Tolnaftate

Abstract

Mycotoxic effects of Thymus serpyllum oil on the asexual reproduction of five species of Aspergillus-A. awamori, A. niger, A. flavus, A. foetidus and A. oryzae-were investigated. Tolnaftate B.P. 1% wlw was used as an antifungal reference drug. In addition to possessing antifungal properties, the oil inhibited -all three stages of asexual reproduction, i.e. spore germination, mycelial growth and spore formation. The intensity of inhibitory effect varied with the species and the concentration of the oil used. A. niger was found to be the most sensitive at its germination stage, whereas A. foetidus was most sensitive at the mycelial growth and spore formation stage. At the same concentration, the effects of the oil and antifungal drug were the same at the mycelial growth stage, as in the case of A. oryzae. Overall, the inhibition of mycelial growth was better via T. serpyllum oil than the antifungal drug. Spore lysis was observed in the case of A. niger when spores were exposed to the oil.

Key Word Index

Thymus serpyllum, Lamiaceae, Aspergillus sp., Aspergillus awamori, Aspergillus niger, Aspergillus, niger, Aspergillus foetidus, Aspergillus flavus, Aspergillus oryzae, asexual reproduction, spore lysis.

Introduction

The antifungal activities of numerous herbs and spices have been reported by various workers and proved to be at least partially due to their essential oils (1-4). The antifungal activities shown by plants may be toxinogenesis inhibition (5), lethal effect (6-7), growth inhibition (8-9) or growth retardation (10). Fungal reproduction consists of three steps: spore germination, mycelium formation and sporulation. Different workers have reported the effects of spices and members of the Umbelliferae on mycelial growth, sporulation and spore germination (5,2-12).

Thymus serpyllum, locally known as masho, belongs to the Lamiaceae family. Members of Lamiaceae are mostly herbs with quadrangular stems and squarish leaves with numerous aromatic glands. T. serpyllum possesses strong antiseptic properties and enjoys an important place in the Ayurvedic system of medicines because of the presence of two isomeric phenols in its oil, thymol and carvacrol.

The present study deals with an investigation of the antifungal activities of T. serpyllum oil as inhibitor of spore germination, mycellial growth and spore formation of five Aspergillus species.

Materials and Methods

Oil isolation: The oil of T. serpyllum was obtained by hydrodistillation. Dried, crushed flowering plants (5 kg) were water distilled using a Dean Starke apparatus (13). The oil analyzed by gas chromatography and the percentage composition of the oil was determined with the help of a Shimadzu CR6A model computing integrator.

Cultures: Five strains of Aspergillus-A. awamori, A. flavus, A.foetidus, A. niger and A. oryzae-obtained from the Pakistan Council of Scientific and Industrial Research Laboratories Complex, Lahore, Pakistan, were used. These cultures were maintained on Sabouraud dextrose Agar (SDA) (14) and subcultured after every 20 days.

Antifungal studies: The basic medium used for the studies was SDA. There were three different dilutions of oil prepared, i.e. 1%, 0.05% and 0.01%, and one treatment (0.01%) for the standard antifungal drug Tolnaftate B.P. 1%w/ w. Oil dilutions were prepared by dispersing the calculated amount of oil in 0.3% agar solution and then adding to the rest of the medium. The standard of the antifungal drug was obtained by mixing a calculated amount of Tolnaftate BP 0.1% w/w powder in the medium. The control received no oil or antifungal drug.

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Mujeeb Ur Rahman*

PCSIR Laboratories, PO Box 387, Mastung Road, Quetta, Balochistan, Pakistan

Shereen Gul

Department of Botany, Government Girls College, Quetta, Balochistan, Pakistan

*Address for correspondence

Received: November 2001

Revised: June 2002

Accepted: August 2002

Copyright Allured Publishing Corporation May/Jun 2003
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