Sea Buckthorn

Botanical Profile

Note on species delimitation: Sweet orange (Citrus sinensis) and bitter orange (Citrus × aurantium) should be considered separately in botanical and phytochemical statements.

Hippophae rhamnoides is a thorny deciduous shrub of the Elaeagnaceae with bright orange accessory fruits. From a raw-material perspective, pulp, juice, pomace, seed oil, pulp oil, leaves and phenolic-rich extracts must be clearly distinguished.

Hippophae rhamnoides L. is a perennial, usually strongly branched and thorny shrub to small tree. The species has narrow silvery-green leaves, inconspicuous unisexual flowers and conspicuous orange to orange-red fruit clusters. Botanically, the fruit portions used are juicy accessory fruits with very high proportions of organic acids, lipophilic pigments and seeds. Sea buckthorn grows on sandy, gravelly, saline or wind-exposed sites, on coasts, riverbanks, dunes and in continental mountain regions. The plant can associate with Frankia actinobacteria in root nodules and thereby contribute to nitrogen enrichment of nutrient-poor sites. For raw-material science, fruit juice, fruit pomace, seeds, seed oil, pulp oil and leaves must be considered separately.

Phytochemistry

Sea buckthorn fruits contain organic acids, sugars, pectins, carotenoids, flavonoids, phenolic acids, tocopherols, phytosterols and vitamin-rich fractions. Particularly characteristic are carotenoids such as beta-carotene, lycopene, zeaxanthin and other orange pigments that contribute to the intense fruit colour. Pulp oil and seed oil differ in fatty-acid profile: seed oil frequently contains linoleic and alpha-linolenic acids, whereas pulp oil may contain relatively high proportions of palmitoleic acid. Leaves contain flavonoids, tannins and phenolic accompanying substances. Composition depends strongly on subspecies, origin, cultivar, ripeness, fraction, pressing, drying and oil extraction. For extracts and oils, oxidative stability, pigment content, fatty-acid pattern and residue analysis are important quality parameters.

Traditional Uses

Sea buckthorn is known as a sour wild fruit in Eurasian coastal, mountain and steppe regions. Regionally, the fruits were processed into juices, purées, syrups, fruit preparations and preserved products. In northern and continental regions, sea buckthorn was important because of its intense acidity, colour and good processing suitability. Fruit, oil and leaves appear in different contexts of use in various European, Central Asian and Tibetan traditions. The fruit is perceived primarily as a sour-aromatic food raw material, while oils and leaves have their own raw-material traditions. Historical information describes inherited uses and should not be equated with modern health-related statements.

Current Research

Research on Hippophae rhamnoides addresses fruit quality, carotenoids, polyphenols, seed and pulp oils, fatty-acid profiles, antioxidant test systems, skin models, agronomic breeding and processing technology. Differences between juice, pomace, seed oil and pulp oil are particularly studied. Analytical work focuses on pigment stability, oil quality, tocopherols, phytosterols and polyphenol profiles. Experimental studies address cell and animal models as well as technological applications in foods and cosmetics. Results depend strongly on raw-material fraction and manufacturing process and must not be transferred indiscriminately to all sea buckthorn products.

Sources

• Plants of the World Online: Hippophae rhamnoides L.; Royal Botanic Gardens, Kew.
• Review articles on Hippophae rhamnoides, sea buckthorn fruits and sea buckthorn oils.
• Pharmacognostic and food raw-material literature on sea buckthorn.