Linear polyketides produced by co-culture of Penicillium crustosum and Penicillium fellutanum

Two new polyketides, penifellutins A (1) and B (2), possessing a 22 carbon linear skeleton, were isolated from a co-culture of the deep-sea-derived fungi Penicillium crustosum PRB-2 and Penicillium fellutanum HDN14-323. Meanwhile, two esterification products of 1, penifellutins C (3) and D (4), were obtained because compound 1 could be esterified spontaneously when stored in methanol. Their configurations were difficult to determine because of chiral central crowdedness, structural flexibility and instability. As such, we solved this issue by comprehensively using Mo2(OAc)4-based CD experiments, density functional theory calculation of 13C NMR, DP4 + probability analysis and many chemical reactions, including making acetonide derivative, Mosher’s method, PGME method, etc. Compounds 1 and 2 show obvious inhibitory activity on the liver hyperplasia of zebrafish larvae at a concentration of 10 μmol/L, while 3 and 4 show no activity, indicating that two carboxyls in the structure are important active sites.

Two new phenylpropanoid glycosides from the aerial parts of Lespedeza cuneata

Two new phenylpropanoid glycosides named cuneataside E(1) and cuneataside F(2), were isolated from the aerial parts of Lespedeza cuneata(Dum. Cours.) G. Don, whose structures were E and Z isomer, respectively. Their structures were elucidated on the basis of comprehensive spectroscopic analysis(UV, IR, HR-ESI-MS, 1D and 2D NMR). In in vitro bioassays at 10 μmol/L, compound 1showed moderate hepatoprotective activity against N-acetyl-p-aminophenol(APAP)-induced toxicity in He G2 cells.

Discovery of Natural Co-occurring Enantiomers of Monoterpenoid Indole Alkaloids

Main observation and conclusion Two new pairs of monoterpenoid indole alkaloids(MIAs)enantiomers as well as their new congeners were isolated from stems of Tabernaemontana bovina Lour.(Apocynaceae).Their structures were elucidated by spectroscopic analyses and confirmed by X-ray diffractions and computational calculations.Tabovine A,tabovine B and tabovines C-D possessed unprecedented 6/5/5/6/6,6/5/5/6/5 and 6/5/6/6/6 ring systems,respectively.It is the first time to report co-occurring enantiomers of MIAs.Additionally,the explanation concerning biogenesis of MIAs was provided.The findings would open a new window where we could disclose more diverse MIAs.

Monoterpenoid Indole Alkaloids with Promoting Neurite Growth from Tabernaemontana divaricata

Phytochemical investigations on Tabernaemontana divaricata led to the isolation of seven undescribed monoterpenoid indole alkaloids,taberdicatines A-G(1-7).Taberdicatines A-C might be derived from Aspidosperma-type alkaloid,less skeletal carbons in 1-2 and an additional carbon in 3.Taberdicatines D-E(4-5)were attributed to Iboga alkaloids with enantiomeric skeleton,respectively.Alkaloid 3 could promote the neurite growth of mouse primary cortical neurons at the concentration of 5 pimol/L.