Mantidisflavin A: A Riboflavin Derivative Featuring a 6/6/6/5/5 Skeleton from the Egg Cases of the Insect Tenodera sinensis Saussure and Its Anti-Renal Fibrosis Activity.

Mantidisflavin A (1) was isolated from the egg cases of the Tenodera sinensis Saussure. It exhibits an unprecedented 6/6/6/5/5 skeleton, accompanied by the formation of two additional fused heterocycles through a novel C-C bond and an oxygen bridge on riboflavin backbone. The structure of 1 was identified by spectroscopic and computational methods. To assess the inhibitory effect against renal fibrosis, compound 1 was evaluated in TGF-ß1-induced rat kidney epithelial cells, and the results were compared to those of its precursor, riboflavin.

X-ray Study of Cembranoids with Flexible Rings from Boswellia papyrifera Resins Allowing Structural Revision of Misleading Structures from the Past 70 Years.

Thirty new, highly oxygenated and stereogenic 14-membered macrocyclic diterpenoids, papyrifuranols A-Z (1-26) and AA-AD (27-30), and eight known analogs have been isolated from Boswellia papyrifera resins. All the structures were characterized by detailed spectral analyses, quantum calculations, X-ray diffraction, and modified Mosher's methods. Notably, six previously reported structures were revised. Our study points out misleading factors of macrocyclic cembranoid (CB) representation in the past seven decades by analyzing of 25 X-ray structures, lending a hand for the innately challenging structure identification of such flexible macrocyclic CBs and avoiding following the tracks of an overturned cart during future structure characterization and total synthesis. Biosynthetic conversions of all the isolates are proposed, and wound healing bioassays reveal that papyrifuranols N-P could significantly stimulate the proliferation and differentiation of umbilical cord mesenchymal stem cells.

Click linker: efficient and high yielding synthesis of a new family of kojic acid congeners as cytotoxic agents.

Highly efficient methodology was developed for the construction of functionalized Kojic acid involving Click linker via 1,3-dipolar cycloaddition and their cytotoxicity against MCF-7, MIAPaCa-2 and DU145 mammalian cell lines were evaluated. Preliminary studies on structure-activity-relationship (SAR) revealed that substitution at C-2 of kojic acid as well as C-5 of 1,2,3-triazole motif played a major role in the activity profile. Kojic acid 1,2,3-triazole analogue 3 b containing an alkyl chain (n = 6) exhibited two fold potent activity than the parent compound, kojic acid against MCF-7 and MIA PaCa-2 cell lines. It induced apoptosis in these cell lines via ID1/PARP1 mediated pathway. The structures of the new analogues of kojic acid 1,2,3-triazole were confirmed by the detailed spectroscopic data analysis.

COX-2 and iNOS inhibitory epimeric meroterpenoids from Ganoderma cochlear and structure revision of cochlearol Q.

Four novel epimeric meroterpenoids, ganadone A (1), 3',10'-di-epi-ganadone A (2), 10'-epi-ganadone A (3), and 3'-epi-ganadone A (4) as well as another pairs of epimers, ganadone B (5) and 10'-epi-ganadone B (6), with a same basic skeleton compound ganadone C (7), together with two lactonized meroterpenoids, ganadones D and E (8 and 9) were isolated from the fruiting bodies of Ganoderma cochlear. Compounds 1-7 were constructed with fascinating adjacent 6',7'-bifuran ring system. Fortunately, we have revised our previously reported structure cochlearol Q, which was proposed pyrano[6',7'-b]pyran ring system into 6',7'-bifuran motif. All the isolates were characterized by analysis of HRESIMS, NMR spectroscopy and 1 was supported by X-ray crystallography analysis. The absolute stereochemistry of 1-9 were assigned by quantum chemical calculations. Biological evaluation of 1-9 showed that 5, 6, and 9 have significant anti-inflammatory potentials.

Liquidambarines A - C, three new abietane diterpenoids from Liquidambar formosana Hance and their anti-inflammatory activities.

Liquidambarines A - C (1-3), three new abietane-type diterpenoids, together with five known compounds (4-8) were isolated from the resin of Liquidambar formosana Hance. Their structures were elucidated by the combination of spectroscopic and computational methods. We explored their anti-inflammatory potential by analyzing the protein expression of iNOS and COX-2. Compounds 1 and 3 exhibit significant anti-inflammatory activities without cytotoxicity. These experimental studies suggest these new abietane-type diterpenoids have the potential to be candidates for inflammation-associated diseases.

Biotransformation of Artemisinin to 14-Hydroxydeoxyartemisinin: C-14 Hydroxylation by Aspergillus flavus.

The biotransformation of the front-line antimalarial drug, artemisinin (1) by the filamentous fungus Aspergillus flavus MTCC-9167 was investigated. Incubation of compound 1 with A. flavus afforded a new hydroxy derivative (2) along with three known metabolites (3-5). The new compound was characterized as 14-hydroxydeoxyartemisinin (2) by extensive spectroscopic data analysis (IR, 1H and 13C NMR, HSQC, HMBC, COSY, NOESY, and HR-ESIMS). The known metabolites were identified as deoxyartemisinin (3), artemisinin G (4), and 4α-hydroxydeoxyartemisinin (5). This is the first report of hydroxylation of a secondary methyl of artemisinin at C-14 by the fungus A. flavus, which is synthetically not accessible. In addition, these compounds were evaluated for their in vitro antiplasmodial activity. Artemisinin G (4) exhibited IC50 values in the submicromolar range, which was better than those of the nonperoxidic metabolites.

Self gelating isoracemosol A, new racemosaceramide A, and racemosol E from Barringtonia racemosa.

Phytochemical investigation into the CHCl3 extract of the fruits of Barringtonia racemosa resulted in the isolation of two new metabolites along with isoracemosol A and betulinic acid as known metabolites. The new compounds were characterised as phytosphingosine-type ceramide [(2S,3S,4R)-2-[(2R)-2-hydroxyhexadecanoyl amino]-hexacos-8(E)-ene-1,3,4-triol, 1] and racemosol E [21ß-acetoxy-22α-(2-methylbutyroxy)-olean-12-ene-3ß,16α,28-triol, 2] on the basis of extensive spectroscopic data analysis and chemical modifications. In addition, the self-gelating property of isoracemosol A (3) was investigated for the first time, which leads to the unexpected agglomerated porous-like morphology.

Epimeric Excolides from the Stems of Excoecaria agallocha and Structural Revision of Rhizophorin A.

Excolides A-B (1-4) represent the first examples of a new class of secolabdanoids with an unprecedented framework, which were isolated from the stems of Excoecaria agallocha. Their structures were determined by spectroscopic analysis, chemical modifications, CD, and single-crystal X-ray analysis (1 and 4) as excolide A (1), 11-epi-excolide A (2), 11,13-di-epi-excolide A (3), and excolide B (4). In addition, the structure of rhizophorin A (7), a novel bicyclic secolabdanoid, was revised as excolide A (1).

Biotransformation of agallochaexcoerin A by Aspergillus flavus.

Agallochaexcoerin A (1), a seco-manoyl oxide diterpenoid was metabolised by pathogenic fungus, Aspergillus flavus, in growth media to yield a new metabolite, termed agallochaexcoerin G (2). It was confirmed by using IR, UV, (1)H NMR and HR-ESI-MS techniques. This microbial bioconversion was achieved by unusual dehydration at C-4 position.