Symplocosionosides A-C, Three Megastigmane Glycosides, a Neolignan Glucoside, and Symplocosins A and B, Two Triterpene Glycosyl Esters from the Leaves of <i>Symplocos cochinchinensis</i>var. <i>Philippinensis</i>

From the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis, 12 compounds were isolated. Spectroscopic analyses of compounds 1 - 3 established their structures to be megastig-mane glycosides, named symplocosionosides A-C. The absolute structure of 1 was determined by the modified Mosher’s method. Compound 4 was found to be a neolignan glucoside and named symplocosneolignan. The structures of com-pounds 5 and 6, named symplocosins A and B, were elucidated to be the saponins of hederagenin sugar esters. The structures of the remaining known compounds (7 - 12) were identified by comparison of spectroscopic data with those reported in the literature.

Acatulides A-G,neuroprotective macrolides from Acaulium album H-JQSF

Fungal symbionts co-evolve with hosts and microbial co-inhabitants to acquire an unpredictable potential for producing novel bioactive metabolites,but the knowledge about the topic remains patchy and superficial.Here we present the chemical characterization of acatulides A-G(1-7)as architecturally unprecedented macrolides from the solid-state culture of Acaulium album H-JQSF,an arthropod-associated fungus.The acatulide structures were elucidated by spectroscopic analysis,modified Mosher's method and single-crystal X-ray diffraction.The plausible biosynthetic pathways for compounds 1-4 are proposed.Interestingly,acatulides B-D(2-4)and G(7)were demonstrated to be neuroprotective against the 1-methyl-4-phenylpyridinium(MPP+)-induced damage to SH-SY5Y cells and nematode Caenorhabditis elegans(C.elegans).

Isolation and characterization of three pairs of verrucosidin epimers from the marine sediment‑derived fungus Penicillium cyclopium and confguration revision of penicyrone A and related analogues

Verrucosidins,a methylatedα-pyrone class of polyketides rarely reported upon,have been implicated in one or more neurological diseases.Despite the signifcance of verrucosidins as neurotoxins,the absolute confgurations of most of the derivatives have not been accurately characterized yet.In this study,three pairs of C-9 epimeric verrucosidin derivatives,including the known compounds penicyrones A and B(1a/1b)and 9-O-methylpenicyrones A and B(2a/2b),the new compounds 9-O-ethylpenicyrones A and B(3a/3b),together with the related known derivative verrucosidin(4),were isolated and identifed from the culture extract of Penicillium cyclopium SD-413,which was obtained from the marine sediment collected from the East China sea.Their structures were established based on an in-depth analysis of nuclear magnetic resonances(NMR)and mass spectroscopic data.Determination of the absolute confgurations of these compounds was accomplished by Mosher’s method and time-dependent density functional theory(TDDFT)calculations of electronic circular dichroism(ECD)and optical rotation(OR).The confgurational assignment of penicyrone A demonstrated that the previously reported C-6 absolute confguration of verrucosidin derivatives needs to be revised from(6S)to(6R).The 9R/9S epimers of compounds 1–3 were found to exhibit growth inhibition against some pathogenic bacteria,indicating that they have potential as lead compounds for the creation of antimicrobial agents.

A new sesquiterpene lactone and a new aromatic glycoside from Illicium difengpi

A new sesquiterpene lactone(1)and a new aromatic glycoside(2),together with three known compounds(3–5)were isolated from the stem bark of Illicium difengpi K.I.B et K.I.M.Their structures were determined by spectroscopic methods,including 1D and 2D NMR,HRESIMS,and chemical methods.The absolute configuration of the secondary alcohol in 1 was confirmed by Mosher’s method.Compound 2 exhibited significant anti-inflammatory activity with IC50 value of 6.72 mmol/L.

Cembrane-type diterpenoids from the South China Sea soft coral Sarcophyton mililatensis

Eight cembrane-type diterpenoids, namely,(t)-(6 R)-6-hydroxyisosarcophytoxide(1),(t)-(6 R)-6-acetoxyisosarcophytoxide(2),(t)-17-hydroxyisosarcophytoxide(3), sarcomililatins A–D(4–7), and sarcomililatol(8), were isolated from the soft coral Sarcophyton mililatensis collected from Weizhou Island, Guangxi Autonomous Region, together with 2 known related analogues,(t)-isosarcophytoxide(9) and(t)-isosarcophine(10). The structures of these compounds were elucidated by a combination of detailed spectroscopic analyses, chemical methods, and comparison with reported data.The absolute configuration of compound 1 was established by the modified Mosher's method, while the absolute configurations of compounds 4 and 5 were assigned by electronic circular dichroism(ECD)spectroscopy and that of compound 8 was established by time-dependent density functional theory electronic circular dichroism(TD-DFT ECD) calculation. In in vitro bioassays, compound 9 displayed significant cytotoxicity against the human cancer cell lines human promyelocytic leukemia cells(HL-60)and human lung adenocarcinoma cells(A-549) with IC_(50) values of 0.7870.21 and 1.2670.80 μmol/L,respectively. Compounds 4 and 9 also showed moderate inhibitory effects on the TNFα-induced Nuclear factor kappa B(NF-κB, a therapeutical target in cancer) activation, showing IC_(50) values of 35.23712.42 and 22.5274.44 μmol/L, respectively.