Chemical Analysis and Antifungal Activity of the Essential Oil of Calea clematidea

Abstract

The chemical composition of the essential oils of Calea clematidea Baker obtained by hydrodistillation of the leaves and flowers was analysed by GC and GC/MS and the oils were assayed for their antifungal activities. The essential oil of the leaves showed a high content of a new natural epoxy terpenoid, named clemateol (ca. 70 %), with minor amounts of o-vanillin (6.5 %), spathulenol (4.2 %), α-terpinene (4.0 %), germacrene B (2.9 %), yomogi alcohol (1.8 %), (E)-caryophylene (1.7 %), m-cymenene (1.6 %), and α-gurjunene (1.5 %), while the essential oil of the flowers was characterized by a higher content of thymol methyl ether (ca. 80 %), with minor amounts of clemateol (4.8 %) and o-cymene (4.7 %). The antimicrobial activity of the oils was also evaluated against dermatophytes for their possible use in pharmaceutical preparations for topical applications. The oil of the leaves (MIC > 3.57 mg/ml), clemateol (MIC > 1.52 mg/ml), and the alcohol 2 (MIC > 2.82 mg/ml) showed a moderate antifungal activity against Trichophyton tonsurans, Trichophyton rubrum, Trichophyton menthagrophytes var. interdigitale, Epidermophyton floccosum, Microsporum gypseum, Microsporum canis and Microsporum nanum.

References

• 1 Burkart A. Flora Ilustrada de Entre Rios. ISAC eds. Entre Rios, Argentina; 1974: 394-7
• 2 Lombardo A. Flora Montevidensis. Intendencia Municipal de Montevideo eds. Montevideo, Uruguai; 1983: 256-7
• 3 Ober A G, Fronczek F R, Fischer N HJ. Two new sesquiterpene lactones from Calea subcordata and the molecular structure and absolute configuration of subcordatolide D. J. Nat.  Prod.. 1987;  50 604-1
• 4 Martinez M V, Sanchez F, Joseph-Nathan P. Thymol derivatives from Calea nelsoni .  Phytochemistry. 1987;  26 2577-9
• 5 Martinez M V, Esquievel B, Ortega A. Two caleines from Calea zacatechichi .  Phytochemistry. 1987;  26 2104-6
• 6 Ortega A, Lopes J C, Maldonado E A. A tris-norsesquiterpene lactone and other sesquiterpenes from Calea crocinervosa .  Phytochemistry. 1989;  28 2735-6
• 7 Wussow J R, Urbatsch L E, Sullivan G A. Calea (Asteraceae) in Mexico, Central America, and Jamaica.  Systematic Botany. 1985;  10 241-67
• 8 Thomas A F, Pawlak W. The synthesis and reactions of yomogi alcohol. Conversion of the artemisyl skeleton to the santolinyl skeleton by a 1,2-shift of a vinyl group. Synthesis of santolinatriene. Helv. Chim.  Acta. 1971;  54 1823-45
• 9 Massada Y. Analysis of essential oil by gas chromatography and spectrometry. John Wiley & Sons New York; 1976
• 10 Association of Official Analytical C hemists. Official methods of analysis of AOAC International. 16^th ed. AOAC International Arlington; 1995
• 11 Masaki Y, Miura T, Ochiai M. Alcoholysis of epoxides catalyzed by tetracyanoethylene. Synlett 1993: 847-9
• 12 Greene T W, Wuts P GM. Protective groups in organic synthesis. In: Greene TW, Wuts, PGM Protection for the hydroxyl group, Including 1,2- and 1,3-Diols. John Wiley & Sons, INC 1991: 10-142
• 13 Adams R P. Identification of essential oil components by gas chromatography/Mass Spectroscopy. Allured Publishing Co Carol Stream, Illinois; 1995