[Exploration research on hepatotoxic constituents from Polygonum multiflorum root]

Area of Science:

• Pharmacology
• Toxicology
• Natural Products Chemistry

Background:

• Polygonum multiflorum root is a traditional Chinese medicine with known potential for liver toxicity.
• Anthraquinones are suspected to be the primary causative agents of this hepatotoxicity.
• Understanding the specific toxic mechanisms is crucial for safe clinical use.

Purpose of the Study:

• To identify the specific anthraquinone constituents in Polygonum multiflorum root responsible for liver toxicity.
• To evaluate the cytotoxic effects of these compounds on liver cells and tissues.
• To determine if the observed toxicity in vitro translates to in vivo risk at typical dosage levels.

Main Methods:

• Cytotoxicity assays using HepG2 cells to screen 11 anthraquinone derivatives.
• Precision-cut rat liver slices were used to assess the effects on liver tissue integrity.
• Enzyme leakage (ALT, AST, GGT, LDH) and protein content were measured to quantify liver damage.
• MTT reduction assay was employed to evaluate cellular metabolic activity.

Main Results:

• Rhein, emodin, and physcion-8-O-β-D-glucopyranoside demonstrated significant cytotoxicity against HepG2 cells and liver slices at high concentrations (≥400 μmol•L⁻¹).
• These compounds induced significant leakage of liver enzymes (ALT, AST, LDH) and reduced protein content in liver slices.
• However, the concentrations required to induce toxicity in vitro are substantially higher than those typically encountered from therapeutic doses of Polygonum multiflorum root.

Conclusions:

• While specific anthraquinones like rhein and emodin can damage liver cells and tissues at high concentrations, they are unlikely to be the primary cause of hepatotoxicity at standard therapeutic doses of Polygonum multiflorum.
• Further research is needed to elucidate other potential mechanisms or constituents contributing to the observed liver toxicity of Polygonum multiflorum root.
• The study suggests that current therapeutic dosages of Polygonum multiflorum root are unlikely to cause liver damage due to anthraquinone-induced toxicity.