Hippophae

Hippophae, the sea-buckthorns, are deciduous shrubs in the family Elaeagnaceae. The name sea-buckthorn may be hyphenated^[1] to avoid confusion with the buckthorns (Rhamnus, family Rhamnaceae). It is also referred to as sandthorn, sallowthorn,^[2] or seaberry.^[3]

Distribution

Seven species are recognized, two of them probably of hybrid origin,^[4] native over a wide area of Europe and Asia.

Hippophae rhamnoides, the common sea-buckthorn, is by far the most widespread of the species in the genus, with the ranges of its eight subspecies extending from the Atlantic coasts of Europe across to northwestern Mongolia and northwestern China. In western Europe, it is largely confined to sea coasts where salt spray off the sea prevents other larger plants from outcompeting it, but in central Asia, it is more widespread in dry semidesert 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. 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. They typically grow in dry, sandy areas.

More than 90% or about 1,500,000 ha (5,800 sq mi) of the world's natural sea-buckthorn habitat is found in China, Mongolia, Russia, northern Europe and Canada where the plant is used for soil, water and wildlife conservation and anti-desertification purposes and for consumer products.^[5]

Description

The shrubs reach 0.5–6 metres (1.6–19.7 ft) tall, rarely up to 10 metres (33 ft) in central Asia. The leaf arrangement can be alternate, or opposite.^[6]

Common sea-buckthorn has branches that are dense and stiff, and very thorny. The leaves are a distinct pale silvery-green, lanceolate, 3–8 centimetres (1.2–3.1 in) long and less than 7 millimetres (0.28 in) broad. It is dioecious, with separate male and female plants. The male produces brownish flowers which produce wind-distributed pollen. The female plants produce orange berry-like fruit 6–9 millimetres (0.24–0.35 in) in diameter, soft, juicy and rich in oils. The roots distribute rapidly and extensively, providing a non-leguminous nitrogen fixation role in surrounding soils.

Hippophae salicifolia (willow-leaved sea-buckthorn) is restricted to the Himalayas, to the south of the common sea-buckthorn, growing at high altitudes in dry valleys; it differs from H. rhamnoides in having broader (to 10 millimetres (0.39 in)) and greener (less silvery) leaves, and yellow berries. A wild variant occurs in the same area, but at even higher altitudes in the alpine zone. It is a low shrub not growing taller than 1 metre (3.3 ft) with small leaves 1–3 centimetres (0.39–1.18 in) long.

Species

• Hippophae goniocarpa
• Hippophae gyantsensis
• Hippophae litangensis
• Hippophae neurocarpa
• Hippophae rhamnoides – common sea-buckthorn
• Hippophae salicifolia
• Hippophae tibetana

A study of nuclear ribosomal internal transcribed spacer (ITS) sequence data^[7] showed that the genus can be divided into three monophyletic clades:

• H. tibetana
• H. rhamnoides with the exception of H. rhamnoides ssp. gyantsensis (=H. gyantsensis)
• remaining species

A study using chloroplast sequences and morphology,^[4] however, recovered only two clades:

• H. tibetana, H. gyantsensis, H. salicifolia, H. neurocarpa
• H. rhamnoides

Natural history

The fruit is 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, dun-bar, emperor moth, mottled umber and Coleophora elaeagnisella.

Uses

Fruit harvesting

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 then frozen, allowing the berries to be easily shaken off.

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.^[8]

Landscape uses

Sea-buckthorn is also a popular garden and landscaping shrub with an aggressive basal shoot system used for barrier hedges and windbreaks, 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.^[9] Branches may be used by florists for designing ornaments.

The plant is the regional flora of the Finnish region of Satakunta. In Mongolia, this shrub is planted as part of the anti-desertification efforts. Sea-buckthorn was once distributed free of charge to Canadian prairie farmers by PFRA to be used in shelterbelts.^[10]

Nutrients and potential health effects

Sea-buckthorn berries are edible and nutritious, though astringent and oily, unpleasant to eat raw, unless 'bletted' (frosted to reduce the astringency) and/or mixed as a drink 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.^[11][12] 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.^[11]

Nutrient and phytochemical constituents of sea-buckthorn berries are under basic research in inflammatory disorders, cancer mechanisms or positive effect on bone marrow after chemotherapy,^[13] or other diseases,^[14] although no specific health benefits have yet been proven 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 grams^[12] with an average content (695 mg per 100 grams) about 15 times greater than oranges (45 mg per 100 grams)^[15] – 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^[12][16] and polyphenols. Flavonols were found to be the predominating polyphenols while phenolic acids and flavan-3-ols (catechins) represent minor components.^[17]

Consumer products

Sea-buckthorn fruit can be used to make pies, jams, lotions, fruit wines and liquors. The juice or pulp has other potential applications in foods, beverages or cosmetics products.

Fruit drinks were among the earliest sea-buckthorn products developed in China. Seabuckthorn-based juice is popular in Germany and Scandinavian countries. It provides a nutritious beverage, rich in vitamin C and carotenes.

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.^[18]

The seed and pulp oils have nutritional properties that vary under different processing methods.^[19] Sea-buckthorn oils are used as a source for ingredients in several commercially available cosmetic products and nutritional supplements.

Traditional medicine

Different parts of sea-buckthorn have been used as traditional therapies for diseases.^[14] Bark and leaves have been used for treating diarrhea and dermatological disorders. Berry oil, either taken orally or applied topically, is believed to be a skin softener.

In Indian, Chinese and Tibetan medicines, sea-buckthorn fruit may be added to medications in belief it affects pulmonary, gastrointestinal, cardiac, blood or metabolic disorders.^[14] Basic research using leaf extracts as a model of tea consumption showed potential anti-obesity properties in mice.^[20][21]

Organizations

In 2005, the "EAN-Seabuck" network between European Union states, China, Russia and New Independent States was funded by the European Commission to promote sustainable crop and consumer product development.^[22] In Mongolia, there is an active National Association of Seabuckthorn Cultivators and Producers.

The International Seabuckthorn Association,^[23] 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.

See also

• Sea buckthorn oil
• Wolfberry, a native Asian plant occasionally mistaken for sea-buckthorn

References

Further reading

External identifiers for Hippophae
Encyclopedia of Life	61951
ITIS	503044
NCBI	48233
Also found in: Wikispecies

• Beveridge, Thomas H. J.; Li, Thomas S. C. (2003). Sea buckthorn (Hippophae rhamnoides L.) production and utilization. Ottawa: NRC Research Press. ISBN 0-660-19007-9. 
• Li TSC, Oliver A. Sea buckthorn factsheet, British Columbia Ministry of Agriculture, Food and Fisheries, May 2001
• Todd, J. Introduction to sea-buckthorn, Ontario Ministry of Food, Agriculture and Rural Affairs, February, 2006

External links

Wikisource has the text of the 1905 New International Encyclopedia article Swallowthorn.

• United States Department of Agriculture Seaberry Profile
• Plants for a Future
• Purdue University list of articles
• Series of high quality photos at Hort.net
• Crops for the Future:Sea-buckthorn (Hippophae rhamnoides)
• National Association of Seabuckthorn Cultivators and Producers of Mongolia