A single oral dose of a Valeriana officinalis L standardized extract reduced muscular strength without affecting neuromuscular tone in mice

Valeriana officinalis L. is a medicinal plant traditionally used for its calming properties and also for muscle relaxation [1] but unlike data on smooth muscle, those on skeletal muscle are scarce and inconsistent [2]. We assessed whether a standardized extract of the fresh plant (EPS V. officinalis, PiLeJe) had myorelaxant effects by decreasing skeletal muscle strength and/or neuromuscular tone.

Mice received a single dose of the V. officinalis extract at 2 (EPS 2) or 5 g/kg (EPS 5) p.o.; tetrazepam (TTZ) at 10 mg/kg i.p.; or corresponding vehicles. Maximal muscle strength was measured using a grip test, while global skeletal muscle function (endurance and neuromuscular tone) was assessed in a wire hanging test.

In the grip test, both doses of the extract induced a significant decrease in maximal absolute and relative strength versus controls (relative strength: -18.2% at 2 g/kg, p < 0.001 and -14.5% at 5 g/kg, p < 0.01; Figure 1A). Decrease was similar with TTZ (relative strength: -23.3%, p < 0.001).

In the wire hanging test, both extract doses decreased the 100 seconds score (˜20%; Figure 1B) and the impulse parameter (˜14%) but these decreases were not significant. By contrast, both the 100 seconds score (-83.3%, p < 0.001) and the impulse parameter (-67.3%, p < 0.001) were strongly decreased with TTZ.

This study provides clear evidence that the standardized extract of V. officinalis tested decreases skeletal muscle strength without any significant effects on endurance and neuromuscular tone. With a selective milder effect than standard drugs, this extract could be an interesting alternative myorelaxant particularly in terms of side effects.

Fig. 1

[1] Occhiuto F et al. J Pharm Pharmacol 2009; 61: 251 – 256

[2] Hattesohl M et al. Phytomedicine 2008; 15: 2 – 15