis for label information on foods like wolfberries that may be claimed to furnish health benefits.
In June 2007, the FSA announced its decision that wolfberries indeed had a history of use in Great Britain before 1997.Accordingly, wolfberries do not require registration as a novel food.
Marketing claims under scrutiny in Canada and the United States
By one specific example in the CBC interview, Earl Mindell (then working for direct-marketing company FreeLife International, Inc.) claimed the Memorial Sloan-Kettering Cancer Center in New York had completed clinical studies showing that use of wolfberry juice would prevent 75% of human breast cancer cases, a statement false in three ways:
- no such project has been undertaken at Memorial Sloan-Kettering
- according to the National Cancer Institute of the US National Institutes of Health, no natural or pharmaceutical agent has been shown in clinical trials to fully prevent[dubious – discuss] breast cancer, only to reduce its risk; specifically, there are no completed or ongoing clinical trials in the United States testing the effects of wolfberries or juice on breast cancer outcomes or any other disease and
- scientific evidence for wolfberry phytochemicals or wolfberry juice having cancer-preventive properties is limited. There are preliminary laboratory studies and one Chinese clinical trial.
During 2006, the U.S. Food and Drug Administration (FDA) placed two goji juice distributors on notice with warning letters about marketing claims. These statements were in violation of the United States Food, Drug and Cosmetic Act [21 USC/321 (g)(1)] because they “establish the product as a drug intended for use in the cure, mitigation, treatment, or prevention of disease” when wolfberries or juice have had no such scientific evaluation. Additionally stated by the FDA, the goji juice was “not generally recognized as safe and effective for the referenced conditions” and therefore must be treated as a “new drug” under Section 21(p) of the Act. New drugs may not be legally marketed in the United States without prior approval of the FDA.
On May 29, 2009, a class action lawsuit was filed against FreeLife in the United States District Court of Arizona. This lawsuit alleges false claims, misrepresentations, false and deceptive advertising and other issues regarding FreeLife’s Himalayan Goji Juice, GoChi, and TaiSlim products. This lawsuit seeks remedies for consumers who have purchased these products over the past several years.
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