Bioassay-guided fractionation of the fungus Eurotium repens resulted in the isolation of two new benzyl derivatives, (E)-2-(hept-1-enyl)-3-(hydroxymethyl)-5-(3-methylbut-2-enyl)benzene-1,4-diol (1) and (E)-4-(hept-1-enyl)-7-(3-methylbut-2-enyl)-2,3-dihydrobenzofuran-2,5-diol (2) along with seven known compounds (3–9) including five benzaldehyde compounds, flavoglaucin (3), tetrahydroauroglaucin (4), dihydroauroglaucin (5), auroglaucin (6) and 2-(2′,3-epoxy-1′,3′-heptadienyl)- 6-hydroxy-5-(3-methyl-2-butenyl)benzaldehyde (7), one diketopiperazine alkaloid echinulin (8), and 5,7-dihydroxy-4-methylphthalide (9). The chemical structures of these compounds were established on the basis of extensive 1D, 2D NMR and HRMS data. Compounds 1–4 and 6 showed good binding affinity for human opioid or cannabinoid receptors. These findings have important implications for psychoactive studies with this class of compounds.

Kratom (Mitragyna speciosa), a native herb of Southeast Asia, is widely known for its psychoactive properties. Recent increase in the use of kratom as a recreational drug has increased the risk of its interaction with conventional drugs if taken concomitantly. A few reports are available related to the effects of kratom on the activity of cytochrome P450 enzymes (CYPs), but there are no reports of its effects on pregnane X receptor (PXR), a transcription factor that regulates the expression of CYPs and P-glycoprotein (P-gp). This study was carried out to evaluate the effects of a methanolic extract of kratom leaves, an alkaloid rich fraction and its 5 indole and 4 oxindole alkaloids on PXR activation and the resulting changes in the mRNA expression of PXR target genes (CYP3A4, CYP1A2, and P-gp). A significant activation of PXR was observed by the extract (3-fold), alkaloidal fraction (4-fold) and all 9 alkaloids (4- to 6-fold) that was associated with an increased mRNA expression which resulted into an increase in the activity of CYP3A4, CYP1A2, and P-gp. These results indicate that high consumption of Mitragyna speciosa extract along with the conventional drugs may lead to potential herb-drug interactions due to its effects on PXR.

Bioassay-guided fractionation of a fungus Neocosmospora sp. (UM-031509) resulted in the isolation of three new resorcylic acid lactones, neocosmosin A (2), neocosmosin B (3) and neocosmosin C (4). Three known resorcylic acid lactones, monocillin IV (1), monocillin II (5) and radicicol (6) were also isolated and identified. The structures of these compounds were established on the basis of extensive 1D and 2D NMR spectroscopic analysis, mass spectrometric (ESI-MS) data and X-ray crystallography. Compounds 4–6 show good binding affinity for the human opioid receptors. These findings have important implications for evaluating the potential psychoactive effects with this class of compounds.

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Phytochemical investigation of the soil microfungus Eupenicillum parvum led to the isolation of two new compounds: a chromone derivative euparvione (1) and a new mycophenolic derivative euparvilactone (2), as well as thirteen known compounds. The structures of the new compounds were elucidated by means of extensive IR, NMR, and MS data and by comparison of data reported in the literature. The structure of the known compound 6 was confirmed by X-ray crystallography. Several isolated compounds were evaluated for in vitro binding assays using opioid receptors (subtypes δ, κ, and µ) and cannabinoid receptors (CB1 and CB2). Compound 10 displayed the best selective µ-opioid receptor and CB1 receptor binding affinities showing values of 47% and 52% at a 10 µM concentration, respectively. These findings provide insight into the potential therapeutic utility of this class of compounds.