Evaluation of the permeation of peat substances through human skin in vitro

in-vitro Grade A 2003

Authors: Beer, André-M., Junginger, H.E., Lukanov, J., Sagorchev, P.

Journal: International Journal of Pharmaceutics 253 : 169–175

Key Findings

Peat substances CAN permeate through human full-thickness skin (200 μm) — proven in vitro with excised human skin
HPLC analysis revealed 18 fractions of water-soluble fulvic and ulmic acid derivatives in aqueous peat extracts
Fractions 7–11 and 14 selectively permeate skin and have pharmacological effects on smooth muscle tissue
Permeated fractions activate α2 adrenergic receptors and D2 dopamine receptors
Fraction 14 shows strongest stimulatory effect on smooth muscle contractile activity (~25% of ACH maximum)
Human skin shows SELECTIVE permeability — not all peat fractions permeate, only specific fulvic/ulmic acid derivatives

Landmark study proving that biologically active substances from peat CAN permeate through human skin. This is the key evidence bridging the gap between “peat contains bioactive compounds” and “those compounds actually reach the body during topical treatment.”

Method

Aqueous peat extract (from Wulfes Neudorf–Platendorf, Germany) was characterized by HPLC, identifying 18 fractions. In vitro diffusion studies were performed using excised human breast skin (dermatomed to 200 μm thickness) in flow-through cells. Permeated fractions were tested for pharmacological activity on guinea pig smooth muscle tissue.

Critical Findings

Selective permeability: Human skin does NOT allow all peat substances through — only specific fulvic and ulmic acid fractions (7–11 and 14 of 18 HPLC fractions) permeate.
Pharmacological activity confirmed: The permeated fractions have definite stimulatory effects on smooth muscle contractile activity (SCA), proving they pass through skin in pharmacologically active quantities.
Receptor identification: Effects attributed to activation of α2 adrenergic receptors and D2 dopamine receptors.
Time-dependent effects: Fractions 7–11 show sustained stimulation (>90 min), while fraction 14 shows initial strong effect that diminishes after 87 min.

Significance for Knowledge Graph

This paper is foundational evidence for the mineral-delivery and transdermal absorption mechanisms. It proves that peat therapy has a genuine “chemical effect” beyond the well-established thermal effect — bioactive substances reach the body through the skin during treatment. This validates the entire mechanism chain from substance → skin permeation → biological effect.

Also introduces ulmic acids as a distinct bioactive fraction — a new substance entity for the knowledge graph.