A New Carvotacetone Derivative from the Aerial Part of Sphaeranthus africanus.

Sphaeranthus africanus L. is native in Vietnam. Little is known about α-glucosidase inhibition of Sphaeranthus africanus and its isolated compounds.

Diorygmones A-B, two new guaiane-sesquiterpenes from the cultured lichen mycobiont of .

is a native crustose-lichen in Vietnam. A mycobiont of this lichen was isolated, then cultivated. The present study described the isolation and structural elucidation of two new guaiane-type sesquiterpenes, namely diorygmones A-B.

α-Glucosidase inhibitory derivatives of protocetraric acid.

Lichen-derived depsidones have been a successful source for alpha-glucosidase inhibitory agents with numerous advantages. In this article, derivatives of protocetraric acids were designed and synthesised. Diels-Alder reaction, esterification, and Friedel-Crafts alkylation of protocetraric acid with different reagents under Lewis acid were performed.

α-Glucosidase Inhibitory Cycloartanes from the Vietnamese Combretum quadrangulare.

Leaves of Combretum quadrangulare Kurz showed potent α-glucosidase inhibition. Two new cycloartane-type triterpenes, combretic acids D and E were isolated from the bioactive fraction. The chemical structures were determined using NMR and MS methods.

Tecomastane, a new megastigmane from the flowers of .

is a tropical plant that is widely used in folk medicine. Little is known about the chemical constituents of flowers of this plant. From flowers of the native plant in Vietnam, 12 compounds were isolated and elucidated, including one new compound tecomastane () and eleven known compounds, (3,5,6,7)-5,6-epoxy-3-hydroxy-7-megastigmane-9-one (), bosciallin (), chakyunglupulin B (), (2,6)-2,6-dimethyloctane-1,8-diol (), cleroindicin F (), rengyoxide (), 3,4-dihydroxybenzoic acid (), methyl 3,4-dihydrobenzoate (), 3,5-dihydroxybenzoic acid (), luteolin (), and indole-3-carboxylic acid ().

Two new phenolic compounds from collected in Vietnam.

is a tropical plant that is widely used in Asian folk medicine. Little is known about the alpha-glucosidase inhibition and antimicrobial properties of compounds from this plant. In the present study, the phytochemical study of the aerial parts of collected in Vietnam was conducted using multiple chromatographic methods.

Biological Activities of Lichen-Derived Monoaromatic Compounds.

Lichen-derived monoaromatic compounds are bioactive compounds, associated with various pharmacological properties: antioxidant, antifungal, antiviral, cytotoxicity, and enzyme inhibition. However, little is known about data regarding alpha-glucosidase inhibition and antimicrobial activity. Very few compounds were reported to have these activities.

Cycloartanes from leaves of growing in Vietnam.

Two new cycloartanes, combretic acid C () and combretanone I (), were isolated from the leaves of Kurz, together with the previously-reported combretic acids A-B ( and ) and combretanone A (). An extensive set of spectroscopic methods were used to elucidate the structures of these compounds. Cytotoxicity against the K562 cancer cell line was evaluated.

Norquandrangularic acid D, a new trinorcycloartane isolated from the leaves of .

Phytochemical investigation on the leaves of growing in Vietnam afforded a new trinorcycloartane triterpenoid, norquandrangularic acid D (), along with three known compounds, betulinic acid (), luteolin (), and apigenin (). Their structures were elucidated using spectroscopic methods and comparison was made with reports in the literature. Compounds and were evaluated for -glucosidase inhibition.

A new resorcinol derivative from the bark of (Primulaceae).

Chemical investigation of the Vietnamese plant Roem. & Schult. (Primulaceae) led to the isolation of the new compound 3-methoxy-5-nonylphenol () along with five known ones 2,8,10-trihydroxy-6-benzo[]chromen-6-one (), 2-hydroxy-5-methoxy-3-nonylbenzo-1,4-quinone (), 5-(3-hydroxypropyl)-7-methoxy-3-(methylbenzofuran-2-yl)-3-methoxyphenol (), 2,8-dihydroxy-7-methoxy-3,9-diundecyldibenzofuran-1,4-dione () and 10-hydroxy-4-methoxy-2,11-diundecylgomphilactone ().

Flavones from Growing in Vietnam and Their Alpha-Glucosidase Inhibitory Activity.

Kurz is widely used in folk medicine in Eastern Asia and is associated with various ethnopharmacological properties including hepatoprotective, antipyretic, analgesic, antidysenteric, and anthelmintic activities. Previous phytochemical investigations reported the presence of numerous triterpenes (mostly cycloartanes, ursanes, lupanes, and oleananes) along with dozens of flavonoids. However, the extracts of and isolated flavonoids have not been evaluated for their alpha-glucosidase inhibition.

Two new phenolic compounds from the Vietnamese lichen .

Chemical investigation of the lichen (Nyl.) Hale led to the isolation of two new phenolic compounds, 2-ethylhexyl orsellinate () and tinctorinone (). The structures were determined by analysis of their MS and NMR data as well as by comparison with literature data.

Manilkzapotane, a novel dimeric alkylresorcinol derivative from the stem bark of .

A novel dimeric alkylresorcinol derivative, manilkzapotane (), along with seven known compounds, lupeol acetate (), lupeol (), arjunolic acid (), ergosterol peroxide (), taraxerol (), hederagonic acid (), and glochidiol () were isolated from the stem bark of . Their structures were determined on the basis of spectroscopic data. DFT-NMR chemical shift calculations and a modified probability (DP4+) method were applied to define the relative configuration of .

Parmosidone K, a new -depsidone from the lichen .

Further phytochemical investigation on led to one new -depsidone, parmosidone K together with one known compound, barbatic acid. Their structures were determined by 1D and 2D NMR analysis, high resolution mass spectroscopy, and comparison their NMR data with those reported in literatures. Parmosidone K was evaluated for α-glucosidase inhibition and revealed the powerful activity with IC value of 3.

Synthesis, α-glucosidase inhibition, and molecular docking studies of novel N-substituted hydrazide derivatives of atranorin as antidiabetic agents.

A series of novel N-substituted hydrazide derivatives were synthesized by reacting atranorin, a compound with a natural depside structure (1), with a range of hydrazines. The natural product and 12 new analogues (2-13) were investigated for inhibition of α-glucosidase. The N-substituted hydrazide derivatives showed more potent inhibition than the original.

New diterpenoids from the stems of growing in Vietnam.

Phytochemical analysis of stem extracts afforded two new atisane compounds, 3-acetoxy-16,17,18-trihydroxyatisane () and 3,14,16,17-tetrahydroxyatisane () together with three known compounds, 20-deoxy-16-hydroxyingenol (), 14[S],16,17-trihydroxyatisan-3-one (), and agallochaol C (). Their structures were elucidated by spectroscopic data analysis and comparison with published NMR data. Compounds were evaluated for -glucosidase inhibition and cytotoxicity.

Design, modification of phyllanthone derivatives as anti-diabetic and cytotoxic agents.

Twelve benzylidene derivatives, one Baeyer-Villiger oxidative, six imine derivatives were successfully designed and synthesised from phyllanthone. In the search for potential new anti-diabetic agents, phyllanthone along with its benzylidene and oxidation analogues were evaluated for enzyme inhibition against -glucosidase. In the benzylidene series, most analogues displayed stronger activity than the mother compound.

Design and synthesis of new lupeol derivatives and their -glucosidase inhibitory and cytotoxic activities.

A series of lupeol derivatives , , , , and were designed, synthesised and evaluated for their -glucosidase inhibitory and cytotoxic activities. Among synthetic derivatives, lupeol analogues and containing a benzylidene chain exhibited the best activity against -glucosidase and superior to the positive agent with the IC values of 29.4 ± 1.

Subnudatones A and B, new trans-decalin polyketides from the cultured lichen mycobionts of Pseudopyrenula subnudata.

Chemical investigation of the cultured polyspore-derived mycobionts of a Pseudopyrenula subnudata lichen led to the isolation of two new compounds, subnudatones A and B (1 and 2), together with four known compounds, 1-(2-hydroxy-1,2,6-trimethyl-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)ethanone (3), libertalide C (4), aspermytin A (5), and 6,7-dimethoxy-4-hydroxymellin (6). Their chemical structures were elucidated by extensive 1D and 2D NMR analysis and high resolution mass spectroscopy, and comparisons were made with the literature. The absolute configuration of 1 was defined unambiguously using single crystal X-ray crystallography.

Dilatatone, a new chlorinated compound from .

Chemical investigation of the lichen led to the isolation of a new chlorinated compound, named dilatatone (), along with a known compound, sernanderin (). Their chemical structures were determined by analysis of their 1 D and 2 D NMR spectra, HRESIMS, and ECD data. Both compounds showed weak glucosidase inhibitor activity.

A new labdane-type diterpenoid from the leaves of L.

A new labdane-type diterpenoid, named vitexnegundin (), along with seven known compounds, including vitexilactone (), vitetrifolin D (), 13-hydroxy-5(10),14-halimadien-6-one (), (rel 3,5,8,9,10)-3,9-dihydroxy-13(14)-labden-16,15-olide (), artemetin (), vitexcarpin () and penduletin (), were isolated from the leaves of L. Their structures were elucidated by using spectroscopic methods, X-ray crystallographic analysis and comparison with those reported in the literature. Moreover, all isolated compounds were evaluated for their antimicrobial activity against ESBL-producing strain and methicillin-resistant .

Nervisides I-J: Unconventional Side-Chain-Bearing Cycloartane Glycosides from .

Two new cycloartane glycosides, nervisides I-J, were isolated from whole plants. Their structures were unambiguously established by interpretation of their HRESIMS and 1D and 2D NMR data. These cycloartanes comprised a stereogenic center at C-24, the configuration of which was assigned based on DFT-NMR calculations and the subsequent DP4 probability score.

Synthesis and cytotoxic evaluation of usnic acid benzylidene derivatives as potential anticancer agents.

A series of usnic acid benzylidene derivatives (groups ) were designed, synthesized and evaluated for their anticancer activity in the search for potentially new anticancer agents. Compounds , , , and exhibited the most potent cytotoxcity against K562 cell line with IC values of 10.0 ± 3.

Further terpenoids from Euphorbia tirucalli.

The phytochemical investigation of Euphorbia tirucalli L. (Euphorbiaceae) yielded four new compounds, including a rare cadalene-type sesquiterpene (tirucadalenone), two tirucallane triterpenoids, euphorol L and euphorol M, with the latter being described as an epimeric mixture, and a euphane triterpene, namely, euphorol N, together with 7 known compounds. Their structures and absolute configurations were elucidated from analysis of 1D (1H, J-modulated C) and 2D NMR (HSQC, HMBC and NOESY), high-resolution mass spectrometry (HRESIMS), optical rotation, and GIAO NMR shift calculation followed by CP3 analysis, along with comparison with literature reports.