Hypervalent iodine-mediated cyclization of bishomoallylamides to prolinols

• Smaher E. Butt,
• Konrad Kepski,
• Jean-Marc Sotiropoulos and
• Wesley J. Moran

Beilstein J. Org. Chem. 2024, 20, 2455–2460, doi:10.3762/bjoc.20.209

• many organocatalysts [3][4][5], natural products (e.g., the potent α-glucosidase inhibitor (−)-codonopsinol B) [6][7], and pharmaceutical drug molecules such as saxagliptin and ramipril (Figure 1) [8]. Accordingly, the development of methods to access substituted prolines and pyrrolidines is an

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• Staphylococcus aureus (MIC: 64 µg/mL) and DPPH radical-scavenging activity (IC50: 12 μg/mL) [205]. It furthermore inhibited α-glucosidase with an IC50 value of 6.3 µM [206]. Graphislactones C and D (39 and 40) were isolated from the lichen Graphis scripta var. pulverulenta [45][165], graphislactone C was later

• especially active against the kinase pp60c-Src (IC50: 20 nM) [231]. Altenusin turned out to be an inhibitor of α-glucosidase and pancreatic lipase (IC50: 46.1, 21.5 µM, respectively) [238], and of neutral sphingomyelinase (nSMase) with an IC50 value of 28 µM (but not of aSMase) [230][239]. It inhibited tau

• ] and from Talaromyces sp. [243]. It showed significant α-glucosidase inhibition with an IC50 value of 2.2 μM [244] and was a potent scavenger of DPPH and of nitrite [243]. Decarboxyaltenusin (50) was reported in 1974 to be obtained by chemical decarboxylation of altenusin (47) and by reduction of

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• over 260 secondary metabolites from Penicillium [5], exhibiting not only antibacterial and anticancer activities but also potent antioxidant properties, inhibition of GSK-3β and α-glucosidase activities, and interaction with the pregnane X receptor (PXR). These compounds are categorized into

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• with an α,β-butenolide-type, whereas compound 3 is a dimeric caged cassane diterpenoid with unique 6/6/6/6/6/5/6/6/6 nonacyclic ring system. The structures of 1 and 3 were characterized by extensive spectroscopic analysis combined with computational ECD analyses. The α-glucosidase inhibitory activity

• of isolated compounds was evaluated, and compounds 1 and 3 showed significant α-glucosidase inhibitory activity with IC50 values of 66 and 44 μM. Keywords: α-glucosidase inhibitory activity; cassane diterpenoid; Fabaceae; medicinal plant; Pterolobium macropterum; Introduction Diabetes mellitus is a

• common metabolic disease that affects how the body uses blood glucose. In 2021, 537 million patients suffered from diabetes worldwide, and the number is feared to increase to 783 million in 2045 [1]. Type 2 diabetes account for the majority of the cases [2]. Currently, inhibition of α-glucosidase, the

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• characterized as an oxa[1.7]meta-paracyclophane framework. In the literature we can find reports about the isolation/synthesis of combretastatins D and their analogues which showed different biological activities, e.g., antineoplastic, anti-inflammatory, and α-glucosidase inhibition [13][14][15]. The presence

• glucose absorption by inhibiting the associated enzymes such as α-glucosidase, is one of the effective therapeutic methods in diabetes mellitus treatment [78]. Thus, Olanipekun and co-workers [19] evaluated the isolated corniculatolides and isocorniculatolides in their work against α-glucosidase from

• authors suggested that the presence of hydroxy substituents at C-11 and C-12 played a significant role in the α-glucosidase inhibition [19]. The cytotoxicity of the aforementioned compounds was also evaluated using the sulforhodamine B (SRB) assay against MIAPaCa-2, DU145, MCF-7, and HTC-116 human cancer

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• . Codonopsinol B, together with its N-nor-methyl analogue 2, proved to be a potent α-glucosidase inhibitor (Figure 1). The potency it showed is higher than that of the known natural alkaloids such as radicamines A and B [3][4], and codonopsinol [5]. In contrast, the unnatural enantiomers of 1 and radicamine A

• were inactive towards the examined α-glucosidases. The enantiomer of 2 was the only one that still exhibited inhibitory activity against yeast α-glucosidase [2]. To our knowledge, the sole total synthesis of (−)-codonopsinol B and similar hydroxylated pyrrolidines to date was reported in the above

• naturally occurring (−)-codonopsinol B (1) and its N-nor-methyl analogue 2 were found to be effective α-glucosidase inhibitors, their racemic forms showed no evident antiproliferative activities against the selected human cancer cell lines U87-MG, HepG2, JEG-3 and MOLM-13 as well as immortalized proximal

New furoisocoumarins and isocoumarins from the mangrove endophytic fungus Aspergillus sp. 085242

• Ze’en Xiao,
• Senhua Chen,
• Runlin Cai,
• Shao’e Lin,
• Kui Hong and
• Zhigang She

Beilstein J. Org. Chem. 2016, 12, 2077–2085, doi:10.3762/bjoc.12.196

• characterized spectroscopically and isolated from a natural source for the first time. Asperisocoumarins A–D (1–4) related to the class of furo[3,2-h]isocoumarins are rarely occurring in natural sources. Compounds 2, 5, and 6 showed moderate α-glucosidase inhibitory activity with IC50 of 87.8, 52.3, and 95.6 μM

• , respectively. In addition, compounds 1 and 3 exhibited weak radical scavenging activity with EC50 values of 125 and 138 μM, respectively. Keywords: α-glucosidase; Aspergillus; DPPH·; furoisocoumarin; isocoumarin; Introduction Isocoumarins are an important group of natural products with diverse structural

• isopentenyl substituent with two adjacent carbonyl groups seems to be rare in natural isocoumarin derivatives and asperisocoumarin F (6) presents as a scaffold with an ether dimer of isocoumarin. All isolates were evaluated for their α-glucosidase inhibitory activity using clinical acarbose (IC50 of 628.3 μM

New depsidones and isoindolinones from the mangrove endophytic fungus Meyerozyma guilliermondii (HZ-Y₂) isolated from the South China Sea

• Senhua Chen,
• Zhaoming Liu,
• Yayue Liu,
• Yongjun Lu,
• Lei He and
• Zhigang She

Beilstein J. Org. Chem. 2015, 11, 1187–1193, doi:10.3762/bjoc.11.133

• exhibited strong α-glucosidase inhibitory activity with IC50 values ranging from 2.1 to 13.3 μM. Moreover, kinetic studies of compounds 2 and 6 showed that both of them were noncompetitive inhibitors of α-glucosidase. Keywords: endophytic fungus; depsidone; α-glucosidase inhibitory activity; isoindolinone

• [13][14][15][16][17]. Recently, a chemical investigation of the endophytic fungal strain Meyerozyma guilliermondii (HZ-Y2), obtained from the roots of the mangrove plant Kandelia obovata, was carried out. The EtOAc extract of a fermentation broth of the fungus showed α-glucosidase inhibitory activity

• ). In the bioactivity assay, all depsidones showed strong α-glucosidase inhibitory activity with IC50 values ranging from 2.1 to 13.3 μM. Details of the isolation, structure elucidation, and biological activity of these compounds are reported herein. Results and Discussion Botryorhodine E (1) was

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

• Mathieu L. Lepage,
• Antoine Mirloup,
• Manon Ripoll,
• Fabien Stauffert,
• Anne Bodlenner,
• Raymond Ziessel and
• Philippe Compain

Beilstein J. Org. Chem. 2015, 11, 659–667, doi:10.3762/bjoc.11.74

• ; fluorescent probes; iminosugars; 4-methylumbelliferone; multivalency; pyrene; Introduction Since the isolation in the 1970’s of 1-deoxynojirimycin (DNJ) from natural sources and the finding of its biological activity as an α-glucosidase inhibitor, thousands of sugar mimetics with a nitrogen atom replacing

Aspergiloid I, an unprecedented spirolactone norditerpenoid from the plant-derived endophytic fungus Aspergillus sp. YXf3

• Zhi Kai Guo,
• Rong Wang,
• Wei Huang,
• Xiao Nian Li,
• Rong Jiang,
• Ren Xiang Tan and
• Hui Ming Ge

Beilstein J. Org. Chem. 2014, 10, 2677–2682, doi:10.3762/bjoc.10.282

• anti-oxidant, and acetylcholinesterase (AChE), α-glucosidase, and topoisomerase IIα inhibitory activities at a concentration of 50 μg/mL. Antimicrobial activities against a variety of plant pathogenic bacteria (Xanthomonas oryzae pv. oryzae Swings, Xanthomonas oryzae pv. oryzicola Swings, Acidovorax

• biosynthetically derived from hypothetical intermediate pimarane compound 2, the hemiketal lactone ring-opening product of aspergiloid E. In biological tests, 1 showed no cytotoxic, antimicrobial, anti-oxidant, acetylcholinesterase (AChE), α-glucosidase, and topoisomerase IIα inhibitory activities. In order to

• graminearum Schw., Fusarium coeruleum Sacc., Botrytis cinerea Pers., and Fusarium oxysporum f. sp. cubense race 4), and Candida albicans (ATCC 10231), and the antioxidant, acetylcholinesterase (AChE) , α-glucosidase, and topoisomerase IIα inhibitory activities were performed in accordance with the primary

Amine-linked diglycosides: Synthesis facilitated by the enhanced reactivity of allylic electrophiles, and glycosidase inhibition assays

• Ian Cumpstey,
• Jens Frigell,
• Elias Pershagen,
• Tashfeen Akhtar,
• Elena Moreno-Clavijo,
• Inmaculada Robina,
• Dominic S. Alonzi and
• Terry D. Butters

Beilstein J. Org. Chem. 2011, 7, 1115–1123, doi:10.3762/bjoc.7.128

• ) altrosides recently reported by Jenkins et al. [47]. These results are in accordance with those reported for other disaccharide mimetics, such as aza-C-disaccharides, which showed no significant inhibition towards commercially available glycosidases [48]. We also investigated inhibition of α-glucosidase II

• -linked diglycosides have not been shown to have intrinsic biological activity before. However, the inhibitory activity, where it exists, is weak for these compounds, and the nature of the binding and the basis for inhibition is not clear. α-Glucosidase II cleaves two linkages in nature in the

• biosynthesis of N-linked glycoproteins: Glc(α1→3)Glc and Glc(α1→3)Man. The Alt(N2–6)Man structure does not bear an immediately obvious resemblance to either of these substructures. Moreover, it has been proposed that a mannose-binding lectin domain of the α-glucosidase II β-subunit is also important for its

Metathesis access to monocyclic iminocyclitol-based therapeutic agents

• Ileana Dragutan,
• Valerian Dragutan,
• Carmen Mitan,
• Hermanus C.M. Vosloo,
• Lionel Delaude and
• Albert Demonceau

Beilstein J. Org. Chem. 2011, 7, 699–716, doi:10.3762/bjoc.7.81

• (135), a naturally occurring iminocyclitol with a lipophilic substituent at the anomeric position, is active on α-glucosidase which is a valid proof that α-alkylation at C1 does not supress the glycosidase inhibitory effect. Its lack of activity on β-galactosidase once again indicates that the relative

• configuration proved to be potent β-glucosidase inhibitors that showed only weak activity towards α-glucosidase and α-mannosidase [78][79][80]. Malto-oligosaccharides and analogues of di- and trisaccharides containing polyhydroxylated azepane moieties are glucosidase or HIV/FIV-protease blockers, or both. As

Synthesis of densely functionalized enantiopure indolizidines by ring- closing metathesis (RCM) of hydroxylamines from carbohydrate- derived nitrones

• Marco Bonanni,
• Marco Marradi,
• Francesca Cardona,
• Stefano Cicchi and
• Andrea Goti

Beilstein J. Org. Chem. 2007, 3, No. 44, doi:10.1186/1860-5397-3-44

• solution of MeOH afforded protonated indolizidines 21–22 in good yields (Scheme 4). Analogously, deprotection of 20 gave pyrrolazepine 23, which displayed good inhibition of α-glucosidase from yeast (90% at 1 mM).[23] Compounds 17 and 23, containing an azepane moiety, might be of biological interest as

Synthesis and glycosidase inhibitory activity of new hexa- substituted C8-glycomimetics

• Olivia Andriuzzi,
• Christine Gravier-Pelletier,
• Gildas Bertho,
• Thierry Prangé and
• Yves Le Merrer

Beilstein J. Org. Chem. 2005, 1, No. 12, doi:10.1186/1860-5397-1-12

• as diabetes, cancer and viral infections including AIDS. Thus, inhibition of intestinal α-glucosidases can be used to treat diabetes through the lowering of blood glucose levels, and α-glucosidase inhibitors are being marketed against type 2 (non-insulinodependent mellitus) diabetes (i.e.: Glyset® or