Aloperine-Type Alkaloids with Antiviral and Antifungal Activities from the Seeds of Sophora alopecuroides L.

As a continuous flow investigation of novel pesticides from natural quinolizidine alkaloids, the chemical compositions of the seeds of Sophora alopecuroides were thoroughly researched. Fifteen new aloperine-type alkaloids (1-15) as well as six known aloperine-type alkaloids (16-21) were obtained from the extract of S. alopecuroides. The structures of 1-21 were confirmed via HRESIMS, NMR, UV, IR, ECD calculations, and X-ray diffraction. The antiviral activities of 1-21 against tobacco mosaic virus (TMV) were detected following the improved method of half-leaf. Compared with ningnanmycin (protective: 69.7% and curative: 64.3%), 15 exhibited excellent protective (71.7%) and curative (64.6%) activities against TMV. Further biological studies illustrated that 15 significantly inhibited the transcription of the TMV-CP gene and increased the activities of polyphenol oxidase (PPO), peroxidase (POD), superoxide dismutase (SOD), and phenylalanine ammonia-lyase (PAL). The antifungal activities of 1-21 against Phytophythora capsica, Botrytis cinerea, Alternaria alternata, and Gibberella zeae were screened according to a mycelial inhibition test. Compound 13 displayed excellent antifungal activity against B. cinerea (EC50: 7.38 µg/mL). Moreover, in vitro antifungal mechanism studies displayed that 13 causes accumulation of reactive oxygen species and finally leads to mycelia cell membrane damage and cell death in vitro.

Isolating Antipathogenic Fungal Coumarins from Coriaria nepalensis and Determining Their Primary Mechanism In Vitro.

Through bioassay-guided isolation, eight undescribed coumarins (1-8), along with six reported coumarins (9-14), were obtained from Coriaria nepalensis. The new structures were determined by using IR, UV, NMR, HRESIMS, and ECD calculations. The results of the biological activity assays showed that compound 9 exhibited broad spectrum antifungal activities against all tested fungi in vitro and a significant inhibitory effect on Phytophthora nicotianae with an EC50 value of 3.00 µg/mL. Notably, compound 9 demonstrated greater curative and protective effects against tobacco balack shank than those of osthol in vivo. Thus, 9 was structurally modified to obtain new promising antifungal agents, and the novel derivatives (17b, 17j, and 17k) exhibited better effects on Sclerotinia sclerotiorum than did lead compound 9. Preliminary mechanistic exploration illustrated that 9 could enhance cell membrane permeability, destroy the morphology and ultrastructure of cells, and reduce the exopolysaccharide content of P. nicotianae mycelia. Furthermore, the cytotoxicity results revealed that compound 9 exhibited relatively low cytotoxicity against HEK293 cell lines with an inhibition rate of 33.54% at 30 µg/mL. This research is promising for the discovery of new fungicides from natural coumarins with satisfactory ecological compatibility.

Quinolizidine Alkaloids and Isoflavones from the Herb of Thermopsis lupinoides and Their Antiviral, Antifungal, and Insecticidal Activities.

As part of our ongoing investigation of natural bioactive substances from the genus Thermopsis of the tribe Fabaceae for agricultural protection, the chemical constituents of the herb Thermopsis lupinoides were systematically investigated, which led to the isolation of 39 quinolizidine alkaloids (QAs) (1-39), including 14 new QAs (1-14) and 14 isoflavones (40-53). Their structures were elucidated through comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS), ECD calculations, and X-ray crystallography. The antitomato spotted wilt virus (TSWV) and antifungal (against Botrytis cinerea, Gibberella zeae, Phytophythora capsica, and Alternaria alternata) and insecticidal (against Aphis fabae and Tetranychus urticae) activities of the isolated compounds were screened using the lesion counting method, mycelial inhibition assay, and spray method, respectively. The bioassay results showed that 34 exhibited excellent protective activity against TSWV, with an EC50 value of 36.04 µg/mL, which was better than that of the positive control, ningnanmycin (86.03 µg/mL). The preliminary mechanistic exploration illustrated that 34 induced systemic acquired resistance in the host plant by acting on the salicylic acid signaling pathway. Moreover, 1 showed significant antifungal activity against B. cinerea (EC50 value of 20.83 µg/mL), while 2 exhibited good insecticidal activity against A. fabae (LC50 value of 24.97 µg/mL). This research is promising for the invention of novel pesticides from QAs with high efficiency and satisfactory ecological compatibility.

Three new quinolizidine alkaloids from the roots of Sophora tonkinensis.

Three new quinolizidine alkaloids (1 - 3), including one new naturally isoflavone and cytisine polymer (3), along with 6 known ones were isolated from the ethanol extract of Sophora tonkinensis Gagnep. Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, HRESIMS, 1D and 2D NMR), combined with ECD calculations. The antifungal activity against Phytophythora capsica, Botrytis cinerea, Gibberella zeae, and Alternaria alternata of the compounds was evaluated in a mycelial inhibition assay. Biological tests indicated that compound 3 exhibited strong antifungal activity against P. capsica with EC50 values of 17.7 µg/ml.

Four new pregnane C21 steroids isolated from the roots of Cynanchum auriculatum.

Four new steroids cynansteroid G-I (1-3) and cynansteroid K (4), a new natural product 5,6-deacidizingcaudatin (5), and a known compound glycocaudatin (6), were isolated from the roots of Cynanchum auriculatum. The structures of new compounds were identified by comprehensive spectroscopic analyses, including NMR, HRESI-MS, ECD, UV, and IR spectral data. The cytotoxic activities of all the isolates against two human tumour cell lines (COLO-205 and BGC-823) were screened, unfortunately, which were weaker than positive control.

UPLC-Q-Orbitrap-MS/MS-Guided Isolation of Bioactive Withanolides from the Fruits of Physalis angulata.

Physalis angulata Linn. is an exotic Amazonian fruit that is commonly recognized as wild tomato, winter cherry, and gooseberry. While its fruit is known to contain many nutrients, such as minerals, fibers, and vitamins, few papers have investigated withanolide derivatives from its fruits. UPLC-Q-Orbitrap-MS/MS, which produces fragmentation spectra, was applied for the first time to guide the isolation of bioactive withanolide derivatives from P. angulata fruits. As a result, twenty-six withanolide derivatives, including two novel 1,10-secowithanolides (1 and 2) and a new derivative (3), were obtained. Compounds 1 and 2 are rare rearranged 1,10-secowithanolides with a tetracyclic 7/6/6/5 ring system. All structures were assigned through various spectroscopic data and quantum chemical calculations. Nine withanolide derivatives exhibited significant inhibitory effects on three tumor cell lines with IC50 values of 0.51-13.79 µM. Moreover, three new compounds (1-3) exhibited potential nitric oxide inhibitory effects in lipopolysaccharide-stimulated RAW264.7 cells (IC50: 7.51-61.8 µM). This investigation indicated that fruits of P. angulata could be applied to treat and prevent cancer and inflammatory-related diseases due to their potent active withanolide derivatives.

Matrine-Type Alkaloids with Anti-Tomato Spotted Wilt Virus Activity from the Root of Sophora tonkinensis Gagnep.

As a continuation of our research on the development of pesticide active quinolizidine alkaloids (QAs) from the family Fabaceae, the chemical constituents of the root of Sophora tonkinensis Gagnep. were systematically investigated. Seventeen new matrine-type alkaloids (1-17), including one new naturally occurring compound (17), along with 20 known ones were isolated from the EtOH extract of S. tonkinensis. Notably, compound 5 possessed an unprecedented 6/6/5/4/6/6 hexacyclic system. Their structures were confirmed via comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS), ECD calculation, and X-ray crystallography. Biological tests indicated that compounds 1, 4, 10, 12, 13, and 30 displayed significant anti-tomato spotted wilt virus (TSWV) activities compared with the positive control ningnanmycin. Moreover, compound 12 strongly inhibited the expression of the TSWV N, NSs, and NSm genes and TSWV NSs protein in plant host. Furthermore, compounds 4, 10, 12, 20, and 22 exhibited moderate insecticidal activities against TSWV thrip vector (Frankliniella occidentalis).

Two new isoflavones from the roots of Sophora tonkinensis.

Two new isoflavones (1 and 2), as well as eight known ones were isolated from the roots of Sophora tonkinensis Gagnep. Compound 1 represents an unprecedented polymerization pattern constructed by isoflavone and cytisine. Their structures were elucidated by comprehensive spectroscopic data analysis, combined with ECD calculations. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity compared with the positive control ningnanmycin. Moreover, compound 6 exhibited potent α-glucosidase inhibitory activity with IC50 value of 47.4 mg/L.

Quinoline Alkaloids from the Roots of Orixa japonica with the Anti-Pathogenic Fungi Activities.

A new quinoline alkaloid, 5-hydroxy-6-methoxy-N-methyl-2-phenylquinoline-4-one (1), and seventeen known quinoline alkaloids (2-18) were isolated from the roots of Orixa japonica. The structure of 1 was determined by analysis of spectroscopic data. Among them, compounds 2, 3, and 13 were isolated from this plant for the first time. All isolates were screened for the anti-pathogenic fungi activities, including Rhizoctonia solani, Magnaporthe oryzae, and Phomopsis sp. The results showed that five compounds (4, 8, 10, 11, and 12) exhibited significant anti-pathogenic fungi effects at 50.0 µg/mL. In special, compound 10 exhibited the best antifungal activities toward R. solani and M. oryzae with the IC50 values of 37.86 and 44.72 µM, respectively, better than that of the positive control, hymexazol (IC50 121.21 and 1518.18 µM, respectively). Moreover, eleven new quinoline alkaloids derivatives (12a-12k) were designed and synthesized to investigate the structure-activity relationships (SARs). The SARs analysis indicated that the furo[2,3-b]quinoline skeleton and the methoxy at C-7 (compounds 8, 11, and 12) played a key role for improving the antifungal activities.

Maillard Reaction Products with Anti-Tobacco Mosaic Virus Activities Generated in Processed Thermopsis lanceolata R. Br. Seed Extract.

Six novel Maillard reaction products (MRPs) (1-6) were isolated from the processed Thermopsis lanceolata R. Br. seed extract, along with one biogenetically related intermediate (7). Compounds 1-4 possessed three rare dimerization patterns constructed by cytisine, whereas compounds 5 and 6 represented the first example of the addition products of cytisine and 5,6-dihydroxy-4-hexanolide. Their structures were elucidated by comprehensive spectroscopic data analysis and quantum chemistry calculations including GIAO 13C{1H} NMR and ECD calculation, combined with single-crystal X-ray diffraction analysis. Biologically, compound 3 displayed significant anti-tobacco mosaic virus activity compared with the positive control ningnanmycin.

Quinolizidine Alkaloids with Antitomato Spotted Wilt Virus and Insecticidal Activities from the Seeds of Thermopsis lanceolata R. Br.

As part of our ongoing investigation of pesticide active quinolizidine alkaloids (QAs) from the family Fabaceae, the chemical constituents of the seeds of Thermopsis lanceolata R. Br. were systematically investigated. Bioassay-guided fractionation and purification of the crude extract led to the isolation of seventeen new QAs (1-17), including three new naturally occurring compounds (15-17), along with 15 known compounds (18-32). Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, NMR, and HRESIMS) and quantum chemistry calculations (13C NMR and ECD). The antitomato spotted wilt virus activities and insecticidal activities against Aphis fabae, Nilaparvata lugens (Stal), and Tetranychus urticae of compounds 1-32 were screened using the lesion counting method, spray method, and rice-stem dipping method, respectively. Biological tests indicated that compounds 6, 9, 10, and 18 displayed significant anti-TSWV activities compared with the positive control ningnanmycin. Compounds 3, 4, and 5 showed better insecticidal activities against A. fabae with LC50 values of 10.07, 12.07, and 6.56 mg/L, respectively. Moreover, compounds 5, 18, and 24 exhibited moderate insecticidal activities against N. lugens (Stal) with LC50 values of 37.91, 53.44, and 31.21 mg/L, respectively. Furthermore, compounds 9 and 10 exhibited moderate insecticidal activities against T. urticae.

Three New Pregnanes Isolated from the Cynanchum auriculatum.

Three new compounds named cynansteroid A (1), cynansteroid B (2) and cynansteroid C (3), together with nine known C21 -steroidal pregnane sapogenins (4-12) were isolated from the hydrolytic extract of the roots of Cynanchum auriculatum. The structures of cynansteroid A-C (1-3) were ascertained via the detailed analysis of the HR-ESI-MS, 1D and 2D NMR, and the calculated and experimental ECD data of cynansteroid B (2). Compound 11 displayed moderate inhibitory activity toward Verticillium dahliae Kleb (IC50 =37.15 µM), furthermore, compounds 11 and 12 showed significant inhibitory activity against Phomopsis sp. (IC50 =16.49 µM and 17.62 µM, respectively).

Thermlanseedlines A-G, seven thermopsine-based alkaloids with antiviral and insecticidal activities from the seeds of Thermopsis lanceolata R. Br.

Seven undescribed thermopsine-based alkaloids (1-7), including one undescribed biogenetically related intermediate (7), were isolated from the seeds of Thermopsis lanceolata R. Br. Compound 1 possessed a 6/6-6 tricyclic skeleton, while compounds 2-6 represented three rare dimerization patterns constructed by quinolizidine alkaloids. Their structures were elucidated by comprehensive spectroscopic data analysis as well as ECD calculations. Biologically, compound 6 displayed significant anti-Tomato spotted wilt virus (TSWV) activity compared with the positive control ningnanmycin. Moreover, compound 1 exhibited good insecticidal activity against Aphis fabae with LC50 value of 25.2 mg/L.

Oreocharioside A-G, new acylated C-glycosylflavones from Oreocharis auricula (Gesneriaceae).

Seven new acylated C-glycosylflavones, oreocharioside A-G, together with two known compounds were isolated from the whole plant of Oreocharis auricula. Their structures were characterized by the comprehensive analysis of their NMR, IR, UV, CD spectra and HRESIMS data. All the new compounds were evaluated for the antioxidant and anti-inflammatory activities. The results showed that compounds 1 and 2 had significant DPPH and ABTS radical scavenging activities, with the IC50 values of 0.32-3.20 µg/mL. Compounds 2 and 3 exhibited the higher potency among all the new compounds in reducing TNF-α production.

Two new cytisine-type alkaloids from the seeds of Thermopsis lanceolata.

Two new (1 and 2) cytisine-type alkaloids that were chemically inseparable isomers (present in a 1:1 ratio) were identified from the seeds of Thermopsis lanceolata R. Br. Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, NMR, HRESIMS) and ECD calculation. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity, while compounds 1 and 2 displayed moderate insecticidal activities against Aphis fabae with LC50 value of 43.15 and 46.47 mg/L, respectively.

Chemical constituents from the flowers of Hypericum monogynum L. with COX-2 inhibitory activity.

Hypericum monogynum L. (Hypericaceae) has been used as a folk Chinese medicine for the treatment of inflammatory related diseases. Cyclooxygenase-2 (COX-2) is a crucial target for the development of agents to treat inflammation. To search for anti-inflammatory compounds from traditional Chinese medicines, a chemical constituent study along with COX-2 inhibitory activity analysis was performed for this plant. In this study, sixteen chemical monomers, including three undescribed oxidative degradation polycyclic polyprenylated acylphloroglucinols (PPAPs, hypemoins C-E), two undescribed PPAPs (hypemoins A and B), and 11 known compounds, were identified from the flowers of H. monogynum. Their structures were characterized by HRESIMS, NMR techniques, ECD, and single crystal X-ray diffraction. Four flavonoid derivatives showed remarkable COX-2 inhibitory activities, with IC50 values ranging from 0.220 ± 0.006 to 1.655 ± 0.098 µM. Among these compounds, the possible recognition mechanism between quercetin 3-(6″-O-caffeoyl)-ß-3-D-galactoside and COX-2 was predicted by molecular docking analysis. Moreover, the multidrug resistance reversal activities for the selected compounds were evaluated.

Hymoins A-D: Two Pairs of Polyprenylated Acylphloroglucinols from Hypericum monogynum and Their Light-Induced Transformation.

Hymoins A-D (1-4), two pairs of light-induced transformative polyprenylated acylphloroglucinols with an unprecedented pentacyclic skeleton, were isolated from the flowers of Hypericum monogynum. The first decarbonylative ring contraction of complex natural products was investigated by light irradiation. Their structures were elucidated by nuclear magnetic resonance analysis, X-ray crystallography, and electronic circular dichroism calculations. In addition, compound 3 showed moderate inhibition efficacy of the platelet-activating-factor-induced aggregation of rabbit platelets.

Hypermoins A-D: Rearranged Nor-Polyprenylated Acylphloroglucinols from the Flowers of Hypericum monogynum.

Hypermonins A-D (1-4), four rearranged nor-polycyclic polyprenylated acylphloroglucinols (PPAPs) with unprecedented skeletons, together with two new biosynthesis related PPAPs (5 and 6) were isolated and identified from the flowers of Hypericum monogynum. Hypermoins A-D represented the first examples of highly modified norPPAPs characterized by a rare 7/6/6/5-tetracyclic system. From the biogenic synthesis pathway analysis, all isolates shared the same biosynthetic intermediate, and the addition of two methyls or one methyl to this intermediate through methyltranferase could generate different types of PPAPs (1-7). Their planner structures as well as absolute configuration were confirmed via spectroscopic analysis, ECD calculation, and X-ray crystallography. All isolates potentially reversed multidrug resistance (MDR) activity in both two cancer cells, HepG2/ADR and MCF-7/ADR. Specifically, hypermoin E (5) and hyperielliptone HA (7) were found to be the best MDR modulators with the reversal fold ranging from 41 to 236, which is higher than the positive control verapamil.

Anti-tobacco mosaic virus (TMV) activity of chemical constituents from the seeds of Sophora tonkinensis.

Two new compounds, including one new arylbenzofuran (1) and one new pterocarpanoid (2), along with nine known ones, were isolated from the seeds of Sophora tonkinensis. The structures of the new compounds were elucidated based on a comprehensive spectroscopic data analysis. Compounds 2 and 3 exhibited good anti-tobacco mosaic virus (TMV) activities with the protective inhibition rate of 69.62% and 68.72% respectively, at concentration of 100 µg/ml.

Two new seco-polycyclic polyprenylated acylphloroglucinol from Hypericum sampsonii.

Hypsampsone A (1) and hyperhexanone F (2), two novel seco-polycyclic polyprenylated acylphloroglucinols, were isolated from Hypericum sampsonii. Hypsampsone A (1) features the first spirocyclic system fused with 5/6/5/5 tetracyclic skeleton. Hyperhexanone F (2) represents the second novel 1,2-seco-bicyclo[3.3.1]-PPAP skeleton. Their structures were established by extensive spectroscopic analysis, computer-assisted structure elucidation software, and calculated electronic circular dichroism spectra. A plausible biogenetic pathway of 1 was also proposed. Compounds 1 and 2 showed moderate multidrug resistance reversal activity to adriamycin (ADR) resistant cancer cell lines, HepG2/ADR and MCF-7/ADR, with the fold-reversals ranging from 16 to 38 at noncytotoxic concentration of 10 µM.