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 seaberry¹.

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.² The shrubs reach 0.5–6 m tall, rarely up to 10 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, juicy and rich in oils. The berries are an important winter food resource for some birds, notably fieldfares.

Close-up of fruit of Common Sea-Buckthorn (Hippophae rhamnoides)

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. A wild variant occurs in the same area, but at even higher altitudes in the alpine zone^{citation needed}. It is a low shrub not growing taller than 1 m with small leaves 1-3 cm long.

Uses

Harvesting and landscaping

Harvesting is difficult due to the dense thorn arrangement among the berries on each branch. 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, allowing the berries to be easily shaken off. The branches are cut, deep frozen to −32°C, then shaken or abraded for removal of the berries.

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 or the crushed pulp are later frozen for storage.

The most effective way to harvest berries and not damage branches is by using a berry-shaker. 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 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 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 several provinces of Canada.³⁴

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 as wind breaks and to stabilize riverbanks and steep slopes. They have value in northern climates for their landscape qualities, as the colorful berry clusters are retained through winter.⁵ Branches may be used by florists for designing ornaments. The plant is the regional flora of the Finnish region of Satakunta.

Nutrients and potential health effects

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 or grape juice.

When the berries are pressed, 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 saturated and polyunsaturated fats; and the bottom layer is sediment and juice.⁶⁷ Containing fat sources applicable for cosmetic purposes, the upper two layers can be processed for skin creams and liniments, whereas the bottom layer can be used for edible products like syrup.⁶

Nutrient and phytochemical constituents of sea-buckthorn berries have potential value as antioxidants that may affect inflammatory disorders, cancer²⁸ or other diseases,⁹ although no specific health benefits have yet been proved by clinical research in humans.

The fruit of the plant has a high vitamin C content—in a range of 114 to 1550 mg per 100 grams²⁷ with an average content (695 mg per 100 grams) about 12 times greater than the 50 mg of vitamin C per 100 grams found in orange— placing sea-buckthorn fruit among the most enriched plant sources of vitamin C[1]. The fruit also contains dense contents of carotenoids, vitamin E, amino acids, dietary minerals, β-sitosterol and polyphenolic acids.²⁷¹⁰

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.^{citation needed}

Consumer products

Sea-buckthorn fruit can be used to make pies, jams, lotions and liquors.² The juice or pulp has other potential applications in foods or beverages.² For example, in Finland, it is used as a nutritional ingredient in baby food.^{citation needed} Fruit drinks were among the earliest seabuckthorn products developed in China. Seabuckthorn based juice is even popular in Germany and Scandinavian countries.It provides a nutritious beverage, rich in Vitamin C and crotenes. 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.¹¹

The seed and pulp oils have nutritional properties that vary under different processing methods.²¹² Sea-buckthorn oils are used as a source for ingredients in several commercially available cosmetic products and nutritional supplements.²

Traditional medicine

Different parts of sea-buckthorn have been used as traditional therapies for diseases[2] (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 [3][4].

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.

Organizations

The International Seabuckthorn Association, formerly 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. From 1995 to 2000, ICRTS published the research journal, Hippophae, which appears to be no longer active.

Contents