Derrisrobustones A-D, isoflavones from the twig extract of Derris robusta (DC.) Benth. and their α-glucosidase inhibitory activity.

Three previously undescribed isoflavones, derrisrobustones A-C, and a previously undescribed natural isoflavone, derrisrobustone D, along with eight known isoflavones, were isolated from the twig extract of Derris robusta (DC.) Benth. All structures were identified by extensive spectroscopic analysis. Derrisrobustones A-C were obtained as scalemic mixtures and were resolved by chiral HPLC. The (1″R, 2″R) absolute configuration of (+)-derrisrobustone B was established by single-crystal X-ray crystallography using Cu Kα radiation. The absolute configurations of derrisrobustones A and C were determined by analysis of experimental and calculated ECD data. All compounds were evaluated for their α-glucosidase inhibitory activity. Of these, derrubone displayed the best α-glucosidase inhibitory activity with an IC50 value of 64.2 µM.

New Pyrrolobenzoxazine Sesquiterpenoid Derivatives from the Fungus Talaromyces trachyspermus.

Three new pyrrolobenzoxazine sesquiterpenoids, talatrachyoxazines A - C (1:  - 3: ), together with fourteen known compounds (4:  - 17: ), were isolated from the fungus Talaromyces trachyspermus EU23. Their structures were identified by spectroscopic evidence and mass spectrometry. The absolute configurations of 1:  - 3: were determined by NOESY data and comparison of their calculated and experimental electronic circular dichroism (ECD) spectra. Compound 1: showed cytotoxic activity against HelaS3, KB, HT-29, MCF-7, and HepG2 cell lines with IC50 values of 7, 11, 10, 12, and 10 µM, respectively. Compounds 1: and 14: showed weak antibacterial activity against the gram-positive bacteria Bacillus cereus and Bacillus subtilis, while 1:  - 3: and 14: showed weak antibacterial activity against the gram-negative bacterium Pseudomonas aeruginosa. In addition, compound 1: showed weak antibacterial activity against Escherichia coli.

Spirosteroids and α-glucosidase inhibitory norlignans from Asparagus racemosus Willd. roots.

Three undescribed spirosteroids, asparacemosones A-C, an undescribed spiro-21-norsteroid, asparacemosone D, along with seven known compounds were isolated from Thai herbal plant Asparagus racemosus Willd. roots. Their structures were elucidated by spectroscopic analysis including NMR, UV, IR and mass spectrometry. The absolute configurations of asparacemosones A, B, and D were determined by single crystal X-ray diffraction using CuKα radiation. Among the isolated compounds, the norlignan nyasol and three acetylenic norlignans demonstrated potent α-glucosidase inhibition, with IC50 values ranging from 0.003 to 0.004 µM which is 5 × 104 fold more potent than the standard acarbose.

Bioactive oxaphenalenone dimers from the fungus Talaromyces macrosporus KKU-1NK8.

Six new polyketide-derived oxaphenalenone dimers, talaromycesone C (1) and macrosporusones A-E (2-6), together with eight known analogs, were isolated from the mycelium of the fungus Talaromyces macrosporus KKU-1NK8. Their structures were established based on their spectroscopic data and MS. The absolute configurations of new compounds 1-6 were determined by ECD analyses. Compounds 3 and 8 exhibited antimalarial activity against Plasmodium falciparum. Compound 3 showed activity against NCI-H187 cells, while compound 8 displayed activity against KB, MCF-7 and NCI-H187 cell lines. In addition, compound 11 showed antibacterial activity against Bacillus cereus, Staphylococcus aureus and MRSA.