Sea buckthorn oil
Sea buckthorn oil is derived from plants in a group of species of the genus Hippophae, the most commonly used of which is Hippophae rhamnoides. As species belonging to this genus accumulate lipids in the mesocarp (the fleshy part of the fruit), oil can be extracted from either the seeds or the pulp of the fruit. The resulting oils (seed oil and pulp oil, also often referred to as fruit/berry oil) are used in dietary supplements, nutraceuticals, cosmetics and skin care products.
Oil content in seeds of sea buckthorn is on average 7-11 % while oil content of the fruit pulp is around 1.5-3 % (per fresh weight).
Seed oil is characterized by high contents of polyunsaturated fatty acids while pulp oil contains monounsaturated fatty acids and carotenoids. Both oils also contain dense amounts of tocopherols, tocotrienols  and plant sterols.
Oils from sea buckthorn seeds and pulp differ considerably in fatty acid composition. While linoleic acid and α-linolenic acid are the major fatty acids in seed oil, sea buckthorn pulp oil contains approximately 65% combined of the monounsaturated fatty acid, palmitoleic acid, and the saturated fatty acid, palmitic acid. This results in a major difference between the two oils in term of appearance and consistency. Sea buckthorn fruit oil is dark orange in color and has a thick consistency (it is liquid at room temperature, but becomes much thicker if refrigerated), whereas the seed oil is pale yellow and does not solidify under refrigeration.
Tocopherols and tocotrienols
α-Tocopherol is the major vitamin E compound in sea buckthorn. Seed oil also contains considerable amounts of gamma-tocopherol. The total amount of tocopherols and tocotrienols is roughly 64–300 mg/100 g in seed oil and 100–481 mg/100 g in pulp oil.
As carotenoids are the pigments that give sea buckthorn berry its distinctive orange-red colour, these compounds are present in considerable amounts both in pulp oil and in seed oil; the average carotenoid content of pulp oil is 350 mg/100 g as compared to 67.5 mg/100 g in seed oil. However, the total content of carotenoids in pulp oil varies (300–2000 mg/100 g) greatly between different growth locations and subspecies, and between components, where total carotenoids were up to 85 mg/100 g in seed oil, and up to 1000 mg/100 g in pulp oil. In general, the main carotenoids present in pulp oil are beta-carotene, zeaxanthin and lycopene.
Both seed and pulp oil also contain considerable amounts of plant sterols (12-23 g/kg and 10-29 g/kg of oil, respectively). Beta-sitosterol is the major sterol compound throughout the berry which constitutes 57-83% of total sterols.
Sea buckthorn oil may be useful as a cosmetics agent or topical medication for skin disorders, although there is no high-quality research proving effectiveness or safety of such uses. It has been used in Asian and Russian traditional medicine for centuries. Some dietary supplement products contain sea buckthorn oil.
Preliminary research on sea buckthorn oil has been conducted for its potential biological properties, but there is no high-quality evidence as of 2018 that it has any confirmed benefits. Sea buckthorn oil is under preliminary research for its possible effects on blood pressure, cholesterol, and blood triglycerides and for its use by oral intake to improve antioxidant status by increasing blood levels of beta-carotene and vitamin E. Taking sea buckthorn oil supplements does not help with eczema.
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