Oxidatively rearranged cycloartane triterpenoids from the seeds of Pseudolarix amabilis

One novel and eight known oxidatively rearranged cycloartane triterpenoids were isolated from the seeds of Pseudolarix amabilis. The structure of the new isolate was elucidated on extensive spectroscopic analyses. Results indicated that pseudolarolide Q (4) exhibited strong antimicrobial activity against Gram-positive Staphylococcus aureus and Candida albicans at the MICs of 6.08 and 24.32 μM, respectively. Pseudolarolide I (2) showed the 11β-HSD1 inhibitory property at the IC₅₀ value of 34.5 nM.     

Five New Cycloartane‐Type Triterpenoid Saponins from Nervilia fordii

Five new cycloartane glycosides, nervisides D–H ( 1 – 5 ), were isolated from the AcOEt‐ and H₂O‐soluble portions of the 90% EtOH extract of the aerial part of the plant Nervilia fordii. The structures of the isolated glycosides were elucidated by extensive spectroscopic analysis including HR‐ESI‐MS and NMR data. The isolated nervisides D–H were evaluated for the cytotoxic activity in vitro against human‐tumor cell lines (CNE, Hep‐2 and HepG2) with the MTT method.     

Alpha-glucosidase inhibitory activity of ethanol extract,fractions and purified compounds from the wood of Albizia myriophylla

Albizia myriophylla Benth. is a medicinal herb which is used as a traditional remedy for various ailments including diabetes in Thailand. In our continued investigation of the biological activity of A. myriophylla, the ethanol extract, fractions and the isolated compounds from the wood of this plant were evaluated for in vitro α-glucosidase inhibition using spectrophotometric method. The plant ethanol extract and its different fractions possessed α-glucosidase inhibitory activity in a concentration-dependent manner. Dichloromethane fraction of the wood ethanol extract exhibited the highest percent inhibition against α-glucosidase (69.30%) among all fractions. Subsequent α-glucosidase inhibition assay proved that indenoic acid (1), 8-methoxy-7, 3′,4′-trihydroxyflavone (2) and 3,4,7,3′-tetrahydroxyflavan (3) were partially rational for antidiabetic effect of this plant species. Among these compounds, 3 (IC₅₀ 98.59 μg/mL) exhibited potent inhibition of α-glucosidase, compared with a positive control acarbose (IC₅₀ 125 μg/mL). The inhibitory effect towards α-glucosidase of compounds 1–3 was reported herein for the first time.     

A new morphinandienone alkaloid from the stems of Fissistigma tungfangense

A new morphinandienone alkaloid, fissistigmine A (1), together with three known alkaloids (2?4), were isolated and identified from the stems of Fissistigma tungfangense. Among them, fissistigmine A (1) represents the first example of a novel naturally occurring morphinandienone alkaloid with a unique cleavage of the C-9?N-17 bond. All isolated compounds were evaluated for their anti-rheumatoid arthritis activities via examining their anti-proliferative effects on synoviocytes in vitro. Compound 1 exhibited inhibitory effect on the proliferation of synoviocytes with an IC₅₀ value of 114.6 ± 2.2 μM.     

Two new protostane-type triterpenoids from Alisma orientalis

Two new protostane-type triterpenoids, 17-epi alisolide (1) and 24-epi alismanol D (2), were isolated from Alisma orientalis together with one known compound. Their structural elucidations were conducted by NMR, UV and HRESIMS spectroscopic analyses, and comparison with the literature data. All the isolated compounds were evaluated for inhibitory effects on HCE-2. Compound 2 displayed moderate inhibitory activity against HCE-2 with IC₅₀ value of 23.1 μM.     

A new guaiane sesquiterpene from cultures of the fungus Fulvifomes kanehirae

A new guaiane sesquiterpene (1) was isolated from cultures of the fungus Fulvifomes kanehirae. Its structure was elucidated by spectroscopic methods including extensive 2D-NMR techniques. Meanwhile, the compound was tested for its inhibitory activity against isozymes of 11β-hydroxysteroid dehydrogenases (11β-HSD).     

New cadinane sesquiterpenoids from Mikania micrantha

Abstract

Chemical investigation of the aerial parts of Mikania micrantha led to the isolation of eight sesquiterpenoids and ten diterpenoids, including five cadinane sesquiterpenoids (1?5), three bisabolene sesquiterpenoids (6???8), nine ent-kaurane diterpenoids (9–17), and an abietane diterpenoid (18). Among them, 1???3 are new and feature a rare lactone or furan ring derived from C-6 isopropyl group side chain. Compound 18 was isolated from genus Mikania for the first time, and was also the first example of abietane-type diterpenoids from this plant. Their structures were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, HRESIMS, and ECD). All compounds were examined for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophage cells, and compound 18 exhibited pronounced inhibition on NO production (IC₅₀ = 11.04?µM), being comparable to the positive control, quercetin (IC₅₀ = 11.15?µM).     

β-Secretase inhibition by C-methylisoflavones from Abronia nana

The methanol extract of Abronia nana suspension cultures were subjected to column chromatography to identify potential inhibitors of β-secretase, which is a major factor in Alzheimer’s disease development. Two new C-methylisoflavones boeravinone T (1) and U (4) were isolated with three knowns boeravinone B (2), J (3) and X (5). The half-maximal inhibitory concentration (IC₅₀) values of compounds 1–5 were 18.29, 8.57, 7.87, 12.02 and 5.30 μM, respectively. The most potent 5, non-competitively inhibited β-secretase [inhibition constant (K_i) = 3.79 μM]. Compounds 1–5 did not inhibit other proteases such as chymotrypsin, trypsin and elastase at concentrations up to 1 mM, indicating that they were relatively specific inhibitors of β-secretase. A free hydroxyl group at C-3 position of the C-methylisoflavone skeleton appeared to be responsible for the stronger inhibitory activity against β-secretase.     

Pheophytin analogues from the medicinal lichen Usnea diffracta

A new pheophytin, (13²S, 17S, 18S)-13²-hydroxy-20-chloro-ethylpheophorbide a (3), along with two known analogues (1–2) were isolated from the lichen Usnea diffracta Vainio (Parmeliaceae). Among them, compound 3 was a rare C-20-chloro type pheophytin obtained from lichens. Their structures were elucidated by extensive spectroscopic analysis, and all the compounds were obtained for the first time from U. diffracta. Compounds (1–3) were evaluated for their xanthine oxidase (XO) inhibitory activities in vitro, and the results showed that 1–3 possessed significant enzyme inhibitory actions with IC₅₀ values of 46.9 ± 3.8, 75.9 ± 7.4 and 42.1 ± 1.7 μg/mL, respectively.     

Phenolic compounds isolated from Morus nigra and their α-glucosidase inhibitory activities

Abstract

A novel benzofuranone unprecedentedly with a prenyl group at C-3, nigranol A (1), a new flavonol, nigranol B (2), and three known compounds, sanggenon M (3), nigrasin C (4), and nigrasin A (5) were isolated from the twigs of Morus nigra Linn. Their structures were elucidated on the basis of the analysis of multiple spectroscopic data. All of the compounds, along with eight previously isolated ones (6–13) were investigated for their α-glucosidase inhibitory activities. The result showed that compounds 1–13 except 4 exhibited prominent inhibitory activities against α-glucosidase. Among them, compounds 2 and 7 were the best α-glucosidase inhibitory candidates with IC₅₀ values at 1.63 and 1.43?μM, respectively. Furthermore, the structure-activity relationships of the sanggenon-type flavanones were summarized.     

Lipoxygenase inhibitory activity of Cuspidaria pulchra and isolated compounds

This work evaluated the in vitro inhibitory activity of the crude ethanolic extract from the aerial parts of Cuspidaria pulchra (Cham.) L.G. Lohmann against 15-lipoxygenase (15-LOX). The bioassay-guided fractionation of the n-butanol fraction, which displayed the highest activity, led to the isolation of three compounds: caffeoylcalleryanin (1), verbascoside (2) and 6-hydroxyluteolin-7-O-β-glucoside (3). Assessment of the ability of the isolated compounds to inhibit 15-LOX revealed that compounds 1, 2 and 3 exerted strong 15-LOX inhibitory activity; IC₅₀ values were 1.59, 1.76 and 2.35 μM respectively. The XTT assay showed that none of the isolated compounds seemed to be significantly toxic.     

Two new sesquineolignans from the seeds of Crataegus pinnatifida and their β-amyloid aggregation inhibitory activitiy

Two new sesquineolignans, hawthornsesquinins K and L (1 and 2), were isolated from the seeds of Crataegus pinnatifida. Their structures were determined by spectroscopic analyses, including 1D, 2D NMR and HRESIMS data. All isolated compounds were tested for their β-amyloid aggregation inhibitory activity and neuroprotective effects against H₂O₂-induced damage in SH-SY5Y cells. The results indicated that compound 1 showed prominent inhibition of Aβ_1–42 aggregation and significant neuroprotective effect on H₂O₂-induced cellular damage in SH-SY5Y cells.     

Protein tyrosine phosphatase 1B inhibitors from a marine-derived fungal strain aspergillus sp. SF-5929

Abstract

In the course of our continuing investigation of bioactive secondary metabolites from marine-derived fungal strains, a racemate of a novel diphenolic derivative named (±)-tylopilusin D (1) along with ten previously known secondary metabolites (2–11) were isolated from a marine-derived fungal strain Aspergillus sp. SF-5929. Their structures were elucidated mainly by analysis of NMR and MS data. In addition, the inhibitory effects of the isolated compounds against protein tyrosine phosphatase 1B (PTP1B) activity were evaluated, and compounds 1, 2, and 5–7 inhibited PTP1B activity with IC₅₀ values ranging from 3.3 to 8.1?µM. Kinetics studies suggested that compounds 1, 2, and 5 had noncompetitive inhibitory effects against PTP1B.     

Three new labdane-type diterpenoids from Callicarpa macrophylla Vahl.

Three new labdane-type diterpenoids, callicapene M3-M5 (1–3) were isolated from the Callicarpa macrophylla Vahl. Their structures were identified by spectroscopic method. The isolated compounds were evaluated for inhibitory activity on NO production in LPS-activated RAW 264.7 macrophage cells by using MTT assays. Compounds 1–3 showed potent inhibitory activity, with IC₅₀ value of 48.15, 46.31 and 38.72?μM respectively.     

New C20-gibberellin diterpene from the leaves of Schefflera sessiliflora De P. V.

From the leaves of Schefflera sessiliflora De P. V., one new C₂₀-gibberellin diterpene 2β,12β-dihydroxygibberellin (12β-hydroxy-GA₁₁₀ or 2β-hydroxy-GA₁₁₂) (1), together with three known compounds, trans-tiliroside (2), kaempferol 3-O-β-d-glucuronopyranoside (3), 5-p-trans-coumaroylquinic acid (4), was isolated for the first time from the genus Schefflera by various chromatography methods. Their structures were elucidated by IR, UV, HR-ESI-MS, NMR 1D and 2D experiments and comparison with previous reported data. The α-glucosidase inhibitory activity of all compounds was measured. The isolates (2, 3) showed better α-glucosidase inhibitory activity (IC₅₀ = 134.60, 147.10 μM, respectively) than the standard drug acarbose (IC₅₀ = 214.50 μM).     

New naphthopyrones from marine-derived fungus Aspergillus niger 2HL-M-8 and their in vitro antiproliferative activity

A new cytotoxic dimeric naphthopyrone, aurasperone H (1), together with eight related known polyketides (2–9) was isolated from a marine-derived fungus Aspergillus niger 2HL-M-8. The structure of new compound 1 was elucidated on the basis of its spectroscopic data (1D, 2D NMR and CD). Compound 1 exhibited moderate inhibitory activity against the human lung adenocarcinoma A549 and the human leukaemia HL-60 cell lines. Compound 5 displayed significant in vitro antiproliferative activity against HL-60 cell line with an IC₅₀ value of 0.8 μM.     

A new triterpenoid glucoside from Leucas zeylanica

Abstract

A new triterpenoid glucoside, leuctriterpencoside (1), along with two known compounds (2–3) were isolated from Leucas zeylanica. The structure of the new compound was elucidated using comprehensive spectroscopic methods. Compound 1 showed significant inhibitory activity against α-glucosidase (IC₅₀ value of 0.85?±?0.12?μM).     

A new bibenzyl derivative with nuclear factor-kappaB inhibitory activity from Schefflera arboricola (Araliaceae)

A new bibenzyl derivative (1), 4-acetoxy-3,5,3′,4′-tetramethoxybibenzyl, along with eight known compounds (2–9), was isolated from the twigs and leaves of Schefflera arboricola (Araliaceae). The isolated compounds were elucidated mainly by means of one-dimensional, two-dimensional NMR and MS, and by comparison with the literature data. Compounds 2–5 and 7–9 are first reported from this plant. In the in vitro assays, compound 1 displayed moderate nuclear factor-kappaB inhibitory activity.     

A new aldehyde compound from the fruit of Pandanus tectorius Parkinson ex Du Roi

From the fruit of Pandanus tectorius Parkinson ex Du Roi, one new (1) and six known aldehyde compounds (2–7) were isolated by various chromatography methods. Based on their spectroscopic data, these compounds were identified as (Z)-4-hydroxy-3-(4-hydroxy-3-methylbut-2-en-1-yl) benzaldehyde (1), p-hydroxybenzaldehyde (2), syringaldehyde (3), (E)-ferulaldehyde (4), (E)-sinapinaldehyde (5), vanillin (6) and 5-hydroxymethylfurfual (7). The α-glucosidase inhibitory activity of all compounds was measured. The isolated compounds (1–6) showed better α-glucosidase inhibitory activity (IC₅₀ values ranging from 36.5 to 192.4 μM) than the standard drug acarbose (IC₅₀ = 214.5 μM).     

New 2-arylbenzofurans from the root bark of Artocarpus gomezianus and their α-glucosidase inhibitory activity

Two new 2-arylbenzofurans, namely 13-O-methyllakoochin B (1) and artogomezianin (2), were isolated from the root bark of Artocarpus gomezianus, along with six known compounds (3–8). The structures of new compounds were determined by spectroscopic and chemical methods. All of the isolates were evaluated for their α-glucosidase inhibitory activity. Artogomezianin (2) and lakoochin A (3) exhibited strong α-glucosidase inhibitory activity with IC₅₀ values of 18.25 and 26.19 µM, respectively, as compared with the positive control acarbose.