Wedtrilosides A and B, two new diterpenoid glycosides from the leaves of Wedelia trilobata (L.) Hitchc. with α-amylase and α-glucosidase inhibitory activities.

In the ongoing research to find new diabetes constituents from the genus Wedelia, the chemical constituent of Wedelia trilobata leaves, a Vietnamese medicinal plant species used to treat type 2 diabetes mellitus, was selected for detailed investigation. From a methanolic extract, two new ent-kaurane diterpenoids, wedtrilosides A and B (1 and 2), along with five known metabolites (3-7), were isolated from W. trilobata. The chemical structures of (1-7) were assigned via spectroscopic techniques (IR, 1D, 2D NMR and HR-QTOF-MS data) and chemical methods. The isolates were evaluated for α-amylase and α-glucosidase inhibitory activities compared to the clinical drug acarbose. Among them, compounds 4, 6, and 7 showed the most potent against α-glucosidase enzyme with IC50 values of 27.54 ±â€¯1.12, 173.78 ±â€¯2.37, and 190.40 ±â€¯2.01 µg/mL. While moderate inhibitory effect against α-amylase was observed with compounds 6 and 7 (with IC50 = 181.97 ±â€¯2.62 and 52.08 ±â€¯0.56 µg/mL, respectively). The results suggested that the antidiabetic properties from the leaves of W. trilobata are not simply a result of each isolated compound, but are due to other factors such as the accessibility of polyphenolic groups to α-amylase and α-glucosidase activities.

Chemical Constituents from Cimicifuga dahurica and Their Anti-Proliferative Effects on MCF-7 Breast Cancer Cells.

This study was designed to search for novel anti-cancer compounds from natural plants. The 70% ethanolic extract from the rizhomes of Cimicifuga dahurica (Turcz.) Maxim. (Ranunculaceae) was found to possess significant in vitro anti-proliferative effects on MCF-7 breast cancer cells. A phytochemical investigation using assay-guided fractionation of the ethanolic extract of C. dahurica resulted in the isolation of one new phenolic amide glycoside 3, two new lignan glycosides 4 and 7, one new 9,19-cycloartane triterpenoid glycoside 6, and thirteen known constituents 1, 2, 5, and 8⁻17. The structures of 3, 4, 6, and 7 were established using contemporary NMR methods and from their HRESIMS data. The anti-proliferative effects of isolated compounds were evaluated using the BrdU-proliferation kit. Five among the 17 isolated compounds showed significant anti-proliferative effects (p ≤ 0.05), wherein compound 7 showed the most significant anti-proliferative and cell cycle arresting effect (p ≤ 0.05) which followed a dose dependent manner. Western blot protein expression analysis showed a down expression of c-Myc and cyclin D1 which further elucidated the anti-proliferation mechanism of compound 7 while apoptotic effects were found in association with Bcl-2 family protein expression variations. Conclusively this study reports the isolation and identification of 17 compounds from C. dahurica, including four novel molecules, in addition to the fact that compound 7 possesses significant anti-proliferative and apoptotic effects in vitro that may require further exploration.

α-Amylase and α-Glucosidase Inhibitory Activities of Chemical Constituents from Wedelia chinensis (Osbeck.) Merr. Leaves.

As part of an ongoing search for new natural products from medicinal plants to treat type 2 diabetes, two new compounds, a megastigmane sesquiterpenoid sulfonic acid (1) and a new cyclohexylethanoid derivative (2), and seven related known compounds (3-9) were isolated from the leaves of Wedelia chinensis (Osbeck.) Merr. The structures of the compounds were conducted via interpretation of their spectroscopic data (1D and 2D NMR, IR, and MS), and the absolute configurations of compound 1 were determined by the modified Mosher's method. The MeOH extract of W. chinensis was found to inhibit α-amylase and α-glucosidase inhibitory activities as well as by the compounds isolated from this extract. Furthermore, compound 7 showed the strongest effect with IC50 values of 112.8 ± 15.1 µg/mL (against α-amylase) and 785.9 ± 12.7 µg/mL (against α-glucosidase). Compounds 1, 8, and 9 showed moderate α-amylase and α-glucosidase inhibitory effects. Other compounds showed weak or did not show any effect on both enzymes. The results suggested that the antidiabetic properties from the leaves of W. chinensis are not simply a result of each isolated compound but are due to other components such as the accessibility of polyphenolic groups to α-amylase and α-glucosidase activities.

A new rearranged abietane diterpene and other constituents from Clerodendrum philipinum.

From the methanolic extract of the roots of Clerodendrum philipinum, a new rearranged abietane diterpene (1) and eight known compounds were isolated by various chromatography methods. Their structures were identified by means of spectroscopic methods, including 1D- and 2D-NMR, as 17(15-->16),18(4-->3)-bisabeo-11,12,14,16-tetrahydroxy-3,5,8,11,13,15-abietahexaen-7-one (1), binankadsurin A, clerodenoside A, martynoside, acteoside, isoacteoside, astragalin, p3-sitosterol, and daucosterol. Binankadsurin A was found for the first time from a Clerodendrum species.