https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Secondary metabolites of fungi from marine habitats.

http://www.rkmvc.ac.in/vins/articles/13-FBR-Bioprospecting.pdf

Fungal endophytes and bioprospecting

A note on the influence of extractives on the photo-discoloration and photo-degradation of wood

Aromatic abietane diterpenoids: their biological activity and synthesis

Eight known abietane-type diterpenes were isolated from the weak acidic fraction of the n-hexane extract from cones of Taxodium distichum, one of the extant, living fossil conifers. They were identified as 6,7-dehydroroyleanone (1), taxodal (2), taxodione (3), salvinolone (4), 14-deoxycoleon U (5), 5,6-dehydrosugiol (6), sandaracopimaric acid (7), and xanthoperol (8). The structures of these compounds were determined by comparison of NMR spectral data with published data. The antitermitic (termicidal and antifeedant) activities of the compounds 1-8 against the subterranean termite, Reticulitermes speratus Kolbe, were evaluated. Compounds 1 and 3 showed potent termicidal activity, and 5 and 8 showed potent antifeedant activity. Compound 1 was found to be one of the representative bioactive compounds in the n-hexane extract of T. distichum cones. Compounds 1-8, with the exception of 7, were oxides of ferruginol (9). Therefore, the presence of various oxidation forms of the abietane-type structure reflects their various bioactivities.

Antitermitic Activities of Abietane-type Diterpenes from Taxodium distichum Cones

Three cyclohexenone derivatives, (4S,5S,6S)-5,6-epoxy-4-hydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (1), (4R,5R)-4,5-dihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (2), and (4R,5S,6R)-4,5,6-trihydroxy-3-methoxy-5-methyl-cyclohex-2-en-1-one (3), were isolated from unpolished rice fermented with an xylariaceous endophytic fungus (strain YUA-026). The structures of three compounds were established on the basis of spectroscopic analyses and chemical conversion. The minimum inhibitory concentrations of 1 and 3 were 100 μg/ml and 400 μg/ml against Staphylococcus aureus, 100 μg/ml and 200 μg/ml against Pseudomonas aeruginosa, and 200 μg/ml and >400 μg/ml against Candida albicans, respectively. In addition, 1 and 3 exhibited phytotoxic activity against lettuce.

https://www.tandfonline.com/doi/pdf/10.1271/bbb.69.287

Three Oxygenated Cyclohexenone Derivatives Produced by an Endophytic Fungus

• Tree age is one of the most important factors to affect the natural durability of wood. • The purpose of this study was to determine the natural termite resistance of heartwood and sapwood of teak (Tectona grandis Linn. fil.) for trees aged 8, 30 and 51 years. Reticulitermes speratus Kolbe was employed as a test termite using a no-choice feeding method. • The heartwood and sapwood of all of the trees tested exhibited antitermitic activity. Based on the mean mass loss due to termite activity, the sapwood and heartwood regions of 8-year-old trees are the most susceptible to termites while the heartwood regions of the 30-year-old trees showed termite resistance similar to the termite resistance of 51-year-old trees. • The mass loss is moderately correlated with n-hexane extractive content, total extractive content, brightness and redness of the wood.

/pdf/variation-in-the-natural-termite-resistance-of-teak-tectona-1k4oyscytw.pdf

Variation in the natural termite resistance of teak (Tectona grandis Linn. fil.) wood as a function of tree age

Keywords: Tectona grandis / extractives / tectoquinone / desoxylapachol / tree age Abstract • Quinones are primarily responsible for the natural durability of teak. • The previous paper in this series reported on the natural termite resistance of teak trees of different ages (8-, 30- and 51-year-old trees). In this study, the radial distribution of quinones (tectoquinone, lapachol, desoxylapachol and its isomer) and other components in the ethanol-benzene (1:2) extract were measured by means of gas chromatography. • Significant differences in desoxylapachol or its isomer content were found among the outer heart- wood of 8-, 30- and 51-year old trees, as well as between the inner and outer parts of the heartwood. • All toxic quinone contents were positively correlated with the total extractive content. The highest correlation degree was measured in the isodesoxylapachol content. • Although linearly related, only modest correlations were observed between the natural termite re- sistance parameters and the content of tectoquinone and isodesoxylapachol. Mots-cles : Tectona grandis / extractibles / tectoquinone / desoxylapachol / âge des arbres

/pdf/radial-distribution-of-quinones-in-plantation-teak-tectona-54lly9s8xs.pdf

Radial distribution of quinones in plantation teak (Tectona grandis L.f.)

The chemical composition of Taxodium distichum cones and the antifungal activities of twelve diterpenoids against two wood decay fungi, Trametes versicolor (white-rot) and Fomitopsis palustris (brown-rot) were examined. The chemical composition of the major extractive fraction, the n-C6H14 extract, was evaluated and its antifungal properties were identified. Twelve diterpenoids including ten abietane-type components were isolated from the n-C6H14 extract: 6,7-dehydroferruginol (1), ferruginol (2), 6,7-dehydroroyleanone (3), sandaracopimaric acid (4), taxodione (5), taxodal (6), taxodone (7), sugiol (8), xanthoperol (9), salvinolone (10), 5,6-dehydrosugiol (11), and 14-deoxycoleon U (12). Compounds 5 and 12 were highly active against both wood-decay fungi. In particular, the activities of these compounds against F. palustris were potent. The results suggest that the position and the number of hydroxyl groups on abietane-type structures may be related to antifungal activities against T. versicolor and F. palustris.

Koetsu Takahashi

Papers

Antitermitic Activities of Abietane-type Diterpenes from Taxodium distichum Cones

Three Oxygenated Cyclohexenone Derivatives Produced by an Endophytic Fungus

Variation in the natural termite resistance of teak (Tectona grandis Linn. fil.) wood as a function of tree age

Radial distribution of quinones in plantation teak (Tectona grandis L.f.)

Antifungal Abietane-Type Diterpenes from the Cones of Taxodium distichum Rich