Comparative Assessment of Functional Components and Antioxidant Activities between <i>Hippophae rhamnoides</i> ssp. <i>sinensis</i> and <i>H. tibetana</i> Berries in Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau is the main production area of Hippophae rhamnoides ssp. sinensis (Rha) and H. tibetana (Tib), but studies on the types and contents of soluble sugars, organic acids, free phenolics, bound phenolics, vitamin C (VC), tocopherol (VE) and carotenoids of the two sea buckthorn berries from this region have not been reported. In this paper, we found that the soluble sugars in Rha and Tib were mainly glucose and fructose; Rha exhibited a higher content of total sugar and fructose compared to Tib. The organic acids were mainly quinic acid and malic acid; Rha exhibited a higher content of total acids and quinic acid, but lower tartaric acid and citric acid compared to Tib. Rha also possessed a higher total (free and bound) phenolic as well as total (free and bound) flavonoid content than those in Tib; twelve phenolic compounds were analyzed, among which flavonols were dominant. Catechin, isorhamnetin and quercetin were the main phenolic substances. VC and VE (γ-tocopherol (γ-VE) and δ-tocopherol (δ-VE)) were higher in Rha than Tib. The total carotenoid, lutein, β-carotene and lycopene content of Tib was remarkably higher than that in Rha. Moreover, both Rha and Tib showed good in vitro and cellular antioxidant activities, and Rha had a stronger antioxidant activity. Taken together, Rha had a higher antioxidant activity, which may be due to its higher content of phenolics, flavonoids, VC and VE