Antimicrobial spiroketal macrolides and dichloro-diketopiperazine from Micromonospora sp. FIMYZ51.

Four compounds (1-4) featuring with an L-rhodinose and spiroketal, possess uncommon continuous hydroxy groups in the macrolide skeleton, and a dichloro-diketopiperazine (5) were isolated from a marine derived Micromonospora sp. FIMYZ51. The determination of the relative and absolute configurations of all isolates was achieved by extensive spectroscopic analyses, single-crystal X-ray diffraction analysis, and ECD calculations. According to structural characteristic and genomic sequences, a plausible biosynthetic pathway for compound 1-4 was proposed and a spirocyclase was inferred to be responsible for the formation of the rare spirocyclic moiety. Compounds 1-4 exhibited potent antifungal activities which is equal to itraconazole against Aspergillus niger. Compounds 1-5 exhibited different degree of inhibitory activities against opportunistic pathogenic bacteria of endocarditis (Micrococcus luteus) with MIC values ranging from 0.0625 µg/mL to 32 µg/mL. Compounds 2 and 3 showed moderate cytotoxicity against drug-resistant tumor cell lines (Namalwa and U266). The result not only provides active lead-compounds, but also reveal the potential of the spirocyclase gene resources from Micromonospora sp., which highlights the promising potential of the strain for biomedical applications.

Corynoxine triggers cell death via activating PP2A and regulating AKT-mTOR/GSK3ß axes in NSCLC.

This study investigates the anticancer activity and pharmacological mechanisms of Corynoxine (Cory) in non-small cell lung cancer (NSCLC). Cory, a natural product derived from the Chinese herbal medicine Uncaria rhynchophylla, demonstrates promising pharmacological activity. Cell proliferation and viability were evaluated via MTT and colony formation assays. Flow cytometry was employed to analyze cell apoptosis, cycle distribution, and mitochondrial membrane potential. Autophagy was detected using fluorescence microscopy and electron microscopy. Western blotting, protein overexpression, gene knockdown, co-immunoprecipitation, and bioinformatics characterized Cory's impact on signaling pathways. The research indicates that Cory inhibits the proliferation of NSCLC cells in vivo and in vitro. Cory enhances PP2A activity, inhibits the AKT/mTOR signaling pathway triggering autophagy, while suppressing the AKT/GSK3ß signaling pathway to induce cellular apoptosis in NSCLC. Notably, the activation of PP2A plays a crucial role in Cory's antitumor effects by inhibiting AKT. In vivo experiments validated Cory's efficacy in NSCLC treatment. These findings highlight the promising role of Cory as a lead compound for drug development in NSCLC therapy, providing a viable option for addressing this challenging disease.

Neuroinflammation and Acetylcholinesterase Inhibitory Potentials of a Spiroketal-Enol Ether Polyyne Isolated from Artemisia pallens Wall. ex DC.

Artemisia pallens Wall. ex DC (Asteraceae) is cultivated for the production of high-value essential oil from its aerial biomass. In this study, the chemical composition of the root (crop-residue) essential oil was investigated for the first time, using column-chromatography, GC-FID, GC-MS, LC-QTOF, and NMR techniques, which led to the identification of twenty constituents, with isolation of (E)-2-(2',4'-hexadiynylidene)-1,6-dioxaspiro [4.5]dec-3-ene (D6). The D6 was evaluated in vitro for neuroinflammation and acetylcholinesterase inhibitory potential. It showed inhibition of neuroinflammation in a concentration-dependent manner with significant inhibition of pro-inflammatory cytokines (TNF-α and IL-6) in LPS-stimulated BV2 microglial cells. D6 did not have any significant effect on the viability of the cells at the therapeutic concentrations. D6 also has shown acetylcholinesterase inhibitory potential (51.90±1.19 %) at the concentration of log 106  nM. The results showed that D6 has a potential role in the resolution of neuroinflammation, and its acetylcholinesterase inhibitory potential directs further investigation of its role in the management of Alzheimer's disease-related pathogenesis.

Acetylenic spiroketal enol ethers from Artemisia rupestris and their synergistic antibacterial effects on methicillin-resistant Staphylococcus aureus.

Synergistic bioassay-guided isolation of the extracts of Artemisia rupestris L, which belongs to the family Asteraceae, afforded two acetylenic spiroketal enol ethers, namely rupesdiynes A (1) and B (2). Their structures were determined based on spectroscopic analysis and experimental and calculated ECD investigations. The two compounds exhibited synergistic activity and were able to reduce the minimum inhibitory concentration (MIC) of oxacillin four-fold, with a fractional inhibitory concentration index (FICI) of 0.5 in combination with oxacillin against the oxacillin-resistant EMRSA-16. Biofilm formation inhibitory and Ethidium bromide (EtBr) efflux assay were further employed to verify the possible mechanism of the synergistic antibacterial effect. Additionally, molecular docking studies were conducted to investigate the binding affinities of the two compounds with penicillin-binding protein 2a (PBP2a) of EMRSA-16. Taken together, rupesdiynes A (1) and rupesdiyne B (2) showed moderate synergistic activity against EMRSA-16 with oxacillin via inhibiting biofilm formation and efflux pump activity, respectively.

Accelerated abdominal lipid depletion from pesticide treatment alters honey bee pollen foraging strategy, but not onset, in worker honey bees.

Honey bee abdominal lipids decline with age, a change thought to be associated with the onset of foraging behavior. Stressors, such as pesticides, may accelerate this decline by mobilizing internal lipid to facilitate the stress response. Whether bees with stressor-induced accelerated lipid loss vary from controls in both the onset of foraging and nutritional quality of collected pollen is not fully understood. We asked whether stressors affect foraging behavior through the depletion of abdominal lipid, and whether stress-induced lipid depletion causes bees to forage earlier and for fattier pollen. We tested this by treating newly emerged bees with one of two pesticides, pyriproxyfen (a juvenile hormone analog) and spirodiclofen (a fatty acid synthesis disruptor), that may affect energy homeostasis in non-target insects. Bees fed these pesticides were returned to hives to observe the onset of foraging behavior. We also sampled foraging bees to assay both abdominal lipids and dietary lipid content of their corbicular pollen. Initially, spirodiclofen-treated bees had significantly more abdominal lipids, but these declined faster compared with controls. These bees also collected less, yet more lipid-rich, pollen. Our results suggest that bees with accelerated lipid decline rely on dietary lipid content and must collect fattier pollen to compensate. Pyriproxyfen treatment reduced the age at first forage but did not affect abdominal or collected pollen lipid levels, suggesting that accelerated fat body depletion is not a prerequisite for precocious foraging.

Comparison of Ophiopogon japonicus and Liriope spicata var. prolifera from Different Origins Based on Multi-Component Quantification and Anticancer Activity.

The tuberous root of Ophiopogon japonicus (Thunb.) Ker-Gawl. is a well-known Chinese medicine also called Maidong (MD) in Chinese. It could be divided into "Chuanmaidong" (CMD) and "Zhemaidong" (ZMD), according to the geographic origins. Meanwhile, the root of Liriope spicata (Thunb.) Lour. var. prolifera Y. T. Ma (SMD) is occasionally used as a substitute for MD in the market. In this study, a reliable pressurized liquid extraction and HPLC-DAD-ELSD method was developed for the simultaneous determination of nine chemical components, including four steroidal saponins (ophiopojaponin C, ophiopogonin D, liriopesides B and ophiopogonin D'), four homoisoflavonoids (methylophiopogonone A, methylophiopogonone B, methylophiopogonanone A and methylophiopogonanone B) and one sapogenin (ruscogenin) in CMD, ZMD and SMD. The method was validated in terms of linearity, sensitivity, precision, repeatability and accuracy, and then applied to the real samples from different origins. The results indicated that there were significant differences in the contents of the investigated compounds in CMD, ZMD and SMD. Ruscogenin was not detected in all the samples, and liriopesides B was only found in SMD samples. CMD contained higher ophiopogonin D and ophiopogonin D', while the other compounds were more abundant in ZMD. Moreover, the anticancer effects of the herbal extracts and selected components against A2780 human ovarian cancer cells were also compared. CMD and ZMD showed similar cytotoxic effects, which were stronger than those of SMD. The effects of MD may be due to the significant anticancer potential of ophiopognin D' and homoisoflavonoids. These results suggested that there were great differences in the chemical composition and pharmacological activity among CMD, ZMD and SMD; thus, their origins should be carefully considered in clinical application.

Hyperacmosin R, a New Decarbonyl Prenylphloroglucinol with Unusual Spiroketal Subunit from Hypericum acmosepalum.

Two previously undescribed polycyclic polyprenylated acylphloroglucinols, hyperacmosins R-S (1-2), were obtained from the aerial parts of Hypericum acmosepalum. Their structures were elucidated by extensive spectroscopic analysis and electronic circular dichroism calculation (ECD). Compound 1 featured an unprecedented 5,8-spiroketal subunit as well as the loss of C-2' carbonyl in the phloroglucinol ring. In addition, compounds 1 and 4 showed weak hepatoprotective activity against paracetamol-induced HepG2 cell damage at 10 µm. The plausible biosynthetic pathway of 1 was proposed via a retro-Clasisen reaction and decarboxylation.

Expedited Total Synthesis of (±)-Brevianamide A via the Strategic Use of Gold(I) Catalysis.

Two concise and complementary routes to the polycyclic alkaloid (±)-brevianamide A from readily available amino acid building blocks are presented. Key to the synthesis is the strategic use of a gold(I)-catalyzed cascade process that quickly assembles the characteristic pseudoindoxyl motif of the natural product along with the two adjacent quaternary centers in a single step. This sequence, which exemplifies the structural complexity that can be achieved with gold catalysis, allowed for the shortest and highest-yield synthesis of (±)-brevianamide A to date (four steps LLS, 14% overall yield).

Norprzewalsone A, a Rearranged Polycyclic Polyprenylated Acylphloroglucinol with a Spiro[cyclopentane-1,3'-tricyclo[7.4.0.01,6]tridecane] Core from Hypericum przewalskii.

Norprzewalsone A (1), a rearranged polyprenylated polycyclic acylphloroglucinol (PPAP) with a new carbon skeleton, along with a new congener, norprzewalsone B (2), were isolated from Hypericum przewalskii. Compound 1 possessed a new 5/6/5/6/6 pentacyclic ring system based on a spiro[cyclopentane-1,3'-tricyclo[7.4.0.01,6]tridecane] core, which might be derived from the common [3.3.1]-type bicyclic polyprenylated acylphloroglucinol (BPAP) via the key retro-Claisen, intramolecular cyclization, and Diels-Alder cyclization reactions. Their structures and absolute configurations were confirmed by spectroscopic data, calculated 1D NMR data with DP4+ probability analyses, and electronic circular dichroism calculations and comparison. More significantly, compound 1 exhibited a moderate inhibitory effect on NO production in lipopolysaccharide-stimulated RAW264.7 cells.

Voacanga globosa Spirobisindole Alkaloids Exert Antiviral Activity in HIV Latently Infected Cell Lines by Targeting the NF-kB Cascade: In Vitro and In Silico Investigations.

Since the efficiency in the transcription of the HIV genome contributes to the success of viral replication and infectivity, we investigated the downregulating effects of the spirobisindole alkaloids globospiramine (1), deoxyvobtusine (2), and vobtusine lactone (3) from the endemic Philippine medicinal plant, Voacanga globosa, during HIV gene transcription. Alkaloids 1-3 were explored for their inhibitory activity on TNF-α-induced viral replication in two latently HIV-infected cell lines, OM10.1 and J-Lat. The induction of HIV replication from OM10.1 and J-Lat cells elicited by TNF-α was blocked by globospiramine (1) within noncytotoxic concentrations. Furthermore, globospiramine (1) was found to target the NF-ĸB activation cascade in a dose-dependent manner when the transcriptional step at which inhibitory activity is exerted was examined in TNF-α-induced 293 human cells using transient reporter (luciferase) gene expression systems (HIV LTR-luc, ĸB-luc, and mutant ĸB-luc). Interrogation through molecular docking against the NF-ĸB p50/p65 heterodimer and target sites of the subunits comprising the IKK complex revealed high binding affinities of globospiramine (1) against the S281 pocket of the p65 subunit (BE = -9.2 kcal/mol) and the IKKα activation loop (BE = -9.1 kcal/mol). These findings suggest globospiramine (1) as a molecular inspiration to discover new alkaloid-based anti-HIV derivatives.

Two antibacterial spiro compounds from the roots of Artemisia pallens wall: evidence from molecular docking.

Bioassay-guided isolation from acetone extract of the roots of Artemisia pallens Wall yielded two spiro compounds (1 and 2). The structures of these compounds were determined on the basis of spectroscopic techniques such as IR, MS, 1 D and 2 D- NMR. The acetone extract, fractions and the isolated two compounds were investigated for their antibacterial activity against two gram negative (E. coli, P. aeruginosa) and two gram positive (S. aureus, B. subtilis) bacterial strains. Compound (2) showed the best spectra of activity with IC50 and MIC values between 2.48-3.08 and 12.78 - 21.77 µM and Compound (1) with 2.57-3.69 and 38.17 - 80.57 µM, respectively, for the four bacterial strains, whereas inactive against Mycobacterium tuberculosis. Molecular docking study could further help in understanding the various interactions between these compounds and DNA gyrase active site in detail and thereby could provide valuable insight into the mechanism of action.

In vitro metabolism of tebuconazole, flurtamone, fenhexamid, metalaxyl-M and spirodiclofen in Cannabis sativa L. (hemp) callus cultures.

BACKGROUND: Cannabis sativa L. (hemp) is a medicinal plant producing various cannabinoids. Its consumption is legalized for medical use due to the alleged positive health effects of these cannabinoids. To satisfy the demand, C. sativa plants are propagated in contained growth chambers. During indoor propagation, pesticides usually are used to ensure efficient production. However, pesticide registration and safe application in C. sativa has not been investigated in detail. RESULTS: With this study the metabolic degradation of pesticides in recently established C. sativa callus cultures was examined. Tebuconazole, metalaxyl-M fenhexamid, flurtamone and spirodiclofen were applied at 10 µm for 21 days. Results were compared with metabolism data obtained from Brassica napus L., Glycine max (L.) Merr., Zea mays L. and Tritium aestivum L. callus cultures as well as in metabolism guideline studies. The successfully established C. sativa callus cultures were able to degrade pesticides by oxidation, demethylation, and cleavage of ester bonds in phase I, as well as glycosylation and conjugation with malonic acid in phase II and III. Initial metabolites were detected after Day (D)7 and were traced at D21. CONCLUSION: The resulting pathways demonstrate the same main degradation strategies as crop plants. Because metabolites could be the main residue, the exposure of consumers to these residues will be of high importance. We present here an in vitro assay for a first estimation of pesticide metabolism in C. sativa. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Natural spirocyclic alkaloids and polyphenols as multi target dementia leads.

The U rhynchophylla, U tomentosa, Isatis indigotica Fortune, Voacanga Africana, herbal constituents, fungal extracts from Aspergillus duricaulis culture media, include spirooxindoles, polyphenols or bridged spirocyclic alkaloids. Their constituents exhibit specific and synergistic multiple neuroprotective properties including inhibiting of Aß fibril induced cytotoxicity, NMDA receptor inhibition in mice models of Alzheimer's disease (AD). The pioneering research from Woodward to Waldmann has advanced the synthesis of spirocyclic alkaloids. Furthermore, the elucidation of the genetic analysis, biochemical pathways that links strictosidine to the alkaloids akuammicine, stemmadenine, tabersonine, catharanthine, will now enable the biotechnological generation, also stimulate synthesis of related bridged spirocyclic alkaloids for medicinal investigations. From the value of spirocyclic structures as multi target dementia leads, we hypothesise that simpler Lipinski-like natural/synthetic alkaloid analogues may likewise be discovered that provide neurocognitive enhancing activities against dementia and AD.

Molecular docking and toxicity assessment of spirodiclofen: protective role of lycopene.

In this study, toxic effects of spirodiclofen and protective role of lycopene against toxic effects were investigated by using physiological, cytogenetic, anatomical, and biochemical parameters. Allium cepa L. bulbs were used as test material. The bulbs were divided into six groups as one control and five application groups. Bulb in the control group was germinated with tap water, and in treatment groups, 20-mg L-1 dose of spirodiclofen 215- and 430-mg L-1 doses of lycopene were applied. Spirodiclofen application caused a decrease in physiological parameters such as germination percentage, root length, and weight increase. Spirodiclofen administration caused a decrease in the percentage of mitotic index (MI) and an increase in DNA fragmentation, micronucleus (MN), and chromosomal aberration (CA) frequency. Spirodiclofen application caused an increase in the level of the oxidant compound malondialdehyde (MDA), changes in the level of antioxidant enzymes, and disruption of the oxidant/antioxidant balance in the cell. Molecular interactions between spirodiclofen and antioxidant enzymes were determined by molecular docking analysis. In addition to physiological, biochemical, and genetic abnormalities, spirodiclofen also caused deformations in the anatomy of the A. cepa root tip meristematic cells. Lycopene treatment showed a protective effect by suppressing the toxic effects of spirodiclofen, causing a significant improvement in the values of selected physiological, cytogenetic, anatomical, and biochemical parameters. As a result, spirodiclofen insecticide caused toxic effects on various parameters in A. cepa, which is a eukaryotic model organism. In order to elucidate the toxicity mechanism, each parameter is associated with each other. Molecular docking method has revealed the effects of spirodiclofen on antioxidant enzymes. Lycopene application together with spirodiclofen resulted in the regression of all toxic effects and improvement in the root tissue. This result shows that lycopene has a strong protective property against spirodiclofen toxicity.

Prolonged Treatment with Centella asiatica Improves Memory, Reduces Amyloid-ß Pathology, and Activates NRF2-Regulated Antioxidant Response Pathway in 5xFAD Mice.

BACKGROUND: The medicinal herb Centella asiatica has been long been used for its neuroprotective and cognitive enhancing effects. We have previously shown that two weeks of treatment with a water extract of Centella asiatica (CAW) improves cognition and activates the endogenous antioxidant response pathway without altering amyloid-ß (Aß) plaque burden. OBJECTIVE: Here, we assess the effect of long-term treatment of CAW in the 5xFAD mouse model of Aß accumulation. METHODS: Four-month-old 5xFAD mice were treated with CAW in their drinking water (2 g/L) for three months at which point they underwent cognitive testing as well as analysis of Aß plaque levels and antioxidant and synaptic gene expression. In order to confirm the involvement of the antioxidant regulatory transcription factor NRF2 on the effects of CAW on synaptic plasticity, neurons isolated from 5xFAD mice were also treated with CAW and the targeted inhibitor ML385. RESULTS: Three months of treatment with CAW improved spatial and contextual memory as well as executive function in 5xFAD mice. This improvement was accompanied by increased antioxidant gene expression and a decrease in Aß plaque burden relative to untreated 5xFAD animals. In isolated neurons, treatment with ML385 blocked the effects of CAW on dendritic arborization and synaptic gene expression. CONCLUSION: These results suggest that prolonged CAW exposure could be beneficial in Alzheimer's disease and that these effects likely involve NRF2 activation. Moreover, these findings suggest that targeting NRF2 itself may be a relevant therapeutic strategy for improving synaptic plasticity and cognitive function in Alzheimer's disease.

The Main Alkaloids in Uncaria rhynchophylla and Their Anti-Alzheimer's Disease Mechanism Determined by a Network Pharmacology Approach.

Alzheimer's disease (AD) is a growing concern in modern society, and effective drugs for its treatment are lacking. Uncaria rhynchophylla (UR) and its main alkaloids have been studied to treat neurodegenerative diseases such as AD. This study aimed to uncover the key components and mechanism of the anti-AD effect of UR alkaloids through a network pharmacology approach. The analysis identified 10 alkaloids from UR based on HPLC that corresponded to 90 anti-AD targets. A potential alkaloid target-AD target network indicated that corynoxine, corynantheine, isorhynchophylline, dihydrocorynatheine, and isocorynoxeine are likely to become key components for AD treatment. KEGG pathway enrichment analysis revealed the Alzheimers disease (hsa05010) was the pathway most significantly enriched in alkaloids against AD. Further analysis revealed that 28 out of 90 targets were significantly correlated with Aß and tau pathology. These targets were validated using a Gene Expression Omnibus (GEO) dataset. Molecular docking studies were carried out to verify the binding of corynoxine and corynantheine to core targets related to Aß and tau pathology. In addition, the cholinergic synapse (hsa04725) and dopaminergic synapse (hsa04728) pathways were significantly enriched. Our findings indicate that UR alkaloids directly exert an AD treatment effect by acting on multiple pathological processes in AD.

Shuganning injection, a traditional Chinese patent medicine, induces ferroptosis and suppresses tumor growth in triple-negative breast cancer cells.

BACKGROUND: Triple-negative breast cancer (TNBC), lacking targeted therapies currently, is susceptible to ferroptosis, a recently defined form of cell death. PURPOSE: To evaluate the anticancer activity of Shuganning injection (SGNI), a traditional Chinese patent medicine, on TNBC cells; To elucidate the mechanism of SGNI induced ferroptosis. METHODS: The anticancer activity of SGNI was examined via in vitro cell proliferation assays and in vivo xenograft growth assay. Ferroptosis was determined by flow-cytometric analysis of lipid ROS, labile iron pool measurement, and propidium iodide exclusion assay. The dependency on heme oxygenase 1 (HO-1) of SGNI induced ferroptosis was confirmed by genetic knockdown and pharmacological inhibition of the protein. RESULTS: SGNI selectively inhibited the proliferation of TNBC cells compared to non-TNBC breast cancer cells and normal cells. The cell death induced by SGNI in TNBC cells showed distinct morphology from apoptosis and could not be rescued by the pan-caspase inhibitor Z-VAD(OMe)-FMK. On the other hand, SGNI induced cell death was blocked by the lipid ROS scavengers ferrostatin-1 and liproxstatin-1, the acyl-CoA synthetase long chain family member 4 inhibitor rosiglitazone, and the iron chelators 1,10-phenanthroline and deferoxamine. These data indicated that SGNI induced a ferroptotic cell death of TNBC cells. Mechanistically, SGNI induced ferroptosis was dependent on HO-1, which promotes intracellular labile iron pool accumulation, and was alleviated by HO-1 knockdown and inhibition by tin protoporphyrin IX. In line with the in vitro data, SGNI significantly inhibited the xenograft growth of TNBC cell line MD-MB-231 in nude mice. CONCLUSION: Collectively, our study elaborates on a promising regimen for TNBC treatment through induction of ferroptosis by SGNI, a traditional Chinese patent medicine currently available in the clinic, which merits further investigation.

Pharmacokinetics of Eleven Kratom Alkaloids Following an Oral Dose of Either Traditional or Commercial Kratom Products in Rats.

Kratom, Mitragyna speciosa Korth., is being widely consumed in the United States for pain management and the reduction of opioid withdrawal symptoms. The central nervous system (CNS) active alkaloids of kratom, including mitragynine, 7-hydroxymitragynine, and numerous additional compounds, are believed to derive their effects through opioid receptor activity. There is no literature describing the systemic exposure of many of these alkaloids after the consumption of kratom. Therefore, we have developed and validated a bioanalytical method for the simultaneous quantitation of 11 kratom alkaloids (mitragynine, 7-hydroxymitragynine, corynantheidine, speciogynine, speciociliatine, paynantheine, corynoxine, corynoxine-B, mitraphylline, ajmalicine, and isospeciofoline) in rat plasma. The validated method was used to analyze oral pharmacokinetic study samples of lyophilized kratom tea (LKT) and a marketed product, OPMS liquid shot, in rats. Among the 11 alkaloids, only mitragynine, 7-hydroxymitragynine, speciociliatine, and corynantheidine showed systemic exposure 8 h postdose, and the dose-normalized systemic exposure of these four alkaloids was higher (1.6-2.4-fold) following the administration of the commercial OPMS liquid. Paynantheine and speciogynine levels were quantifiable up to 1 h postdose, whereas none of the other alkaloids were detected. In summary, the method was successfully applied to quantify the exposure of individual kratom alkaloids after an oral dose of traditional or commercial products. This information will contribute to understanding the role of each alkaloid in the overall pharmacology of kratom and elucidating the pharmacokinetic differences between traditional and commercial kratom products.

Benzannulated 5,5-spiroketal sesquiterpenes from the roots of Angelica Pubescens.

Two new tetrahydrobenzannulated 5,5-spiroketal sesquiterpenes (1 and 2) and three novel benzannulated 5,5-spiroketal sesquiterpenes (3-5) namely angepubesins A-E, together with a new heliannane-type benzannulated sesquiterpene namely angepubesin F (6) and two known monoterpenes (7 and 8), were isolated from the roots of Angelica Pubescens. Their structures were identified by various spectroscopic analyses (NMR, MS, UV, IR), in combination with 13C NMR calculation as well as MAE, CMAE, DP4 + and MAEΔΔδ values analyses. The absolute configurations of 1-6 were determined by modified Mosher's method, ECD calculation and single-crystal X-ray diffraction (Cu Kα). Furthermore, the inhibitory activities of these isolated compounds against nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells were evaluated. The results showed that compounds 2-4, 6 and 7, especially 6, displayed markedly inhibitory effects on NO production in a concentration-dependent manner. Mechanical study revealed that compound 6 could significantly inhibit the expression of nitric oxide synthase (iNOS) protein at a concentration of 10 µM. In addition, compound 6 suppressed the activation of JAK-STAT and NF-κB pathways.

One-pot enantioselective synthesis of (S)-spirobrassinin and non-natural (S)-methylspirobrassinin from amino acids using a turnip enzyme.

The enantioselective synthesis of (S)-(-)-spirobrassinin, which features a unique sulfur-containing spirooxindole skeleton, was achieved by focusing on the phytoalexin generation in Brassicaceae plants. Specifically, (S)-(-)-spirobrassinin was obtained in a one-pot fashion from L-tryptophan through a reaction involving S-spirocyclization with various turnip enzymes and constituents, i.e., using the turnip as a reaction reagent, catalyst, and reaction vessel. Surprisingly, this strategy also enabled the one-pot enantioselective synthesis of the novel non-natural spirooxindole (S)-(-)-5-methylspirobrassinin from 5-methyl-DL-tryptophan.