Polyherbal Formulation Enhancing Cerebral Slow Waves in Sleeping Rats

Biol Pharm Bull. 2020;43(9):1356-1360. doi: 10.1248/bpb.b20-00285.


Polyherbal medicines are composed of multiple herbs and have traditionally been used in East Asian countries for the remedy of physiological symptoms. Although the effects of polyherbal formulations have been investigated at the molecular and behavioral levels, less is known about whether and how medicinal herbs affect the central nervous system in terms of neurophysiology. We introduced a novel blended herbal formulation that consisted of 35% linden, 21% mulberry, 20% lavandin, 20% butterfly pea, and 4% tulsi. After intraperitoneal administration of this formulation or saline, we simultaneously recorded epidural electrocorticograms (ECoGs) from the olfactory bulb (OB), primary somatosensory cortex (S1), and primary motor cortex (M1), along with electromyograms (EMGs) and electrocardiograms (ECGs), of rats exploring an open field arena. Using the EMGs and OB ECoGs, we segmented the behavioral states of rats into active awake, quiet awake, and sleeping states. Compared to saline, herbal medicine significantly shortened the total sleep time. Moreover, we converted the ECoG signal into a frequency domain using a fast Fourier transform (FFT) and calculated the powers at various ECoG oscillation frequencies. In the sleeping state, a slow component (0.5-3 Hz) of S1 ECoGs was significantly enhanced following the administration of the formulation, which suggests a region- and frequency-specific modulation of extracellular field oscillations by the polyherbal medicine.

Keywords: electrocorticogram; herbal medicine; open field; primary somatosensory cortex; rat; slow wave.

MeSH terms

  • Animals
  • Behavior, Animal / drug effects
  • Behavior, Animal / physiology
  • Brain Waves / drug effects*
  • Brain Waves / physiology
  • Electrocorticography / instrumentation
  • Electrocorticography / methods
  • Electrodes, Implanted
  • Electromyography
  • Injections, Intraperitoneal
  • Male
  • Models, Animal
  • Morus / chemistry
  • Motor Cortex / drug effects
  • Motor Cortex / physiology
  • Olfactory Bulb / drug effects
  • Olfactory Bulb / physiology
  • Plant Extracts / administration & dosage*
  • Rats
  • Sleep / drug effects*
  • Sleep / physiology
  • Somatosensory Cortex / drug effects
  • Somatosensory Cortex / physiology
  • Stereotaxic Techniques
  • Tilia / chemistry
  • Time Factors
  • Wakefulness / physiology
  • Wisteria


  • Plant Extracts