Antitumor activity and interleukin-1 induction by tannins

Area of Science:

• Natural Products Chemistry
• Immunology
• Pharmacology

Background:

• Tannins are plant-derived polyphenols with diverse biological activities.
• Interleukin-1 (IL-1) plays a crucial role in immune responses and inflammation.
• Understanding the structure-activity relationship of tannins is key to developing new therapeutic agents.

Purpose of the Study:

• To investigate the relationship between the chemical structure of tannins, their antitumor activities, and their ability to induce IL-1.
• To identify specific tannin structures responsible for antitumor effects and IL-1 induction.

Main Methods:

• Fifteen different tannins were administered to mice intraperitoneally.
• Mice were subsequently inoculated with S-180 tumor cells.
• In vitro studies assessed IL-1 beta production by human peripheral macrophages stimulated with various tannins.

Main Results:

• Oligomeric ellagitannins containing tellimagrandin I or II units, such as tellimagrandin II, rugosin A, hirtellin B, oenothein B, and oenothein A, exhibited significant antitumor activity.
• Agrimonin, a dimer, also showed strong antitumor effects.
• Monomeric and oligomeric ellagitannins stimulated IL-1 beta production in macrophages, with more potent stimulation observed for those with strong antitumor activity.

Conclusions:

• Oligomeric ellagitannins, characterized by tellimagrandin I or II, casuarictin, or related structural units, possess antitumor properties.
• These active tannins effectively induce IL-1 beta, suggesting an immunomodulatory mechanism contributing to their antitumor effects.