Comparative assessment of phenolics, antioxidant and antiproliferative activities between Hippophae rhamnoides ssp. sinensis and H. tibetana leaf in Qinghai-Tibet Plateau

Hippophae rhamnoides ssp. sinensis (Rha) and H. tibetana (Tib) are two species of sea buckthorn which distribute in Qinghai-Tibet Plateau. Our results showed that both sea buckthorn leaf exhibited high total phenolic and flavonoid content, and Rha leaf showed much higher level. In addition, 66 phenolic compounds were detected, belonging to classes of benzoic acid derivatives, flavonols, flavanols, flavanones, and so on. Classes of benzoic acid derivatives and flavonols were most abundant, among them ellagic acid and rutin were the most and second abundant phenols. Besides, methyl gallate, 2,6-dihydroxybenzoic acid, 4-hydroxybenzoic acid, gentisic acid, narcissin, astragalin, nicotiflorin, prunin, procyanidin B3, cyanidin 3-O-rutinoside chloride, delphinidin 3-glucoside, gallocatechin, taxifolin, aromadendrin and trans-3,3',4',5,5',7-Hexahydroxyflavanone were the first time to be identified in SBT leaf. Furthermore, significant free radical scavenging effects of ABTS and DPPH, ferric reducing antioxidant ability, cellular antioxidant properties and anti-proliferation activity against HepG2 cells were observed in the aqueous ethanol extracts of sea buckthorn leaf. While Rha showed stronger inhibitory effects, which might due to the higher content of total phenolic and flavonoid profiles. Our finding clearly supported that Rha leaf as a wild and non-pollution plant could be a better choice as a healthy food resource.

Automated summary

Both sea buckthorn leaf of Hippophae rhamnoides ssp. sinensis (Rha) and H. tibetana (Tib) exhibited high levels of total phenolic and flavonoid content, with Rha showing significantly higher levels. The presence of 66 phenolic compounds, including ellagic acid, rutin, and other compounds, was detected in sea buckthorn leaf for the first time. The aqueous ethanol extracts of sea buckthorn leaf showed strong antioxidant properties and anti-proliferation activity against HepG2 cells, with Rha showing stronger effects due to its higher content of total phenolic and flavonoid profiles.