α‐Glucosidase Inhibitory Xanthones from the Roots of Garcinia fusca

Two new compounds, fuscaxanthones J ( 1 ) and K ( 2 ), together with eight known xanthones ( 3 – 10 ) were isolated from an ethyl acetate extract of the roots of Garcinia fusca. Their structures were determined using spectroscopic methods, mainly 1D‐ and 2D‐NMR. α‐Glucosidase inhibitory activity of the isolated compounds was evaluated and fuscaxanthone J ( 1 ) showed the most significant effect with an IC₅₀ value of 8.3 ± 1.8 μm (compared with acarbose, IC₅₀ = 214.5 ± 2.3 μm ).     

Cytotoxic Triterpenoids from Roots of Actinidia chinensis

Phytochmical investigation of roots of Actinidia chinensisPlanch . led to the isolation triterpenoids 1 – 16 , including a new compound 2α,3α,23,24‐tetrahydroxyursa‐12,20(30)‐dien‐28‐oic acid ( 1 ). Their structures were identified on the basis of spectroscopic analysis, including 1D‐ and 2D‐NMR, HR‐ESI mass spectrometry, and by comparison with the literatures. The cytotoxicities of triterpenoids 1 – 16 against a panel of cultured human cancer cell lines (HepG2, A549, MCF‐7, SK‐OV‐3, and HeLa) were evaluated. The new compound 1 exhibited moderate antitumor activities with IC₅₀ values of 19.62 ± 0.81, 18.86 ± 1.56, 45.94 ± 3.62, 62.41 ± 2.29, and 28.74 ± 1.07 μm , respectively. The experiment data might be available to explain the use of roots of A. chinensis to treat various cancers in traditional Chinese medicine.     

Bioactivity‐Guided Isolation of Anti‐Inflammatory Constituents of the Rare Mushroom Calvatia nipponica in LPS‐Stimulated RAW264.7 Macrophages

Calvatia species, generally known as puffball mushrooms, are used both as sources of food and as traditional medicine. Among the Calvatia genus, Calvatia nipponica (Agaricaceae) is one of the rarest species. Using bioassay‐guided fractionation based on anti‐inflammatory effects, five alkaloids ( 1 – 5 ), two phenolics ( 6 and 7 ), and a fatty acid methyl ester ( 8 ) were isolated from the fruiting bodies of C. nipponica. Compound 8 was identified from C. nipponica for the first time, and all isolates ( 1 – 8 ) were tested for inhibition of nitric oxide (NO) production in lipopolysaccharide (LPS)‐stimulated RAW264.7 macrophages. Compound 7 showed mild inhibition while compound 8 significantly inhibited NO production with an IC₅₀ value of 27.50 ± 0.08 μm . The mechanism of NO inhibition of compound 7 was simulated by molecular docking analysis against nitric oxide synthase (iNOS), which revealed the interactions of 7 with the key amino acid residue and the heme in the active site. With the most potent inhibition against LPS‐induced inflammation, compound 8 was further investigated with respect to its mechanism of action, and the activity was found to be mediated through the inhibition of iNOS and COX‐2 expression.     

Superbanone,A New 2‐Aryl‐3‐benzofuranone and Other Bioactive Constituents from the Tube Roots of Butea superba

Phytochemical investigation from the tube roots of Butea superba, led to the isolation and identification of a new 2‐aryl‐3‐benzofuranone named superbanone ( 1 ), one benzoin, 2‐hydroxy‐1‐(2‐hydroxy‐4‐methoxyphenyl)‐2‐(4‐methoxyphenyl)ethanone ( 2 ), eight pterocarpans ( 3  –  10 ), and eleven isoflavonoids ( 11  –  21 ). Compound 2 was identified for the first time as a natural product. The structure of the isolated compounds was elucidated using spectroscopic methods, mainly 1D‐ and 2D‐NMR. The isolated compounds and their derivatives were evaluated for α‐glucosidase inhibitory and antimalarial activities. Compounds 3 , 7 , 8 , and 11 showed promising α‐glucosidase inhibitory activity (IC₅₀ = 13.71 ± 0.54, 23.54 ± 0.75, 28.83 ± 1.02, and 12.35 ± 0.36 μm , respectively). Compounds 3 and 11 were twofold less active than the standard drug acarbose (IC₅₀ = 6.54 ± 0.04 μm ). None of the tested compounds was found to be active against Plasmodium falciparum strain 94. On the basis of biological activity results, structure–activity relationships are discussed.     

Terpenes from Euphorbia antiquorum and Their in Vitro Anti‐HIV Activity

Three new compounds ( 1 – 3 ), including two euphane type triterpenes, 24,24‐dimethoxy‐25,26,27‐trinoreuphan‐3β‐ol ( 1 ) and (24S)‐24‐hydroperoxyeupha‐8,25‐dien‐3β‐ol ( 2 ), and an ent‐atisine diterpene, ent‐atisane‐3α,16α,17‐triol ( 3 ), were isolated from an acetone extract of the stems of Euphorbia antiquorum, together with eight known diterpenes ( 4 – 11 ). The structures of compounds ( 1 – 11 ) were elucidated using NMR and MS spectroscopic methods. Compound 7 showed moderate activity against HIV‐1 replication in vitro (EC₅₀ = 1.38 μm ).     

Vibsane‐Type Diterpenoids from Viburnum odoratissimum and Their Cytotoxic and HSP90 Inhibitory Activities

Four new vibsane‐type diterpenoids, vibsanol I ( 1 ), 15‐hydroperoxyvibsanol A ( 2 ), 14‐hydroperoxyvibsanol B ( 3 ), 15‐O‐methylvibsanin U ( 4 ), and a new natural product, 5,6‐dihydrovibsanin B ( 5 ), as well as six known analogues, were isolated from the twigs and leaves of Viburnum odoratissimum. Their structures were elucidated by spectroscopic analyses and chemical derivatization method. All compounds showed different levels of cytotoxicity against five cell lines (HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480). Remarkably, 14,18‐O‐diacetyl‐15‐O‐methylvibsanin U ( 4a ) showed significant cytotoxicity against HL‐60, A‐549, SMMC‐7721, MCF‐7, and SW480, with IC₅₀ values of 0.15 ± 0.01, 0.69 ± 0.01, 0.41 ± 0.02, 0.75 ± 0.03, and 0.48 ± 0.03 μm , respectively. In addition, vibsanin K ( 10 ) was identified as a HSP90 inhibitor with an IC₅₀ value of 19.16 μm .     

New 4,5‐seco‐20(10→5)‐abeo‐Abietane Diterpenoids with Anti‐Inflammatory Activity from Isodon lophanthoides var. graciliflorus (Benth.) H.Hara

Three new 4,5‐seco‐20(10→5)‐abeo‐abietane diterpenoids, 16‐hydroxysalvilenone ( 1 ), 15‐hydroxysalprionin ( 2 ), and 11β,15‐dihydroxysalprionin‐12‐one ( 3 ), and nine known abietane diterpenoids, 4 – 12 , along with one known sempervirane diterpenoid, hispidanol A ( 13 ), were isolated from the aerial parts of Isodon lophanthoides var. graciliflorus. The structures of compounds 1 – 3 were determined on the basis of spectroscopic methods including extensive analysis of NMR and mass spectroscopic data. All diterpenoids were tested for their TNF‐α inhibitory effects on LPS‐induced RAW264.7 cells. Compound 9 (16‐acetoxyhorminone) was the most potent with an IC₅₀ value of 3.97±0.70 μm .     

Four New Flavonoids with α‐Glucosidase Inhibitory Activities from Morus alba var. tatarica

Four new flavonoids, mortatarins A–D ( 1 – 4 , resp.), along with eight known flavonoids ( 5 – 12 ) were isolated from the root bark of Morus alba var. tatarica. Their structures were established on the basis of spectroscopic data analysis, and the absolute configuration of 4 was determined by analysis of its CD spectrum. All isolates were tested for inhibitory activities against α‐glucosidase. Compounds 4, 7 , and 8 exhibited a significant degree of inhibition with IC₅₀ values of 5.0±0.3, 7.5±0.5, and 5.9±0.2 μM , respectively.     

Temperature sensitivity of biomass‐specific microbial exo‐enzyme activities and CO2 efflux is resistant to change across short‐ and long‐term timescales

Accurate representation of temperature sensitivity (Q₁₀) of soil microbial activity across time is critical for projecting soil CO₂ efflux. As microorganisms mediate soil carbon (C) loss via exo‐enzyme activity and respiration, we explore temperature sensitivities of microbial exo‐enzyme activity and respiratory CO₂ loss across time and assess mechanisms associated with these potential changes in microbial temperature responses. We collected soils along a latitudinal boreal forest transect with different temperature regimes (long‐term timescale) and exposed these soils to laboratory temperature manipulations at 5, 15, and 25°C for 84 days (short‐term timescale). We quantified temperature sensitivity of microbial activity per g soil and per g microbial biomass at days 9, 34, 55, and 84, and determined bacterial and fungal community structure before the incubation and at days 9 and 84. All biomass‐specific rates exhibited temperature sensitivities resistant to change across short‐ and long‐term timescales (mean Q₁₀ = 2.77 ± 0.25, 2.63 ± 0.26, 1.78 ± 0.26, 2.27 ± 0.25, 3.28 ± 0.44, 2.89 ± 0.55 for β‐glucosidase, N‐acetyl‐β‐d ‐glucosaminidase, leucine amino peptidase, acid phosphatase, cellobiohydrolase, and CO₂ efflux, respectively). In contrast, temperature sensitivity of soil mass‐specific rates exhibited either resilience (the Q₁₀ value changed and returned to the original value over time) or resistance to change. Regardless of the microbial flux responses, bacterial and fungal community structure was susceptible to change with temperature, significantly differing with short‐ and long‐term exposure to different temperature regimes. Our results highlight that temperature responses of microbial resource allocation to exo‐enzyme production and associated respiratory CO₂ loss per unit biomass can remain invariant across time, and thus, that vulnerability of soil organic C stocks to rising temperatures may persist in the long term. Furthermore, resistant temperature sensitivities of biomass‐specific rates in spite of different community structures imply decoupling of community constituents and the temperature responses of soil microbial activities.     

The oxalyl‐CoA synthetase‐regulated oxalate and its distinct effects on resistance to bacterial blight and aluminium toxicity in rice

• Oxalic acid is widely distributed in biological systems and known to play functional roles in plants. The gene AAE3 was recently identified to encode an oxalyl‐CoA synthetase (OCS) in Arabidopsis that catalyses the conversion of oxalate and CoA into oxalyl‐CoA. It will be particularly important to characterise the homologous gene in rice since rice is not only a monocotyledonous model plant, but also a staple food crop.
• Various enzymatic and biological methods have been used to characterise the homologous gene.
• We first defined that AAE3 in the rice genome (OsAAE3) also encodes an OCS enzyme. Its K_m for oxalate is 1.73 ± 0.12 mm , and V_m is 6824.9 ± 410.29 U·min^?1·mg protein^?1. Chemical modification and site‐directed mutagenesis analyses identified thiols as the active site residues for rice OCS catalysis, suggesting that the enzyme might be regulated by redox state. Subcellular localisation assay showed that the enzyme is located in the cytosol and predominantly distributed in leaf epidermal cells. As expected, oxalate levels increased when OCS was suppressed in RNAi transgenic plants. More interestingly, OCS‐suppressed plants were more susceptible to bacterial blight but more resistant to Al toxicity.
• The results demonstrate that the OsAAE3‐encoded protein also acts as an OCS in rice, and may play different roles in coping with stresses. These molecular, enzymatic and functional data provide first‐hand information to further clarify the function and mechanism of OCS in rice plants.

     

Variations in Essential Oil Composition and Antioxidant Activity in Perovskia abrotanoides Kar. Collected from Different Regions in Iran

Essential oil (EO) composition, phenolic content, and antioxidant activity were investigated in 17 P. abrotanoides populations collected from different geographical regions in Iran. The highest (3.61%) and lowest (1.25%) essential oil yields were measured in populations from Semnan Province (PSESM₂) and PISKS from Isfahan Province, respectively. GC/MS analysis identified camphor (4.05 – 35.94%), 1,8‐cineole (7.15 – 24.34%), borneol (0 – 21.75%), and α‐pinene (2.05 – 10.33%) as the main constituents of Perovskia essential oil. Cluster analysis classified the studied populations into four different groups: (I) high camphene, (II) high camphor/1,8‐cineole, (III) high borneol/δ‐3‐carene, and (IV) high α‐cadinol/trans‐caryophyllene. The highest flavonoid and phenolic contents were detected in PISAK from Isfahan Province (4.09 ± 0.05 mgQE/gDW, 58.51 ± 1.63 mgGAE/gDW) and PKRGS from Khorasan Province (3.80 ± 0.002 mgQE/gDW, 66.86 ± 0.002 mgGAE/gDW). DPPH and reducing power activity model systems identified PMASA and PKRKL as the populations with the highest antioxidant activity. Finally, the data obtained represented valuable information for introducing elite populations with EO components favorable to pharmaceutical and industrial applications.     

Characterization of an ethanol‐tolerant 1,4‐β‐xylosidase produced by Pichia membranifaciens

Aims: The purification and biochemical properties of the 1,4‐β‐xylosidase of an oenological yeast were investigated. Methods and Results: An ethanol‐tolerant 1,4‐β‐xylosidase was purified from cultures of a strain of Pichia membranifaciens grown on xylan at 28°C. The enzyme was purified by sequential chromatography on DEAE cellulose and Sephadex G‐100. The relative molecular mass of the enzyme was determined to be 50 kDa by SDS‐PAGE. The activity of 1,4‐β‐xylosidase was optimum at pH 6·0 and at 35°C. The activity had a K_m of 0·48 ± 0·06 mmol l^?1 and a V_max of 7·4 ± 0·1 μmol min^?1 mg^?1 protein for p‐nitrophenyl‐β‐d ‐xylopyranoside. Conclusions: The enzyme characteristics (pH and thermal stability, low inhibition rate by glucose and ethanol tolerance) make this enzyme a good candidate to be used in enzymatic production of xylose and improvement of hemicellulose saccharification for production of bioethanol. Significance and Impact of the Study: This study may be useful for assessing the ability of the 1,4‐β‐xylosidase from P. membranifaciens to be used in the bioethanol production process.     

Age‐ and temperature‐dependent oviposition model of Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) with Tetranychus urticae as prey

In this study, we developed an oviposition model of Neoseiulus californicus (McGregor) with Tetranychus urticae Koch as prey. To obtain data for the model, we investigated the longevity, fecundity and survivorship of adult female N. californicus at six constant temperatures (16, 20, 24, 28, 32 and 36°C), 60–70% RH and a photoperiod of 16 : 8 (L : D) h. Longevity (average ± SE) decreased as temperature increased and was longest at 16°C (46.7 ± 5.25 days) and shortest at 36°C (12.8 ± 0.75 days). Adult developmental rate (1/average longevity) was described by the Lactin 1 model (r² = 0.95). The oviposition period (average±SE) was also longest at 16°C (29.8 ± 2.93 days) and shortest at 36°C (6.7 ± 0.54 days). Fecundity (average±SE) was greatest at 24°C (43.8 ± 3.23 eggs) and lowest at 36°C (15.9 ± 1.50 eggs). The oviposition model comprised temperature‐dependent fecundity, age‐specific cumulative oviposition rate and age‐specific survival rate functions. The temperature‐dependent fecundity was best described by an exponential equation (r² = 0.81). The age‐specific cumulative oviposition rate was best described by the three‐parameter Weibull function (r² = 0.96). The age‐specific survival rate was best described by a reverse sigmoid function (r² = 0.85).     

Triterpenes and Meroterpenes with Neuroprotective Effects from Ganoderma leucocontextum

Ganoderma leucocontextum is a well‐known medicinal mushroom cultivated in the Tibet Plateau of China. Chemistry investigation on the fruiting bodies of this mushroom resulted in the isolation of sixteen secondary metabolites including three new lanostane triterpenes, ganoleucoins Q – S ( 1 – 3 ), as well as thirteen known compounds ( 4 – 16 ). The structures of compounds 1 – 3 were determined by NMR, MS, CD spectral analysis, and chemical derivation method. The neuroprotective effects of compounds 1 – 16 were tested on PC12 cells. Compounds 1 and 2 showed protective effects against the H₂O₂ induced damage with the survival rate of 83.19 ± 0.92%, 73.37 ± 1.25% at the concentration of 200 μm , respectively. Meanwhile, compounds 1 and 2 induced neurite outgrowth at 50 – 200 μm . The results from this study suggested that G. leucocontextum and its metabolites may be potential functional food ingredients for the prevention of neurodegenerative diseases.     

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 .     

Bergamotane Sesquiterpenes with Alpha‐Glucosidase Inhibitory Activity from the Plant Pathogenic Fungus Penicillium expansum

Two new bergamotane sesquiterpene lactones, named expansolides C and D ( 1 and 2 ), together with two known compounds expansolides A and B ( 3 and 4 ), were isolated from the plant pathogenic fungus Penicillium expansum ACCC37275. The structures of the new compounds were established by detailed analyses of the spectroscopic data, especially 1D‐, 2D‐NMR, and HR‐ESI‐MS. In an in vitro bioassay, the epimeric mixture of expansolides C and D ( 1 and 2 ) (in a ratio of 2:1 at the temprature of the bioassay) exhibited more potent α‐glucosidase inhibitory activity (IC₅₀ =0.50 ± 0.02 mm ) as compared with the positive control acarbose (IC₅₀ = 1.90 ± 0.05 mm ). To the best of our knowledge, it was the first report on the α‐glucosidase inhibitory activity of bergamotane sesquiterpenes.     

New Cyclohexadepsipeptides from an Entomogenous Fungus Fusarium proliferatum and Their Cytotoxicity and Autophagy‐Inducing Activity

Five new cyclohexadepsipeptides termed as enniatins R – V ( 1 – 5 ) and seven known cyclohexadepsipeptides ( 6 – 12 ) were isolated from the solid culture of Fusarium proliferatum, a fungus isolated from the cadaver of an unidentified insect collected in Tibet. Their structures were elucidated by NMR and MS spectroscopic analysis. The X‐ray single‐crystal structure of 6 was reported for the first time. Enniatins R and S represented the first enniatins incorporating with an unusual 2,3‐dihydroxy‐isovaleric acid (Div) residue. The cytotoxicity and autophagy‐inducing activities of 1 – 12 were evaluated in vitro. Beauvenniatin F ( 11 ) exhibited strong cytotoxicity against K562/A (adriamycin‐resistant K562) with IC₅₀ value of 3.78 μm , and also autophagy‐inducing activity at the concentration of 20 μm in GFP‐LC3 stable HeLa cells.     

Neuraminidase Inhibitors from marine‐derived actinomycete Streptomyces seoulensis

Aims

This work was performed to characterize new secondary metabolites with neuraminidase (NA) inhibitory activity from marine actinomycete strains.

Methods and Results

An actinomycete strain IFB‐A01, capable of producing new NA inhibitors, was isolated from the gut of shrimp Penasus orientalis and identified as Streptomyces seoulensis according to its 16S rRNA sequence (over 99% homology with that of the standard strain). Repeated chromatography of the methanol extract of the solid‐substrate culture of S. seoulensis IFB‐A01 led to the isolation of streptoseolactone ( 1 ), and limazepines G ( 2 ) and H ( 3 ). The structures of 1 – 3 were determined by a combination of IR, ESI‐MS, 1D (¹H and ¹³C NMR, and DEPT) and 2D NMR experiments (HMQC, HMBC, ¹H‐¹H COSY and NOESY). Compounds 1 – 3 showed significant inhibition on NA in a dose‐dependent manner with IC₅₀ values of 3·92, 7·50 and 7·37 μmol l^?1, respectively.

Conclusions

This is the first report of two new ( 1 and 2 ) and known ( 3 , recovered as a natural product for the first time in the work) NA inhibitors from the marine‐derived actinomycete S. seoulensis IFB‐A01.

Significance and Impact of the Study

The three natural NA inhibitors maybe of value for the development of drug(s) necessitated for the treatment of viral infections.     

Iridoids from Pedicularis verticillata and Their Anti‐Complementary Activity

Three new iridoids named as pediverticilatasin A – C ( 1 – 3 , resp.), together with five known iridoids ( 4 – 8 , resp.) were isolated from the whole plants of Pedicularis verticillata. The structures of three new compounds were identified as (1S,7R)‐1‐ethoxy‐1,5,6,7‐tetrahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4(3H)‐one ( 1 ), (1S,4aS,7R,7aS)‐1‐ethoxy‐1,4a,5,6,7,7a‐hexahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4‐carboxylic acid ( 2 ), (1S,4aS,7R,7aS)‐1‐ethoxy‐1,4a,5,6,7,7a‐hexahydro‐7‐hydroxy‐7‐methylcyclopenta[c]pyran‐4‐carbaldehyde ( 3 ). Their structures were elucidated on the basis of spectroscopic methods and compared with the NMR spectra data in the literature. All compounds were evaluated for their anti‐complementary activity on the classical pathway of the complement system in vitro. Among which, compounds 1 , 3 , and 6 exhibited anti‐complementary effects with CH₅₀ values ranging from 0.43 to 1.72 mm , which are plausible candidates for developing potent anti‐complementary agents.     

Sesquiterpene Lactones with COX‐2 Inhibition Activity from Artemisia lavandulaefolia

Two new sesquiterpene lactones, artelavanolides A ( 1 ) and B ( 2 ), and four known sesquiterpene lactones ( 3 – 6 ) were isolated from the leaves of Artemisia lavandulaefolia. Their structures were elucidated based on the analysis of spectroscopic data (1D, 2D‐NMR and HR‐ESI‐MS). The absolute configuration of 1 was determined by the analysis of single‐crystal X‐ray diffraction data. Artelavanolide A ( 1 ) is a rare sesquiterpene lactone possessing an unusual skeleton with the linkage of Me(14)–C(1) that is probably formed through a rearrangement of the guaiane‐type sesquiterpenoids. Artelavanolide B ( 2 ) is a new highly unsaturated guaianolide. Compounds 1 – 6 were tested for activities on the inhibition of COX‐2 enzyme in vitro. All of compounds exhibited inhibitory activity against COX‐2 with IC₅₀ values ranging from 43.29 to 287.07 μm compared with the positive control, celecoxib (IC₅₀ = 18.10 μm ). Among them, 3 showed the best COX‐2 inhibitory activity with an IC₅₀ value of 43.29 μm .