Two Pairs of Enantiomeric Alkaloid Dimers from Macleaya cordata

Discovery of sesquiterpenoids from the roots of Chloranthus henryi Hemsl. var. hupehensis (Pamp.) K. F. Wu and their anti-inflammatory activity by IKBα/NF-κB p65 signaling pathway suppression

Phytochemical analysis of Chloranthus henryi var. hupehensis roots led to the identification of a new eudesmane sesquiterpenoid dimer, 18 new sesquiterpenoids, and three known sesquiterpenoids. Among the isolates, 1 was a rare sesquiterpenoid dimer that is assembled by a unique oxygen bridge (C11-O-C8') of two highly rearranged eudesmane-type sesquiterpenes with the undescribed C16 carbon framework. (+)-2 and (-)-2 were a pair of new skeleton dinorsesquiterpenoids with a remarkable 6/6/5 tricyclic ring framework including one γ-lactone ring and the bicyclo[3.3.1]nonane core. Their structures were elucidated using spectroscopic data, single-crystal X-ray diffraction analysis, and quantum chemical computations. In the LPS-induced BV-2 microglial cell model, 17 suppressed IL-1β and TNF-α expression with EC50 values of 6.81 and 2.76 µM, respectively, indicating its excellent efficacy in inhibiting inflammatory factors production in a dose dependent manner and without cytotoxicity. In subsequent mechanism studies, compounds 3, 16, and 17 could reduce IL-1β and TNF-α production by inhibiting IKBα/p65 pathway activation.

Insights on Antitumor Activity and Mechanism of Natural Benzophenanthridine Alkaloids

Benzophenanthridine alkaloids are a class of isoquinoline compounds, which are widely found in the plants of papaveraceae, corydalis, and rutaceae. Biological activities and clinical studies have shown that benzophenanthridine alkaloids have inhibitory effects on many cancers. Considering that the anticancer activities and mechanisms of many natural benzophenanthridine alkaloids have been discovered in succession, the purpose of this paper is to review the anticancer effects of benzophenanthridine alkaloids and explore the application potential of these natural products in the development of antitumor drugs. A literature survey was carried out using Scopus, Pubmed, Reaxys, and Google Scholar databases. This review summarizes and analyzes the current status of research on the antitumor activity and antitumor mechanism of natural products of benzophenanthridine from different sources. The research progress of the antitumor activity of natural products of benzophenanthridine from 1983 to 2023 was reviewed. The antitumor activities of 90 natural products of benzophenanthridine and their related analogues were summarized, and the results directly or indirectly showed that natural products of benzophenanthridine had the effects of antidrug-resistant tumor cell lines, antitumor stem cells, and inducing ferroptosis. In conclusion, benzophenanthridine alkaloids have inhibitory effects on a variety of cancers and have the potential to counteract tumor resistance, and they have great application potential in the development of antitumor drugs.

(+)/(-)-Yanhusamides A-C, three pairs of unprecedented benzylisoquinoline-pyrrole hetero-dimeric alkaloid enantiomers from Corydalis yanhusuo

A chemical investigation on the aqueous extract of Corydalis yanhusuo tubers led to the isolation and structural elucidation of three pairs of trace enantiomeric hetero-dimeric alkaloids, (+)/(-)-yanhusamides A-C (1-3), featuring an unprecedented 3,8-diazatricylco[5.2.2.0^2,6]undecane-8,10-diene bridged system. Their structures were exhaustively characterized by X-ray diffraction, comprehensive spectroscopic data analysis, and computational methods. Guided by the hypothetical biosynthetic pathway for 1-3, a gram-scale biomimetic synthesis of (±)-1 was achieved in 3 steps using photoenolization/Diels-Alder (PEDA) [4+2] cycloaddition. Compounds 1‒3 exhibited potent inhibition of NO production induced by LPS in RAW264.7 macrophages. The in vivo assay showed that oral administration of 30 mg/kg of (±)-1 attenuated the severity of rat adjuvant-induced arthritis (AIA). Additionally, (±)-1 induced a dose-dependent antinociceptive effect in the acetic acid-induced mice writhing assay.

Oxidative Stress Response and Metal Transport in Roots of Macleaya cordata Exposed to Lead and Zinc

Heavy metal pollution possesses potential hazards to plant, animal and human health, which has become the focus of recent attention. Hence, phytoremediation has been regarded as one of the most important remediation technologies for heavy-metal-contaminated soils. In this research, a dominant mine tailing plant, Macleaya cordata, was used as the experimental material to compare the metal transport and oxidative stress response in its roots under lead (Pb) and zinc (Zn) treatments. The result showed that Pb was mainly accumulated in the roots of M. cordata under the Pb treatment; less than 1% Pb was transported to the parts above. An analysis of the Zn content demonstrated a 39% accumulation in the shoots. The production of reactive oxygen species was detected using the in situ histological staining of roots, which showed that hydrogen peroxide in the root tips was observed to increase with the increase in both Pb and Zn concentrations. No significant superoxide anion changes were noted in the root tips under the Pb treatment. An analysis of the root enzyme activity showed that increase in NADPH oxidase activity can be responsible for the production of superoxide anions, subsequent the inhibition of root growth and decrease in antioxidant enzyme activities in the roots of M. cordata exposed to excess Zn. In total, this research provides evidence that the root of M. cordata has a high antioxidant capacity for Pb stress, so it can accumulate more Pb without oxidative damage. On the other hand, the Zn accumulated in the roots of M. cordata causes oxidative damage to the root tips, which can stimulate more Zn transport to the shoots to reduce the damage to the roots. This result will provide a basis for the application of M. cordata in the phytoremediation of soil polluted by Pb-Zn compounds.

Cytotoxic alkaloids from the fruit pods of Macleaya microcarpa

19 compounds, including seven previously undescribed alkaloids ((-)-macleayin K (1), (+)-macleayin K (2), macleayin M (3), macleayin N (4), macleayin L (5), macleayin O (6), oxohydrastinine A (7), one new natural product (8), and 11 known compounds, were isolated from the fruit pods of Macleaya microcarpa. Their structures were defined based on NMR, HRESIMS, and electronic circular dichroism (ECD) data. A network pharmacology approach combined with molecular docking and in vitro validation was performed to determine the bioactivity, key targets of the 19 compounds against breast cancer (BC) and cervical cancer (CC). EGFR and PIK3CA could become potential therapeutic targets based a network pharmacology. Moreover, molecular docking suggested that the 19 compounds combined well with EGFR and PIK3CA, respectively. Their cytotoxicity of selected compounds was tested against the MCF-7 and HeLa cells, and the preliminary structure-activity relationship is discussed. Compounds 1 (IC₅₀: 6.00 μM) and 2 (IC₅₀: 6.82 μM) exhibited strong inhibitory activity against the HeLa cells and are worthy of further study.

Application of Central Composite Design-Based Response Surface Methodology in Optimization of the Preparation Process of Sanguinarine Chitosan Microspheres

We designed the present experiment to prepare the sanguinarine chitosan microspheres. First, using the chitosan as a carrier, we prepared sanguinarine microspheres by emulsion cross-linking method, and determined the drug loading and encapsulation efficiency of sanguinarine microspheres by high performance liquid chromatography (HPLC). Then, taking the particle size as the evaluation indicator, we optimized the preparation process by the central composite design-based response surface methodology (CCD-based RSM). Finally, we performed in vitro release test to examine the cumulative release of sanguinarine microspheres. As a result, the optimal process conditions: 0.06 g for sanguinarine dosage, 0.07 g for chitosan dosage, 2% for acetic acid concentration, 3:10 for volume ratio of oil to water, 40 °C for emulsion cross-linking temperature, 500 r/min for rotation speed, and 5% for emulsifier dosage. Under such conditions, the sanguinarine microspheres had round shape, the average particle size was (8.14±0.13) μm, the particle size distribution was 2–20 μm, the drug loading was (4.58±0.93)%, and the encapsulation efficiency was (54.64±0.39)%, the cumulative release within 24 h was (78.34±1.08)%. In conclusion, we successfully prepared the sanguinarine chitosan microspheres, and they have excellent morphology, suitable particle size, and good sustained-release effect.

Natural Enantiomers: Occurrence, Biogenesis and Biological Properties

The knowledge that natural products (NPs) are potent and selective modulators of important biomacromolecules (e.g., DNA and proteins) has inspired some of the world’s most successful pharmaceuticals and agrochemicals. Notwithstanding these successes and despite a growing number of reports on naturally occurring pairs of enantiomers, this area of NP science still remains largely unexplored, consistent with the adage “If you don’t seek, you don’t find”. Statistically, a rapidly growing number of enantiomeric NPs have been reported in the last several years. The current review provides a comprehensive overview of recent records on natural enantiomers, with the aim of advancing awareness and providing a better understanding of the chemical diversity and biogenetic context, as well as the biological properties and therapeutic (drug discovery) potential, of enantiomeric NPs.

Phaeosphspirone (1/1'), a pair of unique polyketide enantiomers with an unusual 6/5/5/6 tetracyclic ring from the desert plant endophytic fungus Phaeosphaeriaceae sp

Phaeosphspirone, an undescribed polyketide with a unique 6/5/5/6-fused tetracyclic system, and two known analogues, herbarin and O-methylherbarin, were purified from the endophytic fungus Phaeosphaeriaceae sp. isolated from the desert plant Bassia dasyphylla. The connectivity and relative configuration of phaeosphspirone was elucidated by comprehensive HR-ESI-MS and NMR analysis together with a computer-assisted structure elucidation (CASE) method. A pair of enantiomers existing in phaeosphspirone were separated by HPLC chromatography after reacting with chiral reagents, from which the absolute configuration of phaeosphspirone was simultaneously determined based on Mosher's rule. This tandem strategy provides a useful approach for the separation and stereochemical determination of enantiomers possessing secondary hydroxyl groups. The structural feature of phaeosphspirone, herbarin and O-methylherbarin together with gene cluster analysis suggested their polyketide biosynthetic origin. Herbarin and O-methylherbarin exhibited moderate cytotoxicity against three cancer cell lines.

Macleayins A From Macleaya Promotes Cell Apoptosis Through Wnt/β-Catenin Signaling Pathway and Inhibits Proliferation, Migration, and Invasion in Cervical Cancer HeLa Cells

Macleayins A (MA), a novel compound, was isolated from Macleaya cordata (Willd.) R. Br. and Macleaya microcarpa (Maxim.) Fedde. The plant species are the member of Papaveraceae family and have been used traditionally for diverse therapeutic purposes. According to the reported studies, the chemical constituents, as well as crude extracts of these plants, could attenuate the proliferation of several cancer cell lines, such as HL-60, A549, HepG2, and MCF-7. The current study aimed to investigate the anticervical cancer activity of MA and its related molecular mechanism. Isolation of MA was carried out using various column chromatographic methods, and its structure was elucidated with ¹H NMR. The cytotoxicity of MA was determined against HeLa cell lines via CCK-8 assay. The cell proliferation, apoptosis, cell cycle, migration, and invasion were measured by EdU labeling, Annexin-V APC/7-AAD double staining, PI staining, and transwell assay, respectively. The protein expression levels of c-Myc, β-catenin, cyclin D1, and MMP-7 in the cells were evaluated by western blotting. The Wnt/β-catenin signaling cascade activation was verified using the Dual-Glo® Luciferase assay. We found that MA inhibited the growth of HeLa cells at 72 h (IC₅₀ = 26.88 µM) via inducing apoptotic process, reduced the proliferation rate by 29.89%, and decreased the cells migration and invasion as compared to the untreated group. It arrested the cell cycle at the G1 phase and its treatment inhibited the expression of related proteins c-Myc, β-catenin, cyclin D1, and MMP-7 in the Wnt/β-catenin signaling cascade. Further, the Wnt/β-catenin signaling cascade activation in MA-treated HeLa cells was attenuated in a dose-dependent manner. These findings demonstrate the anticancer effects of MA on a mechanistic level, thus providing a basis for MA to become a potential candidate drug for resistance of cervical carcinoma.

Efficient extraction and purification of benzo[c]phenanthridine alkaloids from Macleaya cordata (Willd) R. Br. by combination of ultrahigh pressure extraction and pH-zone-refining counter-current chromatography with anti-breast cancer activity in vitro

INTRODUCTION

Macleaya cordata (Willd) R. Br. (Papaveraceae family) is a well-known traditional Chinese medicine used to treat muscle pain, inflamed wounds, and bee bites. Benzo[c]phenanthridine alkaloids are the main active ingredients in M. cordata. In this work, sanguinarine and chelerythrine were efficiently extracted and purified by ultrahigh-pressure extraction (UHPE) technique and pH-zone-refining counter-current chromatography (PZRCCC) from M. cordata.

OBJECTIVE

To develop an efficient UHPE method followed by an efficient separation technique using PZRCCC for benzo[c]phenanthridine alkaloids from the study plant species, and to evaluate the study samples for anti-breast cancer activity.

METHODOLOGY

The optimal extraction conditions were optimised as extraction pressure 200 MPa, extraction solvent 95% ethanol, solid-liquid ratio 1:30 (g/mL) and extraction time 2 min. A two-phase n-hexane/ethyl acetate/i-propanol/water (1:3:1.5:4.5, v/v) solvent system was optimised with 10 mmol triethylamine in the upper phase and 10 mmol trifluoroacetic acid in lower phase in PZRCCC. The sample loading was optimised as 2.50 g. Moreover, the samples were evaluated for anti-breast cancer activity later on.

RESULTS

The 2.50 g sample loading yielded 0.45 g of sanguinarine and 0.59 g chelerythrine in one-step separation using PZRCCC. The anti-breast cancer activities of sanguinarine and chelerythrine were found stronger than positive control (vincristine 5.04 μg/mL) with half-maximal inhibitory concentration values of 0.96 and 3.00 μg/mL, respectively.

CONCLUSION

This study showed that the established methods were efficient in extraction (UHPE) and separation (PZRCCC) of the sanguinarine and chelerythrine from M. cordata.

Systematic characterization of alkaloids in Eomecon chionantha Hance using ultrahigh-performance liquid chromatography-tandem quadrupole Exactive Orbitrap mass spectrometry with a four-step screening strategy

RATIONALE

Eomecon chionantha Hance (ECH), a traditional folk herb, is commonly used to treat traumatic injuries based on its analgesic and anti-inflammatory properties. Previous studies have reported that alkaloids are the major bioactive components in ECH. Therefore, identification of alkaloids from ECH contributes to the discovery of its potential active ingredients and quality control in clinic treatments.

METHODS

A four-step screening strategy was performed as follows. (1) Extracting the accurate masses of ions related to different molecules. (2) Screening different types of compounds using their molecular cations, protonated molecules, diagnostic product ions and fragmentation pathways. (3) Comparing the characteristic product ion formulae to obtain the type and number of substituents. (4) Using the biosynthetic pathways of isoquinoline alkaloids to determine the concentration of alkaloids.

RESULTS

Ultrahigh-performance liquid chromatography-tandem quadrupole Exactive Orbitrap mass spectrometry (UHPLC/Q-Exactive Orbitrap MS) analysis combined with the four-step screening strategy was used to profile the alkaloids in ECH. The structures of 95 alkaloids in ECH were unambiguously identified or reasonably assigned, of which 76 were reported in ECH for the first time. Six types of benzylisoquinoline alkaloids were identified in ECH: six benzyltetrahydroisoquinolines, nine protopines, five N-methyltetrahydroprotoberberines, six protoberberines, eight benzophenanthridines and sixty-one dihydrobenzophenanthridines.

CONCLUSIONS

This comprehensive study identified the alkaloids in ECH, thus providing a practical reference for further research. The UHPLC/Q-Exactive Orbitrap MS method, combined with the four-step screening strategy, which was developed and successfully applied to identify the alkaloids in ECH, may also be applicable for the efficient screening of other herbal medicines.

Bioactive Molecules from Mangrove Streptomyces qinglanensis 172205

Five new compounds 15R-17,18-dehydroxantholipin (1), (3E,5E,7E)-3-methyldeca-3,5,7-triene-2,9-dione (2) and qinlactone A–C (3–5) were identified from mangrove Streptomyces qinglanensis 172205 with “genetic dereplication,” which deleted the highly expressed secondary metabolite-enterocin biosynthetic gene cluster. The chemical structures were established by spectroscopic methods, and the absolute configurations were determined by electronic circular dichroism (ECD). Compound 1 exhibited strong anti-microbial and antiproliferative bioactivities, while compounds 2–4 showed weak antiproliferative activities.

Isolation and identification of alkaloids from Macleaya microcarpa by UHPLC-Q-TOF-MS and their cytotoxic activity in vitro, antiangiogenic activity in vivo

Background

Extensive bioactivities of alkaloids from the genus Macleaya (Macleaya cordata (Willd.) R. Br. and Macleaya microcarpa (Maxim.) Fedde) have been widely reported, as well as more and more concerned from the scientific communities. However, systematic research on the phytochemical information of M. microcarpa is incomplete. The aim of this study was to rapidly and conveniently qualitative analyze alkaloids from M. microcarpa by ultra-performance liquid chromatography/quadrupole-time-of-fight mass spectrometry (UHPLC–Q-TOF-MS) using accurate mass weight and characteristic fragment ions, furthermore separate and identify the main alkaloids, test antitumor activity in vitro and antiangiogenic activity in vivo.

Results

A total of 14 alkaloids from fruits of M. microcarpa were identified by UHPLC–Q-TOF-MS, including 5 protopines, 2 benzophenanthridines, 1 dimer, 1 dihydrobenzophenanthridines and 5 unknown structure compounds. Two major alkaloids were isolated by various column chromatographic methods. Their structures were determined by NMR data and related literatures. The two major alkaloids were evaluated for intro cytotoxic activities against HL-60, MCF-7, A-549, and in vivo antiangiogenic activity using transgenic zebrafish.

Conclusions

Current qualitative method based on UHPLC–Q-TOF-MS technique provided a scientific basis for isolation, structural identification, and in vitro or in vivo pharmacological further study of alkaloids from M. microcarpa in the future.

Protein Tyrosine Phosphatase 1B Inhibitory Iridoids from Psydrax subcordata

Phytochemical investigation of the leaves and bark of Psydrax subcordata has led to the isolation of six new iridoids, subcordatanols I-V (1-4 and 6) and 1-O-methylcrescentin I (5), along with two known analogues (7 and 8). Among them, subcordatanol I (1) is the first example of a 3,8-monoepoxy-iridoid featuring a caged 2-oxa-bicyclo[3.2.1]octane core. The absolute stereochemistry at C-4 of 3, 4, and 6 was established through their acid-catalyzed reaction products subcordatalactones A (3a), B (4a), and C (6a), respectively. Subcordatanols I (1) and II (2), as well as subcordatalactones A (3a) and B (4a), displayed inhibitory activity against protein tyrosine phosphatase 1B (PTP1B). Enzyme kinetic studies indicated that 3a and 4a are competitive inhibitors. A molecular docking study is also reported.

Inhibitory Effect of Kurarinone on Growth of Human Non-small Cell Lung Cancer: An Experimental Study Both in Vitro and in Vivo Studies

Kurarinone, a flavonoid isolated from Sophora flavescens Aiton, has been reported to have significant antitumor activity. However, the cytotoxic activity of kurarinone against non-small cell lung cancer (NSCLC) cells is still under explored. In our study, we have evaluated the inhibitory effects of kurarinone on the growth of NSCLC both in vivo and in vitro as well as the molecular mechanisms underlying kurarinone-induced A549 cell apoptosis. The results showed that kurarinone effectively inhibited the proliferation of A549 cells with little toxic effects on human bronchial epithelial cell line BEAS-2B. FASC examination and Hoechst 33258 staining assay showed that kurarinone dose-dependently provoked A549 cells apoptosis. Mechanistically, kurarinone significantly decreased the ratio of Bcl-2/Bax, thereby causing the activation of caspase 9 and caspase 3, and reduced the expression of Grp78, which led to relieve the inhibition of caspase-12 and caspase-7, as well as suppressing the activity of AKT. Meanwhile, modeling results from the Surflex-Dock program suggested that residue Ser473 of Akt is a potential binding site for kurarinone. In vivo, kurarinone inhibited the growth of A549 xenograft mouse models without apparent signs of toxicity. Our study indicated that kurarinone has the potential effects of anti-NSCLC, implemented through activating mitochondria apoptosis signaling pathway, as well as repressing the activity of endoplasmic reticulum pathway and AKT in A549 cells.

Racemic indole alkaloids from the seeds of Peganum harmala

Five pairs of new 2-oxoindole alkaloids, (±)-peganumalines A-E (1-5), and a new indole alkaloid, peganumaline F (6), along with two known analogues, were isolated from the seeds of Peganum harmala. Their structures and absolute configurations were elucidated through spectroscopic analyses and quantum chemistry calculations. Notably, (±)-peganumalines A (1) represent a pair of rare 2-oxoindole dimeric alkaloid enantiomer with the hitherto unknown carbon skeleton. All isolates were tested for antiproliferative and antibacterial activities.

Hypermonins A and B, two 6-norpolyprenylated acylphloroglucinols with unprecedented skeletons from Hypericum monogynum

Hypermonins A and B, two novel 6-norpolycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from the leaves and twigs of Hypericum monogynum.

Antiproliferative Dimeric Aporphinoid Alkaloids from the Roots of Thalictrum cultratum

Inspired by the intriguing structures and bioactivities of dimeric alkaloids, 11 new thalifaberine-type aporphine-benzylisoquinoline alkaloids, thalicultratines A-K, a tetrahydroprotoberberine-aporphine alkaloid, thalicultratine L, and five known ones were isolated from the roots of Thalictrum cultratum. Their structures were defined on the basis of NMR and HRESIMS data. The antiproliferative activities of compounds 1-17 were evaluated against human leukemia HL-60 and prostate cancer PC-3 cells. Most alkaloids showed potent cytotoxicity against selected cancer cells. Preliminary SARs are discussed. The most active new compound (3), with an IC₅₀ value of 1.06 μM against HL-60 cells, was selected for mechanism of action studies. The results revealed that compound 3 induced apoptosis and arrested the HL-60 cell cycle at the S phase with the loss of mitochondria membrane potential. The nuclear morphological Hoechst 33258 staining assay was also carried out, and the results confirmed apoptosis.

LC-MS guided isolation of three pairs of enantiomeric alkaloids from Macleaya cordata and their enantioseparations, antiproliferative activity, apoptosis-inducing property

(±)-Macleayins F-H (1-3), three pairs of new enantiomeric alkaloid dimers, along with four known alkaloids (4-7) as their plausible biogenetic precursors, were isolated from the aerial parts of Macleaya cordata. Compounds 1-3 were obtained under the guidance of LC-MS investigation, and their structures were elucidated by analysis of the 1D and 2D NMR spectroscopic data. The racemic mixtures were successfully separated by chiral HPLC, and the absolute configurations of enantiomers were determined by electronic circular dichroism (ECD) spectroscopy. Compounds 1-7 showed antiproliferative activity against HL-60 with IC₅₀ values of 1.34-41.30 μM, especially compounds 1-2 exhibited the best inhibitory activity against HL-60 cell lines. In addition, the preliminary mechanism investigation for compound 2 using Annexin V/7-AAD double-staining assay, DAPI staining assay and JC-1 staining method, indicated that 2 inhibited cancer cell proliferation potentially through inducing apoptosis via the mitochondria-related pathway and arrested cell cycle of HL-60 cells at S phase.

Medicinal plants of the genus Macleaya (Macleaya cordata, Macleaya microcarpa): A review of their phytochemistry, pharmacology, and toxicology

In the genus Macleaya, Macleaya cordata and Macleaya microcarpa have been recognized as traditional herbs that are primarily distributed in China, North America, and Europe and have a long history of medicinal usage. These herbs have been long valued and studied for detumescence, detoxification, and insecticidal effect. This review aims to provide comprehensive information on botanical, phytochemical, pharmacological, and toxicological studies on plants in the genus Macleaya. Plants from the genus of Macleaya provide a source of bioactive compounds, primarily alkaloids, with remarkable diversity and complex architectures, thereby having attracted attention from researchers. To date, 291 constituents have been identified and/or isolated from this group. These purified compounds and/or crude extract possess antitumor, anti-inflammatory, insecticidal, and antibacterial activities in addition to certain potential toxicities. Macleaya species hold potential for medicinal applications. However, despite the pharmacological studies on these plants, the mechanisms underlying the biological activities of active ingredients derived from Macleaya have not been thoroughly elucidated to date. Additionally, there is a need for research focusing on in vivo medical effects of Macleaya compounds and, eventually, for clinical trials.

The Genome of Medicinal Plant Macleaya cordata Provides New Insights into Benzylisoquinoline Alkaloids Metabolism

The overuse of antibiotics in animal agriculture and medicine has caused a series of potential threats to public health. Macleaya cordata is a medicinal plant species from the Papaveraceae family, providing a safe resource for the manufacture of antimicrobial feed additive for livestock. The active constituents from M. cordata are known to include benzylisoquinoline alkaloids (BIAs) such as sanguinarine (SAN) and chelerythrine (CHE), but their metabolic pathways have yet to be studied in this non-model plant. The active biosynthesis of SAN and CHE in M. cordata was first examined and confirmed by feeding ¹³C-labeled tyrosine. To gain further insights, we de novo sequenced the whole genome of M. cordata, the first to be sequenced from the Papaveraceae family. The M. cordata genome covering 378 Mb encodes 22,328 predicted protein-coding genes with 43.5% being transposable elements. As a member of basal eudicot, M. cordata genome lacks the paleohexaploidy event that occurred in almost all eudicots. From the genomics data, a complete set of 16 metabolic genes for SAN and CHE biosynthesis was retrieved, and 14 of their biochemical activities were validated. These genomics and metabolic data show the conserved BIA metabolic pathways in M. cordata and provide the knowledge foundation for future productions of SAN and CHE by crop improvement or microbial pathway reconstruction.

Structurally Diverse Alkaloids from the Seeds of Peganum harmala

Investigation of the alkaloids from Peganum harmala seeds yielded two pairs of unique racemic pyrroloindole alkaloids, (±)-peganines A-B (1-2); two rare thiazole derivatives, peganumals A-B (3-4); six new β-carboline alkaloids, pegaharmines F-K (5-10); and 12 known analogues. Their structures, including stereochemistry, were elucidated through spectroscopic analyses, quantum chemistry calculations, and single-crystal X-ray diffraction. Notably, the incorporation of pyrrole and indole moieties in peganines A-B, thiazole fragments in peganumals A-B, and a C-1 α,β-unsaturated ester motif in pegaharmine F (5) are all rare, and their presence in the genus Peganum were demonstrated for the first time. All isolates were tested for antiproliferative activities against the HL-60, PC-3, and SGC-7901 cancer cell lines, and compounds 9, 11, 12, and 13 exhibited moderate cytotoxicity against HL-60 cancer cell lines with IC₅₀ values in the range of 4.36-9.25 μM.

Cytotoxic neolignans from the traditional Chinese medicine Daphniphyllum macropodum Miq

Four new neolignans (1–4) were isolated from the seeds of Daphniphyllum macropodum Miq. and the evaluated for their antiproliferative activity showed that 2 could induced the apoptosis in A549 cells through activating the mitochondrial pathway.

A Series of β-Carboline Alkaloids from the Seeds of Peganum harmala Show G-Quadruplex Interactions

In this study, we screened 17 medicinal plants for binding activity to G-quadruplex d(TTGGGTT)4 by (1)H NMR spectroscopy and found that the crude extract of Peganum harmala L. seeds showed the most potential binding activity. Subsequently, (1)H NMR- and bioassay-guided isolation of the extract of P. harmala L. was performed to obtain four pairs of partially racemized β-carboline alkaloids, pegaharmines A-D (1-4). Their structures and absolute configurations were determined by extensive NMR analyses, X-ray crystallography, ECD calculations, and CD exciton chirality approaches. Interestingly, pegaharmine D (4), which showed the strongest G-quadruplex interaction, exhibited significant cytotoxic activity against three cancer cell lines. This work contributed a practical strategy for the discovery of novel G-quadruplex ligands from natural products and provided potential insights for using β-carboline alkaloids as anticancer lead compounds specifically targeting G-quadruplexes.

Synthesis, Biological Activity, and Apoptotic Properties of NO-Donor/Enmein-Type ent-Kauranoid Hybrids

Herein, we reported on a series of synthetic nitric oxide-releasing enmein-type diterpenoid hybrids (9a–i). All the target compounds showed potent antibacterial activity against selected Gram-positive bacteria S. aureus and B. subtilis. The antiproliferative activity against human tumor K562, MGC-803, CaEs-17 and Bel-7402 cells, and human normal liver cells L-02 was tested and the structure activity relationships (SARs) were also concluded. Compounds 9b and 9d showed the best activity against S. aureus and B. subtilis with the same minimal inhibitory concentrations (MICs) of 4 and 2 μg/mL, respectively. The derivative 9f displayed IC₅₀ values of 1.68, 1.11, 3.60 and 0.72 μM against the four cancer cell lines above and 18.80 μM against normal liver cells L-02; meanwhile, 9f also released a high level of NO at the time point of 60 min of 22.24 μmol/L. Furthermore, it was also found that 9f induced apoptosis via the mitochondria-related pathway and arrested cell cycle of Bel-7402 cells at S phase. These findings might be important to explore new chemical entities for the main causes of in-hospital mortality of S. aureus infection, combined with a solid tumor.

Antiproliferative activity and apoptosis inducing effects of nitric oxide donating derivatives of evodiamine

The first series of nitric oxide donating derivatives of evodiamine were designed and prepared. NO releasing ability of all target derivatives was evaluated in BGC-823, Bel-7402 and L-02 cells. The cytotoxicity was evaluated against three human tumor cell lines (Bel-7402, A549 and BGC-823) and normal human liver cells L-02. The nitrate derivatives 11a and 11b only exhibited moderate activity and furoxan-based derivatives 13a-c, 14a and 14b showed promising activity. 13c showed good cytotoxic selectivity between tumor and normal liver cells and was further investigated for its apoptotic properties on human hepatocarcinoma Bel-7402 cells. The molecular mode of action revealed that 13c caused cell-cycle arrest at S phase and induced apoptosis in Bel-7402 cells through mitochondria-related caspase-dependent pathways.

Racemic alkaloids from Macleaya cordata: structural elucidation, chiral resolution, and cytotoxic, antibacterial activities

Three pairs of new enantiomeric natural alkaloids (±)-macleayins C-E (1–3), together with five pairs of known racemic alkaloids (4–8), were isolated from the aerial parts of Macleaya cordata.