Anthelmintics Phenols

Simple phenols consist of an aromatic ring in which a hydrogen is replaced by a hydroxyl gronp. Their distribntion is widespread among all classes of plants. General properties of simple phenols are bactericidal, antiseptic and anthelmintic. Phenol itself is a standard for other antimicrobial agents. 

Leucaena leucocephala (Lam.) De Wit Yin He Huan (leaf, seed) Leucanol, leucaenine, phenolic compounds, condensed tannins.60-228 This herb is toxic. Anthelmintic, for diabetes, an emollient, emmenagogue. 

Sesamex [51-14-9] (Sesoxane) (30) is a synergist oflow toxicity, acute oral LD50 (rat) = 2000-2270 mg/kg, for pyrethrins and allethrin. 6,7-Dihydroxy 4-methylcoumarin has been offered as an antioxidant for phenolics and polymers, and as an anthelmintic. 2,4,5-Trihydroxybutyrophenone has been available as an antioxidant and light stabilizer for polyolefins, waxes, and foods. IsofLavones, eg (31), have been patented as components of antioxidant compositions for foods and cosmetics (qv) (97). 

Therapeutic Function Antiseptic, Anthelmintic, Antifungal Chemical Name Phenol, 2,2 -methylenebis(4-chloro-Common Name Dichlorophen Structural Formula ... 

Scsernl classes of chemicals iire used as anthelmintics cd include phenols and derivatives, pipera/ine and related oinpounds, aniinialarial compounds (Chapter 9), various Isioocyelic compounds, and natural products. 

The important phenols that have shown marked activity against roundworms are hexylresorcinol (9), 2,4,5-trichlorophenol (10), 2,6-diiodo-4-nitrophenol (disophe-nol, 11), thymol (12), iodothymol (13) and 4-cyano-2-iodo-6-nitrophenol (nitro xynil,14) and butyphen (15). Of these disophenol (11) and nitroxynil (14) are commonly used as veterinary anthelmintics [11,23]. 

Preliminary accounts of a newer modification of the nitro-phenol class of anthelmintics appeared.41,42 This compound, M B 10,755 (IX), was reported active at 8 mg/kg in sheep or calves (1/5 of the maximum tolerated dose) against mature Fasciola hepatica, when given intramuscularly or subcutaneously. Activity against immature (4-6 weeks) flukes was observed at the higher dose of 20 mg/kg (1/2 of the MTD). Oral dosing was less satisfactory. 

Most contain carvacrol and thymol in varying amounts. Dried oregano will contain 0.2 to 0.4% of a yellowish volatile oil with thymol and carvacrol in varying amounts. The phenolic content may be 50 to 65%. Carvacrol is found in the oil of oregano, thyme, marjoram, and summer savory. It is practically insoluble in water. It is used as a disinfectant and in organic synthesis. Therapeutically, it is used as an anti-infective and anthelmintic. 

Hexylresorcinol is another phenolic compound of one-time value against roundworms but is now considered obsolete as an anthelmintic its usefulness essentially remains as a topical bactericidal antiseptic. 

Phenolic natural products (acylphloroglucinols) from the male fern Dryopteris filix-mas. The natural product is a mixture of six homologues (R, R =methyl, ethyl, propyl) with three main components, see table. Use F. exhibit anthelmintic activity. Ether extracts or solutions of the active principles in a fatty oil in combination with the subsequent administration of a laxative are used as a remedy for tapeworms. As a result of the low therapeutic range and the difficulties in standardization, F. have been mostly replaced by synthetic agents (they are still used occasionally in veterinary medicine). 

The anthelmintic action of phenols is similarly potentiated by soaps and again it is important to avoid excess of the soap, because micelles can retain most of the phenol and deny it to the worms (Alexander and Trim, 1946). Below the critical micelle concentration of the soap, an adjuvant effect of the soap on the phenol is observable. No soap penetrates into the worms. 

Thymol has antibacterial, antifungal and antiparasitic properties. It is less toxic than phenol, the LD50 of thymol being 980 mg/kg for rats in contrast to 530 mg/kg for phenol. Its antibacterial properties mean that it inhibits plaque formation, and therefore it finds use in oral care appUcations. It has been used as a fungicidal treatment for fabrics and as an anthelmintic for both humans and animals. Synthetic thymol finds relatively little use in perfumes and flavors, oils, such as thyme and basil, being used in preference. 

Thymol and carvacrol, usually the major phenols present in oregano, have strong fungicidal, anthelmintic, irritant, and other properties (see thyme). 

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