During antidermatophytic screening of some essential oils, Curcuma longa L. exhibited the strongest antifungal activity, completely inhibiting the mycelial growth of ringworm, caused by the fungi-Microsporum gypseum and Trichophyton mentagrophytes. The essential oil from leaves of Curcuma longa was fungicidal at 2.5 l/ml at which it tolerated heavy doses of inoculum. The fungicidal activity of the oil was thermostable up to 80 ºC and self life up to 24 months in storage. The oil also showed a broad fungitoxic spectrum, inhibiting the mycelial growth of other fungi, viz., Epidermophyton floccosum, M. nanum, T. rubrum, T. violaceum. Moreover, up to 5 % concentration it did not exhibit any adverse effect on mammalian skins. The oil has been formulated in the form of an ointment, 1 % w/v and subjected to topical testing on patients of the Out Patient Department (OPD) at Moti Lal Nehru Medical College, Allahabad. Patients were selected on the basis of KOHpositive results and diagnosed tenia corporis. After the second week of treatment, all patients were KOH-negative. At the end of medication, 75 % of patients recovered completely while 15 % showed significant improvement from the disease. The ointment thus, can be exploited commercially after ongoing successful clinical trials. Relationship of the dermatophytes to the toxicity of the oil vis-a-vis phylogeny using molecular data of the pathogens have also been discussed.

During antifungal screening of essential oils of some higher plants against human pathogenic fungi, oils of Mentha spicata (L.) and Taxodium distichum (L.) Rich. exhibited significant activity against the test pathogens Epidermophyton floccosum (Harz) Langeron and Milochevitch, Microsporum gypseum (Bodin.) Guiart and Gregoraki and Microsporum nanum Fuentes. The minimum inhibitory concentrations (MICs) of the oil of M. spicata were found to be 1.8 µl/ml for E. floccosum, M. gypseum and M. nanum. In the case of T. distichum the minimum inhibitory concentrations (MICs) were found to be 2.0 µl/ml for M. gypseum and 2.5 µl/ml for E. floccosum and M. nanum. The oils also exhibited potency against heavy doses of inoculum (30 mycelial discs, each 5 mm in diameter) at these MICs concentrations. On comparison with the synthetic antifungal drugs myconazole and ketaconazole, these oils were found to be more effective.