New Steroids from the South China Sea Soft Coral Lobophytum sp.

Two new steroids, (22R,23S)‐3β‐hydroxy‐23‐methyl‐17,20‐epoxyergost‐5‐en‐22‐yl acetate and (22R,23S)‐5‐hydroperoxy‐23‐methyl‐5α‐17,20‐epoxyergost‐6‐ene‐3β,22‐diol, were isolated from the South China Sea soft coral Lobophytum sp., together with two related known ones. The structures of all compounds were elucidated by extensive spectroscopic analysis and by comparing their spectral data with those previously reported. The structure of (22R,23S)‐3β‐hydroxy‐23‐methyl‐17,20‐epoxyergost‐5‐en‐22‐yl acetate was further confirmed through chemical correlation. All the isolates were evaluated for the in vitro inhibitory activity against NF‐κB, a potential target for the treatment of cancer, and (22R,23S)‐5‐hydroperoxy‐23‐methyl‐5α‐17,20‐epoxyergost‐6‐ene‐3β,22‐diol exhibited moderate inhibition activity with IC₅₀ value of 8.96 μg/mL.     

Toxicity and Sublethal Effects of Phthalides Analogs to Rhyzopertha dominica

Phthalides and their precursors have demonstrated a large variety of biological activities. Eighteen phthalides were synthesized and tested on the stored grain pest Rhyzopertha dominica. In the screening bioassay, compounds rac‐(2R,2aS,4R,4aS,6aR,6bS,7R)‐7‐bromohexahydro‐2,4‐methano‐1,6‐dioxacyclopenta[cd]pentalen‐5(2H)‐one ( 15 ) and rac‐(3R,3aR,4R,7S,7aS)‐3‐(propan‐2‐yloxy)hexahydro‐4,7‐methano‐2‐benzofuran‐1(3H)‐one ( 17 ) showed mortality similar to the commercial insecticide, Bifenthrin® (≥90 %). The time (LT₅₀) and dose (LD₅₀) necessary to kill 50 % of the R. dominica population were determined for the most efficacious phthalides 15 and 17 . Compound 15 presented the lowest LD₅₀ (1.97 μg g^?1), being four times more toxic than Bifenthrin® (LD₅₀=9.11 μg g^?1). Both compounds presented an LT₅₀ value equal to 24 h. When applied at a sublethal dose, both phthalides (especially compound 15 ), reduced the emergence of the first progeny of R. dominica. These findings highlight the potential of phthalides 15 and 17 as precursors for the development of insecticides for R. dominica control.     

Benzopyran Derivatives and an Aliphatic Compound from a Mangrove Endophytic Fungus Penicillium citrinum QJF‐22

Two new benzopyran derivatives, (2R,4S)‐5‐methoxy‐2‐methyl‐3,4‐dihydro‐2H‐1‐benzopyran‐4‐ol and (2S,4R,2′S,4′R)‐4,4′‐oxybis(5‐methoxy‐2‐methyl‐3,4‐dihydro‐2H‐1‐benzopyran), and a new aliphatic compound, (3E,5Z,8S,10E)‐8‐hydroxytrideca‐3,5,10,12‐tetraen‐2‐one, together with three known benzopyran derivatives, were obtained from a mangrove endophytic fungus Penicillium citrinum QJF‐22 collected in Hainan island. Their structures were determined by analysis of spectroscopic data and the relative configuration of (2R,4S)‐5‐methoxy‐2‐methyl‐3,4‐dihydro‐2H‐1‐benzopyran‐4‐ol was also confirmed by single‐crystal X‐ray diffraction. The absolute configurations of four compounds were established by comparison of ECD spectra to calculations. The configuration of (3E,5Z,8S,10E)‐8‐hydroxytrideca‐3,5,10,12‐tetraen‐2‐one was confirmed by comparison of optical value to the similar compound. The configurations of the compounds (2S,4S)‐5‐methoxy‐2‐methyl‐3,4‐dihydro‐2H‐1‐benzopyran‐4‐ol and (2R,4R)‐5‐methoxy‐2‐methyl‐3,4‐dihydro‐2H‐1‐benzopyran‐4‐ol were first determined. (3R,4S)‐3,4,8‐Trihydroxy‐3,4‐dihydronaphthalen‐1(2H)‐one exhibited moderate inhibitory effects on LPS‐induced NO production in RAW264.7 cells with IC₅₀ of 44.7 μM, and without cytotoxicity to RAW264.7 cells within 50 μM.     

Inhibitory Effects of Constituents of an Endophytic Fungus Hypoxylon investiens on Nitric Oxide and Interleukin‐6 Production in RAW264.7 Macrophages

Three new compounds, hypoxyloamide ( 1 ), 8‐methoxynaphthalene‐1,7‐diol ( 2 ), and hypoxylonol ( 3 ), together with seven compounds isolated from nature for the first time, investiamide ( 4 ), hypoxypropanamide ( 5 ), hypoxylonol A ( 6 ), investienol ( 7 ), 2‐heptylfuran ( 8 ), (3S)‐5‐methyl‐8‐O‐methylmellein ( 9 ), (4R)‐O‐methylsclerone ( 10 ), along with 19 known compounds, 11 – 29 , were isolated from the culture broth of Hypoxylon investiens BCRC 10F0115, a fungal endophyte residing in the stems of an endemic Formosan plant Litsea akoensis var. chitouchiaoensis. The structures of the new compounds were established by spectroscopic methods, including UV, IR, HR‐ESI‐MS, and extensive 1D‐ and 2D‐NMR techniques. Of these isolates, 2 , 8‐methoxynaphthalen‐1‐ol ( 15 ), and 1,8‐dimethoxynaphthalene ( 16 ) showed nitric oxide (NO) inhibitory activity with IC₅₀ values of 11.8±0.9, 17.8±1.1, and 13.3±0.5 μM , respectively, stronger than the positive control quercetin (IC₅₀ 36.8±1.3 μM ). Compounds 2, 15 , and 16 also showed interleukin‐6 (IL‐6) inhibitory activity with IC₅₀ values of 9.2±1.7, 18.0±0.6, and 2.0±0.1 μM , stronger than the positive control quercetin (IC₅₀ 31.3±1.6 μM ). To the best of our knowledge, this is the first report on guaiane sesquiterpene metabolites, 3, 6 , and 7 , from the genus Hypoxylon.     

Tirucallane Triterpenoids from the Stems of Brucea mollis

Three new tirucallane triterpenoids, brumollisols A–C ( 1 – 3 , resp.), together with five known analogues, (23R,24S)‐23,24,25‐trihydroxytirucall‐7‐ene‐3,6‐dione ( 4 ), piscidinol A ( 5 ), 24‐epipiscidinol A ( 6 ), 21α‐methylmelianodiol ( 7 ), and 21β‐methylmelianodiol ( 8 ), were isolated from an EtOH extract of the stems of Brucea mollis. Their structures were elucidated by means of spectroscopic methods including 1D‐ and 2D‐NMR techniques and mass spectrometry. In the in vitro assays, compound 6 exhibited significant cytotoxic activity against A549 and BGC‐823 cancer cells with IC₅₀ values of 1.16 and 3.01 μM , respectively. At a concentration of 10 μM , compounds 1 – 5, 7 , and 8 were found to inhibit NO production in mouse peritoneal macrophages with inhibitory ratios ranging from 39.8±7.7 to 68.2±4.5%.     

A Comparative Study on Hulled Adlay and Unhulled Adlay through Evaluation of Their LPS‐Induced Anti‐Inflammatory Effects,and Isolation of Pure Compounds

Coicis semen (=the hulled seed of Coix lacryma‐jobi L. var. ma‐yuen (Rom.Caill. ) Stapf ; Gramineae), commonly known as adlay and Job's tears, is widely used in traditional medicine and as a nutritious food. Bioassay‐guided fractionation of the AcOEt fraction of unhulled adlays, using measurement of nitric oxide (NO) production on lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophage cells, led to the isolation and identification of two new stereoisomers, (+)‐(7′S,8′R,7″S,8″R)‐guaiacylglycerol β‐O‐4′‐dihydrodisinapyl ether ( 1 ) and (+)‐(7′S,8′R,7″R,8″R)‐guaiacylglycerol β‐O‐4′‐dihydrodisinapyl ether ( 2 ), together with six known compounds, 3 – 8 . Compounds 3 and 4 exhibited inhibitory activities on LPS‐induced NO production with IC₅₀ values of 1.4 and 3.7 μM , respectively, and suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2) protein expressions in RAW 264.7 macrophage cells. Simple high‐performance liquid chromatography with ultraviolet detection (HPLC/UV) was used to compare the AcOEt fraction of unhulled adlays responsible for the anti‐inflammatory activity in RAW 264.7 cells and the inactive AcOEt fraction of hulled adlays.     

Chemical Components from Phaeanthus vietnamensis and Their Inhibitory NO Production in BV2 Cells

Phaeanthus vietnamensis Bân is a well‐known medicinal plant which has been used for the treatment of various inflammatory diseases in traditional medicine. Using various chromatographic methods, three new compounds, (7S,8R,8′R)‐9,9′‐epoxy‐3,5,3′,5′‐tetramethoxylignan‐4,4′,7‐triol ( 1 ), 8α‐hydroxyoplop‐11(12)‐en‐14‐one ( 5 ), and (1R,2S,4S)‐4‐acetyl‐2‐[(E)‐(cinnamoyloxy)]‐1‐methylcyclohexan‐1‐ol ( 12 ) along with twelve known compounds were isolated from the leaves of P. vietnamensis. Their chemical structures were elucidated by physical and chemical methods. All compounds were evaluated for the inhibitory activities of nitric oxide production in LPS‐stimulated BV2 cells. As the results, compound 6 showed the most potent inhibitory activity on LPS‐stimulated NO production in BV2 cells with the IC₅₀ values of 15.7 ± 1.2 μm . Compounds 2 , 7 , and 8 significantly inhibited inflammatory NO production with IC₅₀ values ranging from 22.6 to 25.3 μm .     

Secondary Metabolites and Antimycobacterial Activities from the Roots of Ficus nervosa

Bioassay‐guided fractionation of the active AcOEt‐soluble layer led to the isolation of two new pyranocoumarins, 3‐hydroxyxanthyletin ( 1 ) and 3‐methoxyxanthyletin ( 2 ), along with 22 known compounds including four simple coumarins, i.e., xanthyletin ( 3 ), umbelliferone ( 4 ), scopoletin ( 5 ), and (+)‐(S)‐marmesin ( 6 ); nine flavonoids, i.e., carpachromene ( 7 ), parvisoflavone B ( 8 ), alpinumisoflavone ( 9 ) genistein ( 10 ), 2′‐hydroxygenistein ( 11 ), prunetin ( 12 ), cajanin ( 13 ), apigenin ( 14 ), and (2S)‐naringenin ( 15 ); three benzenoids, i.e., 4‐hydroxybenzaldehyde ( 16 ), vanillin ( 17 ), and (S)‐lasiodiplodin ( 18 ); five steroids, i.e., ergosterol peroxide ( 19 ), a mixture of 6β‐hydroxystigmast‐4‐en‐3‐one ( 20 ) and 6β‐hydroxystigmasta‐4,22‐dien‐3‐one ( 21 ), and a mixture of β‐sitosterol ( 22 ) and stigmasterol ( 23 ); and one triterpenoid, i.e., oleanolic acid ( 24 ) from the roots of Ficus nervosa. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR as well as MS analyses. Among these isolates, 3‐hydroxyxanthyletin ( 1 ), genistein ( 10 ), prunetin ( 12 ), and (2S)‐naringenin ( 15 ) showed antimycobacterial activities against Mycobacterium tuberculosis H₃₇R_V in vitro with MIC values of 16, 35, 30, and ≤2.8 μg/ml, respectively.     

Four New Tirucallane Triterpenoids from the Fruits of Melia azedarach and Their Cytotoxic Activities

Four new tirucallane triterpenoids, (21S,23R,24R)‐21,23‐epoxy‐21,24‐dihydroxy‐25‐methoxytirucall‐7‐en‐3‐one ( 2 ), (3S,21S,23R,24S)‐21,23‐epoxy‐21,25‐dimethoxytirucall‐7‐ene‐3,24‐diol ( 8 ), (21S,23R,24R)‐21,23‐epoxy‐24‐hydroxy‐21‐methoxytirucalla‐7,25‐dien‐3‐one ( 11 ), and (21S,23R,24R)‐21,23‐epoxy‐21,24‐dihydroxytirucalla‐7,25‐dien‐3‐one ( 12 ), along with 16 known analogues, 1 , 3  –  7 , 9  –  10 , and 13  –  20 , were isolated from the fruits of Melia azedarach. Their structures were elucidated by spectroscopic methods including 1D‐ and 2D‐NMR techniques and mass spectrometry. These compounds were evaluated for their cytotoxicities against HepG2 (liver), SGC7901 (stomach), K562 (leukemia), and HL60 (leukemia) cancer cell lines. Compound 20 exhibited potent cytotoxicity against HepG2 and SGC7901 cancer cells with the IC₅₀ values of 6.9 and 6.9 μm , respectively.     

Two New Chromone Glycosides from the Roots of Saposhnikovia divaricata

Five chromone glycosides were isolated from the water‐soluble portions of 70% EtOH extract of the roots of Saposhnikovia divaricata, including two new chromone glycosides 1 and 2 . The structures of the chromone glycosides were identified as (3′S)‐3′‐O‐β‐d ‐apiofuranosyl‐(1 → 6)‐β‐d ‐glucopyranosylhamaudol ( 1 ), (2′S)‐4′‐O‐β‐d ‐apiofuranosyl‐(1 → 6)‐β‐d ‐glucopyranosylvisamminol ( 2 ), 3′‐O‐glucopyranosylhamaudol ( 3 ), 4′‐O‐β‐d ‐glucopyranosylvisamminol ( 4 ), and 4′‐O‐β‐d ‐glucopyranosyl‐5‐O‐methylvisamminol ( 5 ) on the basis of extensive spectroscopic methods, and the absolute configurations of the new compounds were elucidated by the electronic circular dichroism (ECD) calculation and acid hydrolysis. The cytotoxic activities of the glycosides 1 – 5 against three human cancer cell lines (PC‐3, SK‐OV‐3, and H460) were evaluated. The result showed that compounds 1 – 5 had weak cytotoxic activities against the human cancer cell lines with IC₅₀ values in the range of 48.54 ± 0.80 – 94.25 ± 1.45 μm .     

New Isoprenylated 2‐Arylbenzofurans and Pancreatic Lipase Inhibitory Constituents from Artocarpus nitidus

Two new isoprenylated 2‐arylbenzofurans, artonitidin A (=(2′R)‐2′,3′‐dihydro‐2′‐(1‐hydroxy‐1‐methylethyl)‐5′,7‐bis(3‐methylbut‐2‐en‐1‐yl)‐2,4′‐bi‐1‐benzofuran‐6,6′‐diol; 1 ) and artonitidin B (=5‐[6‐hydroxy‐7‐(3‐methylbut‐2‐en‐1‐yl)‐1‐benzofuran‐2‐yl]‐4‐(3‐methylbut‐2‐en‐1‐yl)benzene‐1,3‐diol; 2 ), together with 14 known compounds, 3 – 16 , were isolated from the stems of Artocarpus nitidus Trec. The structures were elucidated by spectroscopic methods. Norartocarpin ( 3 ), cudraflavone C ( 5 ), brosimone I ( 8 ), artotonkin ( 11 ), albanin A ( 13 ), and artopetelin M ( 14 ) showed inhibitory effects on pancreatic lipase with IC₅₀ values ranging from 1.8±0.1 to 63.8±3.6 μM .     

Constituents of the Argentine Liverwort Plagiochila diversifolia and Their Insecticidal Activities

Three new compounds, a bicyclogermacrene ( 1 ) and two 2,3‐secoaromadendrane esters ( 2 and 3 ), together with (13S)‐13‐hydroxylabda‐8,14‐diene ( 4 ), fusicogigantone B ( 5 ), 3α,14‐diacetoxy‐2‐hydoxybicyclogermacrene ( 6 ), fusicogigantone A ( 7 ), neofuranoplagiochilal ( 8 ), plagiochiline B ( 9 ), furanoplagiochilal ( 10 ), trans‐nerolidol, spathulenol, α‐tocopherol, and (+)‐globulol were isolated from an Argentine collection of Plagiochila diversifolia. Their structures were elucidated by extensive mono and bidimensional NMR studies. Compounds 4 , 5 , and 6 , incorporated to the larval diet at 100 μg per g of diet, reduced the larval growth of Spodoptera frugiperda (Lepidoptera: Noctuidae) by 70 ± 25, 57 ± 23, and 33 ± 16%, respectively. Compounds 4 and 5 produced 70% and 60% larval mortality at early instars. The latter also showed antifeedant properties in the Choice Test, with a feeding ratio of 0.54 ± 0.16.     

Antimicrobial and Cytotoxic Activity of Extracts of Ferula heuffelii Griseb. ex Heuff. and Its Metabolites

The antimicrobial and cytotoxic activities of isolates (CHCl₃ and MeOH extracts and selected metabolites) obtained from the underground parts of the Balkan endemic plant Ferula heuffelii Griseb . ex Heuff . were assessed. The CHCl₃ and MeOH extracts exhibited moderate antimicrobial activity, being more pronounced against Gram‐positive than Gram‐negative bacteria, especially against Staphylococcus aureus (MIC=12.5 μg/ml for both extracts) and Micrococcus luteus (MIC=50 and 12.5 μg/ml, resp.). Among the tested metabolites, (6E)‐1‐(2,4‐dihydroxyphenyl)‐3,7,11‐trimethyl‐3‐vinyldodeca‐6,10‐dien‐1‐one ( 2 ) and (2S*,3R*)‐2‐[(3E)‐4,8‐dimethylnona‐3,7‐dien‐1‐yl]‐2,3‐dihydro‐7‐hydroxy‐2,3‐dimethylfuro[3,2‐c]coumarin ( 4 ) demonstrated the best antimicrobial activity. Compounds 2 and 4 both strongly inhibited the growth of M. luteus (MIC=11.2 and 5.2 μM , resp.) and Staphylococcus epidermidis (MIC=22.5 and 10.5 μM , resp.) and compound 2 additionally also the growth of Bacillus subtilis (MIC=11.2 μM ). The cytotoxic activity of the isolates was tested against three human cancer cell lines, viz., cervical adenocarcinoma (HeLa), chronic myelogenous leukemia (K562), and breast cancer (MCF‐7) cells. The CHCl₃ extract exhibited strong cytotoxic activity against all cell lines (IC₅₀<11.0 μg/ml). All compounds strongly inhibited the growth of the K562 and HeLa cell lines. Compound 4 exhibited also a strong activity against the MCF‐7 cell line, comparable to that of cisplatin (IC₅₀=22.32±1.32 vs. 18.67±0.75μM ).     

Cytotoxic Steroidal Saponins from the Rhizomes of Tacca integrifolia

Three new steroid saponins (3β,25R)‐spirost‐5‐en‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 1 ), (3β,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐hydroxyfurost‐5‐en‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 3 ), and (3β,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐hydroxyfurost‐5‐en‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[β‐D ‐glucopyranosyl‐(1→4)‐6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 5 ), as well as the new pregnane glycoside (3β,16β)‐3‐{[6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranosyl]oxy}‐20‐oxopregn‐5‐en‐16‐yl (4R)‐5‐(β‐D ‐glucopyranosyloxy)‐4‐methylpentanoate ( 6 ), were isolated from the rhizomes of Tacca integrifolia together with two known (25R) configurated steroid saponins (3β,25R)‐spirost‐5‐en‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 2 ) and (3β,22R,25R)‐26‐(β‐D ‐glucopyranosyloxy)‐22‐methoxyfurost‐5‐en‐3‐yl 6‐deoxy‐α‐L ‐mannopyranosyl‐(1→2)‐[6‐deoxy‐α‐L ‐mannopyranosyl‐(1→3)]‐β‐D ‐glucopyranoside ( 4 ). The cytotoxic activity of the isolated compounds was evaluated in HeLa cells and showed the highest cytotoxicity value for compound 2 with an IC₅₀ of 1.2±0.4 μM . Intriguingly, while compounds 1 – 5 exhibited similar cytotoxic properties between 1.2±0.4 ( 2 ) and 4.0±0.6 μM ( 5 ), only compound 2 showed a significant microtubule‐stabilizing activity in vitro.     

Chemical Constituents of the Rare Cliff Plant Oresitrophe rupifraga and Their Antineuroinflammatory Activity

Four new ( 1 – 4 ) and thirteen known ( 5 – 17 ) compounds were isolated from a rare cliff plant, Oresitrophe rupifraga. Based on spectroscopic evidence, the new structures were established to be [(2S,3R,4R)‐4‐(4‐methoxybenzyl)‐2‐(4‐methoxyphenyl)‐tetrahydrofuran‐3‐yl]methanol ( 1 ), (3α)‐23‐(acetyloxy)‐3‐hydroxyolean‐12‐en‐29‐oic acid ( 2 ), 3α,23‐(isopropylidenedioxy)olean‐12‐en‐29‐oic acid ( 3 , artifact of isolation), and (3β,15β)‐3‐hydroxycholest‐5‐en‐15‐yl β‐d ‐glucopyranoside ( 4 ), respectively. Among the isolates, compounds 1 , 4 , epieudesmin ( 7 ), and 1‐O‐(9Z,12Z,15Z‐octadecatrienoyl)glycerol ( 17 ) were found to show significant antineuroinflammatory effects by inhibiting the NO production in lipopolysaccharide (LPS)‐stimulated murine BV‐2 microglial cells, with IC₅₀ values of 7.21, 9.39, 4.96, and 8.51 μm , respectively.     

BACE1 (Beta‐Secretase) Inhibitory Phenolic Acids and a Novel Sesquiterpenoid from Homalomena occulta

Four phenolic acids, namely 2‐[(Z)‐heptadec‐11‐enyl]‐6‐hydroxybenzoic acid ( 1 ), 2‐[(6Z,9Z,12Z)‐heptadeca‐6,9,12‐trienyl]‐6‐hydroxybenzoic acid ( 2 ), 2‐[(9Z,12Z)‐heptadeca‐9,12‐dienyl]‐6‐hydroxybenzoic acid ( 3 ), and 2‐hydroxy‐6‐(12‐phenyldodecyl)benzoic acid ( 4 ), and one sesquiterpene, asperpenoid ( 5 ), were isolated from the 95% EtOH extract of the roots of Homalomena occulta, among which 1, 2 , and 5 represent new compounds. Further, the phenolic acids 1 – 4 exhibited BACE1 (β‐secretase) inhibitory activity with IC₅₀ values of 6.23±0.94, 6.28±0.63, 7.93±0.38, and 7.65±0.62 μM , respectively.     

Characterization of (2S,2'R,3'R)-2-(2',3'-[3H]-Dicarboxycyclopropyl)glycine Binding in Rat Brain

Abstract: [(2S,2′R,3′R)-2-(2′,3′-[³H]Dicarboxycyclopropyl)glycine ([³H]DCG IV) binding was characterized in vitro in rat brain cortex homogenates and rat brain sections. In cortex homogenates, the binding was saturable and the saturation isotherm indicated the presence of a single binding site with a K_D value of 180 ± 33 nM and a B_max of 780 ± 70 fmol/mg of protein. The nonspecific binding, measured using 100 µM LY354740, was <30%. NMDA, AMPA, kainate, l (?)-threo-3-hydroxyaspartic acid, and (S)-3,5-dihydroxyphenylglycine were all inactive in [³H]DCG IV binding up to 1 mM. However, several compounds inhibited [³H]DCG IV binding in a concentration-dependent manner with the following rank order of potency: LY341495 = LY354740 > DCG IV = (2S,1′S,2′S)-2-(2-carboxycyclopropyl)glycine > (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid > (2S,1′S,2′S)-2-methyl-2-(2-carboxycyclopropyl)glycine > l -glutamate = ibotenate > quisqualate > (RS)-α-methyl-4-phosphonophenylglycine = l (+)-2-amino-3-phosphonopropionic acid > (S)-α-methyl-4-carboxyphenylglycine > (2S)-α-ethylglutamic acid > l (+)-2-amino-4-phosphonobutyric acid. N-Acetyl-l -aspartyl-l -glutamic acid inhibited the binding in a biphasic manner with an IC₅₀ of 0.2 µM for the high-affinity component. The binding was also affected by GTPγS, reducing agents, and CdCl₂. In parasagittal sections of rat brain, a high density of specific binding was observed in the accessory olfactory bulb, cortical regions (layers 1, 3, and 4 > 2, 5, and 6), caudate putamen, molecular layers of the hippocampus and dentate gyrus, subiculum, presubiculum, retrosplenial cortex, anteroventral thalamic nuclei, and cerebellar granular layer, reflecting its preferential (perhaps not exclusive) affinity for pre- and postsynaptic metabotropic glutamate mGlu2 receptors. Thus, the pharmacology, tissue distribution, and sensitivity to GTPγS show that [³H]DCG IV binding is probably to group II metabotropic glutamate receptors in rat brain.     

Biphenyl‐Type Neolignan Derivatives from the Twigs of Magnolia denudata and Their Anti‐Inflammatory Activity

Two new biphenyl‐type neolignan derivatives, 2‐[2‐(hydroxymethyl)‐1‐benzofuran‐5‐yl]‐4‐(prop‐2‐en‐1‐yl)phenol ( 1 ) and 2′‐ethoxy‐5,5′‐di(prop‐2‐en‐1‐yl)biphenyl‐2‐ol ( 2 ), were isolated from the twigs of Magnolia denudata, together with six known compounds ( 3 – 8 ). The structures of 1 and 2 were determined through extensive 1D‐ and 2D‐NMR and mass‐spectrometric analyses. Magnolol ( 6 ) and honokiol ( 7 ) exhibited potent inhibition (IC₅₀ values=4.4±0.2 and 0.71±0.13 μg/ml, resp.) of O$\rm{{_{2}^{{^\cdot} -}}}$ generation by human nutrophils in response to N‐formyl‐L ‐methionyl‐L ‐leucyl‐L ‐phenylalanine/cytochalasin B (fMLP/CB). In addition, 2‐[2‐(hydroxymethyl)‐1‐benzofuran‐5‐yl]‐4‐(prop‐2‐en‐1‐yl)phenol ( 1 ), 2′‐ethoxy‐5,5′‐di(prop‐2‐en‐1‐yl)biphenyl‐2‐ol ( 2 ), magnolol ( 6 ), and vanillic acid ( 8 ) inhibited fMLP/CB‐induced elastase release with IC₅₀ values=6.4±1.5, 2.4±0.4, 1.5±0.2, and 4.8±0.5 μg/ml, respectively.     

α-Glucosidase Inhibition by Usnic Acid Derivatives

This study investigated a set of new potential antidiabetes agents. Derivatives of usnic acid were designed and synthesized. These analogs and nineteen benzylidene analogs from a previous study were evaluated for enzyme inhibition of α-glucosidase. Analogs synthesized using the Dakin oxidative method displayed stronger activity than the pristine usnic acid (IC₅₀>200 μM). Methyl (2E,3R)-7-acetyl-4,6-dihydroxy-2-(2-methoxy-2-oxoethylidene)-3,5-dimethyl-2,3-dihydro-1-benzofuran-3-carboxylate ( 6b ) and 1,1′-(2,4,6-trihydroxy-5-methyl-1,3-phenylene)di(ethan-1-one) ( 6e ) were more potent than an acarbose positive control (IC₅₀ 93.6±0.49 μM), with IC₅₀ values of 42.6±1.30 and 90.8±0.32 μM, respectively. Most of the compounds synthesized from the benzylidene series displayed promising activity. (9bR)-2,6-Bis[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 1c ), (9bR)-3,7,9-trihydroxy-8,9b-dimethyl-2,6-bis[(2E)-3-phenylprop-2-enoyl]dibenzo[b,d]furan-1(9bH)-one ( 1g ), (9bR)-2-acetyl-6-[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 2d ), (9bR)-2-acetyl-6-[(2E)-3-(3-chlorophenyl)prop-2-enoyl]-3,7,9-trihydroxy-8,9b-dimethyldibenzo[b,d]furan-1(9bH)-one ( 2e ), (6bR)-8-acetyl-3-(4-chlorophenyl)-6,9-dihydroxy-5,6b-dimethyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 3e ), (6bR)-8-acetyl-6,9-dihydroxy-5,6b-dimethyl-3-phenyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 3h ), (6bR)-3-(2-chlorophenyl)-8-[(2E)-3-(2-chlorophenyl)prop-2-enoyl]-6,9-dihydroxy-5,6b-dimethyl-2,3-dihydro-1H-[1]benzofuro[2,3-f][1]benzopyran-1,7(6bH)-dione ( 4b ), and (9bR)-6-acetyl-3,7,9-trihydroxy-8,9b-dimethyl-2-[(2E)-3-phenylprop-2-enoyl]dibenzo[b,d]furan-1(9bH)-one ( 5c ) were the most potent α-glucosidase enzyme inhibitors, with IC₅₀ values of 7.0±0.24, 15.5±0.49, 7.5±0.92, 10.9±0.56, 1.5±0.62, 15.3±0.54, 19.0±1.00, and 12.3±0.53 μM, respectively.     

New Phenylpropanoid Glycosides from Illicium majus and Their Radical Scavenging Activities

Chemical investigation of the ethanol extract of the branch and leaves of Illicium majus resulted in the isolation of four new phenylpropanoid glycosides ( 1 – 4 ) and one new phenolic glycoside ( 9 ), along with 13 known ones. Spectroscopic techniques were used to elucidate the structures of the new isolates such as 3-[(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-2,3-dihydro-1-benzofuran-5-yl]propyl β-D-glucopyranoside ( 1 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-glucopyranoside ( 2 ), [(2R,3S)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-5-(3-hydroxypropyl)-2,3-dihydro-1-benzofuran-3-yl]methyl 2-O-α-L-rhamnopyranosyl-β-D-xylopyranoside ( 3 ), 3-[(2R,3S)-3-({[2-O-(4-O-acetyl-α-L-rhamnopyranosyl)-β-D-xylopyranosyl]oxy}methyl)-7-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-2,3-dihydro-1-benzofuran-5-yl]propyl acetate ( 4 ), and 4-(2-hydroxyethyl)phenyl 3-O-β-D-glucopyranosyl-β-D-glucopyranoside ( 9 ). Free radical scavenging activities of the isolates were elucidated through the DPPH assay method. The most active compounds, 1-O-caffeoyl-β-D-glucopyranose ( 17 ) and soulieana acid 1 ( 18 ), exhibited moderate radical scavenging activities (IC₅₀=37.7±4.4 μM and IC₅₀=97.2±3.4 μM, respectively). The antibacterial activities of the isolates against Staphylococcus aureus and Escherichia coli were also assessed, and no activity was shown at the measured concentration (<32 μg/mL).