Four new polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) hybrid metabolites, pericoannosin A (1), with an unusual hexahydro-1H-isochromen-5-isobutylpyrrolidin-2-one skeleton, and three cytochalasans, periconiasins D-F (2-4), were isolated from the endophytic fungus Periconia sp. F-31. Their structures and absolute configurations were elucidated through extensive spectroscopic analyses, calculated ECD, and single-crystal X-ray diffraction (Cu Kα). A possible biogenetic pathway is proposed. Compounds 1 and 4 showed anti-HIV activity with IC50s of 69.6 and 29.2 μM, respectively.

Thirty-three metabolites including five phenalenone derivatives (1-5), seven cytochalasins (6-12), thirteen butenolides (13-25), and eight phenyl derivatives (26-33) were isolated from Aspergillus sp. CPCC 400735 cultured on rice. The structures of all compounds were elucidated by NMR, MS, and CD experiments, of which 1-5 (asperphenalenones A-E), 6 (aspochalasin R), and 13 (aspulvinone R) were identified as new compounds. Specifically, asperphenalenones A-E (1-5) represent an unusual structure composed of a linear diterpene derivative linked to a phenalenone derivative via a C-C bond. Compounds 1, 4, 10, and 26 exhibited anti-HIV activity with IC values of 4.5, 2.4, 9.2, and 6.6 μM, respectively (lamivudine 0.1 μM; efavirenz, 0.4 × 10 μM).

Periconianone A (1), a polyoxygenated sesquiterpenoid with a new 6/6/6 tricarbocyclic skeleton, and periconianone B (2) were isolated from the endophytic fungus Periconia sp. Their structures and absolute configurations were elucidated by extensive spectroscopic analyses, calculated ECD, and single-crystal X-ray diffraction (Cu Kα). The biosynthesis of the unusual six-membered carbonic ring of 1 was postulated to be formed through intramolecular aldol condensation. Compounds 1 and 2 showed significant neural anti-inflammatory activity.

Periconiasins A-C (1-3), new cytochalasans with an unprecedented 9/6/5 tricyclic ring system, were isolated from the endophytic fungus Periconia sp. F-31. Their structures and absolute configurations were elucidated by extensive spectroscopic and X-ray crystallographic analyses. Their biosynthesis is proposed to occur from an unusual seven acetate/malonate polyketide backbone attached to one leucine moiety by a PKS-NRPS followed by Diels-Alder and other reactions. 1 and 2 showed significant cytotoxicity against human HCT-8 cancer cells.

Nine new polyoxygenated eremophilane sesquiterpenes, periconianones C-K (1-9), including one unusual isoeremophilane sesquiterpene, periconianone C (1), and four trinor-eremophilane sesquiterpenes, periconianones H-K (6-9), were isolated from the endophytic fungus Periconia sp. F-31. Compound 1 is the first furan-type isoeremophilane reported containing a linkage of C-8/C-11 and a 7,12-epoxy moiety. These compound structures, including absolute configurations, were elucidated through extensive spectroscopic data analysis, electronic circular dichroism, Mo2(AcO)4-induced circular dichroism, and single-crystal X-ray diffraction (Cu Kα). Compounds 2, 5, and 9 showed inhibition effects on lipopolysaccharide-induced NO production in BV2 cells by 10.2%, 18.3%, and 16.1% at a concentration of 1.0 μM, respectively, which is comparable to the positive control curcumin (12.9% at 1.0 μM).

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Seven new phenylspirodrimane derivatives named stachybotrysins A-G (2-8), together with five known compounds (1, 9-12), were isolated from Stachybotrys chartarum CGMCC 3.5365. Stachybotrysin D (5) is the first reported example of a naturally occurring alcoholic O-sulfation of a phenylspirodrimane, and stachybotrysins F and G (7 and 8) are the first examples possessing an isobenzotetrahydrofuran ring with an acetonyl moiety attached. The structures of these compounds were elucidated on the basis of extensive spectroscopic data analysis and by comparison with reported data. The absolute configurations of 1-8 were determined by X-ray single-crystal diffraction, electronic circular dichroism (ECD), and calculated ECD. Compounds 1 and 8 displayed anti-HIV activity with IC values of 15.6 and 18.1 μM, respectively, and 2, 7, 9, and 11 showed inhibitory effect on influenza A virus with IC values ranging from 12.4 to 18.9 μM.

The whole plant of Solanum lyratum THUNB (Solanaceae) is a renowned traditional Chinese medicine. Extracts of this plant and its constituents were reported to exhibit a wide spectrum of biological activities including antitumor, antibacterium, and anti-inflammation.1-3) As part of our search for antitumor compounds, the EtOH extract of S. lyratum was successively partitioned with CHCl 3 , EtOAc, and n-BuOH. The CHCl 3 fraction was sequentially subjected to column chromatography over silica gel, silica gel RP-18, and Sephadex LH-20 to give two new sesquiterpenoids, named lyratol C (1) and lyratol D (2), and two known sesquiterpenoids, dehydrovomifoliol (3) 4) and blumenol A (4). 5) By means of chemical methods and spectroscopic analyses, the structures of the two new compounds were established. In addition, the four isolated compounds were screened for cytotoxicity against three tumor cell lines (HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells), with IC 50 values being in the range 3.7-8.1 mM. Herein we report on the isolation and structure elucidation as well as the evaluation of cytotoxic effects of these four compounds. Results and DiscussionCompound 1 was obtained as a colorless prismatic crystal. Two new sesquiterpenoids, lyratol C (1) and lyratol D (2), together with two known sesquiterpenoids, dehydrovomifoliol (3) and blumenol A (4), were isolated from the whole plant of Solanum lyratum. Their structures were established by spectroscopic analyses. In vitro, the four compounds showed significant cytotoxic activities against three human cancer cell lines, namely, HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells, and gave IC 50 values in the range 3.7-8.1 m mM.