Genome size in Dipsacaceae and Morina longifolia (Morinaceae)

Dipsacaceae and Morinaceae have for a long time been regarded as separate but related families, whereas according to APG III they are included within the larger family Caprifoliaceae. Although genome size studies seldom provide conclusive characters for higher level systematics, they can yield useful information at a lower taxonomy level. In this study, we used DNA flow cytometry (supplemented by Feulgen densitometry) for measurement of genome size variation in the Dipsacaceae genera Cephalaria, Dipsacus, Knautia, Lomelosia, Pterocephalus, Scabiosa, Sixalix, Succisa, and Succisella, and Morina of the Morinaceae. At the monoploid level the Dipsacaceae genera (x = 7–10) vary 5.94-fold between 0.902 and 5.362 pg DNA (1Cx-value), whereas Morina longifolia (x = 17) has only 0.670 pg DNA. At the holoploid level 11.58-fold variation occurs between 0.902 and 10.446 pg DNA (1C-value). In Knautia sect. Trichera ploidy levels 2x, 4x, 6x are accompanied by corresponding increments of C-values, but genome downsizing is observed. In Knautia sect. Tricheroides the only investigated species K. integrifolia (2n = 20) has only 0.60-fold the mean genome size of sect. Trichera. Scabiosa canescens (2n = 2x = 16) has approximately double the C-value of all other Austrian Scabiosa species at the diploid level (pseudopolyploidy). These values raise concern against DNA-ploidy estimations at the interspecific level when chromosome numbers are unknown. The species sorted into two major clades of an existing phylogenetic tree of Dipsacaceae differ characteristically in their range of Cx-values. The Knautia–Cephalaria–Dipsacus–Succisella clade has the great majority of its Cx-values larger than those of the Scabiosa–Pterocephalus–Lomelosia clade.     

Development and Function of the Elaiosome in Knautia (Dipsacaceae)

The fruits of the genus Knautia differ from those of all other Dipsacaceae by the possession of a white, ± hemispherical basal appendage (elaiosome). In a series of field experiments Sernander (1906) demonstrated that, due to this elaiosome, the fruits of Knautia are dispersed by ants. Sernander (1906) assumed that the elaiosome is built from fused bracts (forming the epicalyx) whereas Bresinsky (1963) interpreted it as part of the perianth. In the present study the elaiosome development was investigated in four species of all three subgenera of Knautia: subg. Trichera (K. drymeia, K. dipsacifolia), subg. Tricheranthes (K. integrifolia) and subg. Knautia (K. orientalis). A comparison with early stages of the fruit development in other Dipsacaceae (e.g., Lomelosia graminifolia) indicates that the elaiosome is of epicalyx origin. In all species of Knautia the development of the elaiosome begins prior to anthesis and independently of fertilization. The growth of the elaiosome tissue in K. orientalis is mainly caused by periclinal cell divisions in the subepidermal layers of the epicalyx base. In K. dipsacifolia and K. drymeia a meristem around the base of the central bundle, which supplies epicalyx and flower, becomes active and develops cells in cascade-like rows. The elaiosome cells of ripe fruits are filled with numerous oil droplets. Moreover the central bundle increases by the formation of additional phloem cells. In addition, other important morphological adaptations to ant dispersal are demonstrated: the hair-cover of the fruit and strongly lignified horizontal vascular bundles between elaiosome and seed prevent the seed from being eaten; a lignified cramp anchors the elaiosome to the fruit; and thickened and strongly cutinized walls of the epidermis protect the elaiosome during dispersal. In regard to germination, a correlation between the removal of the elaiosome and germination speed and rate was found; fruits with dissected elaiosomes germinate faster and with a higher germination rate than fruits with elaiosomes.     

Revisiting the phylogeny of Dipsacales: New insights from phylogenomic analyses of complete plastomic sequences

Phylogenetic relationships in Dipsacales have long been a major challenge. Although considerable progress has been made during the past two decades, questions remain; the uncertain systematic positions of Heptacodium, Triplostegia, and Zabelia, in particular, impede our understanding of Dipsacales evolution. Here we use 75 complete plastomic sequences to reconstruct the phylogeny of Dipsacales, of which 28 were newly generated. Two primary clades were recovered that form the phylogenetic backbone of Dipsacales. Seven of the primary clades correspond to the recognized families Adoxaceae, Caprifoliaceae s. str., Diervillaceae, Dipsacaceae, Linnaeaceae, Morinaceae, and Valerianaceae, and one corresponds to Zabelia, which was found to be the closest relative of Morinaceae in all analyses. Additionally, our results, with greatly increased confidence in most branches, show that Heptacodium and Triplostegia are members of Caprifoliaceae s. str. and Dipsacaceae, respectively. The results of our study indicate that the complete plastomic sequences provide a fully‐resolved and well‐supported representation of the phylogenetic relationships within Dipsacales.     

Chemical Composition and Antimicrobial Activity of the Essential Oils from New Caledonian Citrus macroptera and Citrus hystrix

The essential oils from the leaves of Citrus macroptera and C. hystrix, collected in New Caledonia, have been analyzed by gas chromatography/mass spectrometry (GC/MS) and evaluated for their antimicrobial activity. A total of 35 and 38 constituents were identified, representing 99.1 and 89.0% of the essential oils, respectively. Both essential oils were rich in monoterpenes (96.1 and 87.0%, resp.), with β‐pinene as major component (33.3 and 10.9%, resp.), and poor in limonene (2.4 and 4.7%, resp.). Other main components of C. macroptera oil were α‐pinene (25.3%), p‐cimene (17.6%), (E)‐β‐ocimene (6.7%), and sabinene (4.8%). The essential oil of C. hystrix was characterized by high contents of terpinen‐4‐ol (13.0%), α‐terpineol (7.6%), 1,8‐cineole (6.4%), and citronellol (6.0%). The antimicrobial activity was evaluated against five bacteria and five fungi strains. Both oils were inactive against bacteria. However, the C. macroptera leaf oil exhibited a pronounced activity against Trichophyton mentagrophytes var. interdigitale, with a minimal‐inhibitory concentration (MIC) of 12.5 μg/ml.     

Population Variability of Nonacosan‐10‐ol and n‐Alkanes in Needle Cuticular Waxes of Macedonian Pine (Pinus peuce Griseb.)

This is the first report on population variability of nonacosan‐10‐ol and n‐alkanes in needle epicuticular waxes of Macedonian pine (Pinus peuce Griseb .) Hexane extracts of needle samples, originating from two natural populations in Montenegro (Zeletin and Sjekirica) and from one population in Serbia (Mokra Gora) were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The amount of nonacosan‐10‐ol varied individually from 41.3 to 72.31% (average 55.9%), with the Sjekirica population being statistically divergent (64.4% on average). The results showed n‐alkanes in epicuticular waxes ranging from C₁₈ to C₃₃. The most abundant alkanes were C₂₉, C₂₅, C₂₇, and C₂₃ (15.5, 11.1, 10.6, and 10.5% on average, resp.). The carbon preference index of Pinus peuce ranged from 1.0 to 4.3 (1.9 on average). Average chain length ranged from 18.4 to 27.7 (average 25.7). A high level of inidividual quantitative variation in all of these hydrocarbon parameters was also detected. These results were compared with published data on other species from the Pinus genus.     

Chemical Composition of the Tuber Essential Oil from Helianthus tuberosus L. (Asteraceae)

Helianthus tuberosus L. (Jerusalem artichoke) is cultivated in Europe and other parts of the world as a food crop and ornamental plant. The volatile oils of the aerial parts of H. tuberosus were investigated more than 30 years ago, but no study could be found to date on the constituents of the tuber essential oil. Herein, the first characterization by GC‐FID, GC/MS, and ¹³C‐NMR analyses of a hydrodistilled essential oil of Jerusalem artichoke tubers was reported. Fresh plant material collected in Serbia (Sample A) and a commercial sample (Sample B) yielded only small amounts of oil (0.0014 and 0.0021% (w/w), resp.). In total, 195 constituents were identified, representing 88.2 and 93.6% of the oil compositions for Samples A and B, respectively. The main constituents identified were β‐bisabolene ( 1 ; 22.9–30.5%), undecanal (0–12.7%), α‐pinene (7.6–0.8%), kauran‐16‐ol ( 2 ; 6.9–9.8%), 2‐pentylfuran (0.0–5.7%), and (E)‐tetradec‐2‐enal (0.0–4.9%). Several rare compounds characteristic for Helianthus ssp. were also detected: helianthol A ( 6 ; 2.1–1.9%), dihydroeuparin ( 10 ; 0.0–2.3%), euparin ( 9 ; 0.0–0.4%), desmethoxyencecalin ( 7 ; traces – 0.2%), desmethylencecalin ( 8 ; 0.0–0.4%), and an isomer of desmethylencecalin (0.0%‐traces). The essential oils isolated from the tuber and the aerial parts share the common major component 1 .     

Two novel saponins from Cephalaria davisiana (Dipsacaceae)

Two novel hederagenin type triterpene saponins, namely davisianoside A (1) and davisianoside B (2) together with ten known compounds (3–12) were isolated from the aerial parts of Cephalaria davisiana (Dipsacaceae). One new prosapogenin (1a) was also obtained after the alkaline hydrolysis of compound 1. The chemical structures of all compounds were established mainly by 1D-, 2D-NMR and HR-ESI/MS analysis as well as chemical methods.The antibacterial and antifungal effects of compounds 1–2 were evaluated against Gram-positive, Gram-negative bacteria and unicellular yeast C. albicans by MIC method.     

Nematicidal screening of essential oils and potent toxicity of Dysphania ambrosioides essential oil against Meloidogyne incognita in vitro and in vivo

It is known that some plant essential oils have pesticide activities. Among the 29 oils evaluated in this study, 14 showed nematicidal activities of 8 to 100% at the concentration of 1,000 μg/ml, compared with a control of 0.01 g/ml Tween 80^®. At a lower concentration of 500 μg/ml, only Dysphania ambrosioides oil caused >90% mortality of second‐stage juveniles (J2) of Meloidogyne incognita. The LC₅₀ and LC₉₅ values for D. ambrosioides oil were 307 μg/ml and 580 μg/ml, respectively. M. incognita eggs placed in D. ambrosioides oil solutions had a significant reduction in J2 hatching compared with controls. Therefore, the oil had a toxic effect on both eggs and J2 of M. incognita. This was in contrast to nematicides on the market that act efficiently only on J2. When J2 were placed in D. ambrosioides oil at its LC₅₀ concentration and inoculated onto tomato plants, the reduction in numbers of galls and eggs was 99.5% and 100%, respectively. Dysphania ambrosioides oil applied to the potting substrate of plants at a concentration of 1,100 μg/ml significantly reduced the number of galls and eggs of M. incognita, whereas a concentration of 800 μg/ml only reduced the number of eggs compared with the controls (Tween 80^® and water). The main components of the D. ambrosioides oil detected by gas chromatography–mass spectrometry were (Z)‐ascaridole (87.28%), E‐ascaridole (8.45%) and p‐cymene (3.35%), representing 99.08% of the total oil composition. Given its nematicidal activity, D. ambrosioides oil represents an exciting raw material in the search for new bioactive molecules for the pesticide industry.     

Variability of n‐Alkanes and Nonacosan‐10‐ol in Natural Populations of Picea omorika

This is the first report of population variability of the contents of n‐alkanes and nonacosan‐10‐ol in the needle epicuticular waxes of Serbian spruce (Picea omorika). The hexane extracts of needle samples originated from three natural populations in Serbia (Vranjak, Zmajeva?ki potok, and Mile?evka Canyon) were investigated by GC and GC/MS analyses. The amount of nonacosan‐10‐ol varied individually from 50.05 to 74.42% (65.74% in average), but the differences between the three investigated populations were not statistically confirmed. The results exhibited variability of the composition of n‐alkanes in the epicuticular waxes with their size ranging from C₁₈ to C₃₅. The most abundant n‐alkanes were C₂₉, C₃₁, and C₂₇ (35.22, 13.77, and 12.28% in average, resp.). The carbon preference index of all the n‐alkanes (CPI_total) of the P. omorika populations (average of populations I–III) ranged from 3.3 to 11.5 (mean of 5.9), while the average chain length (ACL) ranged from 26.6 to 29.2. The principal component and cluster analyses of the contents of nine n‐alkanes showed the greatest difference for the population growing in the Mile?evka Canyon. The obtained results were compared with previous literature data given for other Picea species, and this comparison was briefly discussed.     

Chemical Composition of the Essential Oil and Diethyl Ether Extract of Trinia glauca (L.) Dumort. (Apiaceae) and the Chemotaxonomic Significance of 5‐O‐Methylvisamminol

Analyses by GC, GC/MS, and NMR spectroscopy (1D‐ and 2D‐experiments) of the essential oil and Et₂O extract of Trinia glauca (L .) Dumort . (Apiaceae) aerial parts allowed a successful identification of 220 constituents, in total. The major identified compounds of the essential oil were (Z)‐falcarinol (10.6%), bicyclogermacrene (8.0%), germacrene D (7.4%), δ‐cadinene (4.3%), and β‐caryophyllene (3.2%), whereas (Z)‐falcarinol (47.2%), nonacosane (7.4%), and 5‐O‐methylvisamminol (4.0%) were the dominant constituents of the extract of T. glauca. One significant difference between the compositions of the herein and the previously analyzed T. glauca essential oils (only two reports) was noted. (Z)‐Falcarinol was the major constituent in our case, whereas germacrene D (14.4 and 19.6%) was the major component of the previously studied oils. Possible explanations for this discrepancy were discussed. 5‐O‐Methylvisamminol, a (furo)chromone identified in the extract of T. glauca, has a limited occurrence in the plant kingdom and is a possible excellent chemotaxonomic marker (family and/or subfamily level) for Apiaceae.     

Artemisia magellanica. Chemical Composition of the Essential Oil from an Unexplored Endemic Species of Patagonia

The essential oil composition of the aerial parts of Artemisia magellanica Sch. Bip . (Asteraceae), native to Patagonia, was analyzed by GC‐FID‐MS. This is the first report on the essential oil composition of A. magellanica. A total of 113 components were identified accounting for 95.6–95.7 % of the oil. The essential oil was characterized by a high percentage of γ‐costol (21.0–43.5 %), selina‐4,11‐diene, (Z)‐β‐ocimene, (E)‐β‐farnesene, (Z)‐en‐yn‐dicycloether and 23 different esters (28.7 %). In turn, Artemisia biennis, a species native to North America, which is considered by some authors to be conspecific with A. magellanica, yielded an essential oil that was rich in (Z)‐β‐ocimene (34.7 %), (E)‐β‐farnesene (40.0 %) and the acetylenes (Z)‐ and (E)‐en‐yn‐dicycloethers (11.0 %). Thus, as A. biennis lacks the three main components present in A. magellanica, namely γ‐costol, 2‐methylbutyl 2‐methylbutyrate and selina‐4,11‐diene, these compounds could be considered as potential chemical markers for A. magellanica since they are absent or only found as minor constituents in other members of the genus. The data presented herein is also useful for genus taxonomy.     

Characterization of Secondary Metabolites,Biological Activity and Glandular Trichomes of Stachys tymphaea Hausskn. from the Monti Sibillini National Park (Central Apennines,Italy)

Stachys tymphaea (Lamiaceae) is a perennial herb growing in forest openings and dry meadows of central and southern Italy. It was investigated for the first time here, determining the content of secondary metabolites, the micromorphology of glandular trichomes, the histochemical localization of secretion, and the biological activity of the volatile oil, namely, the cytotoxic, antioxidant, and antimicrobial properties. The plant showed a peculiar molecular pattern, being rich of biophenolic compounds as flavonoids, phenylethanoid glycosides, and caffeoylquinic acid derivatives, but poor of iridoids, which are known as marker compounds of the genus Stachys. The essential oil was characterized by GC‐FID and GC/MS analyses, revealing a high percentage of sesquiterpene hydrocarbons (54.6%), with germacrene D (30.0%) and (E)‐β‐farnesene (12.4%) as the most abundant compounds, while other main components were representatives of the diterpenes (19.2%), represented mainly by (E)‐phytol (11.9%). This composition supported the taxonomic relationships in the genus Stachys, which comprises oil‐poor species producing essential oils rich in hydrocarbons, with germacrene D as one of the predominant components. The micromorphological study revealed three types of glandular hairs, i.e., Type A peltate trichomes, being the primary sites of essential oil biosynthesis, Type B short‐stalked trichomes, typical mucopolysaccharide producers, and Type C long capitate trichomes, secreting a complex mixture of both lipophilic and hydrophilic substances, with a major phenolic fraction. Moreover, the MTT assay revealed the potential of the volatile oil to inhibit A375, HCT116, and MDA‐MB 231 tumor cells lines (IC₅₀ values of 23.9–34.4 μg/ml).     

Chemical Composition of the Essential Oils from Different Morphological Parts of Pinus cembra L.

The essential oils from needles, twigs, bark, wood, and cones of Pinus cembra were analyzed by GC‐FID, GC/MS, and ¹H‐NMR spectroscopy. More than 130 compounds were identified. The oils differed in the quantitative composition. The principal components of the oil from twigs with needles were α‐pinene (36.3%), limonene (22.7%) and β‐phellandrene (12.0%). The needle oil was dominated by α‐pinene (48.4%), whereas in the oil from bark and in the oil from twigs without needles there were limonene (36.2% and 33.6%, resp.) and β‐phellandrene (18.8% and 17.1%, resp.). The main constituents of the wood oil as well as cone oil were α‐pinene (35.2% and 39.0%, resp.) and β‐pinene (10.4% and 18.9%, resp.). The wood oil and the cone oil contained large amounts of oxygenated diterpenes in comparison with needle, twig, and bark oils.     

Inhibitory Effects of Maleimide Derivatives from the Mycelia of the Fungus Antrodia cinnamomea BCRC 36799 on Nitric Oxide Production in Lipopolysaccharide (LPS)‐Activated RAW264.7 Macrophages

Four new maleimide derivatives, antrocinnamomins E–H ( 1 – 4 , resp.), together with (3S,4R)‐1‐hydroxy‐3‐(4‐hydroxyphenyl)‐4‐(2‐methylpropyl)pyrrolidine‐2,5‐dione ( 5 ) and ergosterol were isolated from the mycelia of Antrodia cinnamomea BCRC 36799. The structures were elucidated by 1D‐ and 2D‐NMR spectroscopy, and mass spectrometry. Compounds 1 – 5 were evaluated for their inhibitory effects on nitric oxide (NO) production by macrophages. Compounds 2 and 4 showed stronger inhibition of NO production than the positive control quercetin.     

Composition and Antimicrobial Activity of the Essential Oils of Laserpitium latifolium L. and L. ochridanum Micevski (Apiaceae)

The chemical composition and antimicrobial activity of essential oils of Laserpitium latifolium and L. ochridanum were investigated. The essential oils were isolated by steam distillation and characterized by GC‐FID and GC/MS analyses. All essential oils were distinguished by high contents of monoterpenes, and α‐pinene was the most abundant compound in the essential oils of L. latifolium underground parts and fruits (contents of 44.4 and 44.0%, resp.). The fruit essential oil was also rich in sabinene (26.8%). Regarding the L. ochridanum essential oils, the main constituents were limonene in the fruit oil (57.7%) and sabinene in the herb oil (25.9%). The antimicrobial activity of these essential oils as well as that of L. ochridanum underground parts, whose composition was reported previously, was tested by the broth‐microdilution method against four Gram‐positive and three Gram‐negative bacteria and two Candida albicans strains. Except the L. latifolium underground‐parts essential oil, the other investigated oils showed a high antimicrobial potential against Staphylococcus aureus, S. epidermidis, Micrococcus luteus, or Candida albicans (minimal inhibitory concentrations of 13.0–73.0 μg/ml), comparable to or even higher than that of thymol, which was used as reference compound.     

Variability in the Essential‐Oil Composition of Sideritis scardica Griseb. from Native Bulgarian Populations

The essential‐oil composition of six native populations of Sideritis scardica from Bulgaria was studied by GC‐FID and GC/MS analyses. Altogether, 37 components, representing 73.1 to 79.2% of the total oil content were identified. Among them, α‐pinene (4.4–25.1%), β‐pinene (2.8–18.0%), oct‐1‐en‐3‐ol (2.3–8.0%), phenylacetaldehyde (0.5–9.5%), β‐bisabolene (1.3–11.0%), benzyl benzoate (1.1–14.3%), and m‐camphorene ( 1 ; 0.3–12.4%) were the main compounds. All samples were characterized by low contents of oxygenated mono‐ and sesquiterpenes (≤1.6 and 2.3%, resp.). Principal component analysis (PCA) and cluster analysis (CA) showed a significant variability in the chemical composition of the studied samples as well as a correlation between the oil profiles and the ecological conditions of the natural habitats of S. scardica.     

Two New Steroids from an Endophytic Fungus Phomopsis sp.

Two new steroids, (14β,22E)‐9,14‐dihydroxyergosta‐4,7,22‐triene‐3,6‐dione ( 1 ) and (5α,6β,15β,22E)‐6‐ethoxy‐5,15‐dihydroxyergosta‐7,22‐dien‐3‐one ( 2 ), together with three known steroids, calvasterols A and B ( 3 and 4 , resp.), and ganodermaside D ( 5 ), were isolated from the culture broth of an endophytic fungus Phomopsis sp. isolated from Aconitum carmichaeli. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and their inhibitory activities against six pathogenic fungi were evaluated. Most of the compounds showed moderate or weak antifungal activities in a broth‐microdilution assay.     

Biotransformations of Terpenes by Fungi from Amazonian Citrus Plants

The biotransformations of (RS)‐linalool ( 1 ), (S)‐citronellal ( 2 ), and sabinene ( 3 ) with fungi isolated from the epicarp of fruits of Citrus genus of the Amazonian forest (i.e., C. limon, C. aurantifolia, C. aurantium, and C. paradisiaca) are reported. The more active strains have been characterized, and they belong to the genus Penicillium and Fusarium. Different biotransformation products have been obtained depending on fungi and substrates. (RS)‐Linalool ( 1 ) afforded the (E)‐ and (Z)‐furanlinalool oxides ( 7 and 8 , resp.; 39 and 37% yield, resp.) with Fusarium sp. (1D2), 6‐methylhept‐5‐en‐2‐one ( 4 ; 49%) with F. fujikuroi, and 1‐methyl‐1‐(4‐methypentyl)oxiranemethanol ( 6 ; 42%) with F. concentricum. (S)‐Citronellal ( 2 ) gave (S)‐citronellol ( 12 ; 36–76%) and (S)‐citronellic acid ( 11 ; 5–43%) with Fusarium species, while diastereoisomeric p‐menthane‐3,8‐diols 13 and 14 (20 and 50% yield, resp.) were obtained as main products with Penicillium paxilli. Finally, both Fusarium species and P. paxilli biotransformed sabinene ( 3 ) to give mainly 4‐terpineol ( 19 ; 23–56%), and (Z)‐ and (E)‐sabinene hydrates ( 17 (3–21%) and 18 (11–17%), resp.).     

Chemical Composition,Antibacterial, Schistosomicidal,and Cytotoxic Activities of the Essential Oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae)

We have investigated the chemical composition and the antibacterial activity of the essential oil of Dysphania ambrosioides (L.) Mosyakin & Clemants (Chenopodiaceae) (DA‐EO) against a representative panel of cariogenic bacteria. We have also assessed the in vitro schistosomicidal effects of DA‐EO on Schistosoma mansoni and its cytotoxicity to GM07492‐A cells in vitro. Gas chromatography (GC) and gas chromatography‐mass spectrometry (GC/MS) revealed that the monoterpenes cis‐piperitone oxide (35.2%), p‐cymene (14.5%), isoascaridole (14.1%), and α‐terpinene (11.6%) were identified by as the major constituents of DA‐EO. DA‐EO displayed weak activity against Streptococcus sobrinus and Enterococcus faecalis (minimum inhibitory concentration (MIC) = 1000 μg/ml). On the other hand, DA‐EO at 25 and 12.5 μg/ml presented remarkable schistosomicidal action in vitro and killed 100% of adult worm pairs within 24 and 72 h, respectively. The LC₅₀ values of DA‐EO were 6.50 ± 0.38, 3.66 ± 1.06, and 3.65 ± 0.76 μg/ml at 24, 48, and 72 h, respectively. However, DA‐EO at concentrations higher than 312.5 μg/ml significantly reduced the viability of GM07492‐A cells (IC₅₀ = 207.1 ± 4.4 μg/ml). The selectivity index showed that DA‐EO was 31.8 times more toxic to the adult S. mansoni worms than GM07492‐A cells. Taken together, these results demonstrate the promising schistosomicidal potential of the essential oil of Dysphania ambrosioides.     

Chemical Composition and Antimicrobial Activity of the Essential Oil of Stachys officinalis (L.) Trevis. (Lamiaceae)

Characterization by GC‐FID and GC/MS analyses of the Stachys officinalis (L.) Trevis . essential oil obtained by hydrodistillation of the aerial parts allowed the identification of 190 components that represented 97.9% of the total oil content. The main constituents identified were germacrene D (19.9%), β‐caryophyllene (14.1%), and α‐humulene (7.5%). Terpenoids were by far predominant (89.4%), with sesquiterpene hydrocarbons (69.1%) and oxygenated sesquiterpenes (14.8%) being the most abundant compounds detected in the oil. Based on the present and previously published results, multivariate statistical comparison of the chemical composition of the essential oils was performed within the species. Principal component analysis (PCA) and agglomerative hierarchical clustering (AHC) of the data on the volatile profiles of S. officinalis taxa revealed no pronounced differences among the samples originated from the Balkan Peninsula. Additionally, the oil was screened for in vitro antibacterial and antifungal activity using the broth microdilution assay. The oil's best antimicrobial activities were obtained against the mold Aspergillus niger (minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of 2.5 and 5.0 mg/ml, resp.) and the yeast Candida albicans (MIC and MFC of 5.0 mg/ml).