Sea Buckthorn (Hippophaë rhamnoides ssp. rhamnoides) Berries in Nordic Environment: Compositional Response to Latitude and Weather Conditions

Flavonol glycosides (FGs) in sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) berries of varieties ‘Tytti’ and ‘Terhi’, cultivated in northern Finland (68°02′ N) for six years and southern Finland (60°23′ N) for seven years, were investigated and compared by HPLC-DAD-ESI-MS/MS. The average total content of 23 identified glycosides of isorhamnetin and quercetin was 103 ± 23 and 110 ± 21 mg/100 g fresh berries in ‘Terhi’ and ‘Tytti’, respectively. The total contents of FGs, flavonol diglycosides, and triglycosides in both varieties were higher in the north than in the south, whereas total flavonol monoglycoside content behaved vice versa (p < 0.05). Among the 89 weather variables studied, the sum of the daily mean temperatures that are 5 °C or higher from the start of growth season until the day of harvest was the most important variable which associated negatively with the accumulation of FGs in berries. Such influence was much stronger in berries from the north than from the south.