Mean essential oil content (%)^b, and the concentrations (%)^c of alpha-thujene, alpha-pinene, sabinene, myrcene, alpha-terpinene, limonene, gamma-terpinene, terpinolene, 4-terpineol, pregeijerene B, delta-cadinene, elemol, in essential oil obtained from the 11 distillation times, and podophyllotoxin content (%)^d in extracted or unextracted samples.

a<p>Within each column, means followed by the same letter are not significantly different at the 5% level of significance.</p>b<p>Percentage of essential oil by weight in fresh plant material.</p>c<p>Percentage of each analyte in essential oil by weight.</p>d<p>Percentage of podophyllotoxin by weight in dry needles.</p><p>Mean essential oil content (%)^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106057#nt102" target="_blank">b</a>}, and the concentrations (%)^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106057#nt103" target="_blank">c</a>} of alpha-thujene, alpha-pinene, sabinene, myrcene, alpha-terpinene, limonene, gamma-terpinene, terpinolene, 4-terpineol, pregeijerene B, delta-cadinene, elemol, in essential oil obtained from the 11 distillation times, and podophyllotoxin content (%)^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106057#nt104" target="_blank">d</a>} in extracted or unextracted samples.</p

Plot of Distillation time versus the content (wt/wt%) in essential oil of elemol, alpha-pinene, pregeijerene B, limonene, sabinene, and 4-terpineol along with the fitted (solid line) Power–concave (elemol), Power-convex (alpha-pinene), third order polynomial (pregeijerene B, sabinene), and Second order polynomial (limonene, 4-terpineol) regression models.

<p>Plot of Distillation time versus the content (wt/wt%) in essential oil of elemol, alpha-pinene, pregeijerene B, limonene, sabinene, and 4-terpineol along with the fitted (solid line) Power–concave (elemol), Power-convex (alpha-pinene), third order polynomial (pregeijerene B, sabinene), and Second order polynomial (limonene, 4-terpineol) regression models.</p

Plot of Distillation time versus essential oil content (wt/wt%) and the concentration in essential oil (%) of alpha-thujene, alpha-terpinene, gamma-terpinene, terpinolene, and delta-cadinene along with the fitted (solid line) Power–concave regression model.

<p>Plot of Distillation time versus essential oil content (wt/wt%) and the concentration in essential oil (%) of alpha-thujene, alpha-terpinene, gamma-terpinene, terpinolene, and delta-cadinene along with the fitted (solid line) Power–concave regression model.</p

Antifungal Activity against Plant Pathogens of Metabolites from the Endophytic Fungus Cladosporium cladosporioides

Bioassay-guided fractionation of Cladosporium cladosporioides (Fresen.) de Vries extracts led to the isolation of four compounds, including cladosporin, <b>1</b>; isocladosporin, <b>2</b>; 5′-hydroxyasperentin, <b>3</b>; and cladosporin-8-methyl ether, <b>4</b>. An additional compound, 5′,6-diacetylcladosporin, <b>5</b>, was synthesized by acetylation of compound <b>3</b>. Compounds <b>1</b>–<b>5</b> were evaluated for antifungal activity against plant pathogens. Phomopsis viticola was the most sensitive fungus to the tested compounds. At 30 μM, compound <b>1</b> exhibited 92.7, 90.1, 95.4, and 79.9% growth inhibition against Colletotrichum acutatum, Colletotrichum fragariae, Colletotrichum gloeosporioides, and <i>P. viticola</i>, respectively. Compound <b>2</b> showed 50.4, 60.2, and 83.0% growth inhibition at 30 μM against <i>Co. fragariae</i>, <i>Co. gloeosporioides</i>, and <i>P. viticola</i>, respectively. Compounds <b>3</b> and <b>4</b> were isolated for the first time from <i>Cl. cladosporioides</i>. Moreover, the identification of essential structural features of the cladosporin nuclei has also been evaluated. These structures provide new templates for the potential treatment and management of plant diseases

Biological activities of ophiobolin K and 6-epi-ophiobolin K produced by the endophytic fungus <i>Aspergillus calidoustus</i>

<div><p>Endophytic fungi represent ubiquitous microbial organisms able to live in the tissues of different plants around the world and represent a prolific source of bioactive metabolites. In the present study, the endophytic fungus <i>Aspergillus calidoustus</i> was isolated from the medicinal plant <i>Acanthospermum australe</i> (<i>Asteraceae</i>), and identified using molecular, physiological and morphological methods. A methylene chloride crude extract of <i>A. calidoustus</i> has been produced and subjected to antifungal bioassay-directed fractionation which resulted in the isolation of the two bioactive compounds: ophiobolin K and 6-epi-ophiobolin K. These pure compounds displayed antifungal activity against fungal plant pathogens, protozoal activity against <i>Trypanosoma cruzi</i>, and cytotoxic activity against human tumoral cell lines. The results show that <i>A. calidoustus</i> was able to produce the antifungal and cytotoxic metabolites ophiobolin K and 6-epi-ophiobolin K, which may help the fungus to colonise and occupy the substratum as well as survive in natural environments.</p></div