Cordythiazole A, the first member of thiazole alkaloids from Chinese cordyceps, with α-glucosidase inhibitory activity.

Chinese cordyceps, also known as Dong-Chong-Xia-Cao, is widely recognized as a famous precious tonic herb, and used as traditional Chinese medicine for centuries. It is mainly used for regulating the immune system and improving functions of the lung and kidney, with anti-tumor, anti-inflammatory, and anti-diabetic activities. Due to its rarity and preciousness, a few chemical components are isolated and identified. Moreover, most of them are common chemical components and widely distributed in other natural resources, such as nucleosides, sterols, fatty acids, sugar alcohols, and peptides. Therefore, a large number of active substances of Chinese cordyceps is still unclear. During our search for chemical constituents of Chinese cordyceps, a new thiazole alkaloid, cordythiazole A (1), was isolated and identified. Its structure was elucidated by comprehensive spectroscopic analysis and single-crystal X-ray diffraction analysis. This is the first report of the presence of thiazole alkaloid in Chinese cordyceps, which adds a new class of metabolite of Chinese cordyceps. Furthermore, a putative biosynthesis pathway of cordythiazole A was proposed based on possible biogenic precursor, genes, and literatures. In addition, it showed α-glucosidase inhibitory activity with potency close to that of acarbose. The discovery of cordythiazole A with α-glucosidase inhibitory activity adds a new class of potential anti-diabetes ingredient in Chinese cordyceps.

Chemical Constituents from the Flower of Hosta plantaginea with Cyclooxygenases Inhibition and Antioxidant Activities and Their Chemotaxonomic Significance.

Two new phenolic glucosides, hostaflavanone A (1) and anti-1-phenylpropane-1,2-diol-2-O-ß-d-glucopyranoside (2), together with six known compounds, anti-1-phenylpropane-1,2-diol (3), phenethyl-O-ß-d-glucopyranoside (4), phenethanol-ß-d-gentiobioside (5), phenethyl-O-rutinoside (6), (1S, 3S)-1-methyl-1,2,3,4-tetrahydro-ß-carboline-3-carboxylic acid (7), and (1R, 3S)-1-methyl-1,2,3,4-tetrahydro-ß-carboline-3-carboxylic acid (8), were isolated from the flower of Hosta plantaginea, and their structures were elucidated by nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectroscopy (HRESIMS), and circular dichroism (CD) analyses. The cyclooxygenases (COX-1 and COX-2) inhibition and antioxidant activities of compounds 1 and 4-6 were investigated, and they showed moderate cyclooxygenases inhibition activities. Moreover, only compound 1 exhibited moderate antioxidant activity, with an IC50 value of 83.2 µM, while 4-6 showed insignificant activity with IC50 values of 282, 257, and 275 µM, respectively. This is the first report of compounds 3 and 5-8 from the Liliaceae family. The chemotaxonomic significance of the isolated compounds was also summarized.

Aldgamycins J-O, 16-Membered Macrolides with a Branched Octose Unit from Streptomycetes sp. and Their Antibacterial Activities.

Six new 16-membered macrolides with a rare branched octose unit, aldgamycins J-O (1-6), along with two known compounds, swalpamycin B (7) and chalcomycin (8), were isolated from Streptomyces sp. HK-2006-1. Their structures were determined by detailed spectroscopic and X-ray crystallographic analysis. Natural products containing branched sugar units are rare. Aldgaropyranose and decarboxylated aldgaropyranose are branched octoses, specifically aldgarose-type branched octose. Until now, only 11 compounds have been reported to contain an aldgarose-type branched octose. The discovery of aldgamycins J-O (1-6) adds new members of this type of natural product. All the compounds (1-8) herein were tested for antimicrobial activities against Gram-positive Staphylococcus aureus 209P, Gram-negative Escherichia coli ATCC0111, and two fungi, Candida albicans FIM709 and Aspergillus niger R330. Most of these compounds showed antibacterial activity against S. aureus. Their preliminary structure-activity relationships are proposed.

Synthesis of bufalin derivatives with inhibitory activity against prostate cancer cells.

Bufalin possesses a strong anti-cancer effect, but the cardiac toxicity targeting the Na(+), K(+)-ATPase limits its application. Here, two bufalin derivatives, bufadienolactam (1) and secobufalinamide (2), were synthesised by treating bufalin with ammonium acetate in dimethylformamide solution. Their structures were elucidated by extensive spectroscopic methods. The structure of compound 2 was further confirmed by single-crystal X-ray diffraction analysis. Compounds 1 and 2 expressed strong inhibitory activities against androgen-dependent prostate cancer cells (IC50 values about 10 µM), but only weak inhibition on Na(+), K(+)-ATPase (Ki about 70 µM), indicating that they might be potential anti-prostate cancer agents without severe cardiac toxicity.