Thuwalallenes A–E and Thuwalenynes A–C: New C15 Acetogenins with Anti-Inflammatory Activity from a Saudi Arabian Red Sea Laurencia sp.

Thuwalallenes A–E (1–3, 5 and 8) and thuwalenynes A–C (4, 6, 7), new C15 acetogenins featuring uncommon ring systems, along with cis-maneonene D (9), thyrsiferol (10) and 23-acetyl-thyrsiferol (11) were isolated from the organic extract of a population of the red alga Laurencia sp., collected at Rose Reef off the village of Thuwal in the Red Sea waters of the Kingdom of Saudi Arabia. The structure elucidation of the isolated natural products was based on extensive analysis of their spectroscopic data. Compounds 1–6, 8, 10 and 11 were evaluated for their anti-inflammatory activity by quantifying nitric oxide (NO) release in response to TLR4 stimulation in macrophages. Besides compound 4 that did not exhibit any activity, all other tested metabolites inhibited NO production from activated macrophages. Among them, thyrsiferol (10) and 23-acetylthyrsiferol (11) displayed activity with IC50 values in the low nM scale without cytotoxicity

Comparative study of the essential oil composition of the foliage of 54 Pinus taxa: isolation and structure elucidation of secondary metabolites from the species PINUS HELDREICHII Christ., PINUS PINEA L. and PINUS NIGRA subsp. NIGRA Arn.

In the framework of this study, the chemical composition of the organic extracts of three Pinus species, as well as the needle essential oils of 54 Pinus taxa were investigated. Specifically, cones of Pinus heldreichii, fresh needles of Pinus nigra subsp. nigra and bark of Pinus pinea were exhaustively extracted and the crude extracts were subjected to a series of chromatographic separations. The cones of P. heldreichii yielded 38 metabolites in total. Specifically, twenty abietane diterpenes, eight diterpenes featuring the pimarane skeleton, four labdane diterpenes, two macrocyclic cembrane diterpenes, two podocarpene derivatives, one oxygenated sesquiterpene and one steroid. Among these, three metabolites were new natural products (one abietane and two pimarane diterpenes), one abietane diterpene was isolated for the first time from Gymnospermae, four metabolites were isolated for the first time from the genus Pinus and twenty-seven diterpenes were reported for the first time from P. heldreichii. In addition, the spectroscopic data of 20 metabolites were fully assigned for the first time.In total, 12 metabolites were isolated from the fresh needles of P. nigra subsp. nigra, five of which were identified as abietane diterpenes, four diterpenes possessed a labdane skeleton, one was a steroid and two were phenolic compounds. Among these metabolites, one abietane diterpene and one phenolic compound were new natural products, five metabolites were reported for the first time from this species, while full assignment of the spectroscopic data for six diterpenes was reported.Furthermore, the chromatographic separation of P. pinea bark extract resulted in the isolation of a flavonoid derivative and a mixture of ferulic acid esters.The fresh needles of 46 pine species, including 37 and 17 taxa of the subgenera Pinus and Strobus, respectively, were subjected to hydrodistillation and the essential oils obtained were analyzed by means of GC–FID and GC–MS. Among the analyzed taxa, significant quantitative and qualitative differences were observed. Monoterpenes, sesquiterpenes and diterpenes dominated the pine foliage oils, with most of the oils characterized by the presence of the monoterpene hydrocarbons α- and β-pinene and the sesquiterpene hydrocarbon germacrene D. This is the rst report on the chemical composition of the essential oils of 21 pine taxa, including 15 taxa of the subgenus Pinus and six taxa of the subgenus Strobus.Στα πλαίσια της παρούσας διδακτορικής διατριβής μελετήθηκε η χημική σύσταση των οργανικών εκχυλισμάτων διαφορετικών φυτικών τμημάτων των ειδών Pinus heldreichii Christ., Pinus nigra subsp. nigra Arn. και Pinus pinea L. Επίσης, μελετήθηκε η χημική σύσταση των αιθερίων ελαίων από το φύλλωμα 46 ειδών του γένους Pinus (54 taxa) που συλλέχθηκαν είτε από φυσικές θέσεις είτε από βοτανικούς κήπους.Οι κώνοι του είδους P. heldreichii υποβλήθηκαν σε εξαντλητική εκχύλιση με οργανικούς διαλύτες και το εκχύλισμα που προέκυψε υποβλήθηκε σε σειρά χρωματογραφικών διαχωρισμών μέσω των οποίων απομονώθηκαν και ταυτοποιήθηκαν συνολικά 38 μεταβολίτες, συγκεκριμένα είκοσι διτερπένια αβιετικού τύπου, οκτώ με σκελετό πιμαρανίου, τέσσερα λαβδανικού τύπου, δύο μακροκυκλικά διτερπένια τύπου κεβρανίου, δύο διτερπένια παράγωγα ποδοκαρπενίου, ένα οξυγονωμένο σεσκιτερπένιο και ένα στεροειδές. Μεταξύ αυτών, τρείς διτερπενικοί μεταβολίτες (δύο πιμαρικού και ένας αβιετικού τύπου) ήταν νέα φυσικά προϊόντα, ένας μεταβολίτης σκελετού αβιετανίου αναφέρεται πρώτη φορά σε Γυμνόσπερμα, τέσσερεις μεταβολίτες αναφέρονται πρώτη φορά στο γένος Pinus, ενώ εικοσιεπτά απομονώνονται πρώτη φορά από το είδος P. heldreichii. Επιπλέον, για είκοσι γνωστούς μεταβολίτες πραγματοποιήθηκε πρώτη φορά η πλήρης απόδοση των φασματοσκοπικών τους δεδομένων.Τα βελονοειδή φύλλα του είδους P. nigra subsp. nigra εκχυλίστηκαν εξαντλητικά με οργανικούς διαλύτες και το εκχύλισμα που παραλήφθηκε υποβλήθηκε σε επιμερισμό μεσω υγρής-υγρής εκχύλισης και στη συνέχεια υποβλήθηκε σε σειρά χρωματογραφικών διαχωρισμών. Συνολικά απομονώθηκαν και ταυτοποιήθηκαν 12 μεταβολίτες και συγκεκριμένα τέσσερα διτερπένια λαβδανικού τύπου, πέντε διτερπένια με σκελετό αβιετανίου, ένα στεροειδές και δύο φαινολικά παράγωγα. Μεταξύ αυτών, δύο μεταβολίτες αποτελούν νέα φυσικά προϊόντα, πέντε αναφέρονται πρώτη φορά από το συγκεκριμένο είδος, ενώ για έξι γίνεται η πλήρης απόδοση των φασματοσκοπικών τους δεδομένων για πρώτη φορά.Επίσης, σε εξαντλητική εκχύλιση με οργανικούς διαλύτες υποβλήθηκε ο φλοιός του είδους P. pinea και το εκχύλισμα που παραλήφθηκε αναλύθηκε χρωματογραφικά οδηγώντας στην απομόνωση ενός φλαβονοειδούς και μίγματος λιπαρών εστέρων του φερουλικού οξέος.Νωπά βελονοειδή φύλλα από 37 taxa του υπογένους Pinus και 17 taxa του υπογένους Strobus υποβλήθηκαν σε υδραπόσταξη και τα αιθέρια έλαια που παραλήφθηκαν, αναλύθηκαν μέσω GC-FID και GC-MS. Μεταξύ των δειγμάτων παρατηρήθηκαν σημαντικές ποσοτικές, αλλά και ποιοτικές διαφορές. Μονοτερπένια, σεσκιτερπένια και διτερπένια κυριαρχούσαν στις αναλύσεις, με τους μονοτερπενικούς υδρογονάνθρακες α- και β-πινένιο και το σεσκιτερπένιο γερμακρένιο D να χαρακτηρίζουν την πλειοψηφία των δειγμάτων. Στην παρούσα μελέτη αναλύθηκε για πρώτη φορά το αιθέριο έλαιο των βελόνων εικοσιενός taxa, συμπεριλαμβανομένων δεκαπέντε του υπογένους Pinus και έξι του υπογένους Strobus

Antimicrobial Activity of the Essential Oil of Greek Endemic Stachys spruneri and its Main Component, Isoabienol

The essential oils of Stachys spruneri Boiss. (sample A and sample B) were analyzed by GC and GC-MS. (+)-Isoabienol was the dominant component (49.5 and 48.2%, respectively of the total oils) among seventy-two identified constituents. Isoabienol was separated, purified by preparative thin-slayer chromatography, and further identified by means of physicochemical and spectrometric analysis. The microbial growth inhibitory properties of the essential oil and its main metabolite, the labdane diterpene isoabienol, were determined using the broth microdilution method against eight laboratory strains of bacteria (Gram- positive: Staphylococcus aureus, S. epidermidis, Micrococcus luteus, Enterococcus faecalis, Bacillus subtilis, and Gram- negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two strains of the yeast Candida albicans. Both essential oil and isoabienol showed considerable activity against all the microorganisms tested, with the isolated compound being most active

Composition and Antimicrobial Activity of the Essential Oils from Different Parts of Cachrys cristata DC. from Greece

Fresh leaves, stems and roots of Cachrys cristata, were subjected to hydrodistillation and the oils obtained were analyzed by means of GC and GC-MS. Sixty eight constituents were in total identified, with (Z)-beta-ocimene (44.2% and 30.5%) dominating in leaves and stems oils, while the major metabolite of the roots was found to be p-tolualdehyde (39.6%), followed by (Z)-beta-ocimene (15.2%). The microbial growth inhibitory properties of the essential oils were determined using the broth microdilution method against seven laboratory strains of bacteria - Gram positive: Staphylococcus aureus, S. epidermidis, Micrococcus luteus, Enterococcus faecalis and Gram negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two strains of the yeast Candida albicans. The essential oils exhibited considerable activity against certain strains of the microorganisms tested, with the leaves oil demonstrating higher antimicrobial activity among the tested samples

Antimicrobial Activity and Essential Oil Composition of Five Sideritis taxa of Empedoclia and Hesiodia Sect. from Greece

Dried aerial parts of five taxa of Greek Sideritis were subjected to hydrodistillation and the oils obtained were analyzed by using GC and GC-MS. A total of 82 compounds were identified and the analysis showed important differences between the samples not only quantitatively but also qualitatively. The microbial growth inhibitory properties of the essential oils were determined using the broth microdilution method against eight laboratory strains of bacteria - Gram positive: Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus, Enterococcus faecalis, Bacillus subtilis and Gram negative: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and two strains of the yeast Candida albicans. The tested essential oils exhibited considerable activity against certain strains of the microorganisms tested, with S. lanata oil presenting MIC values to S. aureus and M. luteus comparable to those of the reference antibiotics

Diversity of Volatile Compounds in the <i>Inula candida</i> / <i>I. verbascifolia</i> Group (Asteraceae-Inuleae) and Its Impact on Species Delimitation

The members of the Inula candida / I. verbascifolia group are perennial and chasmophytic plants attributed to four species and eleven entities at subspecific or varietal level. They are mostly confined to Greece. Volatile compounds of above-ground flowering parts of twenty-three populations covering ten taxonomic entities were obtained after hydrodistillation and analyzed by gas chromatography and mass spectrometry (GC-MS). In most cases, the total percentage of identified constituents reached 89% or above. Seventy-two components were identified. Oxygenated sesquiterpenes prevailed in the I. candida subgroup (47.3–71.5%), with epi-α-cadinol present in all members (13.4–42.7%) but rarely found in the I. verbascifolia subgroup. Considerable amounts of the hydrocarbon aldehydes decanal, undecanal and particularly tridecanal (0.5–35.0%, rarely absent) were predominately found in the I. verbascifolia members but were mostly absent in the I. candida subgroup. Isoalantolactone (12.4–49.5%), identified only in I. subfloccosa, and γ-(Z)-curcumen-12-ol, found only in I. candida subsp. limonella (22.6–42.1%), may serve as chemotaxonomic markers. Two different chemotypes can be distinguished within I. verbascifolia subsp. aschersoniana: a trans-muurola-4(14),5-diene-, γ-cadinene-rich chemotype from north-eastern Greece and a 1-epi-cubenol-, tridecanal-rich chemotype from central Greece. Different statistical algorithms were used to interpret the chemical diversity and identify the most appropriate number of clusters for the taxa. Cluster analyses indicated that the optimum number of clusters that best explain the metabolomic variability of the taxa is two. The degree of membership for each population based on the fuzzy k-means algorithm supported the I. verbascifolia subsp. aschersoniana samples within the I. candida subgroup, whereas I. subfloccosa may belong to any of the two clusters formed, although it also appears to have some unique characteristics

Diversity of Volatile Compounds in the Inula candida / I. verbascifolia Group (Asteraceae-Inuleae) and Its Impact on Species Delimitation

The members of the Inula candida / I. verbascifolia group are perennial and chasmophytic plants attributed to four species and eleven entities at subspecific or varietal level. They are mostly confined to Greece. Volatile compounds of above-ground flowering parts of twenty-three populations covering ten taxonomic entities were obtained after hydrodistillation and analyzed by gas chromatography and mass spectrometry (GC-MS). In most cases, the total percentage of identified constituents reached 89% or above. Seventy-two components were identified. Oxygenated sesquiterpenes prevailed in the I. candida subgroup (47.3&ndash;71.5%), with epi-&alpha;-cadinol present in all members (13.4&ndash;42.7%) but rarely found in the I. verbascifolia subgroup. Considerable amounts of the hydrocarbon aldehydes decanal, undecanal and particularly tridecanal (0.5&ndash;35.0%, rarely absent) were predominately found in the I. verbascifolia members but were mostly absent in the I. candida subgroup. Isoalantolactone (12.4&ndash;49.5%), identified only in I. subfloccosa, and &gamma;-(Z)-curcumen-12-ol, found only in I. candida subsp. limonella (22.6&ndash;42.1%), may serve as chemotaxonomic markers. Two different chemotypes can be distinguished within I. verbascifolia subsp. aschersoniana: a trans-muurola-4(14),5-diene-, &gamma;-cadinene-rich chemotype from north-eastern Greece and a 1-epi-cubenol-, tridecanal-rich chemotype from central Greece. Different statistical algorithms were used to interpret the chemical diversity and identify the most appropriate number of clusters for the taxa. Cluster analyses indicated that the optimum number of clusters that best explain the metabolomic variability of the taxa is two. The degree of membership for each population based on the fuzzy k-means algorithm supported the I. verbascifolia subsp. aschersoniana samples within the I. candida subgroup, whereas I. subfloccosa may belong to any of the two clusters formed, although it also appears to have some unique characteristics

Expanding the terpene biosynthetic code with non-canonical 16 carbon atom building blocks

Humankind relies on specialized metabolites for medicines, flavors, fragrances, and numerous other valuable biomaterials. However, the chemical space occupied by specialized metabolites, and, thus, their application potential, is limited because their biosynthesis is based on only a handful of building blocks. Engineering organisms to synthesize alternative building blocks will bypass this limitation and enable the sustainable production of molecules with non-canonical chemical structures, expanding the possible applications. Herein, we focus on isoprenoids and combine synthetic biology with protein engineering to construct yeast cells that synthesize 10 non-canonical isoprenoid building blocks with 16 carbon atoms. We identify suitable terpene synthases to convert these building blocks into C(16) scaffolds and a cytochrome P450 to decorate the terpene scaffolds and produce different oxygenated compounds. Thus, we reconstruct the modular structure of terpene biosynthesis on 16-carbon backbones, synthesizing 28 different non-canonical terpenes, some of which have interesting odorant properties