Antimicrobial activity of Hyptis ovalifolia towards dermatophytes

Abstract

The essential oil and the aqueous, hexane and methanolic fractions from Hyptis ovalifolia leaves were evaluated for their antifungal activity in vitro against 60 strains of dermatophytes: 10 strains of Microsporum canis, 10 of M. gypseum, 20 of Trichophyton rubrum and 20 of T. mentagrophytes. The extracts inhibited growth of the dermatophytes tested at different concentrations. The most biologically active was the essential oil from the leaves which inhibited 57 isolates (95%) at a concentration of ≤ 500 µg/ml.Key words: dermatophytes -Hyptis ovalifolia -antifungal activity Mycotic infections are probably the most common cause of skin disease in developing countries of tropical regions. Dermatophytosis is the most frequent superficial fungal infection in Brazil. The drugs used against dermatophytosis exhibit several side effects and have limited efficacy (Gupta et al. 1998, Carazo et al. 1999. So that there is a distinct need for the discovery of new safer and more effective antifungal agents. The use of medicinal herbs in the treatment of skin diseases including mycotic infections is an age-old practice in many parts of the world (Irobi et al. 1993). This use has been supported by the isolation of active antifungal compounds from plant extracts (Costa et al. 2000.Previous reports on the activity of ethanolic extract from leaves of Hyptis ovalifolia against dermatophytes have been reported by Souza et al. (2002). In this study the antifungal activity of the essential oil and the aqueous, hexane, and methanolic fractions from H. ovalifolia leaves against 60 dermatophytes is described. partitioned between hexane/methanol. The hexane, methanol and aqueous fractions were reduced to dryness and solutions of each as well as of the essential oil were dissolved in dimethyl sulfoxide (DMSO) prepared for subsequent bioassay. MATERIALS AND METHODS Plant material -Hyptis ovalifoliaDermatophyte isolates -The microorganisms used for the biological evaluation were clinical isolates provided by Laboratório de Micologia, Instituto de Patologia Tropical e Saúde Pública, UFG, and identified by standard procedure (Rebell & Taplin 1970). They were: 10 Microsporum canis, 10 M. gypseum, 20 Trichophyton rubrum and 20 T. mentagrophytes. Sabouraud's dextrose agar at 25ºC was used to maintain isolates. In antifungal assays, the samples were transferred to potato dextrose agar and maintained for 7 days at 25ºC.Antifungal assay -The susceptibility test was performed as described by Cáceres et al. (1993), with the following modifications. The extracts were solubilized in DMSO and a two-fold serial dilution was performed in Sabouraud with chloramphenicol and cycloheximide agar medium, to obtain a concentration range of 3.9 to 1000 µg/ ml, poured into Petri dishes. Thirty seven wells of 3 mm were opened using a Steers inoculator. To each well 10 µl of a dermatophyte suspension were added. This suspension was prepared using 0.85% sterile physiological saline with Tween 80 (0.05%) and adjusted with a spectrophotometer at 530 nm to obtain 90% tra...

In vitro antifungal activity and cytotoxic effect of essential oils and extracts of medicinal and aromatic plants against Candida krusei and Aspergillus fumigatus

“…This is an aromatic plant whose antimicrobial activity as extract or essential oil has not been reported. However, essential oils of other species such as H. suaveolens and H. ovalifolia have antibacterial, anti-C. albicans and anti-dermatophyte activity (Asekun et al, 1999;Souza et al, 2003). Extracts (1) and oils (7) were active against both C. krusei and A. fumigatus; L citriodora was the most active (GM-MIC = 99.21 and 62.5 µg/mL, respectively).…”

Proliferative effect of aqueous extract of Hyptis fructicosa on liver regeneration after partial hepatectomy in rats

“…It has been shown that the Hyptis suaveolens has positive effect on healing wounds 4 . The Hyptis ovalifolia has presented antimicrobial effect 5 . Also, the Hyptis pectinata has enhanced liver regeneration [6][7][8] .…”

Morphology and histochemistry of glandular trichomes in Hyptis villosa Pohl ex Benth. (Lamiaceae) and differential labeling of cytoskeletal elements

“…The bioactive potential of the essential oils of Hyptis species have been proved by their antibacterial (Souza et al 2003), antifungal (Oliveira et al 2004) and antitumoral (CostaLotufo 2004) properties. However, despite the medicinal importance of Hyptis species, studies on the morphology and cellular features in relation to the secretory process of glandular trichomes are lacking to the genus.…”