Antifungal activity of essential oil from Mentha spicata L. and Mentha pulegium L. growing wild in Sardinia island (Italy).

This study aims to evaluate the antifungal activity of Mentha spicata L. and Mentha pulegium L. from Sardinia and to assess their efficacy on virulence factors for Candida albicans, particularly on the inhibition of the germ tube formation. The major compounds of the essential oils were carvone (62.9%) for M. spicata and pulegone (86.2%) for M. pulegium. The essential oil from M. spicata showed a more preeminent effect against Cryptococcus neoformans and the dermatophytes Trichophyton rubrum and T. verrucosum (0.32 µL/mL). Both oils were very effective in inhibiting C. albicans germ tube formation, at doses well below their MIC (0.16 µL/mL).

Isolation of the volatile fraction from Apium graveolens L. (Apiaceae) by supercritical carbon dioxide extraction and hydrodistillation: chemical composition and antifungal activity.

Apium graveolens L. (wild celery), belonging to the family of Apiaceae, is a scaposus hemicryptophyte. Instead, the cultivate plant is an annual or biennial herb widely used as a spice and seasoning in food. A broad range of biological activities have been attributed to A. graveolens. These include antimicrobial activity, larvicidal activity, hepatoprotective activity, nematicidal and mosquito repellent potential and antihyperlipidaemic properties.In this study, the authors compare the composition of the volatile fractions of A. graveolens collected in natural populations in Portugal and Italy and evaluate their potential as antifungal agents.The composition of the volatile oils obtained by hydrodistillation and their antifungal activity are reported. The oils were analysed by gas chromatography-flame ionisation detector and gas chromatography-mass spectrometry methods and their composition were compared with that of the volatile extracts isolated by supercritical CO2. A chemical variability in the extracts depending on the origin of the plants and on the extraction method was observed. The results showed the presence of sedanenolide, neocnidilide and neophytadiene as main components. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guilliermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, T. mentagrophytes var. interdigitale, Trichophyton verrucosum, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oil from Italy rich in neophytadiene is the more active, with MIC values of 0.04-0.64 µL mL(-1). Our results show that A. graveolens volatile extracts may be useful in the clinical treatment of fungal diseases.

Antifungal activity and chemical composition of essential oils from Smyrnium olusatrum L. (Apiaceae) from Italy and Portugal.

The essential oils and supercritical CO2 extracts of wild Smyrnium olusatrum L. growing in Sardinia (Italy) and in Portugal were investigated. For the study, oils were isolated from total plant aerial part (umbels containing seeds). The content of ß-phellandrene (67.3% vs. 42.7%) and α-pinene (31.9% vs. 1.2%), respectively, the main components of Portuguese and Italian essential oils, declined during the maturation stage of the umbels. Contrarily, some other important components, particularly curzerene, germacrene B, germacrone, alexandrofuran, 1-ß-acetoxyfurano-4(15)-eudesmene and 1-ß-acetoxyfurano-3-eudesmene, increased in fruiting umbels. The chemical composition of the Sardinian oil is rather different from those of other origin. The composition of the supercritical extracts and the essential oils is markedly different, particularly due to the high amount of furanosesquiterpenoids in the supercritical fluid extraction. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oils were particularly active against dermatophyte strains and C. neoformans, with MIC values in the range of 0.32-0.64 µL mL⁻¹.

Chemical composition and biological assays of essential oils of Calamintha nepeta (L.) Savi subsp. nepeta (Lamiaceae).

Aerial parts of wild Calamintha nepeta (L.) Savi subsp. nepeta growing spontaneously on the Mediterranean coast (Sardinia Island, Italy) and on the Atlantic coast (Portugal) were used as a matrix for the supercritical extraction of volatile oil with CO(2). The collected extracts were analysed by GC-FID and GC-MS methods and their compositions were compared with that of the essential oil isolated by hydrodistillation, but the differences were not relevant. A strong chemical variability was observed in the essential oils depending on the origin of the samples. The results showed the presence of two chemotypes of C. nepeta. In all Italian samples, pulegone, piperitenone oxide and piperitenone were the main components (64.4-39.9%; 2.5-19.1%; 6.4-7.7%); conversely, the oil extracted from Portuguese C. nepeta is predominantly composed of isomenthone (35.8-51.3%), 1,8-cineole (21.1-21.4%) and trans-isopulegone (7.8-6.0%). The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The Italian oil, rich in pulegone, exhibited significant antifungal activity against Aspergillus and dermatophyte strains, with MIC values of 0.32-1.25 µL mL(-1).

Isolation of Crithmum maritimum L. volatile oil by supercritical carbon dioxide extraction and biological assays.

The chemical composition of the volatile concentrate obtained by supercritical CO2 extraction of aerial parts of Crithmum maritimum L. growing spontaneously in one area of Mediterranean coast (Buggerru, Sardinia Island, Italy) and in two areas of the Atlantic coast (Figueira da Foz and S. Pedro de Moel, Portugal) was investigated by GC and GC-MS. The major oil components identified were p-cymene, beta-phellandrene, gamma-terpinene, thymol methyl ether and dillapiole. The results showed the presence of two chemotypes of C. maritimum with different dillapiole contents, ranging from 0.2 to 64.2% in Portuguese and Italian plants, respectively. The minimal inhibitory concentration (MIC) and the minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oils against yeasts and dermatophyte strains. All the oils exhibited significant antifungal activity against dermatophyte strains. The oil with the higher amount of dillapiole (64.2%) was the most active with MIC values ranging from 0.08-0.32 microL mL(-1).

Genetic and phytochemical difference between some Indian and Italian plants of Withania somnifera (L.) Dunal.

The geographical distribution of Withania somnifera (L.) Dunal is quite wide. However, in Italy, this species is very rare and grows spontaneously only in Sicily and in Sardinia. The PCR-RAPD technique has been utilized in this work to determine the genetic relationship among Sicilian, Sardinian and Indian samples and the HPLC analysis of whitaferin A was used as a marker to evaluate the phytochemical differences. The genetic difference between Indian and Sicilian plants of W. somnifera turned out to be smaller than that between Indian and Sardinian plants of this species. The phytochemical analysis as well showed that the Sardinian specimen strongly differed from the Indian and Sicilian ones in its contents of withaferin A. Our results seem to confirm the hypothesis that the Italian populations of this species may not be indigenous but naturalised. Due to the high withaferin A content of the Sardinian samples, these plants could be used as a source for pharmaceutical purposes.