Dasymaschalolactams A-E, Aristolactams from a Twig Extract of Dasymaschalon dasymaschalum

Five new aristolactam alkaloids (1-5), dasymaschalolactams A-E, and the first isolation of dasymaschalolactone (17) as a natural product, together with 19 known compounds (6-16 and 18-25) were isolated from the twig extract of Dasymaschalon dasymaschalum. Their structures were elucidated by spectroscopic methods as well as comparisons made from the literature. Compounds 20 and 21 showed α-glucosidase inhibitory activities with IC50 values of 4.5 and 24.7 μM, respectively

Uvarialuridols A-C, three new polyoxygenated cyclohexenes from the twig and leaf extracts of Uvaria lurida

The first phytochemical investigation of Uvaria lurida resulted in the isolation and identification of three new polyoxygenated cyclohexenes, (+)-(1R,2S,3R,6S)-uvarialuridols A-C (1-3), together with 10 known compounds (4-13). All new structures were elucidated by spectroscopic methods and HRESIMS. The absolute configurations of compounds 1 and 5 were confirmed by X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of compounds 2-4 were identified from comparisons of their specific rotations and ECD spectra with those of known compounds. Compound 11 showed α-glucosidase inhibitory activity with an IC50 value of 30 μM which was better than the standard control, acarbose (74 μM) whereas, compound 10 exhibited nitric oxide (NO) production inhibitory activity with an IC50 value of 37 μM

Alkaloids and Styryl lactones from <i>Goniothalamus ridleyi</i> King and Their <i>α</i>-Glucosidase Inhibitory Activity

Gonioridleylactam (1), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of Goniothalamus ridleyi King. The structure of gonioridleylactam (1) consists of two different aristolactams linked together with two methylenedioxy bridges at C–3/C–3′ and C–4/C–4′, generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1H-benz[f]indole-4,9-dione, 2), together with eight known compounds (3–10) were also isolated from this plant. Their structures were extensively characterized by spectroscopic methods and comparisons were made with the literature. Compounds 1–4, 7, and 9 were evaluated for their α-glucosidase inhibitory activity. Of these, 3,5-demethoxypiperolide (7) displayed the highest α-glucosidase inhibitory activity, with an IC50 value of 1.25 µM

Alkaloids and Styryl lactones from Goniothalamus ridleyi King and Their &alpha;-Glucosidase Inhibitory Activity

Gonioridleylactam (1), a new compound, is a unique dimeric aristolactam isolated from the EtOAc extract of the twigs of Goniothalamus ridleyi King. The structure of gonioridleylactam (1) consists of two different aristolactams linked together with two methylenedioxy bridges at C&ndash;3/C&ndash;3&prime; and C&ndash;4/C&ndash;4&prime;, generating a ten-membered ring of [1,3,6,8]tetraoxecine. A new natural product, gonioridleyindole (3-hydroxymethyl-1-methyl-1H-benz[f]indole-4,9-dione, 2), together with eight known compounds (3&ndash;10) were also isolated from this plant. Their structures were extensively characterized by spectroscopic methods and comparisons were made with the literature. Compounds 1&ndash;4, 7, and 9 were evaluated for their &alpha;-glucosidase inhibitory activity. Of these, 3,5-demethoxypiperolide (7) displayed the highest &alpha;-glucosidase inhibitory activity, with an IC50 value of 1.25 &micro;M

Inhibition of nitric oxide production by clerodane diterpenoids from leaves and stems of <i>Croton poomae</i> Esser

Chromatographic separation of crude extracts from the leaves and stems of Croton poomae Esser led to the isolation of two new clerodane diterpenes crotonolide K (1) and furocrotinsulolide A acetate (2) and six known clerodane diterpenes (3–8), together with twelve known compounds (9–20). Their structures were established from spectroscopic analysis. The clerodane diterpenoids 1–8 were evaluated for inhibition of nitric oxide (NO) production in LPS-activated RAW 264.7 macrophages. Compounds 1, 2, 5, 7 and 8 showed potent inhibitory effects, with IC50 values ranging from 32.19 to 48.85 μM, which is better than both the standard drugs indomethacin (154.5 μM) and dexamethasone (56.28 μM). </p

Phloroglucinol Benzophenones and Xanthones from the Leaves of Garcinia cowa and Their Nitric Oxide Production and α-Glucosidase Inhibitory Activities

2019 American Chemical Society and American Society of Pharmacognosy. Five new compounds - two phloroglucinol benzophenones, garciniacowones F (1) and G (2), and three xanthones, garciniacowones H (3), I (4), and J (5) - together with seven known xanthones (6-12) were isolated from the fresh leaves of Garcinia cowa. Their structures were elucidated by detailed analysis of NMR and MS data. Compounds 1 and 2 are phloroglucinol benzophenones containing a polyprenylated bicyclo[3.3.1]nonane ring system, while compounds 3-5 are rare xanthones having farnesyl (3 and 5) and geranylgeranyl (5) units at C-8. Compounds 1, 3, 4, 7, 8, and 10 exhibited inhibitory effects on NO production in LPS-induced RAW264.7 macrophage cells with IC50 values ranging from 5.4 to 18.6 μM. Compounds 4 and 8 had α-glucosidase inhibitory activities with IC50 values of 15.4 and 11.4 μM, respectively, which were more potent than that of the acarbose control