Sea Buckthorn in Cardiovascular and Metabolic Health: Evidence for the Role of the Leaves

Most research on sea buckthorn (Hippophae rhamnoides L.) has focused on the berries and oils. This structured narrative review examines the chemical profile of the leaves and evaluates cardiovascular and metabolic evidence from leaf preparations, isolated constituents, and other sea buckthorn materials. Two complementary PubMed searches yielded 3539 unique records. After screening in successive stages, 85 publications were included. A supplementary search in Scopus yielded no unique records. Leaves contain glycosides of isorhamnetin, quercetin, and kaempferol, together with ellagitannins, proanthocyanidins, phenolic acids, and triterpenoids. Their relative amounts vary between cultivars, harvest, processing, extraction, and the denominator used for reporting. Leaf preparations improved selected metabolic, vascular, or inflammatory outcomes in several animal and ex vivo models. Studies of isolated flavonols support biological plausibility but do not identify the compounds responsible for effects of complete leaf preparation. Human trials have examined berries, purée, juice and oils; effects on lipids, glucose regulation, blood pressure, and platelet activity were generally small or inconsistent. No controlled human trial or human pharmacokinetic study has evaluated a chemically characterized leaf preparation. This absence is the main obstacle to clinical translation. The next stage should compare one defined leaf preparation with appropriate controls in validated animal models, test fractions prepared from the same leaf batch, and require replication before human studies of pharmacokinetics, dose, safety, and efficacy. Current evidence supports this sequence but does not justify therapeutic use of sea buckthorn leaves.