text: Quinone methide itself arises by the degradation of tyrosine, leading ultimately to p-cresol. Various quinone methides are directly involved in the process of lignification (creation of complex lignin polymers) in plants.
  Quinone methides have been implicated as the ultimate cytotoxins responsible for the effects of such agents as antitumor drugs, antibiotics, and DNA alkylators. Oxidation to a reactive quinone methide is the mechanistic basis of many phenolic anti-cancer drugs.
  Celastrol is a triterpenoid quinone methide isolated from Tripterygium wilfordii (Thunder of God vine) and Celastrus regelii that exhibits antioxidant (15 times the potency of α-tocopherol), anti-inflammatory, anticancer, and insecticidal  activities.
  Pristimerin, the methyl ester of celasterol, is a triterpenoid quinone methide isolated from Maytenus heterophylla that displays antitumor and antiviral  activities. Pristimerin has also been found to have a contraceptive effect due to its inhibiting effect on the calcium channel of sperm (CatSper).
  Taxodone and its oxidized rearrangement product, taxodione, are diterpenoid quinone methides found in Taxodium distichum (bald cypress), Rosmarinus officinalis (rosemary), several Salvia species and other plants, that display anticancer, antibacterial, antioxidant, antifungal, insecticide, and antifeedant  activities.
  Maytenoquinone, an isomer of taxodione, is a biologically active quinone methide found in Maytenus dispermus.
  Kendomycin is an antitumor antibacterial quinone methide macrolide first isolated from the bacterium Streptomyces violaceoruber. It has potent activity as an endothelin receptor antagonist and anti-osteoporosis agent.
  Elansolid A3 is a quinone methide from the bacterium Chitinophaga sancti that displays antibiotic activity. Antibacterial quinone methides, 20-epi-isoiguesterinol, 6-oxoisoiguesterin, isoiguesterin and isoiguesterinol were found in Salacia madagascariensis. Quinone methides tingenone and netzahualcoyonol were isolated from Salacia petenensis. Nortriterpenoid quinone methide amazoquinone and (7S, 8S)-7-hydroxy-7,8-dihydro-tingenone were isolated from Maytenus amazonica. An antimicrobial quinone methide, 15 alpha-hydroxypristimerin, was isolated from a South American medicinal plant, Maytenus scutioides.