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Six new polyketides, alternaritins A–D [(±)-1–4] and isoxanalteric acid I (8), and 25 known Alternaria toxins were isolated from the culture of an endophytic fungi Alternaria sp. MG1. 3 is a rare fungal metabolite. 6 is a new natural product, and 5, 7, and 9 are known previously but their absolute configurations have not been determined. Three enantiomers [(±)-1, (±)-7, and (±)-15] were separated via chiral HPLC resolution. The structures of those polyketides (1–9) were elucidated by spectrometric analysis using MS and NMR. The absolute configurations were established using X-ray diffraction analysis and statistical comparative analysis of the experimental ECD and OR data, in conjunction with quantum mechanical calculations. All of the compounds were evaluated for their bioactivities. Known compound 27 exerted the most potent cytotoxic activities against HT-1080 and NCI-H1299 cell lines. The new compounds, 2 and 3, showed moderate inhibition on COX-2, while a pair of isomers, 8 and 9, exhibited medium activity on COX-2 and uropathogenic Escherichia coli.

Carpesium humile Winkl is an endemic Chinese species and no previous phytochemical studies have been reported for this species. Two new germacranolides (1 and 2) and a new phytane diterpene (5), together with five known compounds (two sesquiterpenoids and three diterpenoids), were isolated from the aerial parts of C. humile. Their structures were elucidated on the basis of extensive spectroscopic analysis. The conformations and absolute configurations of 1 and 2 were established by combinative analysis of NMR, CD exciton chirality, and X-ray crystallography data. Four germacranolides (1–4) showed strong cytotoxic activities, with broad spectrum activities against six human cancer (HepG2, HeLa, HL60, SGC7901, Lewis, and MDA231) cell lines in vitro using MTT assay, with IC50 values from 3.09 to 7.71 μg/mL. Diterpenes (5, 6, and 8) also displayed good cytotoxic activities for selected cancer cell lines, with IC50 values in the range 5.46–8.08 μg/mL.

Extracts of the aerial parts of Scorzonera divaricata afforded sulfoscorzonin D (1) and sulfoscorzonin E (2), two novel pyrrolidine inner salt alkaloids with a sulfated guaiane sesquiterpene lactone nucleus, along with 22 known compounds. Especially, sulfoscorzonin D containing a unusual monoterpene moiety is very rare. The structures of new compounds were established using spectroscopic analysis including one- and two-dimensional NMR and HRESIMS. The cytotoxicities of compounds 1–4 and 10 against three tumor cell lines (K562, Hela, and HepG2) were evaluated using the MTT assay. Compounds 2 and 10 exhibited moderate cytotoxic activity. The biological properties of 1–3, 5–8, 10–14, and 16–24, were screened against nine different gram-positive and gram-negative bacteria. Compounds 1, 5–8, 10, and 18, showed potent antibacterial activities. Chemical compounds studied in this article Glucozaluzanin C (PubChem CID: 442320); 1β,4α-dihydroxy-5α,6β,7α,11βH-eudermn-12; 6-olide (CID: 11119093); oleanolic acid (CID: 10494); lup-20(29)-ene-3β,28-diol (CID: 72326); (22E)-5α,8α-epidioxyergosta-6,22-dien-3β-ol (CID: 5469431); ergosta-3β,5α, 6β-trialcohol (CID: 44558918); stigma-5-en-3-O-β-glucoside (CID: 5742590); vomifoliol (CID: 12444927); trans-caffeic acid (CID: 689043); trans-p-hydroxy coumaric acid (CID: 637542); 4-hydroxy-3-methoxyphenyl ferulate (CID: 11500646); 7,3′,4′-trihydroxyflavonol (CID: 5281614); tricin (ID: 5281702); luteolin (CID: 5280445); diosmetin (CID: 5281612); 5,7-dihydroxy-8-methoxyflavone (CID: 5281703); 5,7-dihydroxy-6-methoxyflavone (CID: 5320315); methyl-3,4-dihydroxy benzoate (CID: 287064); m-hydroxy benzoic acid (CID: 7420); 7-hydroxy-coumarin (CID: 5281426); and scopoletin (CID: 5280460).

Two new isocoumarins (1 and 2), a new alkaloid (3), and a known N-acetyldopamine dimer (4) were isolated from the ethyl acetate extract of Chinese insect medicine Eupolyphaga sinensis. Their structures were elucidated on the basis of detailed spectroscopic investigations, such as 1D- and 2D NMR spectroscopy, as well as by means of HR-MS. The structure of 1 was firmly confirmed by X-ray crystallography, and the absolute configuration was revealed by experimental and computational optical rotation analyses. Cytotoxicities of 1-4 were measured in vitro against 10 selected cancer cell lines.

A new oxazole (1) was obtained from Chinese insect medicine Aspongopus chinensis, along with three known N-acetyldopamine derivatives (2-4). Their structures were determined on the basis of NMR and ESI-MS analyses. The possible biosynthetic pathways of the isolated compounds are discussed. Cytotoxicities of those compounds against 10 selected cancer cells were measured in vitro.

A new D:B-friedoolean-type triterpene, 3β-acetoxyglutin-5(10)-en-6-oxo (1), together with seventeen known compounds (2-18) was isolated from the roots of Scorzonera austriaca. Their structures were elucidated mainly by NMR and HR-ESI-MS, as well as on comparison with the reported data. Cytotoxicities of compounds 2, 4, 6, 10-14 and 16 against selected cancer cells of human promyelocytic leukemia (HL-60) and human hepatoma (BEL-7404) were measured in vitro.

Three new pyrones, solanapyrones P–R (1–3), were afforded by the extracts of the endophytic fungus Alternaria tenuissima SP-07 isolated from the fresh root of Chinese herbal medicine Salvia przewalskii, along with the known solanapyrones (4–6) and benzopyrones (7–9). Solanapyrones P (1) and Q (2) possess an unprecedented nor-solanapyrone skeleton as natural products. Their structures were determined on the basis of NMR and HR-ESI-MS analysis. The plausible biosynthetic pathways to those unknown compounds were discussed. All the isolated compounds were evaluated for their antibacterial activities against six bacteria.