Antihyperglycemic effects of triterpenoid saponins from the seeds of Aesculus chinensis Bge.

Six undescribed triterpenoid saponins, namely aescuchinosides A-F, along with seven known triterpenoid saponins, were isolated from the seeds of Aesculus chinensis. Barrigenol-like triterpenoids (BATs) constitute these saponins. Protoaescigenin serves as their aglycone, with various oxygen-containing groups, including acetyl, isobutyryl, tigloyl, and angeloyl groups situated at C-21, C-22, and C-28. Various techniques, including 1D and 2D-NMR spectroscopy, high-resolution mass spectrometry, and acid hydrolysis, were employed to determine the structures of these compounds. The antihyperglycemic effects of the isolated compounds were examined in insulin -resistant HepG2 cells induced by palmitic acid treatment. At a concentration of 6 µM, aesculinoside F exhibited a significant increase in glucose consumption. In addition, aesculinoside F demonstrated the potential to improve insulin resistant by upregulating the PI3K/AKT pathway. These results indicate that the seeds of A.chinensis hold promising potential for preventing insulin resistant related disease.

Lignans and clerodane diterpenoids from Tinospora sinensis.

Sixteen lignans with diverse carbon skeletons, including tetrahydrofuran lignans (1, 13-18), 7,9'-dinorlignan (2), dibenzylbutane lignans (9-10), aryl tetrahydronaphthalene lignans (11-12), dihydrobenzofuran neolignans (19-20), 8-O-4' neolignans (21-22), and six clerodane diterpenoid glucosides (3-8) were isolated from the 70% ethanolic extract of the stems of Tinospora sinensis (Lour.) Merr. Their structures were established by spectroscopic analyses and chemical methods. Among all these isolates, compounds 1-2 and 3-4 were determined as previously undescribed lignans and clerodane diterpenoids respectively, and compounds 9-13 and 17-22 were discovered from T. sinensis for the first time. In addition, it was the first time to report three types of lignans including 7,9'-dinorlignan, dihydrobenzofuran neolignan and 8-O-4' neolignan from T. sinensis. The biological activities of all isolated compounds were assessed in terms of their nitric oxide production inhibitory activity in LPS stimulated RAW264.7 cells. The results showed that compound 20 exhibited a mild NO production inhibitory effect with an IC50 value of 17.43 ± 2.06 µM.

Diterpenoids from Isodon rubescens and their nitric oxide production inhibitory activity.

Six new ent-kaurane diterpenoids, isodonrubescins A-F (1-6), together with twenty-five known ent-kaurane diterpenoids (7-31), a known ent-atisane diterpenoid (32), and two known ent-abietane diterpenoids (33-34), were isolated from Isodon rubescens. Their structures were established by means of extensive MS and NMR data analysis. Among the all isolates, compound 7 was found in a natural product for the first time, and ent-atisane diterpenoid was discovered from I. rubescens in Hubei Province, P. R. China for the first time. Furthermore, all the isolated compounds were tested for their NO production inhibitory activity in LPS stimulated RAW264.7 cells. Compounds 7-9, 12, 13, 16, and 17 displayed NO production inhibitory activities with IC50 values ranging from 1.36 to 18.25 µM, respectively.