Total biosynthesis of fungal tetraketide pyrones.

Fungal tetraketide pyrones possess important and potent bioactivities, but their detailed biosynthetic pathways are unknown and synthetic routes to their production are lengthy. Here we investigated the fungal pathways to the multiforisins and compounds related to islandic acid. Heterologous expression experiments yield high titres of these compounds and pathway intermediates. The results both elucidate the pathway and offer a platform for the total biosynthesis of this class of metabolites.

The sporothriolides. A new biosynthetic family of fungal secondary metabolites.

The biosynthetic gene cluster of the antifungal metabolite sporothriolide 1 was identified from three producing ascomycetes: Hypomontagnella monticulosa MUCL 54604, H. spongiphila CLL 205 and H. submonticulosa DAOMC 242471. A transformation protocol was established, and genes encoding a fatty acid synthase subunit and a citrate synthase were simultaneously knocked out which led to loss of sporothriolide and sporochartine production. In vitro reactions showed that the sporochartines are derived from non-enzymatic Diels-Alder cycloaddition of 1 and trienylfuranol A 7 during the fermentation and extraction process. Heterologous expression of the spo genes in Aspergillus oryzae then led to the production of intermediates and shunts and delineation of a new fungal biosynthetic pathway originating in fatty acid biosynthesis. Finally, a hydrolase was revealed by in vitro studies likely contributing towards self-resistance of the producer organism.

Combination of high-resolution accurate mass spectrometry and network pharmacology provides a new method for the chemical constituents' study and target prediction in vivo of Garcinia multiflora.

Garcinia multiflora is a kind of evergreen tree which is widely distributed in the south of China. However, few researches focused on the constituents in different parts of G. multiflora as well as their potential targets and pathways in vivo. To clarify the chemical constituents of G. multiflora rapidly and predict the potential targets as well as pathways in vivo that this plant may have effects on, a feasible and accurate strategy was developed to identify the chemical constituents in fruits, leaves, and branches of G. multiflora by ultra-high performance liquid chromatography with Q-Exactive hybrid quadrupole-orbitrap high-resolution accurate mass spectrometry. Network pharmacology was then employed and a "compounds-targets-diseases" network was established. Sixty-one compounds including polycyclic polyprenylated acylphloroglucinols, xanthones, and flavonoids were finally identified in different parts of G. multiflora, and the contents of seven constituents were quantified, respectively. On the basis of the network pharmacology analysis results, compounds in this plant were speculated to have potential pharmacodynamic effect on cancer, inflammatory, respiratory diseases, cardiovascular diseases, and metabolic diseases. This research will provide a new method for the advanced study on the pharmacodynamic materials basis of G. multiflora, and offer valuable evidences for medicinal purpose of this plant.

Synthesis of novel guttiferone E and xanthochymol derivatives with cytotoxicities by inducing cell apoptosis and arresting the cell cycle phase.

The mixture of GX (guttiferone E and xanthochymol), an inseparable polycyclic polyprenylated acylphloroglucinol (PPAP), showed moderate cytotoxic activities. The chemical transformation of GX yielded three different types of PPAPs (1, 2, and 3/4). A series of analogs were prepared, and the structures of the 40 newly synthesized compounds were elucidated by 1D and 2D NMR and HR-ESI-MS. The derivatives were screened in vitro for antiproliferative activity against five human cancer cell lines: human leukemic cell lines (HEL and K562), cervical cancer cell line (Hela), human breast adenocarcinoma cell line (MCF-7), and human non-small cell lung cancer cell line (A549), using the MTT assay, and most of the derivatives showed good cytotoxic activities. Noticeably, compound 2, a novel tautomer with a hemiketal, exhibited selective cytotoxic activities against HEL (IC50 = 4.79 ±â€¯0.23 µM) and K562 (IC50 = 7.69 ±â€¯0.34 µM) leukemia cells. The mechanism studies indicated that compound 2 induced apoptosis and arrested the cell cycle at the G0/G1 phase in the HEL cell line. Furthermore, compound 2 activated the intrinsic pathway by reducing the expression of anti-apoptotic protein Bcl-2 and cell cycle-specific cyclin D1 and by enhancing the pro-apoptotic protein Bax. Moreover, the caspase-3 and PPRP1 levels were also upregulated. Our present results suggest that compound 2 is a potential candidate for developing novel anti-leukemia agents in the future.

Hypermonins A and B, two 6-norpolyprenylated acylphloroglucinols with unprecedented skeletons from Hypericum monogynum.

Two new 6-norpolycyclic polyprenylated acylphloroglucinols (PPAPs), hypermonins A (1) and B (2), featuring an undescribed decahydroindeno[1,7-bc]furan ring system, were isolated from the leaves and twigs of Hypericum monogynum. These compounds are a pair of epimers with opposite configurations at the C-5 position. Their structures, including their absolute configurations, were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. A plausible biosynthetic pathway of 1 and 2 was also proposed. Compound 1 exhibited a significant protective effect against corticosterone-induced injury in PC12 cells.