Phytochemicals from Dodonaea viscosa and their antioxidant and anticholinesterase activities with structure-activity relationships.

Context Dodonaea viscosa (L.) Jacq (Sapindaceae) has been used in traditional medicine as antimalarial, antidiabetic and antibacterial agent, but further investigations are needed. Objective This study determines the antioxidant and anticholinesterase activities of six compounds (1-6) and two crystals (1A and 3A) isolated from D. viscosa, and discusses their structure-activity relationships. Materials and methods Antioxidant activity was evaluated using six complementary tests, i.e., ß-carotene-linoleic acid; DPPH(•), ABTS(•+), superoxide scavenging, CUPRAC and metal chelating assays. Anticholinesterase activity was performed using the Elman method. Results Clerodane diterpenoids (1 and 2) and phenolics (3-6) - together with three crystals (1A, 3A and 7A) - were isolated from the aerial parts of D. viscosa. Compound 3A exhibited good antioxidant activity in DPPH (IC50: 27.44 ± 1.06 µM), superoxide (28.18 ± 1.35% inhibition at 100 µM) and CUPRAC (A0.5: 35.89 ± 0.09 µM) assays. Compound 5 (IC50: 11.02 ± 0.02 µM) indicated best activity in ABTS assay, and 6 (IC50: 14.30 ± 0.18 µM) in ß-carotene-linoleic acid assay. Compounds 1 and 3 were also obtained in the crystal (1A and 3A) form. Both crystals showed antioxidant activity. Furthermore, crystal 3A was more active than 3 in all activity tests. Phenol 6 possessed moderate anticholinesterase activity against acetylcholinesterase and butyrylcholinesterase enzymes (IC50 values: 158.14 ± 1.65 and 111.60 ± 1.28 µM, respectively). Discussion and conclusion This is the first report on antioxidant and anticholinesterase activities of compounds 1, 2, 5, 6, 1A and 3A, and characterisation of 7A using XRD. Furthermore, the structure-activity relationships are also discussed in detail for the first time.

Meroterpenes with toll-like receptor 3 regulating activity from the endophytic fungus Guignardia mangiferae.

The endophytic fungus Guignardia mangiferae isolated from Ilex cornuta leaves was shown to produce a family of meroterpenes with toll-like receptor 3 regulating activity (1-9), of which 1-3 possessed new structures. The absolute stereochemistry of 1-3 was assigned through a combination of nuclear magnetic resonance experiments, chemical derivation, CD spectra, and single-crystal X-ray diffraction analyses (CuK α ). The precursor labeled cultivation suggests that these meroterpenes are most likely assembled through terpenoid-shikimate pathways. Moreover, meroterpenes 1-3, 5-7, and 9 selectively upregulate, but 4 and 8 downregulate the toll-like receptor 3 expression in mouse dendritic cells at 10.0 µM.

Neuraminidase inhibitory polyketides from the marine-derived fungus Phoma herbarum.

Two new polyketides, arthropsadiol C (1) and massarilactone H (2), together with six known derivatives (3-8) were isolated from the culture broth of the marine-derived fungus Phoma herbarum. Their structures were elucidated on the basis of spectroscopic methods, including 2D NMR techniques. Compounds 2, 4, 5, and 8 showed moderate neuraminidase inhibitory activity with IC(50) values ranging from 4.15 to 9.16 µM.

Ardeemins and cytochalasins from Aspergillus terreus residing in Artemisia annua.

Three new alkaloids, 15b-dehydro-5- N-acetylardeemin ( 3), 10-phenyl-[12]-cytochalasins Z16 ( 6) and Z17 ( 7), were characterized from the liquid culture of the endophytic fungus ASPERGILLUS TERREUS IFB-E030 along with six known derivatives, 5- N-acetylardeemin ( 1), 15b- ß-hydroxyl-5- N-acetylardeemin ( 2), cytochalasin E ( 4), rosellichalasin ( 5), cytochalasins Z11 ( 8), and Z13 ( 9). The structures of the new metabolites were established mainly by a combination of their 1D- and 2D-NMR spectra, single crystal X-ray diffraction, and the modified Mosher reaction. Biological assays indicated that cytochalasin Z17 ( 7) had moderate cytotoxicity against human nasopharyngeal epidermoid tumor KB cell line with an IC (50) value of 26.2 µM.