In Vitro Control of Post-Harvest Fruit Rot Fungi by Some Plant Essential Oil Components

Eight substances that are main components of the essential oils from three Mediterranean aromatic plants (Verbena officinalis, Thymus vulgaris and Origanum vulgare), previously found active against some phytopathogenic Fungi and Stramenopila, have been tested in vitro against five etiological agents of post-harvest fruit decay, Botrytis cinerea, Penicillium italicum, P. expansum, Phytophthora citrophthora and Rhizopus stolonifer. The tested compounds were β-fellandrene, β-pinene, camphene, carvacrol, citral, o-cymene, γ-terpinene and thymol. Citral exhibited a fungicidal action against P. citrophthora; carvacrol and thymol showed a fungistatic activity against P. citrophthora and R. stolonifer. Citral and carvacrol at 250 ppm, and thymol at 150 and 250 ppm stopped the growth of B. cinerea. Moreover, thymol showed fungistatic and fungicidal action against P. italicum. Finally, the mycelium growth of P. expansum was inhibited in the presence of 250 ppm of thymol and carvacrol. These results represent an important step toward the goal to use some essential oils or their components as natural preservatives for fruits and foodstuffs, due to their safety for consumer healthy and positive effect on shelf life extension of agricultural fresh products

Intra- and interpopulation study of volatile constituents of Thymus sect. Teucrioides taxa: isolation of secondary metabolites from Thymus Teucrioides boiss. and Spruner subsp. Candilicus (Beauverd) Hartvig

Various species of the genus Τhymus L. were known since the ancient times and were used extensively in ancient Egypt, Hellas and Rome. The genus Τhymus L. (tribe Menthae, subfamily Nepetoideae), one of the eight most important genera of the family Labiatae, is divided in eight sections. Section Teucrioides comprises of Th. leucospermus, Th. hartvigii and the subspecies of the species of Th. teucrioides.The subject of the present PhD thesis is the intra- and interpopulation study of the taxa of Thymus sect. Teucrioides Jalas, as well as the isolation, structure elucidation and biological evaluation of the secondary metabolites biosynthesized by Thymus teucrioides subsp. candilicus, a member of section Teucrioides.Twenty-two populations of the species and subspecies of section Teucrioides were collected across their distribution range in Hellas. After hydrodistillation, the chemical composition of the essential oils was studied with GC (GC-FID, GC-MS) and the data were subjected to statistical analysis (CA, PCA, ANOVA, Post Hoc Tests - Bonferroni).In addition, the crude extract of Thymus teucrioides subsp. candilicus was subjected to chromatographic separations to yield forty-one secondary metabolites that were identified on the basis of their spectroscopic data. Eight out of forty-three metabolites are new natural products. Seven of them are prenyl-sesquiterpenes (10-16) and feature novel bicyclic carbon skeletons. The eighth new natural product belongs to the class of monoterpenes (6).The cytotoxic activity for a number of the isolated metabolites was evaluated against six cancer cell lines. Moreover, antimicrobial assays were conducted on metabolites 10, 12 and 13, the essential oils and the extracts of Thymus teucrioides subsp. candilicus and Th. leucospermus against the bacteria Streptococcus pneumoniae, multi resistant Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Clostridium perfringens, Salmonella enteritidis, Micrococcus flavus and the fungi Candida albicans, Candida krusei, Aspergillus fumigatus. Finally, the larvicidal and the repellent activity of the essential oils and the extracts of Th. teucrioides subsp. candilicus and Th. leucospermus against the mosquito Culex pipiens biotype molestus, the vector of West Nile Virus, was tested.Tα διάφορα είδη θυμαριού (Τhymus L.) ήταν γνωστά από την αρχαιότητα και χρησιμοποιούνταν ευρέως υπό διάφορες μορφές στην Αίγυπτο, την Ελλάδα και την Ρώμη. Σο γένος Τhymus L. (ομάδα Menthae, υποοικογένεια Nepetoideae), ένα από τα οκτώ σημαντικότερα γένη της οικογένειας των Labiatae, χωρίζεται σε οκτώ sectiones. Η sectio Teucrioides περλαμβάνει τα Th. leucospermus, Th. hartvigii, καθώς επίσης και το σύνολο των υποειδών του Th. teucrioides, τα οποία είναι από τα πιο διακριτά, αλλά ταυτόχρονα και από τα πλέον ποικιλόμορφα μεταξύ των ελληνικών θυμαριών.Σο θέμα της παρούσας διδακτορικής διατριβής είναι αφενός η ενδοπληθυσμιακή και διαπληθυσμιακή μελέτη των taxa του Thymus sect. Teucrioides Jalas, καθώς επίσης και η απομόνωση και ταυτοποίηση φυσικών βιοδραστικών ουσιών ενός εκπροσώπου της sectio, του υποείδους Thymus teucrioides subsp. candilicus.΢υνολικά συλλέχθησαν 22 πληθυσμοί, από 3 έως 6 άτομα αναλόγως της αφθονίας των ατόμων που απάρτιζαν τον πληθυσμό, ειδών και υποειδών και πιθανών υβριδίων του Thymus sectio Teucrioides από όλη την περιοχή εξάπλωσής της sectio Teucrioides στην Ελλάδα. Μετά από απόσταξη των αιθερίων ελαίων μελετήθηκε η χημική σύστασή τους με αέρια χρωματογραφία (GC-FID, GC-MS) και κατόπιν πραγματοποιήθηκε στατιστική ανάλυση των αποτελεσμάτων (CA, PCA, ANOVA, Post Hoc Tests - Bonferroni).Επιπλέον, το εκχύλισμα του υποείδους Thymus teucrioides subsp. candilicus επεξεργάστηκε με τεχνικές υγρής χρωματογραφίας και απέδωσε σαράντα ένα διαφορετικούς δευτερογενείς μεταβολίτες, η δομική ταυτοποίηση των οποίων, πραγματοποιήθηκε με βάση τα φασματοσκοπικά τους δεδομένα.Από τους σαράντα ένα δευτερογενείς μεταβολίτες, οι οκτώ αποτελούν νέα φυσικά προϊόντα. Από τους οκτώ αυτούς δευτερογενείς μεταβολίτες, οι επτά είναι πρενυλιωμένα σεσκιτερπένια και έχουν πρωτότυπους ανθρακικούς σκελετούς (10-16) και ο όγδοος ανήκει στην κατηγορία των μονοτερπενίων (6).Διενεργήθηκαν φαρμακολογικοί έλεγχοι σε αριθμό μεταβολιτών ως προς την κυτταροτοξική δράση έναντι έξι καρκινικών σειρών με αξιόλογα αποτελέσματα. Παράλληλα πραγματοποιήθηκαν βιοδοκιμές αντιμικροβιακής δράσης στους μεταβολίτες 10, 12 και 13, τα αιθέρια έλαια και τα φυτικά εκχυλίσματα των Thymus teucrioides subsp. candilicus και Th. leucospermus έναντι των βακτηριακών στελεχών Streptococcus pneumoniae, multi resistant Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Clostridium perfringens, Salmonella enteritidis, Micrococcus flavus, και των μυκήτων Candida albicans, Candida krusei και Aspergillus fumigatus. Σέλος, ελέγχθηκε η προνυμφοκτόνος και απωθητική δράση των ανωτέρω αιθερίων ελαίων και φυτικών εκχυλισμάτων εκπροσώπων της sectio Teucrioides στο δίπτερο υγειονομικής σημασίας Culex pipiens biotype molestus (κοινό κουνούπι), φορέα του ιού του Δυτικού Νείλου, με ενδιαφέροντα αποτελέσματα

Essential oil composition of Salvia verticillata, S. verbenaca, S. glutinosa and S. candidissima growing wild in Greece

The chemical composition of the essential oils of Salvia verticillata, S. verbenaca, S. glutinosa and S. candidissima, growing wild in Greece, were analysed by GC and GC-MS. Twenty-eight components were characterized for S. verticillata, with β-pinene (30.7%), p-cymene (23.0%) and isopropyl ester of lauric acid (16.8%) as the dominating constituents; 19 components were identified for S. verbenaca, with β-phellandrene (30.3%), (E)-caryophyliene (16.1%) and methyl ester of 6-octadecenoic acid (15.0%) as the major compounds; 23 constituents were determined for S. glutinosa, with butyl butyryl lactate (26.7%) as the most abundant component; and finally 36 constituents were identified for S. candidissima, with α-pinene (11.2%) and 1,8-cineole (9.89%) as the major compounds. Copyright © 2006 John Wiley & Sons, Ltd

Composition of the essential oil of spontaneous rosmarinus officinalis from greece and antifungal activity against phytopathogenic Fungi

The chemical composition of the essential oil of spontaneous Rosmarinus officinalis from Greece was analyzed by GC and GC/MS and tested for its antifungal activity against five phytopathogenic fungi (Sclerotinia sclerotiorum, Phytophthora nicotianae, Sclerotium cepivorum, Fusarium oxysporum f. sp. dianthi and Fusarium proliferatum). Thirty-seven components compounds representing 97.3% of the total oil were identified. The major constituents were α-pinene (24.1%), camphor (14.9%), 1,8-cineole (9.3%), camphene (8.9%), α-terpineol (8.8%) and borneol (8.0%). The most sensitive fungus was Ph. nicotianae, followed by S. sclerotiorum, S. cepivorum, F. proliferatum and F. oxysporum f. sp. dianthi. © 2008, Taylor & Francis Group, LLC. All rights reserved

Activity of the essential oil of salvia pomifera l. ssp. calyclna (sm.) hayek against soil borne pathogens

The antifungal activity of the oil of Salvia pomifera ssp. calycina and its main components (α- and β-thujone) were tested on six phytopathogenic fungal strains. The hydrocarbon and oxygenated fractions of the oil were assessed against Rhizoctonia solani and Sclerotinia sclerotiorum, the two most susceptible fungi to the oil tested. The oil exhibited fungistatic effect at the concentration of 1000 μL/L on R. solani and S. sclerotiorum, whereas its oxygenated fraction showed fungicidal activity at 2000 and 1000 μL/L, respectively. The hydrocarbon fraction had a weak effect on the test organisms. The oxygenated monoterpenes α- and β-thujone exhibited a moderate fungistatic effect to R. solani and S. sclerotiorum, while their inhibitory activity was weak to Verticillium dahliae and the Fusarium species tested. © 2002, Taylor & Francis Group, LLC. All rights reserved

Antifungal activities of selected aromatic plants growing wild in Greece

Essential oils of Origanum onites, Satureja thymbra, Salviafruticosa (Greek sage), and Salvia pomifera subsp. calycina plants growing wild in Greece and their components carvacrol, camphor, and 1,8-cineole, were assayed for antifungal activity against 13 fungal species. Among the fungi tested were food poisoning, plant, animals and human pathogenic species. The oils presented various degrees of inhibition against all the fungi investigated. The highest and broadest activity was shown by the carvacrol content oils (O. onites and S. thymbra), while the oil of sage was the least effective. Carvacrol exhibited the highest and 1,8-cineole the lowest level of antifungal activity among the components tested

Composition and antifungal activity of the essential oil of salvia pomifera subsp. Calycina growing wild in Greece

The hydrodistilled essential oil of the aerial parts of Salvia pomifera subsp. calycina was analyzed by GC/MS. Fifty compounds representing 98% of the oil were identified. The main components of the oil were α-thujone (20.3%), β-thujone (36.3%) and myrcene (5.9%). The biostatic activity of the oil was evaluated in vitro against seven fungal strains. © 1999, Taylor & Francis Group, LLC. All rights reserved

Composition and antimicrobial activity of the essential oil of Salvia ringens

The essential oils of Salvia ringens (samples A and B), were analyzed by means of GC and GC/MS. From the seventy-five identified constituents representing 99.82 and 99.86% of the oils, 1,8-cineole and α-pinene were the major components. Furthermore, sample B exhibited a very interesting antimicrobial profile after it was tested against six Gram (±) bacteria and three pathogenic fungi

Chemical composition, larvicidal evaluation, and adult repellency of endemic Greek Thymus essential oils against the mosquito vector of West Nile virus

The volatile metabolites of Greek wild growing Thymus leucospermus and Thymus teucrioides subsp. candilicus were determined by gas chromatography and gas chromatography-mass spectrometry. The monoterpene hydrocarbon p-cymene (64.2%) dominated T. leucospermus oil, followed by γ-terpinene (7.9%), thymol (4.8%), and borneol (4.7%), whereas the most abundant constituents in T. teucrioides subsp. candilicus oil were p-cymene (25.5%), γ-terpinene (19.0%), thymol (18.8%), borneol (5.7%), and α-pinene (5.7%). The larvicidal and repellent activities of the analyzed essential oils were tested on Culex pipiens larvae and adults, respectively. Additionally, the main metabolite of the essential oils, p-cymene was tested against C. pipiens adults in order to define the affiliation between p-cymene and the repellent properties of the oil. The essential oils of T. leucospermus and T. teucrioides subsp. candilicus provided repellency 78.1% and 72.9%, respectively, statistically equal to the reference product icaridin. The compound p-cymene showed almost no repellent activity. The essential oil of T. leucospermus presented lower larvicidal activity (LC50=34.26 mgl-1) against C. pipiens third-fourth instar larvae while T. teucrioides subsp. candilicus was the most active with an estimated LC50 value of 23.17 mgl-1. © 2011 Springer-Verlag