Denitrification Characteristics of the Low-Temperature Tolerant Denitrification Strain Achromobacter spiritinus HS2 and Its Application.

The low-temperature environment significantly inhibits the growth and metabolism of denitrifying bacteria, leading to an excessive concentration of ammonia nitrogen and total nitrogen in sewage treatment plants during the cold season. In this study, an efficient denitrifying strain of heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria named HS2 was isolated and screened from industrial sewage of a chemical factory in Inner Mongolia at 8 °C. The strain was confirmed to be Achromobacter spiritinus, a colorless rod-shaped bacterium. When cultured with sodium succinate as the carbon source, a carbon-to-nitrogen ratio of 20-30, a shaking rate of 150-180 r/min, and an initial pH of 6-10, the strain HS2 exhibited excellent nitrogen removal at 8 °C. Through the results of whole-genome sequencing, gene amplification, and gas product detection, the strain HS2 was determined to possess key enzyme genes in both nitrification and denitrification pathways, suggesting a HN-AD pathway of NH4+-N → NH2OH → NO2-N → NO → N2O → N2. At 8 °C, the strain HS2 could completely remove ammonia nitrogen from industrial sewage with an initial concentration of 127.23 mg/L. Microbial species diversity analysis of the final sewage confirmed Achromobacter sp. as the dominant genus, which indicated that the low-temperature denitrifying strain HS2 plays an important role in nitrogen removal in actual low-temperature sewage.

Natural Products as Antifungal Agents against Invasive Fungi.

BACKGROUND: Invasive fungal infections (IFIs) are primarily caused by Candida spp., Cryptococcus neoformans, Aspergillus spp., Mucor spp., Sporothrix spp., and Pneumocystis spp., which attack human organs with a strong pathogenicity and exhibit drug resistance against commonly used chemical drugs. Therefore, the search for alternative drugs with high efficacy, low resistance rates, few side effects, and synergistic antifungal effects remains a major challenge. The characteristics of natural products with structural and bioactive diversity, lower drug resistance, and rich resources make them a major focus of the development of antifungal drugs. OBJECTIVES: This review attempts to summarize the origin, structure, and antifungal activity of natural products and their derivatives with MIC ≤ 20 µg/mL or 100 µM, focusing on their MoA and SAR. METHODS: All pertinent literature databases were searched. The search keywords were antifungal or antifungals, terpenoids, steroidal saponins, alkaloid, phenols, lignans, flavonoids, quinones, macrolide, peptide, tetramic acid glycoside, polyene, polyketide, bithiazole, natural product, and derivatives. All the related literature (covering the past 20 years, 2001-2022) was evaluated. RESULTS: In total, 340 natural products and 34 synthesized derivatives with antifungal activity from 301 studies were included in this review. These compounds were derived from terrestrial plants, ocean life, and microorganisms and exhibited in vitro and in vivo potent antifungal activity alone or in combination. The MoA and SARs of reported compounds were summarized whenever applicable. CONCLUSION: In this review, we attempted to review the available literature on natural antifungal products and their derivatives. Most of the studied compounds showed potent activity against Candida species, Aspergillus species, or Cryptococcus species. Some of the studied compounds also demonstrated the ability to impair the cell membrane and cell wall, inhibit hypha and biofilms, and cause mitochondrial dysfunction. Although the MoAs of these compounds are not well understood yet, they can be used as lead components for the development of new, effective, and safe antifungal agents through their novel mechanisms.

Design, synthesis and anti-Chikungunya virus activity of lomerizine derivatives.

Chikungunya fever is an acute infectious disease caused by Chikungunya virus (CHIKV) and transmitted by Aedes mosquito. It is characterized by fever, rash and arthralgia with no effective drugs. Lomerizine (Lom) is a new generation calcium antagonist, which is mainly used in the treatment of migraine. Certain antiviral function of Lom was shown by some research. In our study, a series of new derivatives of Lom were designed and synthesized, and their in-vitro anti-CHIKV activity was tested. The results showed that Lom and its derivatives had potent anti-CHIKV activity and low cytotoxicity. Among them, compounds B1 and B7 showed most potent antiviral activity. Besides, structure-activity relationships, in-silico ADMET properties were also analyzed. Molecular docking study was performed to rationalize the SAR and analyze the possible binding modes between B1 and amino acid residues in the active site of nsP3 protein to enhance the understanding of their action as antiviral agents. These finding provides research basis for the design and synthesis of effective anti-CHIKV drugs with Lom as the lead compound.

Synthesis of baicalein derivatives and evaluation of their antiviral activity against arboviruses.

Natural plant-derived baicalein which is extracted from Chinese herb Scutellaria baicalensis Georgi belongs to the flavonoid compounds and possesses multiple pharmacological activities. In this study, we designed and synthesized new series of derivatives of baicalein (BE) through catalytic coupling reactions, and screened for their antiviral activity against arboviruses including Chikungunya virus (CHIKV), West Nile virus (WNV) or Zika virus (ZIKV). Our results revealed for the first time that BE and its derivatives had potent anti-CHIKV, anti-WNV and anti-ZIKV effects. And modification of 8 or 4' position could lead to obtain potent antiviral compounds against CHIKV, WNV and ZIKV with lower cytotoxicity. Among the baicalein derivatives, C3 and F3 showed the most potent antiviral activities against CHIKV, WNV and ZIKV, which were 5-10 times more potent than baicalein. Our findings will provide research basis for the development of baicalein derivatives as effective antiviral agents.

[Composition and histopathological features of prostatic calculi in patients with benign prostatic hyperplasia].

OBJECTIVE: To analyze the composition of prostatic calculus in patients with BPH and explore its pathogenic factors and histopathological characteristics. METHODS: Strictly following the inclusion and exclusion criteria, we included in this retrospective study 580 cases of bipolar transurethral plasma kinetic prostatectomy (TUPKP) performed in our hospital from May 2015 to May 2019, analyzed the histopathological and calculus-composition features of the patients with BPH complicated by prostatic calculi (the BPH+PC group) and the histopathological data of those with BPH only (the BPH group). We compared the related factors between the two groups of patients and performed uni- and multivariate logistic regression analyses of the data on those in the BPH+PC group. RESULTS: The incidence rate of chronic inflammation was significantly higher in the BPH+PC than in the BPH group (83.1% vs 61.1%, P < 0.05), 90% of the cases moderate to severe and 81% with inflammatory cells mainly distributed in the prostate gland in the BPH+PC group, and 74% with inflammatory cells chiefly distributed in the prostate gland and stroma in the BPH group, with statistically significant difference between the two groups (P < 0.05). Prostatic calculi were found in 302 (52.1%) of the patients, including 71 cases of simple calculi (23.5%) and 231 cases of mixed calculi (76.5%). As for the chemical composition, calcium oxalate was detected in 212 cases (70.2%), carbonate apatite in 206 (68.2%), magnesium ammonium phosphate in 158 (52.3%), and uric acid calculi in 19 (6.3%). The calculus composition was not correlated with the age of the patients. There were statistically significant differences between the two groups of patients in age, prostate volume and IPSS (P < 0.05), but not in the PSA level, postvoid residual urine volume (PRV) or maximum urinary flow rate (Qmax) (P > 0.05). Logistic regression analyses showed that prostatic calculus was significantly correlated with chronic inflammation of the prostate, the patient's age and IPSS (P < 0.05) but not with the PSA level, PRV or Qmax (P > 0.05). CONCLUSIONS: Prostatic calculus has a high incidence in BPH patients and varies widely in composition, chiefly consisting of calcium oxalate and carbonate apatite. The major factors contributing to prostatic calculi include chronic inflammation of the prostate (primarily the severe type), age and BPH. Prostate calculi may aggravate lower urinary tract symptoms, especially urinary storage symptoms, in patients with BPH, but not significantly affect the PSA level.？.

Synergistic antifungal effects of curcumin derivatives as fungal biofilm inhibitors with fluconazole.

Lack of novel antifungal agents and severe drug resistance has led to high incidence and associated mortality of invasive fungal infections. To tackle the challenges, novel antifungal agents with anti-resistant potency are highly desirable. Thus, derivatives of curcumin were synthesized to restore the effectiveness of fluconazole (FLC) against FLC-resistant Candida spp. and structure-activity relationships were then discussed. Some novel derivatives showed promising features as novel antifungal lead compounds. Of them, compound 4 showed good alone or synergistic antifungal activity against FLC-resistant Candida spp. Moreover, compound 4 was proven as a potent inhibitor of Candida albicans biofilm formation and yeast-to-hypha morphological transition whether used alone or in combination with FLC, which was further confirmed by the inhibitory effect on cellular surface hydrophobicity of C. albicans. Compound 4 also inhibits intracellular ATP production of C. albicans and disrupts membrane permeability of C. albicans when used in combination with FLC. The results highlighted the potential of curcumin derivatives to overcome fluconazole-related and biofilm-related drug resistance.

Synthesis and Anti-HCV Activities of 18ß-Glycyrrhetinic Acid Derivatives and Their In-Silico ADMET Analysis.

BACKGROUND: Licorice is widely used as a hepatoprotective herb for thousands of years in Traditional Chinese Medicine, and its main chemical constituent glycyrrhizin (GL) is used as a treatment for chronic hepatitis in Japan for over 20 years. 18ß-Glycyrrhetinic acid (GA) is the main active metabolite of GL. OBJECTIVE: Series of GA derivatives were designed and synthesized, and their anti-HCV activities were screened to investigate the structure-activity relationship (SAR). Besides, their in-silico ADMET properties were analyzed to search for a promising lead compound for further identification of anti-HCV terpenoid candidates. METHODS: GA derivatives were synthesized via reactions of oxidation, oxime, rearrangement, esterification and acylation. In vitro anti-HCV activity of derivatives was tested on the HCV cell culture (HCVcc) system. In-silico ADMET properties analysis was performed via "pkCSM" and "SwissADME" platforms. RESULTS: Eighteen GA derivatives were synthesized, and their structures were confirmed by MS and NMR spectrums. All compounds exhibited superior HCV inhibitory activity to that of GA. Compound 2 possessed the most potent anti-HCV activity with an IC50 value of 0.79 µM, which is nearly 58 times potent than SA (a previously reported potent anti-HCV terpenoids) and >200 times than GA. SAR revealed that the introduction of 3-oxo, short-chain (C1-C3) aliphatic alcohols or cyclic aliphatic amines is conducive to improving anti-HCV activity. In-silico ADMET prediction demonstrated most of the potent compounds possessed favorable ADMET properties. CONCLUSION: Structural modification of GA at 3-position and 30-position is an effective approach to searching for potent anti-HCV agents. Compound 2, with the most potent anti-HCV activity and favorable in-silico ADMET properties, is a promising lead compound for further identification of anti-HCV terpenoid candidates.

Synthesis and In Vitro anti-HCV and Antitumor Evaluation of Schisandronic Acid Derivatives.

BACKGROUND: Schisandronic acid (SA), a triterpenoid from fruits of Schisandra sphenanthera, inhibited pan-genotypic HCV entry into human hepatocytes by interfering with virion-cell membrane fusion. It was a promising lead compound for the development of novel HCV entry inhibition agents. OBJECTIVE: The aim of the present study is to search for compounds with more potent anti-HCV and antitumor activities and explore SARs. A series of novel derivatives of SA were designed and synthesized and evaluated for in vitro, their anti-HCV and antitumor activities. METHODS: SA derivatives were synthesized by reduction, condensation, esterification or amidation. The anti-HCV activity of title compounds was tested by inhibition on HCVcc infection of Huh7 cells, and a preliminary MOA study was conducted by determining inhibition on HCVpp entry into Huh7 cells. The antitumor activity in vitro was determined by MTT methods. RESULTS: In total, 24 novel derivatives were synthesized. Most of the compounds inhibited HCVcc infection. Compounds 5h and 6 showed the most potent anti-HCVcc activities and inhibition of HCVpp entry into Huh7 cells without obvious cytotoxicity. Most of the title compounds showed potent in vitro antitumor activities against Bel7404 and SMMC7721 tumor cell lines. Compounds 5j and 6 exhibited more potent antitumor activity than positive control SA and DOX. CONCLUSION: Structural modification of SA could lead to the discovery of potent anti-HCV or antitumor agents. Compounds 5h, 5j and 6 were promising lead compounds for development of novel HCV entry inhibition or antitumor agents.

Hexafluorotitanic acid-assisted synthesis of large-sized, ultrathin titania nanosheets as multifunctional and high-performance photocatalysts.

A fast cyclohexanol solvothermal pathway was developed to prepare highly dispersed anatase titania (TiO2) nanosheets with an edge length of ∼800 nm and a thickness of ∼6 nm. Under the synergistic control of hexafluorotitanic acid and cyclohexanol, the exposed 001 facets reached ∼98.5% on the TiO2 nanosheets obtained by the treatment at 180 °C for 150 min. Moreover, it was found that the phase transformation and structural development drastically occurred during the solvothermal treatment. When used as a catalyst for photodegradation of rhodamine B, the TiO2 nanosheets exhibited a good recycling stability and a much higher photocatalytic degradation rate (nearly 99% degradation within 2.5 h) than the commercial P25 (93.6%). After being uniformly loaded with 4 wt.% of the Pt nanoparticles, the TiO2 nanosheets displayed a photocatalytic hydrogen production rate of 2.239 mmol g-1 h-1 under simulated solar light, which was much higher than the pristine TiO2 nanosheets (0.045 mmol g-1 h-1) as well as most of the reported TiO2-based photocatalysts. The remarkable photocatalytic activity and good stability of the TiO2 nanosheets with highly exposed 001 facets would make them find potential applications in both water treatment and hydrogen generation from water splitting under solar light.

Synthesis and Cytotoxicity Assessment of Novel 7-O- and 14-O-Derivatives of Glaucocalyxin A.

BACKGROUND: Rabdosia japonica has been historically used in China as a popular folk medicine for the treatment of cancer, hepatitis, and gastricism. Glaucocalyxin A (GLA), an ent-kaurene diterpene isolated from Rabdosia japonica, is one of the main active ingredients showing potent inhibitory effects against several types of tumor cells. To the best of our knowledge, studies regarding the structural modification and Structure- Activity Relations (SAR) of this compound have not yet been reported. OBJECTIVE: The aim of this study was to discover more potent derivatives of GLA and investigate their SAR and cytotoxicity mechanisms. METHODS: Novel 7-O- and 14-O-derivatives of GLA were synthesized by condensation of acids or acyl chloride. The anti-tumor activities of these derivatives against various human cancer cell lines were evaluated in vitro by MTT assays. Apoptosis assays of compound 17 (7,14-diacylation product) were performed on A549 and HL-60 cells by flow cytometry and TUNNEL. The acute toxicity of this compound was tested on mice, at the dose of 300mg per kg body weight. RESULTS: Seventeen novel 7-O- and 14-O-derivatives of GLA (1-17) were synthesized. These compounds showed potent cytotoxicity against the tested cancer cell lines, and almost all of them were found to be more cytotoxic than GLA and oridonin. Of the synthesized derivatives, compound 17 presented the greatest cytotoxicity, with IC50 values of 0.26µM and 1.10µM in HL-60 and CCRF-CEM cells, respectively. Furthermore, this compound induced weak apoptosis of A549 cells but showed great potential in stimulating the apoptosis of HL- 60 cells. Acute toxicity assays indicated that compound 17 is relatively safer. CONCLUSION: The results reported herein indicate that the synthesized GLA derivatives exhibited greater cytotoxicity against leukemia cells than against other types of tumors. In particular, 7,14-diacylation product of GLA was found to be an effective anti-tumor agent. However, the cytotoxicity mechanism of this product in A549 cells is expected to be different than that in other tumor cell lines. Further research is needed to confirm this hypothesis.

Synthesis of phthalide derivatives and evaluation on their antiplatelet aggregation and antioxidant activities.

As part of our continuing efforts to discover structurally interesting bioactive phthalide derivatives, 23 of them with a structure incorporating thiophen or halogens were designed and synthesized, 17 of which are previously unreported. In vitro antiplatelet aggregation activity screening showed that 14b could significantly inhibit platelet aggregation induced by arachidonic acid, compared with edaravone (p < 0.01). Meanwhile, oxidative damage models using SH-SY5Y and PC12 cells induced by H2O2 were built to evaluate the antioxidant activity of the phthalide derivatives. In SH-SY5Y cells, compared with aspirin, 1a significantly increased the relative cell survival rate (p < 0.05). Compared with edaravone, 1a (p < 0.01) and 15b (p < 0.05) significantly increased the relative cell survival rate. In PC12 cells, 1a (p < 0.01), 15b (p < 0.01), and 12a (p < 0.05) remarkably increased the cell survival rate compared with edaravone. The present study identified lead structures to develop potential anti-ischemic stroke agents.

Recent advances in natural antifungal flavonoids and their derivatives.

The resistance of pathogenic fungi and failure of drug therapy increased dramatically. Numerous studies have reported the individual or synergistic antifungal potency of natural and synthesized flavonoids, especially against drug-resistant fungi. This brief review summarizes the structure and individual or synergistic antifungal activity of natural and synthesized flavonoids (literatures mainly cover the past 10 years 2009-2019), with a special focus on the antifungal spectra, structure-activity relationship and mechanisms of actions. These may contribute to a better understanding of flavonoids as multi-target agents in the treatment of mycoses and provide some ideas on the development of novel flavonoids-based antifungals.

Monomeric and dimeric ent-kauranoid-type diterpenoids from rabdosia japonica and their cytotoxicity and anti-HBV activities.

Two new ent-kauranoid-type diterpenoids (1 and 2) and one new rare dimer of ent-kauranoids (3) with a cyclobutane ring by a [2+2] cycloaddition, together with nine known diterpenoids (4-12) were obtained from the aerial parts of Rabdosia japonica. Their chemical structures were established by 1D and 2D NMR techniques and mass spectrometry and by comparison with spectroscopic data reported. All ent-kauranoids were test for their cytotoxic effects against A549, HCT116, CCRF-CEM and HL-60 tumor cell lines. Compounds 1, 2, 4, 5, 7, 10 and 12 showed potent and selective cytotoxicity. In addition, some selected ent-kauranoids were test for their anti-HBV activities, and the results showed compound 8 had inhibitory effect on HBsAg with a 59% inhibition ratio at the concentration of 20µg/mL.

Synthesis and synergistic antifungal effects of monoketone derivatives of curcumin against fluconazole-resistant Candida spp.

Twenty-three monoketone derivatives of curcumin were synthesized to investigate the synergy with fluconazole against fluconazole-resistant Candida spp. The minimal inhibitory concentration (MIC80) and the fractional inhibitory concentration index (FICI) of the antifungal synergist fluconazole were measured against fluconazole-resistant C. albicans, C. tropicalis and C. krusei in vitro. Most of these compounds showed good synergistic activities against C. tropicalis. Among them, compound 9 exhibited significant synergistic activities against Candida spp. SARs were also discussed. In particular, a cell growth test exhibited that a combination of 1 µg ml-1 fluconazole and 64 µg ml-1 or 128 µg ml-1 compound 9 showed the most potent fungicidal effect against C. tropicalis. The synergistic effect may be associated with the changes of the intracellular ATP content and cell membrane permeability. Our results provided a basis for future evaluation and development of these compounds as leads for therapeutics for fluconazole-resistant candidiasis.

Chemical constituents from the rhizome of Polygonum paleaceum and their antifungal activity.

A new compounds neopaleaceolactoside (1), along with nine known compounds phyllocoumarin (2), quercetin (3), quercitrin (4), quercetin-3-methyl ether (5), vincetoxicoside B (6), isoquercitrin (7), kaempferol (8), (-)-epicatechin (9), and chlorogenic acid (10), was isolated from Polygonum paleaceum Wall. Their chemical structures were established based on one-dimensional and two-dimensional nuclear magnetic resonance techniques, mass spectrometry and by comparison with spectroscopic data reported. Some selected compounds were screened for their antifungal activity. Quercetin (3), vincetoxicoside B (6), kaempferol (8), and (-)-epicatechin (9) showed synergistic antifungal activities with the FICI values <0.5. A preliminary structure-activity relationship could be observed that free 3-OH in the structure of flavonoids was important for synergistic antifungal activity.

Constituents from the Roots of Actinidia chinensis and Their Cytochrome P450 Enzyme Inhibitory Activities.

A newly discovered triterpenoid, (2α,3ß)-2,3,23-trihydroxyurs-13(18)-en-28-oic acid (1), along with twelve known compounds (2 - 13), were isolated from the roots of Actinidia chinensis Planch (Actinidiaceae). Their chemical structures were determined by 1D- and 2D-NMR spectra and mass spectrometry (MS). The crude extracts and six main constituents (8 - 13) were tested for cytochrome P450 (CYPs) enzyme inhibitory activity. The results showed that, except for compound 8, compounds 9 - 13 had different inhibitory effects on the cytochrome P450 (CYPs) enzyme, and compound 9 significantly inhibited the catalytic activities of CYP3A4 to < 10% of its control activities.

A Schisandra-Derived Compound Schizandronic Acid Inhibits Entry of Pan-HCV Genotypes into Human Hepatocytes.

Despite recent progress in the development of hepatitis C virus (HCV) inhibitors, cost-effective antiviral drugs, especially among the patients receiving liver transplantations, are still awaited. Schisandra is a traditional medicinal herb used to treat a range of liver disorders including hepatitis for thousands of years in China. To isolate the bioactive compounds of schisandra for the treatment of HCV infection, we screened a schisandra-extracts library and identified a tetracyclic triterpenoid, schizandronic acid (SZA), as a novel HCV entry inhibitor. Our findings suggested that SZA potently inhibited pan-HCV genotype entry into hepatoma cells and primary human hepatocytes without interfering virus binding on cell surface or internalization. However, virion-cell fusion process was impaired in the presence of SZA, along with the increased host membrane fluidity. We also found that SZA inhibited the spread of HCV to the neighboring cells, and combinations of SZA with interferon or telaprevir resulted in additive synergistic effect against HCV. Additionally, SZA diminished the establishment of HCV infection in vivo. The SZA target is different from conventional direct-acting antiviral agents, therefore, SZA is a potential therapeutic compound for the development of effective HCV entry inhibitors, especially for patients who need to prevent HCV reinfection during the course of liver transplantations.

The synthesis and synergistic antifungal effects of chalcones against drug resistant Candida albicans.

To identify effective and low toxicity synergistic antifungal compounds, 24 derivatives of chalcone were synthesized to restore the effectiveness of fluconazole against fluconazole-resistant Candida albicans. The minimal inhibitory concentration (MIC80) and the fractional inhibitory concentration index (FICI) of the antifungal synergist fluconazole were measured against fluconazole-resistant Candida albicans. This was done via methods established by the clinical and laboratory standards institute (CLSI). Of the synthesized compounds, 2'-hydroxy-4'-methoxychalcone (8) exhibited the most potent in vitro (FICI=0.007) effects. The structure activity relationship of the compounds are then discussed.

Trachelogenin, a novel inhibitor of hepatitis C virus entry through CD81.

Although much progress has been made in antiviral agents against hepatitis C virus (HCV) in recent years, novel HCV inhibitors with improved efficacy, optimized treatment duration and more affordable prices are still urgently needed. Here, we report the identification of a natural plant-derived lignan, trachelogenin (TGN), as a potent entry inhibitor of HCV without genotype specificity, and with low cytotoxicity. TGN was extracted and purified from Caulis trachelospermi, a traditional Chinese herb with anti-inflammatory and analgesic effects. A crucial function of TGN was the inhibition of HCV entry during a post-binding step without affecting virus replication, translation, assembly and release. TGN blocked virus infection by interfering with the normal interactions between HCV glycoprotein E2 and the host entry factor CD81, which are key processes for valid virus entry. In addition, TGN diminished HCV cell-to-cell spread and exhibited additional synergistic effects when combined with IFN or telaprevir. In conclusion, this study highlights the effect of a novel HCV entry inhibitor, TGN, which has a target that differs from those of the current antiviral agents. Therefore, TGN is a potential candidate for future cocktail therapies to treat HCV-infected patients.

[Chemical Constituents from Polygonum paleaceum].

Objective: To isolate and identify the chemical constituents from Polygonum paleaceum. Methods: Chemical constituents were isolated and purified by column chromatography on silica gel,Sephadex HL-20 and macroporous resin etc. The chemical structures were identified by MS,NMR and spectral analysis. Results: Ten compounds were isolated and their structures were elucidated as ethyl chlorogenate( 1),methyl chlorogenate( 2), kaempferol-3-O-α-L-rhamnopyranoside( 3), (-)-epicatechin( 4), paleaceolactoside( 5), protocatechuic acid( 6), kaempferol( 7), gallic acid( 8), chlorogenic acid( 9) and isoquercitrin( 10). Conclusion: Compounds 1,3,6,7 and 10 are isolated from this plant for the first time.