A new isoquinoline alkaloid with anti-microbial properties from Berberis jaeschkeana Schneid. var. jaeschkeana

One new isoquinoline alkaloid named berberidione (1) along with four new source alkaloids berberine (2), palmatine (3), jatrorrhizine (4) and chondrofoline (5) and three new source non-alkaloids syringic acid (6), β-sitosterol (7) and stigmasterol (8) was isolated and characterised from different fractions of Berberis jaeschkeana Schneid var. jaeschkeana. All the structures were determined from 1D and 2D spectroscopic data. Crude extract, sub-fractions and isolated compounds showed excellent anti-microbial properties. The toxicity level for the alkaloids was found to be very low on THP-1 cells.     

Urease inhibitory potential of extracts and active phytochemicals of Hypochaeris radicata (Asteraceae)

Abstract

Urease inhibition potential of compound (1), guaiane-type sesquiterpene (2), confertin (3) and scopoletin (4) was carried out with high throughout mechanism-based assay. These compounds were isolated from Hypochaeris radicata L., an Asteraceae family member. The pure compounds were screened for their urease and carbonic anhydrase inhibitory activities. The ethyl acetate fractions were subjected to column chromatography, which resulted in the isolation and purification of four compounds (1–4). On evaluation, compounds (1–4) exhibited selective activity against urease enzyme with an IC₅₀ value of 180.11 ± 2.00, 27.18 ± 0.80, 24.12 ± 0.2 and 30.12 ± 1.10 µM respectively. The compounds (1–4) were found to be inactive against carbonic anhydrase enzyme. Thiourea was used as standard inhibitor (21 ± 0.14 µM) of urease enzyme.     

A New Indole Alkaloid from Cleome droserifolia

The phytochemical investigations on Cleome droserifolia resulted in the isolation and characterization of a new indole alkaloid, 5‐hydroxy‐2‐methoxy‐1‐methyl‐1H‐indole‐3‐carbaldehyde ( 1 ). The structure elucidation was carried out on the basis of 1D‐ and 2D‐NMR techniques. In addition to 1 , two known aromatic derivatives, veratrol ( 2 ) and 2‐methoxy‐4‐methylacetophenone ( 3 ), were also obtained. All these compounds were purified by repeated column chromatography of the CH₂Cl₂ fraction obtained from MeOH extract of Cleome droserifolia. The structure of the new compound 1 was finally confirmed by the combined 1D (¹H‐ and ¹³C‐) and 2D (H? C correlations; HMBC and HSQC) NMR and IR spectroscopy, mass spectrometry (MS), and UV absorption spectroscopy techniques. The comparison of the physical and spectroscopic data with those in the literature provided evidence for the structure confirmation of known compounds. All the purified compounds were subjected to urease and α‐glucosidase enzymes inhibition. The results showed that compound 1 was more potent with an IC₅₀ value 11.97±2.067 μg/ml towards urease inhibition, while the activity of α‐glucosidase enzyme was marginal.     

Structure activity relationship of bergenin,p-hydroxybenzoyl bergenin, 11-O-galloylbergenin as potent antioxidant and urease inhibitor isolated from Bergenia ligulata

Ethanol extract of the aerial parts of Bergenia ligulata was subjected to solvent–solvent separation followed by various chromatographic techniques that lead to isolation of bergenine (1), p-hydroxybenzoyl bergenin (2), 11-O-galloylbergenin (3) and methyl gallate (4) as major constituents. Ethyl acetate fraction showed a dose-dependent urease inhibitory pattern with IC₅₀ value of 54μg/mL. Structures of compounds 1 and 3 were established by XRD and 2, 4 by NMR. All these compounds were subjected to DPPH scavenging activity, reducing power assay and urease inhibitory activity. The EC₅₀ 7.45 ± 0.2 μg/mL and 5.39 ± 0.28 μg/mL values in terms of antioxidant and reducing power, respectively, were less for 3. Compounds 1–3 showed moderate to significant urease inhibitory potential with IC₅₀ 57.1 ± 0.7, IC₅₀ 48.4 ± 0.3 and 38.6 ± 1.5. Antioxidant activities and urease inhibitory potential were investigated and compound 3 was found to be the most active.     

Phenanthrenes from Arundina graminifolia and in vitro evaluation of their antibacterial and anti-haemolytic properties

Chemical investigation and activity test of Arundina graminifolia led to the isolation of six phenanthrenes: blestriarene A (1), shancidin (2), densiflorol B (3), ephemeranthoquinone (4), coelonin (5) and lusianthridin (6). The isolated compounds demonstrated antibacterial and anti-haemolytic activities. It was found that compounds 1 and 2 had medium antibacterial activity against Staphylococcus aureus, Bacillus subtilis and Escherichia coli, with MICs of 20–40 μg/mL and MBCs of 40–320 μg/mL. Bactericidal mechanisms were explored. Rupture of cell wall and membrane and leakage of nuclear mass were observed by transmission electron microscopy (TEM). Moreover, compounds 1–3 attenuated the erythrocyte damage. Compounds 1 and 2 showed significant anti-haemolytic activity with inhibition rate about 50% at 16 μg/mL.     

Lignans from the seeds of Chinese hawthorn (Crataegus pinnatifida var. major N.E.Br.) against β-amyloid aggregation

Phytochemical investigation on the seeds of hawthorn (Crataegus spp.) led to the isolation of a new compound, (7′R, 8′R, 8S)-isolariciresinol (1), along with six known compounds (2–7). The structures of all compounds were determined based on spectroscopic data interpretation. The Aβ_1–42 inhibition activity of all isolated compounds was evaluated in vitro. As a result, compounds 5 and 6 showed stronger inhibition of Aβ_1–42 aggregation than curcumin, with inhibition rates of 70.59 and 68.14% at 20 μM. The possible mechanism of interaction between Aβ_1–42 and the active compounds 5 and 6 was also investigated by molecular docking.     

Bisamides and rhamnosides from mangrove actinomycete Streptomyces sp. SZ-A15

Four new bisamides 1–4, and two new rhamnosides (5, 6), along with four known compounds 7–10, were isolated from a scale culture of the mangrove-derived actinomycete Streptomyces sp. SZ-A15. All structures were determined through analysis of the UV, IR, HRESIMS, 1D and 2D NMR spectra as well as by comparison with literature data. BRD4 inhibition of all isolated compounds was evaluated. As for the ability to inhibit protein BRD4, compound 9 exhibited moderate activity with the value of 78.4 ± 2.2% at 10 μM.     

A new sulphated flavone and other phytoconstituents from the leaves of Tetracera indica Merr. and their alpha-glucosidase inhibitory activity

The bioactivity guided fractionation of Tetracera indica leaves crude ethanolic extract has afforded the isolation and characterization of six compounds including a new natural product viz., 5,7-dihydroxyflavone-O-8-sulphate (1) and five known flavonoids (2–6). The structures of the compounds were elucidated using 1D and 2D NMR and HRESIMS spectroscopic analyses. All the isolated compounds were evaluated for their in vitro inhibitory activity against alpha-glucosidase. Compound 1, 5 and 6 showed strong alpha-glucosidase inhibitory activity, 3 and 4 displayed weak activity while compound 2 was inactive. The interactions of the active compounds with alpha-glucosidase were further investigated using molecular docking to confirm their antidiabetic potential.     

Aloeverasides A and B: Two Bioactive C‐Glucosyl Chromones from Aloe vera Resin

Two new C‐glucosyl chromones named aloeverasides A ( 1 ) and B ( 2 ) were isolated from the resin of Aloe vera (L.) Burm.f . The structures of the two new natural products were elucidated based on 1D‐ (¹H‐ and ¹³C‐NMR) and 2D‐NMR (COSY, HSQC, and HMBC) spectroscopic techniques and mass spectrometry (ESI‐MS). Aloeverasides A ( 1 ) and B ( 2 ) were evaluated for their anticancer activity, and both induced a 76.4 and 70.5% growth inhibition of the breast cancer cell line (MDA‐MB‐231) at a concentration of 100 μm . Both compounds were also evaluated for their 1,1‐diphenyl‐2‐picryl‐hydrazyl antioxidant, urease enzyme, and α‐glucosidase enzyme inhibition activities. Aloeverasides A ( 1 ) and B ( 2 ) displayed good urease enzyme inhibition activities (62 and 55%, resp.), as well as antioxidant activity in which aloeveraside A ( 1 ) had a value of 60% inhibition, while aloeveraside B ( 2 ) demonstrated a more potent antioxidant activity with 80% inhibition.     

Phytochemical profiling,antioxidant, enzyme inhibition and cytotoxic potential of Bougainvillea glabra flowers

Abstract

In this study, phytochemical composition, antioxidant, enzyme inhibition and cytotoxic activities of methanol and dichloromethane (DCM) extracts of Bougainvillea glabra (B. glabra) flowers were investigated. Methanol extract was found to have higher total bioactive contents and UHPLC-MS analysis of methanol extract revealed the presence of well-known phenolic and flavonoid compounds. Antioxidant activities were performed by radical scavenging (DPPH and ABTS), reducing power (FRAP and CUPRAC), phosphomolybdenum (TAC) and metal chelating assays. From our result, we observed that methanol extract had many antioxidant compounds. The DCM extract exhibited higher cholinesterases and α-glucosidase enzyme inhibition, while methanol extract showed significant urease inhibition. Both extracts exhibited strong to moderate cytotoxicity against MCF-7, MDA-MB-231, CaSki, DU-145 and SW-480 cancer cells with IC₅₀ values ranging from 88.49 to 304.7 µg/mL. The findings showed the B. glabra to possess considerable antioxidant, enzyme inhibition and cytotoxic potentials and therefore has potential to discover novel bioactive molecules.     

Bioactive constituents from Croton sparsiflorus Morong

Whole plant extracts of Croton sparsiflorus in methanol have shown significant enzyme inhibition and antioxidant activities. Bioassay-guided isolation of chloroform fraction at pH 3 resulted in the identification of crotsparinine (1) and crotsparine (2), while sparsiflorine (3) was purified from the chloroform fraction at pH 9. The structures of the compounds were confirmed through spectral analyses (EI-MS, ¹H and ¹³C NMR). The isolated compounds 1–3 exhibited remarkable enzyme inhibition activity with IC₅₀ values 27.01 ± 1.1, 22.26 ± 1.0 and 18.02 ± 1.3 μM in xanthine oxidase and 48.42 ± 1.5, 48.05 ± 1.4 and 7.42 ± 1.0 μM in acetylcholine esterase assays, respectively. These compounds also showed potent radical scavenging and reducing properties in DPPH and FRAP assays, respectively. The present results suggest the validity of the traditional uses of C. sparsiflorus in rheumatism and gout. Furthermore, the isolated noraporphine alkaloids can be useful in the treatment of neurodegenerative diseases.     

Six new metabolites produced by Colletotrichum aotearoa 09F0161, an endophytic fungus isolated from Bredia oldhamii

Six new compounds, colletobredins A–D (1–4) and colletomelleins A and B (5 and 6), along with 12 previously identified compounds, were isolated from the culture broth of Colletotrichum aotearoa BCRC 09F0161, a fungal endophyte residing in the leaves of an endemic Formosan plant Bredia oldhamii Hook. f. (Melastomataceae). The structures of the new compounds were established by spectroscopic methods, including UV, IR, HR-ESIMS and extensive 1D and 2D NMR techniques. The effects of some isolates on the inhibition of nitric oxide (NO) production in lipopolysaccharide-activated murine macrophage RAW264.7 cells were evaluated. All these compounds inhibited NO production in activated macrophages without any cytotoxicity at a concentration of 100 μM. Of these isolates, 1 showed weak NO inhibitory activity with IC₅₀ value of 182.2 μM. To the best of our knowledge, this is the first report on isochroman glycoside metabolites (1–4) from the genus Colletotrichum.     

Urease inhibitory profile of extracts and chemical constituents of Pistacia atlantica ssp. cabulica Stocks

The current study was designed to evaluate the urease inhibitory profile of extract and fractions of Pistacia atlantica ssp. cabulica Stocks followed by bioactivity-guided isolated compounds. The crude extract was found significantly active with urease inhibitor (95.40% at 0.2 mg/mL) with IC₅₀ values of 32.0 ± 0.28 μg/mL. Upon fractionation, ethyl acetate fraction displayed 100% urease inhibition with IC₅₀ values of 19.9 ± 0.51 μg/mL at 0.2 mg/mL. However, n-hexane and chloroform fractions exhibited insignificant urease inhibition. Similarly, the isolated compound, transilitin (1) and dihydro luteolin (2) demonstrated marked urease attenuation with 95 and 98% respectively, at 0.15 mg/mL. Both the isolated compounds showed marked potency with IC₅₀ values of 8.54 ± 0.54 and 9.58 ± 2.22 μg/mL, respectively. In short, both the extract and fractions and isolated compounds showed marked urease inhibition and thus a useful natural source of urease inhibition.     

Four new anthraquinones from a soil actinomycete Streptomyces sp. WS-13394 and their bioactivities

Further chemical study of secondary metabolites from the soil actinomycete Streptomyces sp. WS-13394 resulted in the isolation of four new alkylated anthraquinone analogues (5–8). Their structures were elucidated on the basis of extensive spectroscopic analysis, including HR-ESI-MS, 1D and 2D NMR. The new compounds, together with analogues obtained before (1–4), were tested for their in vitro cytotoxicity against Huh-7 and SGC-7901.     

Two new benzolactones from the leaves of Nicotiana tabacum and their anti-tobacco mosaic virus activities

Two new benzolactones, 5-methyl-6-prenyl-isobenzofuran-1(3H)-one (1), 5-hydroxymethyl-6-prenyl-isobenzofuran-1(3H)-one (2), together with four known phenolic compounds (3–6), were isolated from the leaves of Nicotiana tabacum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–6 were evaluated for their anti-tobacco mosaic virus (anti-TMV) activities. The results showed that compounds 1–6 exhibited high anti-TMV activities with inhibition rates in the range of 16.9–26.2%, respectively.     

Three new phenylacetamide glycosides from Dracocephalum tanguticum Maxim and their anti-hyperglycemic activity

Abstract

Three new phenylacetamide glycosides (1–3) together with one known phenylacetamide glycoside (4) and two known flavonoid glycosides (5–6) were isolated from whole plants of Dracocephalum tanguticum. The structure of all compounds were elucidated based on spectroscopic data analysis and comparison with data reported in related literature. Compounds (1–3) were evaluated for their anti-hyperglycemic and anti-fungal (Candida albicans) activities, the results revealed that all of them showed moderate activity with 3T3-L1 adipocytes glucose consumption rate of 20.80?±?1.47%, 21.48?±?2.44%, and 21.57?±?1.35%, respectively at the final concentration of 25?μM. However, none of them showed obvious Candida albicans inhibitory activity.     

Pictalignans D-F,three new neolignan derivatives from Selaginella picta

Abstract

Three new neolignan derivatives (1–3), together with three known isolariciresinol derivatives (4–6) were isolated from Selaginella picta. Their structures were elucidated by spectroscopic methods (1D/2D NMR, HRESIMS and CD). All isolated compounds were assayed on the neuroprotective activity against the injury of HT-22 cells induced by L-Glutamate in vitro. All compounds displayed potent protective effect on HT-22 cells.     

Pyrrolizidine alkaloids from Solenanthus lanatus DC. with acetylcholinesterase inhibitory activity

The whole plant ethanolic extract of Solenanthus lanatus was used for the isolation of acetylcholinesterase inhibitors. A new pyrrolizidine alkaloid, 7-O-angeloylechinatine N-oxide, 1, was isolated together with three known compounds of the same class (3′-O-acetylheliosupine N-oxide, 2, heliosupine N-oxide, 3, and heliosupine, 4), by bioassay-guided approach. Their structures were elucidated by spectroscopic methods. All the isolated compounds showed inhibition activity against the AChE, with IC₅₀ 0.53–0.60 mM.     

Two new clerodane-type diterpenoids from Bornean liverwort Gottschelia schizopleura and their cytotoxic activity

The Bornean liverwort Gottschelia schizopleura was investigated phytochemically for the first time. Two new and four previously known clerodane-type diterpenoids were isolated from the MeOH extract of G. schizopleura through a series of chromatographic techniques. The structures of the new metabolites were established by analyses of their spectroscopic data (1D NMR, 2D NMR, HRESIMS and IR). All the isolated compounds 1–6 were tested against human promyelocytic leukaemia (HL-60), human colon adenocarcinoma (HT-29) and Mus musculus skin melanoma (B16-F10). Compound 1 and 2 showed active inhibition against HL-60 and B16-F10 cells.     

New isolates from leaves of Nicotiana tabacum and their biological activities

Three new isolates (1?3) including one new sterol and two new flavonoids together with three known sterols (4?6) were isolated from the leaves of Nicotiana tabacum. Their structures were determined mainly by spectroscopic methods, including extensive 1D and 2D NMR techniques. All compounds were evaluated for their anti-tobacco mosaic virus and cytotoxic activities. The results showed that compounds 2 and 3 exhibited high anti-TMV activity with inhibition rate of 34.2 and 33.4%, respectively, which were roughly equivalent to that of positive control. The cytotoxicities of compounds 1 and 4–6 against five human tumour cell lines were also tested, and tested compounds showed weak inhibitory activities against some tested human tumour cell lines.