| Toxicity summary | The CIR Expert panel concludes Sodium p-Chloro-m-Cresol, p-Chloro-m-Cresol, Chlorothymol, m-Cresol, o-Cresol, Isopropyl Cresols, Thymol, o-Cymen-5-ol, Cavacrol are safe at concentrations up to 0.5% in cosmeticshowever, the available data are insufficient to support the safety of p-Cresol and Mixed Cresols for use in cosmetic products.Safe for use in cosmetics, with qualificationsIDENTIFICATION AND USE: m-Cresol is colorless, yellowish liquid. It is used as a bactericide for control of crown gall and olive knot on certain fruit and nut trees and ornamentals and the genetic/physiological disorder burr knot on apples. Currently, one product is registered which contains both m-cresol and xylenol. Used as disinfectant/bacteriocide/germicide for animal pathogenic bacteria (G- and G+ vegetative) in households, sickrooms, hospitals, veterinary clinics, and veterinary hospitalson surgical instruments, diagnostic instruments/equipment and on hospital critical rubber/plastic items. Used as an insecticide and miticide on dogs for treatment of lice and fleas. It is also used for making synthetic resinsin photographic developers, explosives. Additionally, m-cresol is chemical intermediate for thymol used in cough/cold medicinals, synthetic pyrethroid insecticides, 3-methyl-6-t-butylphenol, trinitro-m-cresol for explosives, and phenolic resinsdisinfectant ingredientore flotation agentsolvent. m-Cresol, either pure or mixed with p-cresol, is important in the production of contact herbicides. m-Cresol is also a precursor to the pyrethroid insecticides. Furthermore, many flavor and fragrance compounds, such as (-)-methanol and musk ambrette, are derived from m-cresol. Several important antioxidants including synthetic vitamin E are produced from m-cresol. Finally, m-cresol is used as a topical dental antiseptic, and it is also used in insulin preparations. HUMAN EXPOSURE AND TOXICITY: o-Cresol, m-Cresol, and p-Cresol are metabolites of toluene and urinary levels are often used to monitor exposure to and metabolism of toluene. m-Cresol, o-Cresol, and p-Cresol are biomarkers for phenol exposure. The ability of m-Cresol to increase the permeability of human lung fibroblast membranes was reported. m-Cresol is used for endodontic treatments in dentistry and is cytotoxic to human dental pulp cells (D824 cells). ANIMAL STUDIES: In an acute dermal toxicitym-Cresol is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen. |
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