Characterization of a glycosyltransferase from Paris polyphylla for application in biosynthesis of rare ophiopogonins and ginsenosides.

Saponins are bioactive components of many medicinal plants, possessing complicated chemical structures and extensive pharmacological activities, but the production of high-value saponins remains challenging. In this study, a 6'-O-glucosyltransferase PpUGT7 (PpUGT91AH7) was functionally characterized from Paris polyphylla Smith var. yunnanensis (Franch.) Hand. -Mazz., which can transfer a glucosyl group to the C-6' position of diosgenin-3-O-rhamnosyl-(1 â†’ 2)-glucoside (1), pennogenin-3-O-rhamnosyl-(1 â†’ 2)-glucoside (2), and diosgenin-3-O-glucoside (5). The KM and Kcat values of PpUGT7 towards the substrate 2 were 8.4 µM and 2 × 10-3 s-1, respectively. Through molecular docking and site-directed mutagenesis, eight residues were identified to interact with the sugar acceptor 2 and be crucial for enzyme activity. Moreover, four rare ophiopogonins and ginsenosides were obtained by combinatorial biosynthesis, including an undescribed compound ruscogenin-3-O-glucosyl-(1 â†’ 6)-glucoside (10). Firstly, two monoglycosides 9 and 11 were generated using a known sterol 3-O-ß-glucosyltransferase PpUGT80A40 with ruscogenin (7) and 20(S)-protopanaxadiol (8) as substrates, which were further glycosylated to the corresponding diglycosides 10 and 12 under the catalysis of PpUGT7. In addition, compounds 7-11 were found to show inhibitory effects on the secretion of TNF-α and IL-6 in macrophages RAW264.7. The findings provide valuable insights into the enzymatic glycosylation processes in the biosynthesis of bioactive saponins in P. polyphylla var. yunnanensis, and also serve as a reference for utilizing UDP-glycosyltransferases to construct high-value or rare saponins for development of new therapeutic agents.

Antioxidant and anti-Alzheimer's disease activities of 1,8-cineole and its cyclodextrin inclusion complex.

1,8-Cineole is a bicyclic monoterpene widely distributed in the essential oils of various medicinal plants, and it exhibits significant anti-inflammatory and antioxidant activities. We aimed to investigate the therapeutic effect of 1,8-cineole on anti-Alzheimer's disease by using transgenic Caenorhabditis elegans models. Our studies demonstrated that 1,8-cineole significantly relieved Aß1-42-induced paralysis and exhibited remarkable antioxidant and anti-Aß1-42 aggregation activities in transgenic nematodes CL4176, CL2006 and CL2355. We developed a 1,8-cineole/cyclodextrin inclusion complex, displaying enhanced anti-paralysis, anti-Aß aggregation and antioxidant activities compared to 1,8-cineole. In addition, we found 1,8-cineole treatment activated the SKN-1/Nrf-2 pathway and induced autophagy in nematodes. Our results demonstrated the antioxidant and anti-Alzheimer's disease activities of 1,8-cineole, which provide a potential therapeutic approach for Alzheimer's disease.

Insecticide resistance monitoring of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) and its mechanism to chlorantraniliprole.

BACKGROUND: The rice leaffolder, Cnaphalocrocis medinalis (Guenée), has become an increasingly occurring pest in Asia in recent years. Chemical control remains the most efficient and primary tool for controlling this pest. In this study, we report the resistance status of C. medinalis in China to multiple insecticides including chlorantraniliprole and the main resistance mechanism. RESULTS: Significant variations among field populations of C. medinalis in their resistance to 10 insecticides were observed during 2019-2022. Most of the tested field populations have developed low-to-moderate levels of resistance to abamectin (RR = 2.4-22.2), emamectin benzoate (RR = 1.9-40.3) and spinetoram (RR = 4.2-24.8). Some field populations have developed low resistance to chlorpyrifos (RR = 0.9-6.8). Indoxacarb, metaflumizone, methoxenozide and Bacillus thuringiensis (Bt) potency against all tested populations remained similar. For diamides, significantly higher levels of resistance to chlorantraniliprole (RR = 64.9-113.7) were observed in 2022, whereas all tested field populations in 2019-2021 exhibited susceptible or moderate resistance level to chlorantraniliprole (RR = 1.3-22.1). Cross-resistance between chlorantraniliprole and tetraniliprole was significant. Analysis of ryanodine receptor (RyR) mutations showed that mutation of I4712M was present in resistant populations of C. medinalis with different levels of chlorantraniliprole resistance and was the main mechanism conferring diamide resistance. Mutation of Y4621D also was detected in one tested population. Resistance management strategies for the control of C. medinalis are discussed. CONCLUSION: C. medinalis has developed high level of resistance to chlorantraniliprole. RyR mutations were deemed as the mechanism. © 2023 Society of Chemical Industry.

Phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum induced cell apoptosis via MAPK and Akt pathways in human hepatocellular carcinoma cells.

Our present and previous phytochemical investigations on Leptopus lolonum have resulted in the isolation of almost 30 phenylpropanoid-conjugated pentacyclic triterpenoids (PCPTs). During the continuous study on PCPTs, this kind of triterpenoid ester is considered as a natural product with low toxicity because of it's widely distribution in natural plants and edible fruits including kiwi fruit, durian, jujube, pawpaw, apple and pear. In the present work, we report the isolation, structural elucidation and cytotoxic evaluation of four new PCPTs (1-4) which obtained from L. lolonum. In addition, the possible biosynthesis pathway for 28-norlupane triterpenoid and potent effect of phenylpropanoid moiety for increasing the cytotxic effect of triterpenoids were also discussed. Among these compounds, compound 1 exhibited the highest cytotoxic effect on HepG2 cells with IC50 value of 11.87 µM. Further flow cytometry and western blot analysis demonstrated that 1 caused G1 cell cycle arrest by up-regulated the expression of phosphorylated p53 protein in HepG2 cells and induced cell apoptosis via MAPK and Akt pathways. These results emphasized the potential of PCPTs as lead compounds for developing anti-cancer drugs.

New phenylpropanoid-conjugated pentacyclic triterpenoids from the whole plants of Leptopus lolonum with their antiproliferative activities on cancer cells.

Most of Euphorbiaceae plants are considered as folk medicinal plants because of their various pharmacological effects. However, there are eight Leptopus genus plants which belong to Euphorbiaceae have never be investigated. Thus, four Leptopus genus plants were collected to study their chemical constituents and pharmacological activities. In the present work, the cytotoxicities of the extracts of four Leptopus genus plants were evaluated before phytochemical experiments. And nine new phenylpropanoid-conjugated pentacyclic triterpenoids, along with twenty-two known compounds were isolated from the whole plants of Leptopus lolonum. The structures of these new compounds were unequivocally elucidated by HRESIMS and 1D/2D NMR data. All triterpenoids were screened for their cytotoxicities against four cancer cell lines including HepG2, MCF-7, A549 and HeLa. Among these isolates, the triterpenoid with a phenylpropanoid unit showed increasing cytotoxicity on cancer cells, which suggested the importance of the phenylpropanoid moiety.

New pentacyclic triterpenoids isolated from Leptopus chinensis and their hepatoprotective activities on tert-butyl hydroperoxide-induced oxidative injury.

Eight unknown pentacyclic triterpenoids (1-4 and 8-11), along with eight known analogues (5-7 and 12-16) have been first isolated from the dried whole plant of Leptopus chinensis. The structures of the new compounds were determined by comprehensive spectroscopic methods, including 1D and 2D NMR, as well as HRESIMS measurements. Meanwhile, the hepatoprotective activities of the isolated compounds were preliminarily evaluated, and the results indicated that compounds 2, 5 and 16 possess potent protective effects on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in vitro, and further study revealed that 16 significantly alleviates t-BHP-induced hepatotoxicity by effectively improving cell viability and decreasing reactive oxygen species (ROS) generation and the cell apoptosis rate in HepG2 cells.

New sesquiterpenoid glycoside from the rhizomes of Atractylodes lancea.

Six sesquiterpenoids and four lignans (1-10) were isolated from the n-BuOH extract of the rhizomes of Atractylodes lancea. Among them, the new sesquiterpenoid glycoside named (4 R, 5S, 7R)-hinesolone-11-O-ß-ᴅ-glucopyranoside (1), along with three known compounds (2-4) were first obtained from this genus. All the isolates were elucidated by spectroscopic analyses and chemical methods, and the absolute configurations were assigned by electronic circular dichroism spectroscopy technique. In addition, the cytotoxic bioassay of compound 1 was evaluated and results showed it had no significant antitumor activity against human cancer cell lines MCF-7, HepG-2 and Hela.

The dietary freeze-dried fruit powder of Actinidia arguta ameliorates dextran sulphate sodium-induced ulcerative colitis in mice by inhibiting the activation of MAPKs.

In this study, we aimed at investigating the antiinflammatory activity of the freeze-dried fruit powder of Actinidia arguta (FAA) on dextran sulphate sodium (DSS)-induced ulcerative colitis (UC) in mice and the effect of its extract on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. For pharmacodynamic studies, the oral administration of FAA (300 or 600 mg kg-1) could decrease the disease activity index (DAI), reduce the incidence of colon and spleen edemas (caused by inflammation), and alleviate the pathological changes in UC. For research involving biochemical indicators, FAA could decrease the expression of inflammatory markers (such as myeloperoxidase (MPO)) and attenuate the oxidative stress levels. ELISA results revealed that the expressions of proinflammatory cytokines (IL-1ß, IL-6, and TNF-α) were downregulated by FAA. Furthermore, the expression levels of the inflammation-induced activation of p38, JNK, and ERK were decreased by FAA. Hence, it was concluded that FAA could alleviate the UC symptoms in mice and the inflammatory response of macrophages via the MAPK signal pathway. Overall, FAA might have the potential to treat UC when used as a dietary supplement.

Naturally occurring cassane diterpenoids (CAs) of Caesalpinia: A systematic review of its biosynthesis, chemistry and pharmacology.

Natural products, especially diterpenoids, are enriched with numerous compounds with a broad spectrum of therapeutic indications, suggesting that functional moieties serve as a core pharmacophore. Cassane diterpenoids (CAs), as the main and characteristic constituents of medical plants in the Caesalpinia genus, have been widely studied due to their bioactivities, and >450 compounds have been reported since the 1960s, including 283 compounds that have been reported in the past decade. There are five main types of structures for these compounds: tricyclic cassane diterpenoids with a fused furan ring (I) or butanolide lactone (II), tricyclic cassane diterpenoids (III), norcassane diterpenoids (IV), and other types (V). CAs derivatives have a wide range of biological properties, including anti-inflammatory, antimalarial, antitumour, antiviral, antimicrobial, antinociceptive, and antioxidant effects. This review highlights the role of the biosynthetic pathway, including those with abnormal skeletons, as well as advances in structure, pharmacological activities and primarily mechanisms of CAs obtained from the Caesalpinia genus. The findings herein provide new insights into the development of this kind of natural diterpenoids.

16-Tigloyl linked barrigenol-like triterpenoid from Semen Aesculi and its anti-tumor activity in vivo and in vitro.

Barrigenol-like triterpenoids (BATs) showed promising anti-tumor, anti-inflammatory and anti-Alzheimer's activities, while, the inhibitory strength was usually affected by their states with aglycones or glycosides. In order to find more BATs as new anti-tumor agents with much more efficiency, the chemical and pharmaceutical studies were carried out on the acid hydrolysate product (AHP) of Semen Aesculi crude extract. Thirteen BATs, including three new aglycones (1-3), two new glycosides (4, 5) and eight known glycosides (6-13) were obtained. Compound 1, as the main product in AHP, with a tigloyl unit linked at the C-16 position was an unusual aglycone. All compounds exhibited various degrees of inhibitory activity against human breast cell line (MCF-7) and cervical cancer cell line (HeLa) growth, moreover, new aglycones 1 and 2, and the known glycoside 6 (escin Ia) and 9 were found to exhibit potent inhibitory activity which were similar to the positive control (doxorubicin hydrochloride). Compound 1, named 16-tigloyl-O-protoaescigenin, could suppress tumor progression and decreased lung metastasis focuses in mice, and no pathological change was observed at the end of the treatment course. Besides that, the hemolysis experiment between 1 and 6 revealed that the hemolysis toxicity of 1 was much less than that of 6. According to these results, 16-tigloyl-O-protoaescigenin, with the powerful anti-tumor activity and cancer cell apoptosis induction, might be considered as a new promising anti-tumor agent.

Tissue tropisms opt for transmissible reassortants during avian and swine influenza A virus co-infection in swine.

Genetic reassortment between influenza A viruses (IAVs) facilitate emergence of pandemic strains, and swine are proposed as a "mixing vessel" for generating reassortants of avian and mammalian IAVs that could be of risk to mammals, including humans. However, how a transmissible reassortant emerges in swine are not well understood. Genomic analyses of 571 isolates recovered from nasal wash samples and respiratory tract tissues of a group of co-housed pigs (influenza-seronegative, avian H1N1 IAV-infected, and swine H3N2 IAV-infected pigs) identified 30 distinct genotypes of reassortants. Viruses recovered from lower respiratory tract tissues had the largest genomic diversity, and those recovered from turbinates and nasal wash fluids had the least. Reassortants from lower respiratory tracts had the largest variations in growth kinetics in respiratory tract epithelial cells, and the cold temperature in swine nasal cells seemed to select the type of reassortant viruses shed by the pigs. One reassortant in nasal wash samples was consistently identified in upper, middle, and lower respiratory tract tissues, and it was confirmed to be transmitted efficiently between pigs. Study findings suggest that, during mixed infections of avian and swine IAVs, genetic reassortments are likely to occur in the lower respiratory track, and tissue tropism is an important factor selecting for a transmissible reassortant.

Fluorescence detection of glutathione and oxidized glutathione in blood with a NIR-excitable cyanine probe.

Cyanine has been widely utilized as a near infrared (NIR) fluorophore for detection of glutathione (GSH). However, the excitation of most of the reported cyanine-based probes was less than 800 nm, which inevitably induce biological background absorption and lower the sensitivity, limiting their use for detection of GSH in blood samples. To address this issue, here, a heptamethine cyanine probe (DNIR), with a NIR excitation wavelength at 804 nm and a NIR emission wavelength at 832 nm, is employed for the detection of GSH and its oxidized form (GSSG) in blood. The probe displays excellent selectivity for GSH over GSSG and other amino acids, and rapid response to GSH, in particular a good property for indirect detection of GSSG in the presence of enzyme glutathione reductase and the reducing agent nicotinamideadenine dinucleotide phosphate, without further separation prior to fluorescent measurement. To the best of our knowledge, this is the first attempt to explore NIR fluorescent approach for the simultaneous assay of GSH and GSSG in blood. As such, we expect that our fluorescence sensors with both NIR excitation and NIR emission make this strategy suitable for the application in complex physiological systems.

Pathogenicity and transmission of a swine influenza A(H6N6) virus.

Subtype H6 influenza A viruses (IAVs) are commonly detected in wild birds and domestic poultry and can infect humans. In 2010, a H6N6 virus emerged in southern China, and since then, it has caused sporadic infections among swine. We show that this virus binds to α2,6-linked and α2,3-linked sialic acids. Mutations at residues 222 (alanine to valine) and 228 (glycine to serine) of the virus hemagglutinin (HA) affected its receptor-binding properties. Experiments showed that the virus has limited transmissibility between ferrets through direct contact or through inhalation of infectious aerosolized droplets. The internal genes of the influenza A(H1N1)pdm09 virus, which is prevalent in swine worldwide, increases the replication efficiency of H6N6 IAV in the lower respiratory tract of ferrets but not its transmissibility between ferrets. These findings suggest H6N6 swine IAV (SIV) currently poses a moderate risk to public health, but its evolution and spread should be closely monitored.

A NIR fluorescent probe for the rapid detection of Hg2+ in living cells and in vivo mice imaging.

A near-infrared fluorescent probe NIR-Hg, for the detection of Hg2+ ion, has been synthesized directly by condensing Changsha dye with 4-Phenyl-3-thiosemicarbazide and the structure has fully characterized by 1HNMR, 13CNMR, and ESI-MS. The probe has been designed on the basis of the reaction that Hg2+ ion promotes thiosemicarbazide to oxazole in aqueous media and had been induced to produce turn-on fluorescence via an irreversible spirolactam ring-opening process. The probe NIR-Hg has exhibited fast response (1 min), high sensitivity with 44-fold fluorescence intensity enhancement under six equivalent amounts of Hg2+ added, high selectivity over other related metal ions and a low detection limit of 5.8 × 10-8 M in the phosphate buffer. The linear response range covers the concentration of Hg2+ from 5 × 10-7 to 5 × 10-6 M. In addition, the probe has good cell-membrane permeability, which is suitable for fluorescence imaging for Hg2+ in living cells and in vivo mice.

Detection of Avian H7N9 Influenza A Viruses in the Yangtze Delta Region of China During Early H7N9 Outbreaks.

Since the first H7N9 human case in Shanghai, February 19, 2013, the emerging avian-origin H7N9 influenza A virus has become an epizootic virus in China, posing a potential pandemic threat to public health. From April 2 to April 28, 2013, some 422 oral-pharyngeal and cloacal swabs were collected from birds and environmental surfaces at five live poultry markets (LPMs) and 13 backyard poultry farms (BPFs) across three cities, Wuxi, Suzhou, and Nanjing, in the Yangtze Delta region. In total 22 isolates were recovered, and six were subtyped as H7N9, nine as H9N2, four as H7N9/H9N2, and three unsubtyped influenza A viruses. Genomic sequences showed that the HA and NA genes of the H7N9 viruses were similar to those of the H7N9 human isolates, as well as other avian-origin H7N9 isolates in the region, but the PB1, PA, NP, and MP genes of the sequenced viruses were more diverse. Among the four H7N9/H9N2 mixed infections, three were from LPM, whereas the other one was from the ducks at one BPF, which were H7N9 negative in serologic analyses. A survey of the bird trading records of the LPMs and BPFs indicates that trading was a likely route for virus transmission across these regions. Our results suggested that better biosecurity and more effective vaccination should be implemented in backyard farms, in addition to biosecurity management in LPMs.

Antigenic Characterization of H3 Subtypes of Avian Influenza A Viruses from North America.

Besides humans, H3 subtypes of influenza A viruses (IAVs) can infect various animal hosts, including avian, swine, equine, canine, and sea mammal species. These H3 viruses are both antigenically and genetically diverse. Here, we characterized the antigenic diversity of contemporary H3 avian IAVs recovered from migratory birds in North America. Hemagglutination inhibition (HI) assays were performed on 37 H3 isolates of avian IAVs recovered from 2007 to 2011 using generated reference chicken sera. These isolates were recovered from samples taken in the Atlantic, Mississippi, Central, and Pacific waterfowl migration flyways. Antisera to all the tested H3 isolates cross-reacted with each other and, to a lesser extent, with those to H3 canine and H3 equine IAVs. Antigenic cartography showed that the largest antigenic distance among the 37 avian IAVs is about four units, and each unit corresponds to a 2 log 2 difference in the HI titer. However, none of the tested H3 IAVs cross-reacted with ferret sera derived from contemporary swine and human IAVs. Our results showed that the H3 avian IAVs we tested lacked significant antigenic diversity, and these viruses were antigenically different from those circulating in swine and human populations. This suggests that H3 avian IAVs in North American waterfowl are antigenically relatively stable.

Limited Antigenic Diversity in Contemporary H7 Avian-Origin Influenza A Viruses from North America.

Subtype H7 avian-origin influenza A viruses (AIVs) have caused at least 500 confirmed human infections since 2003 and culling of >75 million birds in recent years. Here we antigenically and genetically characterized 93 AIV isolates from North America (85 from migratory waterfowl [1976-2010], 7 from domestic poultry [1971-2012], and 1 from a seal [1980]). The hemagglutinin gene of these H7 viruses are separated from those from Eurasia. Gradual accumulation of nucleotide and amino acid substitutions was observed in the hemagglutinin of H7 AIVs from waterfowl and domestic poultry. Genotype characterization suggested that H7 AIVs in wild birds form diverse and transient internal gene constellations. Serologic analyses showed that the 93 isolates cross-reacted with each other to different extents. Antigenic cartography showed that the average antigenic distance among them was 1.14 units (standard deviation [SD], 0.57 unit) and that antigenic diversity among the H7 isolates we tested was limited. Our results suggest that the continuous genetic evolution has not led to significant antigenic diversity for H7 AIVs from North America. These findings add to our understanding of the natural history of IAVs and will inform public health decision-making regarding the threat these viruses pose to humans and poultry.

A fast-responsive fluorescent probe for sulfite and its bioimaging.

A turn-on fluorescent probe Coumarin-SO2 based on a nucleophilic addition reaction was developed for the rapid detection of SO3(2-) in aqueous media. The probe Coumarin-SO2 displays excellent water solubility, fast response, highly sensitivity and highly selectivity over other biological related species. More importantly, living cell imaging experiments indicate the feasibility of using the probe for the detection of SO3(2-) in biological systems.

A ratiometric fluorescence sensor for Fe(3+) based on FRET and PET processes.

A rhodamine/coumarin-based ratiometric fluorescent Fe(3+) sensor has been designed and synthesized. The sensor exhibits a good response to Fe(3+) ions with high sensitivity, selectivity and a large shift in the emission spectra (>100 nm), which shows Fe(3+) -induced FRET OFF-ON and PET ON-OFF behavior.

Bt crops benefit natural enemies to control non-target pests.

Crops producing insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) control important lepidopteran pests. However, pests such as aphids not susceptible to Cry proteins may require other integrated pest management (IPM) tactics, including biological control. We fed aphids on Bt and non-Bt plants and analyzed the Bt protein residue in aphids and compared the effects of Bt plants and a pyrethroid, lambda-cyhalothrin, on the performance of three natural enemies (predators: Coleomegilla maculata and Eupeodes americanus; parasitoid Aphidius colemani) of the green peach aphid, Myzus persicae. No Bt protein residues in aphids were detected and no significant differences were recorded in the performance of pyrethroid-resistant aphids that fed on Bt broccoli expressing Cry1Ab or Cry1C, or on non-Bt broccoli plants treated or not treated with the pyrethroid. This indicated the aphids were not affected by the Cry proteins or the pyrethroid, thus removing any effect of prey quality. Tri-trophic experiments demonstrated that no C. maculata and E. americanus survived consumption of pyrethroid-treated aphids and that ovipositional behavior of A. colemani was impaired when provided with pyrethroid-treated aphids. In contrast, natural enemies were not affected when fed aphids reared on Bt broccoli, thus demonstrating the safety of these Bt plants for IPM.