A multi-compound extract of Rhodiola rosea reduced acute mild stress-induced corticosterone release in mice more than salidroside alone

We have previously shown that a multi-component hydroethanolic root extract (HRE) of Rhodiola rosea (patented process Phytostandard^®; EPS Rhodiole, PiLeJe Laboratoire) induces a decrease in corticosterone secretion and a faster return to normal plasma corticosterone levels than the vehicle in mice subjected to acute mild stress. In this study, we determined the phytochemical profile of the HRE (HPTLC, HPLC, LC-MS and MS/MS) and compared its effect to one of its active compound, salidroside. After daily gavage with the HRE (240 mg of dry material/kg) or salidroside (equivalence: 3.6 mg/kg) during 2 weeks, mice were subjected or not to acute mild stress (open-field + elevated plus-maze tests). Corticosterone was measured in plasma collected from the mandibular vein at 0, 30, 60 and 90 min after stress initiation. Salidroside, rosavin, various flavonoids, monoterpene glycosides and several phenylpropanoid derivatives were identified in the HRE. Mice supplemented with the HRE presented a dampening of corticosterone secretion compared to salidroside-fed mice at the different time points. No modulation of stress-responsive gene expression was observed in our conditions. These results highlight the advantage of extracts with a composition close to that of the plant totum (i.e. all the active compounds of the plant) compared to a single compound since mice supplemented with the HRE presented a decrease in stress reactivity in an acute mild stress situation which could be associated to a better resilience to stress.