BACE inhibitory flavanones from Balanophora involucrata Hook. f.

One new flavanone (S)-5,7,3′,5′-tetrahydroxy-flavanone-7-O-(6″-galloyl)-β-D-glucopyranose (1), together with one known flavanone and four known dihydrochalcones were isolated from the ethyl acetate partitions from an alcoholic extract of the whole plant of Balanophora involucrata Hook. f. All of the compounds were characterized by spectroscopic methods. Their in vitro BACE inhibitory effects were evaluated. Compounds 1, 2, 4, and 5 were found to be a little more active than the positive control, although all of which are below 50% inhibition at 10 μM.     

Prenylated phloroglucinol derivatives from Hypericum sampsonii

Six new acylphloroglucinol derivatives, sampsonols A-F (1–6), were isolated from the petroleum ether extract of the aerial parts of Hypericum sampsonii. The structures and relative configurations of sampsonols A-F were elucidated by extensive spectroscopic analyses. All these compounds were tested for their in vitro cytotoxic and anti-inflammatory activities. Sampsonols A and B (1 and 2) showed significant cytotoxicity against four human tumor cell lines with IC₅₀ values in the range of 13–28 μM, whereas sampsonols C and F (3 and 6) showed potent inhibitory activities against LPS-induced NO production in RAW 264.7 macrophages with IC₅₀ values of 27.3 and 29.3 μM, respectively.     

A new dicoumarin and anticoagulant activity from Viola yedoensis Makino

A new dicoumarin, named as dimeresculetin (1), together with another dicoumarin, euphorbetin (2) and esculetin (3) were isolated from the ethyl acetate extract of the dried whole plants of Viola yedoensis Makino. The structure of 1 was elucidated as 7-hydroxy-6-[(6,7-dihydroxy-2-oxo-2H-1-benzopyran-5-yl)oxy]-2H-1-benzopyran-2-one on the basis of extensive NMR, as well as the other spectral analysis. Compounds 1–3 exhibited anticoagulant activities with respect to activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT).     

Antidiarrhoeal activity of carbazole alkaloids from Murraya koenigii Spreng (Rutaceae) seeds

The bioassay guided fractionation of the n-hexane extract of the seeds of Murraya koenigii Spreng (Rutaceae) resulted in the isolation of three bioactive carbazole alkaloids, kurryam (I), koenimbine (II) and koenine (III). The structures of the compounds were confirmed from their ¹H-, ¹³C-, and 2D-NMR spectral data. Of the three compounds (I) and (II) exhibited significant inhibitory activity against castor oil-induced diarrhoea and PGE₂-induced enteropooling in rats. The compounds also produced a significant reduction in gastrointestinal motility in the charcoal meal test in Wister rats.     

New flavonol glycosides from Aconitum burnatii Gáyer and Aconitum variegatum L.

Six flavonol glycosides, compounds 1-3 from A. burnatii Gáyer and 4-6 from A. variegatum L., were obtained from their methanol extracts of aerial parts. The identified structures were quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-p-coumaroyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (1), quercetin 3-O-β-d-glucopyranoside-7-O-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (2), quercetin 3-O-β-d-glucopyranoside-7-O-(6-E-caffeoyl)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside (3), kaempferol 3-O-β-d-galactopyranoside-7-O-α-l-arabinopyranoside (4), quercetin 3-O-β-d-glucopyranoside (5), and kaempferol 3-O-β-d-glucopyranoside (6). Compounds 1, 2 and 4 were isolated for the first time. The antioxidant potential of the methanol extracts and pure compounds was tested with different assays.     

Three new water-soluble alkaloids from the leaves of Suregada glomerulata (Blume) Baill

Three new water-soluble alkaloids (1-3) together with twelve known compounds (4-15) have been isolated from the water extract of leaves of Suregada glomerulata. Their structures were determined by spectroscopic analysis and chemical method. Compounds 1-3 were evaluated for their in vitro inhibitory activity against α-glucosidase and HIV-1 replication. However, no significant activities were found.     

A secoiridoid with quinone reductase inducing activity from Cortex fraxini

A new secoiridoid named chinensisol (1) along with twenty known compounds were isolated from the 95% ethanol extract of Cortex fraxini. Their structures were elucidated on the basis of NMR, MS, IR and UV spectral evidences. The quinone reductase (QR) inducing activities of the compounds were evaluated and the results showed that compounds 1, 9 and 14 had moderate QR inducing activities with CD values (concentration required to double the specific activity of QR) of 72.4 ± 7.7, 34.3 ± 3.3 and 42.0 ± 0.4 μM respectively.     

Anti-inflammatory, antioxidant and antifungal furanosesquiterpenoids isolated from Commiphora erythraea (Ehrenb.) Engl. resin

The topical anti-inflammatory, free radical scavenging and antifungal activities of essential oils and extracts of Commiphora erythraea (Ehrenb.) Engl. resin were investigated. The hexane extract significantly inhibited oedema when applied topically in Croton oil-induced ear oedema assay in mice. The same extract showed antioxidant activity in DPPH radical scavenging assay. A bioguided separation of the hexane extract led to the isolation of furanosesquiterpenoids 1 and 2 that showed a weak antifungal activity, while compounds 3-5 resulted to be antioxidant (EC₅₀ 4.28, 2.56 and 1.08 mg/mL, respectively) and anti-inflammatory (30, 26 and 32% oedema reduction, respectively).     

Anti-inflammatory constituents from Tabebuia avellanedae

Five novel compounds were isolated from the water extract of Tabebuia avellanedae, and their structures were established by analysis of NMR spectroscopy and mass spectrometry. Compounds 1–5 at 25 μM showed strong inhibitory activity on the inflammatory cytokine, tumor-necrosis factor-α and interleukin-1β production in cultured human myeloma THP-1 cells co-stimulated with lipopolysaccharide without any significant cytotoxicity, and their anti-allergic and antioxidant activities were evaluated.     

HPLC-based activity profiling of Angelica pubescens roots for new positive GABAA receptor modulators in Xenopus oocytes

A petroleum ether extract of the traditional Chinese herbal drug Duhuo (roots of Angelica pubescens Maxim. f. biserrata Shan et Yuan), showed significant activity in a functional two-microelectrode voltage clamp assay with Xenopus oocytes which expressed recombinant γ-aminobutyric acid type A (GABA_A) receptors of the subtype α₁β₂γ_2S. HPLC-based activity profiling of the active extract revealed six compounds responsible for the GABA_A receptor modulating activity. They were identified by microprobe NMR and high resolution mass spectrometry as columbianetin acetate (1), imperatorin (3), cnidilin (4), osthol (5), and columbianedin (6). In concentration-dependent experiments, osthol and cnidilin showed the highest potentiation of the GABA induced chloride current (273.6% ± 39.4% and 204.5% ± 33.2%, respectively at 300 μM). Bisabolangelone (2) only showed minor activity at the GABA_A receptor. The example demonstrates that HPLC-based activity profiling is a simple and efficient method to rapidly identify GABA_A receptor modulators in a bioactive plant extract.     

Cyclic bisdesmosides from Actinostemma lobatum MAXIM (Cucurbitaceae) and their in vitro cytotoxicity

Two new cyclic bisdesmosides elucidated as lobatoside L (1) and lobatoside M (2) and four known cyclic bisdesmosides (3-6) were isolated from Actinostemma lobatum MAXIM (Cucurbitaceae). Their structures were determined on the basis of spectroscopic analyses including IR, HR-FAB-MS, TOCSY, 1D- and 2D-NMR experiments and chemical reactions. The inhibitory effects of the six compounds on human cancer cell growth (including esophageal squamous carcinoma cell line ECA109, lung cancer cell line A549 and gastric cancer cell line MGC-803) were determined using the MTT assay. The results revealed that the six compounds exhibited cytotoxicity against all the cell lines tested, and compounds 1, 3 and 5 showed significant activities in a dose dependent manner against all the cell lines, especially for compound 1 and 5, the IC₅₀ values for ECA-109 cells were 8.25 μM and 3.71 μM. The results demonstrated that compounds 1 and 5's activities are 2- and 4-fold that of cisplatin.     

Mushroom tyrosinase inhibitors from Aloe barbadensis Miller

Two new chromones, 5-((S)-2′-oxo-4′-hydroxypentyl)-2-(β-glucopyranosyl-oxy-methyl)chromone (1) and 5-((S)-2′-oxo-4′-hydroxypentyl)-2-methoxychromone (2), together with four known analogues, 8-C-glucosyl-7-O-methyl-(S)-aloesol (3), isoaloeresin D (4), 8-C-glucosyl-(R)-aloesol (5), and aloesin (6) were isolated from the aqueous extract of Aloe barbadensis Miller. Their structures were determined on the basis of spectroscopic evidences (1-D and 2-D NMR, HRMS, UV, and IR data), chemical methods and the literature data. The Mosher's method was applied to establish the absolute configuration of compounds 1 and 2. The inhibitory effects of these chromones on the activity of mushroom tyrosinase were examined, and compound 6 was identified as a noncompetitive tyrosinase inhibitor with an IC₅₀ value of 108.62 μg·mL^− 1.     

Chemical constituents of the Vietnamese liverwort Porella densifolia

From the ether extract of Porella densifolia, the first liverwort collected and chemically investigated in Vietnam, a kaurane diterpenoid, ent-kauren-15-one (1) and two sesquiterpene norpinguisone (2) and norpinguisone methyl ester (3) have been purified. Their structures were elucidated by spectroscopic analysis. In addition, an X-ray crystal structure of norpinguisone was obtained, allowing to determine its stereochemistry. Furthermore, the inhibitory activity of nitric oxide (NO) production in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) of compounds 1–3 was examined with their IC₅₀ values of 69.4, 45.5 and 1.68 μM, respectively.     

Chemical constituents from Delphinium chrysotrichum and their biological activity

A new diterpene alkaloid named delphatisine C (1) has been isolated from aerial parts of Delphinium chrysotrichum along with three known norditerpenoid alkaloids delpheline (2), delbrunine (3), and delectinine (4). Their structures were characterized on the basis of their spectral data. All of them were determined by SRB assay for their cytotoxicity, and compound (1) showed significant cytotoxic activities (IC₅₀ = 2.36 μmol/L) against the A549 cell line.     

Antioxidant flavonoids from the seed of Oroxylum indicum

Three new flavonoid glycosides (1-3) and nineteen known compounds (4-22) were isolated from the aqueous ethanolic extract of the seed of Oroxylum indicum. The structures of 1-3 were elucidated on the basis of spectroscopic analysis. Antioxidant activities of all the isolated compounds were evaluated using a DPPH and an ORAC assay. Compounds 3, 5-7, 9 and 12 exhibited potent antioxidant activity in the DPPH assay, while compounds 3-15 showed potent antioxidant capacity in the ORAC assay, and seven antioxidant flavonoids (4-6, 8, 9, 11, 12) were detected as the main ingredients in the methanolic extract of seed of O. indicum using an HPLC analysis.     

New diterpenoids and cytotoxic and anti-inflammatory diterpenoids from Amentotaxus formosana

Two new abietane diterpenoids, ramentoxide (1) and ramentoxidone (2) and a new icetexane diterpenoid, amentonone (3) were isolated from the barks of Amentotaxus formosana. The structures of 1-3 were determined by spectroscopic methods. Known compounds brevitaxin (4), and (+)-ferruginol (5) and ent-kaur-16-en-15-one (6) isolated from this plant revealed potent cytotoxic activity against human breast adenocarcinoma cells, MCF-7 cells with an IC₅₀ value of 0.08 ± 0.05 μg/mL, and significant anti-inflammatory activities, respectively.     

Novel indole C-glycosides from Isatis indigotica and their potential cytotoxic activity

Two novel indole C-glycosides, which were the first reported alkaloids C-glycosides from Isatis indigotica, together with five known alkaloids were isolated. The novel alkaloids were elucidated to be indole-3-acetonitrile-4-methoxy-2-C-β-D-glucopyranoside (1) and N-methoxy-indole-3-acetonitrile-2-C-β-D-glucopyranoside (2) on the basis of spectroscopic analysis. 1 exhibited significant cytotoxic activities against human myeloid leukemia HL-60 and human liver cancer HepG2 cells with the IC₅₀ of 1.3 ± 0.1 and 2.1 ± 0.3 μM, respectively. 2 showed potential cytotoxic activities against HL-60 and human myeloid leukemia Mata cells with the IC₅₀ of 5.1 ± 0.4 and 12.1 ± 0.8 μM, respectively.     

Two new benzofuran derivatives with anti-inflammatory activity from Liriope spicata var. prolifera

Two new benzofuran derivatives, 2-(4′-hydroxybenzyl)-5,6-methylenedioxy-benzofuran () and 2-(4′-hydroxybenzoyl)-5,6-methylenedioxy-benzofuran (), along with 8 known compounds were isolated from 60% EtOH extract of the fibrous roots of Liriope spicata var. prolifera. Their structures were elucidated on the basis of extensive spectroscopic analysis. In an in vitro bioactive assay, the two new benzofuran derivatives showed anti-inflammatory activity. Compounds 1 and 2 exhibited significant inhibitory activity against neutrophil respiratory burst stimulated by phorbol 12-myristate 13-acetate (PMA) with IC₅₀ value of 4.15 ± 0.07 and 5.96 ± 0.37 μM, respectively.     

Antibacterial dihydrobenzopyran and xanthone derivatives from Garcinia cowa stem barks

Two new compounds, garciniacowol (1) and garciniacowone (2) along with 15 known compounds were isolated from the stem barks of Garcinia cowa. Their structures were determined by intensive spectroscopic methods. The structure of 1 was a symmetrical dimeric dihydrobenzopyran derivative, whereas the framework of 2 was a triprenyl caged-xanthone precursor. The antibacterial activities against Escherichia coli TISTR 780, Salmonella typhimurium TISTR 292, Staphylococcus aureus TISTR 1466, and methicillin-resistant S. aureus (MRSA) SK1 of the isolated compounds were also evaluated. Compounds 2 and 9 exhibited good antibacterial activity against MRSA SK1 with the same minimum inhibitory concentration (MIC) value of 2 μg/mL. Moreover, compound 2 also showed good antibacterial activity against S. aureus with an MIC value of 2 μg/mL.     

Aporphine alkaloids,clerodane diterpenes,and other constituents from Tinospora cordifolia

Phytochemical investigation of the methanol extract of Tinospora cordifolia aerial parts led to the isolation of four new and seven known compounds. The structures of two new aporphine alkaloids, N-formylasimilobine 2-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside (tinoscorside A, 1) and N-acetylasimilobine 2-O-β-d-glucopyranosyl-(1 → 2)-β-d-glucopyranoside (tinoscorside B, 2), a new clerodane diterpene, tinoscorside C (3), and a new phenylpropanoid, sinapyl 4-O-β-d-apiofuranosyl-(1 → 6)-O-β-d-glucopyranoside (tinoscorside D, 6) were determined by extensive spectroscopic methods including FTICR-MS and 1D and 2D NMR.