Metabolites from the endophytic fungus Cylindrocarpon sp. isolated from tropical plant Sapium ellipticum.

Three new polyketides, cylindrocarpones A-C (1-3), two new pyridone alkaloids, cylindrocarpyridones A-B (5-6), a new pyrone cylindropyrone (7), together with seven know compounds were isolated from the endophytic fungus, Cylindrocarpon sp., obtained from the tropical plant Sapium ellipticum. The structures of the new compounds were elucidated by extensive analysis of their spectroscopic data (1D and 2D NMR, HRESIMS). The absolute configuration of 19-O-methyl-pyrrocidine B (13) was confirmed by X-ray analysis. All isolated compounds were screened for their cytotoxic and antibacterial activities. Pyrrocidine A (12) exhibited potent cytotoxicity against the human ovarian cancer cell line A2780 with an IC50 value of 1.7 µM. 19-O-Methyl-pyrrocidine B (13) showed moderate antibacterial activity against S. aureus ATCC25923 and ATCC700699 with MIC values of 50 and 25 µM, respectively.

Phytotoxic Potential of Secondary Metabolites and Semisynthetic Compounds from Endophytic Fungus Xylaria feejeensis Strain SM3e-1b Isolated from Sapium macrocarpum.

Bioactivity-directed fractionation of the combined culture medium and mycelium extract of the endophytic fungus Xylaria feejeensis strain SM3e-1b, isolated from Sapium macrocarpum, led to the isolation of three known natural products: (4S,5S,6S)-4-hydroxy-3-methoxy-5-methyl-5,6-epoxycyclohex-2-enone or coriloxine, 1; 2-hydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 2; and 2,6-dihydroxy-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione or fumiquinone B, 3. This is the first report of compound 3 being isolated from this species. Additionally, four new derivatives of coriloxine were prepared: (4R,5S,6R)-6-chloro-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-enone, 4; 6-hydroxy-5-methyl-3-(methylamino)cyclohexa-2,5- diene-1,4-dione, 5; (4R,5R,6R)-4,5-dihydroxy-3-methoxy-5-methyl-6-(phenylamino)cyclohex-2-enone, 6; and 2-((4-butylphenyl)amino)-5-methoxy-3-methylcyclohexa-2,5-diene-1,4-dione, 7. X-ray analysis allowed us to unambiguously determine the structures and absolute configuration of semisynthetic derivatives 4, 5, and 6. The phytotoxic activity of the three isolated natural products and the coriloxine derivatives is reported. Germination of the seed, root growth, and oxygen uptake of the seedlings of Trifolium pratense, Medicago sativa, Panicum miliaceum, and Amaranthus hypochondriacus were significantly inhibited by all of the tested compounds. In general, they were more effective inhibiting root elongation than suppressing the germination and seedling oxygen uptake processes as shown by their IC50 values.

[Effect of environmental factors on the growth and fatty acid composition of five endophytic fungi from Sapium sebiferum].

Five fungi species including Rhizoctonia sp., Sclerotium sp., Acremoniell sp., Chaetomium sp. and Pestalotiopsis sp. screened from the inner bark of Sapium sebiferum (Lével) Roxb. were used to study their growth under different environmental factors, with the biomass and fatty acid composition as main indexes to elucidate the relationship between plant and its endophytic fungi. Compared with that from synthesized medium, a higher biomass was harvested when the fungi were cultured on liquid potato dextrose medium; the unsaturation index of fatty acid (IUFA) was lower, and the main fatty acids in the fungi were linoleic acid, palmitic acid and oleic acid. Compared with the fungi grown on the synthesized medium without Sapium sebiferum's extract, the Sclerotium sp. growth was promoted, and the others were inhibited when the extract was added to the synthesized medium. At the same time, the IUFA were increased. When 0-1.0 mol.L-1 NaCl was added in Sclerotium sp.'s culture medium, the biomass was not changed notably; IUFA in 0-0.5 mol.L-1 NaCl was not significantly different, while in the range of 0.6-1.0 mol.L-1 NaCl, the IUFA was decreased with increasing concentration of NaCl. It indicated that fungus had a stronger tolerance to salt. Sclerotium sp.'s growth was promoted, and the IUFA was increased when plant oil was added in the synthesized medium. The biomass was the highest by adding 1.5% plant oil. The results mentioned above were some way related to the symbiotic relations between the endophytic fungi and their host plant.

[Comparative studies on the fatty acids contained in four species of medicinal plants from family Euphorbiaceae and their endophytic fungi].

OBJECTIVE: The relation of four species of medicinal plants from family Euphorbiaceae and their endophytic fungi was studied to find the source of active substances for developing new pharmaceutical resources. METHOD: The main fatty acids contained in Sapium sebiferum, Euphorbia pekinensis, Euphorbia helioscopia, Bischofia polycarpam and their 28 strains of endophytic fungi were compared and analysed by GC. RESULT: The main fatty acids of the plants are: alpha-linolenic acid, palmitic acid, linolenic acid and oleic acid. Linolenic acid, palmitic acid and oleic acid are the main fatty acids of the endophytic fungi. CONCLUSION: The fatty acids could be produced by the endophytic fungi, which could be used as a factor for identification. There are great differences at the contents of alpha-linolenic acid between the plants and their endophytic fungi, which were suggested to be related with the nutrition absorption and the relationship between the endophytes and the host plant.