Sea-buckthorn

The sea-buckthorns (Hippophae L.) are deciduous shrubs in the genus Hippophae, family Elaeagnaceae. The name sea-buckthorn is hyphenated here to avoid confusion with the buckthorns (Rhamnus, family Rhamnaceae). It is also referred to as "sea buckthorn", seabuckthorn, sandthorn or seaberry. It is known in different languages as: Shaji (Chinese), Duindoorn (Dutch), Tyrni (Finnish), Argousier (French), Sanddorn (German), Olivello Spinoso (Italian), Облепиха (Oblepicha, Russian), Espino de Mar, Falso Espino, Espino Amarillo (Spanish), Havtorn (Swedish and Danish).

Since 2005 in the United States, other such developed countries and the global functional food industry, there has been a rapidly growing recognition of sea-buckthorn berries for their consumer product potential, exceptional nutrient content and antioxidant qualities, giving them commercial status as a novel superfruit.

Description and distribution
There are 6 species and 12 subspecies native over a wide area of Europe and Asia, including China, Mongolia, India, Nepal, Pakistan, Russia, Great Britain, France, Denmark, Netherlands, Germany, Poland, Finland, Sweden and Norway. More than 90 percent or about 1.5 million hectares of the world's sea buckthorn resources can be found in China where the plant is exploited for soil and water conservation purposes. The shrubs reach 0.5–6 m tall, rarely up to 18 m in central Asia, and typically occur in dry, sandy areas. They are tolerant of salt in the air and soil, but demand full sunlight for good growth and do not tolerate shady conditions near larger trees.

The common sea-buckthorn (Hippophae rhamnoides) is by far the most widespread, with a range extending from the Atlantic coasts of Europe right across to northwestern China. In western Europe, it is largely confined to sea coasts where salt spray off the sea prevents other larger plants from out-competing it, but in central Asia it is more widespread in dry semi-desert sites where other plants cannot survive the dry conditions; in central Europe and Asia it also occurs as a subalpine shrub above tree line in mountains, and other sunny areas such as river banks.

Common sea-buckthorn has branches that are dense and stiff, and very thorny. The leaves are a distinct pale silvery-green, lanceolate, 3–8 cm long and less than 7 mm broad. It is dioecious, with separate male and female plants. The male produces brownish flowers which produce wind-distributed pollen.

Berries and leaves
The female plants produce orange berries 6–9 mm in diameter, soft and juicy, and rich in vitamin C (on average 600 mg per 100g and sometimes up to 1500 mg per 100g ); some varieties are also rich in vitamin A, vitamin E, and oils. The berries are an important winter food resource for some birds, notably Fieldfares.

Leaves are eaten by the larva of the coastal race of the Ash Pug moth and by larvae of other Lepidoptera including Brown-tail, The Dun-bar, Emperor Moth, Mottled Umber and Coleophora elaeagnisella.

Hippophae salicifolia (Willow-leaved Sea-buckthorn) is restricted to the Himalaya, to the south of the Common Sea-buckthorn, growing at high altitudes in dry valleys; it differs from H. rhamnoides in broader (to 10 mm broad), greener (less silvery) leaves, and yellow berries. Hippophae tibetana (Tibetan Sea-buckthorn) occurs in the same area, but at even higher altitudes in the alpine zone. It is a low shrub not growing taller than 1 m with small leaves 1-3 cm long.

Two further species, Hippophae goniocarpa and Hippophae neurocarpa, have been described from China, but are not widely accepted as distinct.

Harvesting and landscaping
Harvesting is difficult due to the densely thorny nature of the shrubs. A common harvesting technique is to remove an entire branch, though this is destructive to the shrub and reduces future harvests. A branch removed in this way is next frozen, and then the berries can be easily shaken off. The branches are cut, deep frozen to −32°C. They are slightly defrosted on the surface during the removal of the berries from the branches and afterwards cleaned.

The worker then crushes the berries to remove up to 95% of the leaves and other debris. This causes the berries to melt slightly from the surface as the work takes place at ambient temperature (about 20°C). Berries are later stored at -22°C.

The most effective way to harvest the berries and not damage the branches is by using a berry-shaker which was developed in Estonia some time ago. Mechanical harvesting leaves up to 50% in the field and the berries can be harvested only once in two years. They only get about 25% of the yield that could be harvested with this relatively new piece of machinery.

During the Cold War, Russian and East German horticulturists developed new varieties with greater nutritional value, larger berries, different ripening months and a branch form that is easier to harvest. Over the past 20 years, experimental crops have been grown in the United States, one in Nevada and one in Arizona, and in western provinces of Canada.

Sea-buckthorn is also a popular garden and landscaping shrub, particularly making a good vandal-proof barrier hedge with an aggressive basal shoot system exploited in some parts of the world to stabilize riverbanks and steep slopes. They have value in northern climates for their landscape qualities, as their colorful berry clusters are retained through winter. Branches are used by florists for designing ornaments. The plant is the regional flora of the Finnish region of Satakunta.

Nutrients, potential health effects and cosmetics
Sea-buckthorn berries are multipurposed, edible and nutritious, though very acidic and astringent, unpleasant to eat raw, unless 'bletted' (frosted to reduce the astringency) and/or mixed as a juice with sweeter substances such as apple juice or grape juice. They can also be used to make pies or jam. The consumer industry uses sea-buckthorn berries for jams, juices, lotions, and liquors.

When the berries are pressed for juice, the resulting sea-buckthorn juice separates into three layers: on top is a thick, orange cream; in the middle, a layer containing sea-buckthorn's characteristic high content of unsaturated fats; and the bottom layer, sediment and juice. Containing fat sources used for cosmetic purposes, the upper two layers can be processed for skin creams and liniments, whereas the bottom layer can be used for juices, jams and other edible products.

Nutrient and phytochemical constituents of sea-buckthorn berries, particularly oils, have exceptional properties as antioxidants possibly relevant to inhibiting inflammatory disorders, cancer and numerous other diseases. The seed and pulp oils have been specifically studied for nutritional properties under different methods of processing.

The fruit of the plant has a high vitamin C content&mdash;in a range of 114 to 1550 milligrams per 100 grams with an average content (695 mg per 100 grams: 6.95‰) about 12 times greater than the 50 milligrams of vitamin C per 100 grams (0.5‰) found in orange&mdash;placing sea-buckthorn fruit among the most enriched plant sources of vitamin C. The fruit also contains dense contents of carotenoids, vitamin E, amino acids, dietary minerals, β-sitosterol and polyphenolic acids.

Recently, sea-buckthorn has been used as an ingredient in several commercially available cosmetic products and nutritional supplements.

Apart from being nourishing, the juice has a freezing point of −22 degrees Celsius allowing it to remain a liquid even in sub-zero temperatures. For its troops confronting extremely low temperatures (see Siachen), India's Defence Research Development Organization established a factory in Leh to manufacture a multi-vitamin herbal beverage based on sea-buckthorn juice.

Traditional medicine
Different parts of sea-buckthorn have been used as traditional therapies for diseases (see References). As no applications discussed in this section have been verified by Western science and sufficient clinical trial evidence, such knowledge remains mostly unreferenced outside of Asia and is communicated mainly from person to person.

Grown widely throughout its native China and other mainland regions of Asia, sea-buckthorn is an herbal medicine used over centuries to relieve cough, aid digestion, invigorate blood circulation and alleviate pain. In Mongolia, extracts of sea-buckthorn branches and leaves are used to treat gastrointestinal distress in humans and animals.

Bark and leaves are used for treating diarrhea, gastrointestinal, dermatologic disorders and topical compressions for rheumatoid arthritis. Flowers may be used as a skin softener.

For its hemostatic and anti-inﬂammatory effects, berry fruits are added to medications for pulmonary, gastrointestinal, cardiac, blood and metabolic disorders in Indian, Chinese and Tibetan medicines. Sea-buckthorn berry components have potential anticarcinogenic activity.

Fresh juice, syrup and berry or seed oils are used for colds, fever, exhaustion, as an analgesic or treatment for stomach ulcers, cancer, and metabolic disorders.

Called 'Chharma' in some native languages, oil from fruits and seeds is used for liver diseases, inﬂammation, disorders of the gastrointestinal system, including peptic ulcers and gastritis, eczema, canker sores and other ulcerative disorders of mucosal tissues, wounds, inﬂammation, burns, frostbite, psoriasis, lupus erythematosus, and chronic dermatoses. In ophthalmology, berry extracts have been used for keratitis, trachoma, eyelid injuries and conjunctivitis.

Organizations
An organization called the International Center for Research and Training on Seabuckthorn (ICRTS) was formed jointly in 1988 by the China Research and Training Center on Seabuckthorn, the Seabuckthorn Office of the Yellow River Water Commission, and the Shaanxi Seabuckthorn Development Office. ICRTS published the research journal, Hippophae, from 1995 to 2000 ; it does not appear to be active currently. In 2005, an international collaboration called "EAN-Seabuck" between European Union states, China, Russia and New Independent States was funded by the European Commission to promote sustainable crop and consumer product development from sea buckthorn.