Next Article in Journal
Relationship Between Systemic Inflammatory Response Exponents, Levels of ADAM10, ADAM17 Proteins and Selected Clinical Parameters in Patients with Colorectal Cancer: Original Research Study
Previous Article in Journal
From Cell Architecture to Mitochondrial Signaling: Role of Intermediate Filaments in Health, Aging, and Disease
Previous Article in Special Issue
Antigenic Architecture of the H7N2 Influenza Virus Hemagglutinin Belonging to the North American Lineage
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
IJMS
Volume 26
Issue 3
10.3390/ijms26031103
ijms-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Discovery of Crinasiadine, Trisphaeridine, Bicolorine, and Their Derivatives as Anti-Tobacco Mosaic Virus (TMV) Agents

by
Zhan Hu
1,2,
Jincheng Guo
2,3,
Dejun Ma
2,
Ziwen Wang
2,
Yuxiu Liu
2 and
Qingmin Wang
2,*
1
Key Laboratory of Green Prevention and Control of Tropical Agriculture and Forestry BioDisasters of Ministry of Education, School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China
2
State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin 300071, China
3
Baotou Research Institute of Rare Earths, Baotou 014030, China
*
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2025, 26(3), 1103; https://doi.org/10.3390/ijms26031103
Submission received: 2 December 2024 / Revised: 18 January 2025 / Accepted: 22 January 2025 / Published: 27 January 2025
(This article belongs to the Special Issue Antiviral Drug Design, Synthesis and Molecular Mechanisms)
Browse Figures
Versions Notes

Abstract

:
Plant viral diseases cause great harm to crops in terms of yield and quality. Natural products have been providing an excellent source of novel chemistry, inspiring the development of novel synthetic pesticides. The Amaryllidaceae alkaloids crinasiadine (3a), trisphaeridine (4a), and bicolorine (5a) were selected as parent structures, and a series of their derivatives were designed, synthesized, and investigated for their anti-plant virus effects for the first time. Compounds 13b and 18 exhibited comparable inhibitory activities to ningnanmycin against tobacco mosaic virus (TMV). Preliminary research into the mechanism, involving transmission electron microscopy and molecular docking studies, suggests that compound 18 may interfere with the elongation phase of the TMV assembly process. This study provides some important information for the research and development of agrochemicals with phenanthridine structures.

Graphical Abstract

1. Introduction

The growing global population and the decreasing amount of arable land make agricultural productivity a vital challenge to address [1,2,3]. Plant viruses, which are among the most devastating pathogens, cause enormous losses to agricultural industries worldwide and continue to threaten global food security [4]. Tobacco mosaic virus (TMV), one of the most important plant viruses, is known to infect at least 100 different plant species, including tobacco, tomatoes, peppers, cucumbers, and a number of ornamental flowers [5,6,7]. Unfortunately, few chemical agents have been commercialized as effective products against this plant virus [8,9]. Therefore, there is a critical need to discover and develop agents with different scaffolds or modes of action.
It is well known that natural products provide an excellent source of novel chemistry and have inspired the development of novel synthetic pesticides [10,11]. In the process of discovering and modifying natural products as anti-plant virus agents, our research group first found that tylophorine alkaloids—especially antofine (1a, Figure 1)—had excellent anti-TMV activities, and the structure–activity relationship studies indicated that the phenanthrene ring and the nitrogen in the tertiary amine (2a, Figure 1) were essential for high antiviral activity [12,13]. Subsequently, we have optimized a multi-chiral natural product lycorine (1b, Figure 1) to a simple phenanthridine analog (2b, Figure 1) with good agricultural activities [14].
Indeed, phenanthridine analogs (crinasiadine (3a), trisphaeridine (4a), and bicolorine (5a), Figure 1), as natural products, are present in many Amaryllidaceae plants [15,16], and they have been one of the most widely studied classes of compounds due to their biological activities [17,18]. As early as the 1930s, phenanthridinium compounds were discovered to resist trypanosomes, and the anti-trypanosome drugs Ethidium and Samorin were developed [19,20,21]. To date, these two phenanthridinium trypanocides are still widely used to treat African trypanosomiasis in livestock [21,22,23]. Ethidium bromide (6, Figure 1) can also be used as a fluorescent marker for DNA and RNA, and its derivative propidium iodide (7, Figure 1) can be used as a cell viability probe [17]. Recent studies have found that phenanthridine analogs can inhibit the replication of the hepatitis C virus (HCV) [23,24] and the porcine epidemic diarrhea virus (PEDV) [25], as well as act as an activator of the Wnt/β-catenin signaling pathway [26,27,28,29,30]. When one chlorine atom of the commercially available anticancer drug cisplatin (8, Figure 1) was replaced with phenanthridine, the new compound phenanthriplatin (9, Figure 1) was more likely to enter cancer cells with higher efficacy and fewer side effects [31,32]. Due to their interesting biological activity, several efforts have been made to prepare phenanthridine derivatives [18,33].
In order to continue our previous research [14] and further explore the agricultural activities of phenanthridine compounds, in this work, crinasiadine (3a), trisphaeridine (4a), and bicolorine (5a) were selected as parent structures, and a series of their derivatives were designed, synthesized, and evaluated for their anti-TMV activities. In addition, the preliminary mode of action of compound 18 against the TMV was also explored.

2. Results and Discussion

2.1. Chemistry

In this study, 35 diverse structures of phenanthridine analogs including phenanthridin-6(5H)-one derivatives (3a~i, 13a~e), phenanthridine derivatives (4a~i), 5-methylphenanthridinium chloride derivatives (5a~i) and phenanthridone B-ring-expanded derivatives (16~18) were synthesized (Scheme 1 and Scheme 2). The synthetic routes are given in Scheme 1 and Scheme 2. There are fewer substituents on the benzene ring of the natural products crinasiadine (3a), trisphaeridine (4a) and bicolorine (5a). We synthesized phenanthridine compounds with a common electron-withdrawing group (F, Br) or electron-donating group (OCH3) on the benzene ring as compensation. Phenyl ring-substituted phenanthridin-6(5H)-ones (3a~3g) were synthesized from 2-bromo-N-phenylbenzamides (11a~g) in the presence of t-BuOK and a catalytic amount of AIBN through intramolecular free radical reactions [34]. 2-Bromo-N-phenylbenzamides (11a~g) were obtained with high yields from 2-bromobenzoic (10a~d) and phenyl anilines [34]. Phenanthridin-6(5H)-one (3h) was easily synthesized from 9-fluorenone (12) via Beckmann rearrangement [35]; then, compound 3h [36] reacted with NBS to give compound 3i with good yield. Phenanthridin-6(5H)-one derivatives (3) can be reduced by LiAlH4 to mainly give compound 4′ and a small quantity of compound 4. However, compound 4′ was unstable and easily converted into complex compounds when separated with a normal pressure silica gel column. We found that compound 4′ could be aromatized to phenanthridine derivatives (4) with good yield under oxidizing and acidic environmental conditions. Therefore, the reduction products of phenanthridone analogs (3a~i) without isolation were directly dissolved in CH2Cl2 with an amount of CF3COOH and then stirred with air bubbling to convert them to phenanthridine derivatives (4a~i). With the phenanthridine analogs (4a~i) in hand, it was easy to prepare 5-methylphenanthridinium chloride (5) via dimethyl sulfate according to the procedures reported previously [37]. A mixture of the phenanthridin-6(5H)-one (3h), Cs2CO3, haloalkanes, and anhydrous THF was gently refluxed to give compounds 13a~e with good yield [38]. B-ring-expanded derivatives (16~18) were synthesized to further investigate the structure–activity relationships. 2-Aminobiphenyl (14) was acylated with chloroacetylchloride to give compound 15. According to the literature [39], ring closure resulting in dibenzoazepinone (16) was achieved by an intramolecular Friedel–Crafts alkylation. Then compound 16 reacted with CH3I to form compound 17, and compound 17 was reduced by LiAlH4 to give compound 18 with good yield.

2.2. Antiviral Activity and Structure−Activity Relationships (SARs)

The antiviral activities of the target compounds against TMV in three modes (inactivation effect, curative effect, and protection effect in vivo) with compound 2, commercial antiviral agent ribavirin, and ningnanmycin as standards are shown in Table 1 and Table 2. Generally, the results showed that many compounds (3f, 3h, 4c, 4e, 4i, 5b, 13b, 13c, 16, and 18) exhibited better anti-TMV activities (inactivation effect) than ribavirin at 500 mg/L. Interestingly, the anti-TMV activities of compounds 13b and 18 were as good as those of ningnanmycin at 100 mg/L. In terms of the phenanthridin-6(5H)-one derivatives (3a~i and 13a~e), compound 3h with no substituents on either of the benzene rings exhibited good anti-TMV activities (inactivation effect) at 500 mg/L, while the other compounds (3a~g and 3i), for which the benzene rings had at least one substituent, had decreased anti-TMV activities in various degrees. This result indicated that benzene ring electron-withdrawing substituents (F and Br) or an electron-donating substituent (OCH3) were not conducive to the improvement in the anti-TMV activities of phenanthridin-6(5H)-one derivatives. Although the anti-TMV activities (inactivation effect) of compounds 13a and 13c~e were lower than those of 3h, the anti-TMV activity of 13b was significantly increased, especially the protection effect; these results indicated that modification of the nitrogen atom of phenanthridone could enhance its anti-TMV activity. In terms of the phenanthridine derivatives (4a~i) and 5-methylphenanthridinium chloride derivatives (5a~i), the compounds bearing no substituents on the benzene ring (4h and 5h) exhibited weak anti-TMV activities, while most of the compounds with substituents showed better anti-TMV activities than 4h and 5h, especially compounds 4c, 4e, 4i, and 5b. These results indicated that adding functional groups to benzene rings could improve the anti-TMV activities of the phenanthridine derivatives (4a~i) and 5-methylphenanthridinium chloride derivatives (5a~i). Compounds 16 and 17 were B-ring-expanded derivatives of 3h and 13a, respectively. The anti-TMV activities of compounds 16 and 17 were slightly better than those of compounds 3h and 13a. These results revealed that extending the size of the B-ring may not decrease their anti-TMV activities. Satisfyingly, the reductive product 18 showed excellent anti-TMV activity; in particular, the protection effect was near that of ningnanmycin.

2.3. Preliminary Mode of Action of Anti-TMV

The study of the mode of action of a potent molecule is very important and challenging in the development of pesticides [40]. It is known that the TMV capsid protein can turn into a 20S disk, following which the 20S disk and TMV RNA can further assemble to form rod-shaped TMV virus particles [41]. A preliminary study was undertaken to explore the effect of compound 18 which showed good anti-TMV activity on the TMV assembly. First, the effect of compound 18 on the TMV capsid protein was examined. In the control group (blank control, Figure 2A; DMSO control, Figure 2B), the 20S disks were well formed and were scattered around. When treated with compound 18 (Figure 2C), the 20S disks were also formed but were aggregated to form an irregular polymer (the part circled in yellow in Figure 2C). Subsequently, the effect of compound 18 on TMV self-assembly was explored. TMV cannot self-assemble without RNA (Figure 3A). The control test (Figure 3B,C) showed that TMV could self-assemble normally to form rod-shaped particles with a length of about 300 nm. When adding compound 18 (Figure 3D), the length of the rod-shaped particles was less than 300 nm (their average length was 142 nm), which indicated that the elongation of the assembly process was impeded. These findings suggest that compound 18 may interfere with the normal assembly process of TMV. However, it is important to note that this study is preliminary, and further experiments are required to fully understand the mode of action of compound 18. Additional studies, including the examination of other potential targets and a comparison with other compounds, will be necessary to establish a more comprehensive understanding of its inhibitory mechanism.

2.4. Molecular Docking

To further explore the possible mechanism of action, representative compound 18 and the TMV coat protein (PDB code: 1EI7) were chosen as the ligand and the receptor, respectively, for molecular docking studies using AutoDockTools. The experimental results are shown in Figure 4. The A and B chains of the TMV coat protein are represented in light blue and grey, respectively. The optimal binding mode of compound 18 to the TMV coat protein is on chain A, with a binding energy of −5.22 kcal/mol. Compound 18 primarily interacts with the protein through van der Waals forces with the amino acid residues ILE-21, LEU-23, VAL-69, ILE-133, GLY-135, and SER-138, π-σ interactions with the ILE-24 residue, alkyl interactions with the ILE-24 and π-alkyl interactions with the ILE-24, PRO-20 and LEU-132 residues. These interactions were relatively weak. Future structural optimizations might involve the addition of polar functional groups to enhance hydrogen bonding, which could consequently improve the activity of the compounds.

3. Materials and Methods

3.1. Chemicals

Reagents were purchased from commercial sources and used as received. All anhydrous solvents used for synthesis were dried and purified using standard techniques prior to use.

3.2. Instruments

The melting points of the synthesized compounds were tested using an X-4 binocular microscope (Beijing Tech Instruments Co., Beijing, China). NMR spectra were obtained using a Bruker AV 400 spectrometer (Bruker Corp., Fallanden, Switzerland) in CDCl3, DMSO-d6, or CD3OD solutions with tetramethylsilane (TMS) as the internal standard. The progress of the reaction was monitored by thin-layer chromatography on silica gel GF-254 and detected by UV. High-resolution mass spectra were obtained with an ESI-FTICR MS spectrometer (Ionspec, 7.0 T, Bruker, Saarbrucken, Germany). In vitro 20S disk inhibition reaction and in vitro TMV nanorod assembly reaction were tested via transmission electron microscopy (Tecnai G2 F20, TEI, Hillsboro, OR, USA).

3.3. Chemical Synthesis

Compounds 3a~g [34], 3h [35], 3i [36], 5a~i [37], 13a~e [38], and 16~18 [39] were prepared according to the previously reported procedures with slight modification and the detailed synthetic method and data can be found in the Supporting Information. Compounds 4a~i were prepared using our method.
  • Trisphaeridine (4a)
To a solution of 3a (1.0 g, 4.2 mmol) in dry THF (50 mL), lithium aluminum hydride (LiAlH4, 0.26 g, 6.3 mmol) was added in several portions in an ice bath. Then, the reaction was refluxed for 4 h, quenched with water (1 mL), and filtered. The filtrate was concentrated under reduced pressure. The crude residue was dissolved in CH2Cl2 (100 mL) and then trifluoroacetic acid (CF3COOH, 1 mL) was added. After stirring at room temperature with air bubbling for 6 h, the mixture was then basified (pH = 8) with a saturated NaHCO3 solution and extracted with CH2Cl2 (30 mL × 3). The combined organic phase was washed with brine (30 mL), dried over anhydrous Na2SO4, and concentrated. The residue was purified using column chromatography on silica gel with petroleum ether/ethyl acetate (10:1, v/v) to give trisphaeridine (4a, 0.65 g, 69%) as a white solid; mp 141–142 °C (lit. [42] mp 140–142 °C); 1H NMR (400 MHz, CDCl3) δ 9.05 (s, 1H), 8.32 (d, J = 8.1 Hz, 1H), 8.13 (d, J = 8.1 Hz, 1H), 7.83 (s, 1H), 7.73–7.64 (m, 1H), 7.60 (dd, J = 11.1, 4.0 Hz, 1H), 7.27 (s, 1H), 6.12 (s, 2H).
Phenanthridine analogs 4b~i were prepared similarly to 4a.
  • 2,4-Dimethoxyphenanthridine (4b)
White solid; mp 92–93 °C; yield 74%. 1H NMR (400 MHz, CDCl3) δ 9.43 (d, J = 8.7 Hz, 1H), 9.27 (s, 1H), 8.08 (t, J = 7.9 Hz, 1H), 7.92 (t, J = 7.8 Hz, 1H), 7.69 (t, J = 7.4 Hz, 1H), 7.47 (s, 1H), 6.85 (d, J = 2.4 Hz, 1H), 4.13 (s, 3H), 4.01 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 159.8, 159.2, 154.4, 147.3, 132.8, 131.3, 128.7, 126.9, 125.9, 125.8, 109.7, 102.5, 99.6, 55.8, 55.6. HR-MS (ESI): Calcd for C15H14NO2 [M + H]+ 240.1019; found 240.1023.
  • 8,9-Dimethoxyphenanthridine (4c)
Grey solid; mp 165–167 °C (lit. [42] mp 168–169 °C); yield 67%. 1H NMR (400 MHz, CDCl3) δ 9.20 (s, 1H), 8.45 (d, J = 7.8 Hz, 1H), 8.19 (d, J = 7.8 Hz, 1H), 7.88 (s, 1H), 7.71 (t, J = 6.9 Hz, 1H), 7.69–7.63 (m, 1H), 7.37 (s, 1H), 4.15 (s, 3H), 4.08 (s, 3H).
  • 2-Fluoro-8,9-dimethoxyphenanthridine (4d)
Brown solid; mp 163–164 °C (lit. [43] mp 161–162 °C); yield 48%. 1H NMR (400 MHz, CDCl3) δ 9.10 (s, 1H), 8.13 (dd, J = 9.0, 5.7 Hz, 1H), 8.02 (dd, J = 10.2, 2.7 Hz, 1H), 7.73 (s, 1H), 7.46–7.39 (m, 1H), 7.36 (s, 1H), 4.14 (s, 3H), 4.08 (s, 3H).
  • 2,9-Difluorophenanthridine (4e)
Yellow solid; mp 190–191 °C; yield 64%. 1H NMR (400 MHz, CDCl3) δ 9.21 (s, 1H), 8.21 (dd, J = 8.9, 5.6 Hz, 1H), 8.17–7.99 (m, 3H), 7.62–7.41 (m, 2H). 13C NMR (100 MHz, CDCl3) δ 164.3 (d, JF–C = 253.7 Hz), 161.3 (d, JF–C = 248.5 Hz), 151.6, 140.9, 134.3 (dd, JF–C = 10.0, 4.1 Hz), 132.2 (d, JF–C = 9.5 Hz), 131.8 (d, JF–C = 9.8 Hz), 125.0 (dd, JF–C = 9.0, 4.1 Hz), 123.2, 118.5 (d, JF–C = 24.2 Hz), 117.6 (d, JF–C = 24.2 Hz), 107.6 (d, JF–C = 10.0 Hz), 107.3 (d, JF–C = 10.7 Hz). HR-MS (ESI): Calcd for C13H8F2N [M + H]+ 216.0619; found 216.0624.
  • 9-Fluoro-2,4-dimethoxyphenanthridine (4f)
Yellow solid; mp 259–260 °C; yield 80%. 1H NMR (400 MHz, CDCl3) δ 9.31 (s, 1H), 9.09 (dd, J = 12.6, 2.4 Hz, 1H), 8.17 (dd, J = 8.8, 6.1 Hz, 1H), 7.54 (d, J = 2.3 Hz, 1H), 7.49–7.42 (m, 1H), 6.86 (d, J = 2.4 Hz, 1H). 13C NMR (100 MHz, CDCl3) δ 165.7 (d, JF–C = 254.9 Hz), 161.5, 159.2, 150.9, 142.9, 136.1 (d, JF–C = 12.2 Hz), 132.8 (d, JF–C = 10.2 Hz), 121.7, 116.4 (d, JF–C = 25.4 Hz), 112.6 (d, JF–C = 25.8 Hz), 109.9 (d, JF–C = 4.4 Hz), 100.9, 99.5, 56.2, 56.1. HR-MS (ESI): Calcd for C15H13FNO2 [M + H]+ 258.0925; found 258.0930.
  • 9-Fluorophenanthridine (4g)
White solid; mp 105–106 °C (lit. [42] mp 106–108 °C); yield 45%. 1H NMR (400 MHz, CDCl3) δ 9.25 (s, 1H), 8.46 (dd, J = 8.1, 1.1 Hz, 1H), 8.27–8.18 (m, 2H), 8.09 (dd, J = 8.8, 5.7 Hz, 1H), 7.84–7.76 (m, 1H), 7.75–7.68 (m, 1H), 7.46 (dt, J = 8.5, 2.4 Hz, 1H).
  • Phenanthridine (4h)
White solid; mp 98–99 °C (lit. [42] mp 100–101 °C); yield 82%. 1H NMR (400 MHz, CDCl3) δ 9.30 (s, 1H), 8.68–8.56 (m, 2H), 8.24–8.16 (m, 1H), 8.06 (d, J = 7.8 Hz, 1H), 7.92–7.83 (m, 1H), 7.80–7.65 (m, 3H).
  • 2-Bromophenanthridine (4i)
Yellow solid; mp 160–161 °C (lit. [44] mp 162–163 °C); yield 67%. 1H NMR (400 MHz, CDCl3) δ 9.25 (s, 1H), 8.66 (d, J = 2.1 Hz, 1H), 8.49 (d, J = 8.3 Hz, 1H), 8.08–8.04 (m, 1H), 8.04–8.00 (m, 1H), 7.87 (ddd, J = 8.3, 7.2, 1.3 Hz, 1H), 7.80 (dd, J = 8.7, 2.1 Hz, 1H), 7.77–7.71 (m, 1H).

3.4. Biological Assay

The activities of the target compounds were tested on representative test organisms. To ensure the reliability of data, each bioassay was replicated at least three times. The antiviral activity against TMV was carried out using previously reported methods [14] with tobacco (Nicotiana tabaccum var. Xanthinc) as the test plant.
The detailed biological assay methods are also given in the Supporting Information.

3.5. Mode of Action of Anti-TMV Studies [45]

TMV was purified according to the method provided by Leberman [46]. The TMV capsid protein (TMV CP) was purified with the acetic acid method [47]. TMV RNA was purified using the method provided by Zimmern [48]. All the detailed methods are also given in the Supporting Information.

3.5.1. In Vitro 20S Disk Inhibition Reaction

For drug tests, in vitro 20S disk inhibition reaction was performed at 20 °C for 12 h after adding 9.8 μL TMV capsid proteins (20 mg/mL) and 0.2 μL DMSO or drug (10 nmol/mL, 0.2 μL in DMSO). After the treatment, the sample was used for transmission electron microscope (TEM) characterization.

3.5.2. In Vitro TMV Nanorod Assembly Reaction

Before the assembly of TMV nanorods, the 20S disk was prepared by incubating TMV capsid proteins (20 mg/mL) in 0.1 M phosphate buffer (pH 7.0) at 20 °C for 12 h. The TMV nanorod assembly reaction was performed by mixing 5 μL phosphate buffer (0.1 mol/L, pH 7.0), 4 μL 20S disk (20 mg/mL), and 1 μL TMV RNA (200 ng/μL). The assembly reaction was incubated at 20 °C for 12 h. For drug tests, in vitro TMV reconstitution inhibition reactions were performed by adding 4.8 μL phosphate buffer (0.1 mol/L, pH 7.0), 4 μL 20S disk (20 mg/mL), 1 μL TMV RNA (200 mg/mL), and 0.2 μL DMSO or drug (10 nmol/mL, 0.2 μL in DMSO). After the treatment, the sample was used for transmission electron microscope (TEM) characterization.

3.5.3. Molecular Docking [49,50]

The structure of the TMV coat protein was downloaded from the RCSB Protein Data Bank (PDB ID: 1EI7) [51]. The molecular file for compound 18 (CID: 13095226) was downloaded from PubChem. The potential binding sites on the TMV coat protein were identified using AutoDockTools (version 1.5.7, The Scripps Research Institute, La Jolla, CA, USA), following Olson’s protocol [52]. The docking simulations were performed using the AutoDock algorithm. The global docking was conducted with a grid size that encompassed the entire protein. All other docking parameters are default values, with the following exceptions: ‘Number of GA Runs’ was set to 100, ‘Maximum Number of evals’ was set to 10,000,000, and ‘Maximum Number of generations’ was set to 100,000. The docking results were visualized using PyMOL (version 3.1.3, Schrödinger, New York, NY, USA) and the 2D ligand interaction diagrams were generated using Discovery Studio Visualizer (version 24.1.0, Build 23298, Dassault Systèmes, Vélizy-Villacoublay, France).

4. Conclusions

In summary, 35 compounds including crinasiadine (3a), trisphaeridine (4a), bicolorine (5a), and their derivatives were synthesized, and their anti-TMV activities were investigated for the first time. Many compounds (3f, 3h, 4c, 4e, 4i, 5b, 13b, and 13c) exhibited better anti-TMV activities than ribavirin; in particular, compounds 13b and 18 were as effective as ningnanmycin. The preliminary results suggested that compound 18 could impede the elongation of the TMV assembly process. In this study, phenanthridine analogs exhibit strong anti-TMV activities, highlighting their potential for crop protection. It is important to note that the capacity of phenanthrene compounds to intercalate with DNA and RNA raises substantial concerns regarding their potential toxicity to non-target organisms and their environmental impact [17]. While certain phenanthridine derivatives have been used safely in the treatment of livestock [21,22,23], the wider ecological implications of employing these compounds in crop protection demand further study to guarantee environmental safety. And it is believed that the phenanthridine structure is a promising small molecule, which could play an important role in crop protection.

Supplementary Materials

The supporting information can be downloaded at https://www.mdpi.com/article/10.3390/ijms26031103/s1. References [14,34,35,36,37,38,39,42,46,47,53,54,55,56,57,58] are cited in the supplementary materials.

Author Contributions

Conceptualization, Q.W., Z.H., Z.W. and Y.L.; methodology, Z.H., J.G. and D.M.; software, Z.H., J.G. and D.M.; validation, Z.H., J.G. and D.M.; formal analysis, Z.H., J.G. and D.M.; investigation, Z.H., J.G. and D.M.; resources, Q.W. and Z.H.; data curation, Z.H., J.G. and D.M.; writing—original draft preparation, Z.H.; writing—review and editing, Z.H., D.M., Y.L. and Z.W.; visualization, Z.H., J.G. and D.M.; supervision, Q.W.; project administration, Q.W.; funding acquisition, Q.W. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Nature Science Foundation of China (32202361 and 22077071), the Hainan Provincial Natural Science Foundation of China (No. 322RC563), and the Startup Foundation for Introduced Talents of Hainan University (KYQD(ZR)20023).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data have been stored in the library repository of Nankai University, Tianjin, China.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Lamberth, C.; Jeanmart, S.; Luksch, T.; Plant, A. Current Challenges and Trends in the Discovery of Agrochemicals. Science 2013, 341, 742–746. [Google Scholar] [CrossRef] [PubMed]
  2. Hemathilake, D.M.K.S.; Gunathilake, D.M.C.C. Chapter 31—Agricultural Productivity and Food Supply to Meet Increased Demands. In Future Foods; Bhat, R., Ed.; Academic Press: New Yok, NY, USA, 2022; pp. 539–553. [Google Scholar]
  3. Feeding the Future Global Population. Nat. Commun. 2024, 15, 222. [CrossRef] [PubMed]
  4. Gobert, A.; Quan, Y.; Arrivé, M.; Waltz, F.; Da Silva, N.; Jomat, L.; Cohen, M.; Jupin, I.; Giegé, P. Towards Plant Resistance to Viruses Using Protein-Only Rnase P. Nat. Commun. 2021, 12, 1007. [Google Scholar] [CrossRef] [PubMed]
  5. Scholthof, K.-b.G.; Adkins, S.; Czosnek, H.; Palukaitis, P.; Jacquot, E.; Hohn, T.; Honhe, B.; Saunders, K.; Candresse, T.; Ahlquist, P.; et al. Top 10 Plant Viruses in Molecular Plant Pathology. Mol. Plant Pathol. 2011, 12, 938–954. [Google Scholar] [CrossRef]
  6. Chen, W.; Liu, W.; Jiao, H.; Zhang, H.; Cheng, J.; Wu, C. Development of a Concentration Method for Detection of Tobacco Mosaic Virus in Irrigation Water. Virol. Sin. 2014, 29, 155–161. [Google Scholar] [CrossRef]
  7. Jiang, Q.; Xie, Y.; Zhou, B.; Wang, Z.; Ning, D.; Li, H.; Zhang, J.; Yin, M.; Shen, J.; Yan, S. Nanomaterial Inactivates Environmental Virus and Enhances Plant Immunity for Controlling Tobacco Mosaic Virus Disease. Nat. Commun. 2024, 15, 8509. [Google Scholar] [CrossRef] [PubMed]
  8. Zhang, J.; He, F.; Chen, J.; Wang, Y.; Yang, Y.; Hu, D.; Song, B. Purine Nucleoside Derivatives Containing a Sulfa Ethylamine Moiety: Design, Synthesis, Antiviral Activity, and Mechanism. J. Agric. Food Chem. 2021, 69, 5575–5582. [Google Scholar] [CrossRef] [PubMed]
  9. Jin, J.; Shen, T.; Shu, L.; Huang, Y.; Deng, Y.; Li, B.; Jin, Z.; Li, X.; Wu, J. Recent Achievements in Antiviral Agent Development for Plant Protection. J. Agric. Food Chem. 2023, 71, 1291–1309. [Google Scholar] [CrossRef]
  10. Sparks, T.C.; Sparks, J.M.; Duke, S.O. Natural Product-Based Crop Protection Compounds─Origins and Future Prospects. J. Agric. Food Chem. 2023, 71, 2259–2269. [Google Scholar] [CrossRef] [PubMed]
  11. Späth, G.; Loiseleur, O. Chemical Case Studies from Natural Products of Recent Interest in the Crop Protection Industry. Nat. Prod. Rep. 2024, 41, 1915–1938. [Google Scholar] [CrossRef] [PubMed]
  12. Mingbo, C.; Kailiang, W.; Qingmin, W.; Runqiu, H. Concise Synthesis of Benzoindolizidine Derivatives and Bioactivity Evaluation. Lett. Org. Chem. 2008, 5, 98–102. [Google Scholar] [CrossRef]
  13. Wang, Z.; Wei, P.; Liu, Y.; Wang, Q. D and E Rings May Not Be Indispensable for Antofine: Discovery of Phenanthrene and Alkylamine Chain Containing Antofine Derivatives as Novel Antiviral Agents against Tobacco Mosaic Virus (Tmv) Based on Interaction of Antofine and Tmv Rna. J. Agric. Food Chem. 2014, 62, 10393–10404. [Google Scholar] [CrossRef]
  14. Hu, Z.; Wang, Z.; Liu, Y.; Wang, Q. Leveraging Botanical Resources for Crop Protection: The Isolation, Bioactivity and Structure–Activity Relationships of Lycoris Alkaloids. Pest Manag. Sci. 2018, 74, 2783–2792. [Google Scholar] [CrossRef]
  15. Kornienko, A.; Evidente, A. Chemistry, Biology, and Medicinal Potential of Narciclasine and Its Congeners. Chem. Rev. 2008, 108, 1982–2014. [Google Scholar] [CrossRef] [PubMed]
  16. Ding, Y.; Qu, D.; Zhang, K.; Cang, X.; Kou, Z.; Xiao, W.; Zhu, J. Phytochemical and Biological Investigations of Amaryllidaceae Alkaloids: A Review. J. Asian Nat. Prod. Res. 2017, 19, 53–100. [Google Scholar] [CrossRef] [PubMed]
  17. Tumir, L.M.; Radić Stojković, M.; Piantanida, I. Come-Back of Phenanthridine and Phenanthridinium Derivatives in the 21st Century. Beilstein J. Org. Chem. 2014, 10, 2930–2954. [Google Scholar] [CrossRef] [PubMed]
  18. Talukdar, V.; Vijayan, A.; Kumar Katari, N.; Radhakrishnan, K.V.; Das, P. Recent Trends in the Synthesis and Mechanistic Implications of Phenanthridines. Adv. Synth. Catal. 2021, 363, 1202–1245. [Google Scholar] [CrossRef]
  19. Newton, B.A. The Mode of Action of Phenanthridines: The Effect of Ethidium Bromide on Cell Division and Nucleic Acid Synthesis. J. Gen. Microbiol. 1957, 17, 718–730. [Google Scholar] [CrossRef]
  20. Boibessot, I.; Turner, C.M.R.; Watson, D.G.; Goldie, E.; Connel, G.; Mcintosh, A.; Grant, M.H.; Skellern, G.G. Metabolism and Distribution of Phenanthridine Trypanocides in Trypanosoma Brucei. Acta Trop. 2002, 84, 219–228. [Google Scholar] [CrossRef]
  21. Venturelli, A.; Tagliazucchi, L.; Lima, C.; Venuti, F.; Malpezzi, G.; Magoulas, G.E.; Santarem, N.; Calogeropoulou, T.; Cordeiro-da-Silva, A.; Costi, M.P. Current Treatments to Control African Trypanosomiasis and One Health Perspective. Microorganisms 2022, 10, 1298. [Google Scholar] [CrossRef]
  22. Roy Chowdhury, A.; Bakshi, R.; Wang, J.; Yildirir, G.; Liu, B.; Pappas-Brown, V.; Tolun, G.; Griffith, J.D.; Shapiro, T.A.; Jensen, R.E.; et al. The Killing of African Trypanosomes by Ethidium Bromide. PLoS Pathog. 2010, 6, e1001226. [Google Scholar] [CrossRef] [PubMed]
  23. Igoli, J.O.; Blackburn, G.; Gray, A.I.; Sutcliffe, O.B.; Watson, D.G.; Euerby, M.R.; Skellern, G.G. Chromatographic and Spectroscopic Analysis of the Components Present in the Phenanthridinium Trypanocidal Agent Isometamidium. Anal. Bioanal. Chem. 2015, 407, 1171–1180. [Google Scholar] [CrossRef] [PubMed]
  24. Chen, D.; Cai, J.; Yin, J.; Jiang, J.; Jing, C.; Zhu, Y.; Cheng, J.; Di, Y.; Zhang, Y.; Cao, M.; et al. Lycorine-Derived Phenanthridine Downregulators of Host Hsc70 as Potential Hepatitis C Virus Inhibitors. Future Med. Chem. 2015, 7, 561–570. [Google Scholar] [CrossRef] [PubMed]
  25. Chen, D.-Z.; Fan, S.-R.; Yang, B.-J.; Yao, H.-C.; Wang, Y.-T.; Cai, J.-Y.; Jing, C.-X.; Pan, Z.-H.; Luo, M.; Yuze, Y.-Q.; et al. Phenanthridine Derivative Host Heat Shock Cognate 70 Down-Regulators as Porcine Epidemic Diarrhea Virus Inhibitors. J. Nat. Prod. 2021, 84, 1175–1184. [Google Scholar] [CrossRef] [PubMed]
  26. Wang, S.; Yin, J.; Chen, D.; Nie, F.; Song, X.; Fei, C.; Miao, H.; Jing, C.; Ma, W.; Wang, L.; et al. Small-Molecule Modulation of Wnt Signaling Via Modulating the Axin-Lrp5/6 Interaction. Nat. Chem. Biol. 2013, 9, 579–585. [Google Scholar] [CrossRef] [PubMed]
  27. Chen, D.; Jing, C.; Cai, J.; Wu, J.; Wang, s.; Yin, J.; Li, X.; Li, L.; Hao, X. Design, Synthesis, and Structural Optimization of Lycorine-Derived Phenanthridine Derivatives as Wnt/Β-Catenin Signaling Pathway Agonists. J. Nat. Prod. 2016, 79, 180–188. [Google Scholar] [CrossRef]
  28. Chen, D.; Zhang, H.; Jing, C.; He, X.; Yang, B.; Cai, J.; Zhou, Y.; Song, X.; Li, L.; Hao, X. Efficient Synthesis of New Phenanthridine Wnt/Β-Catenin Signaling Pathway Agonists. Eur. J. Med. Chem. 2018, 157, 1491–1499. [Google Scholar] [CrossRef] [PubMed]
  29. Liu, N.; Jin, Z.; Zhang, J.; Jin, J. Antitumor Evaluation of Novel Phenothiazine Derivatives That Inhibit Migration and Tubulin Polymerization against Gastric Cancer Mgc-803 Cells. Investig. New Drugs 2019, 37, 188–198. [Google Scholar] [CrossRef]
  30. Chen, J.; Duan, Z.; Liu, Y.; Fu, R.; Zhu, C. Ginsenoside Rh4 Suppresses Metastasis of Esophageal Cancer and Expression of C-Myc Via Targeting the Wnt/Β-Catenin Signaling Pathway. Nutrients 2022, 14, 3042. [Google Scholar] [CrossRef]
  31. Czapar, A.E.; Shukla, S.; Steinmetz, N.F.; Zheng, Y.; Riddell, I.A.; Awuah, S.G.; Lippard, S.J. Tobacco Mosaic Virus Delivery of Phenanthriplatin for Cancer Therapy. ACS Nano 2016, 10, 4119–4126. [Google Scholar] [CrossRef] [PubMed]
  32. Almaqwashi, A.A.; Zhou, W.; Naufer, M.N.; Riddell, I.A.; Yilmaz, Ö.H.; Lippard, S.J.; Williams, M.C. DNA Intercalation Facilitates Efficient DNA-Targeted Covalent Binding of Phenanthriplatin. J. Am. Chem. Soc. 2019, 141, 1537–1545. [Google Scholar] [CrossRef]
  33. Dey, A.; Kumar, V.; Chatterjee, R.; Behera, A.; Maurya, R.K.; Burra, A.G.; Kumar, S.; Khatravath, M.; Dandella, R. Recent Advancements in Synthesis of Phenanthridines Via 2-Isocyanobiphenyls. Asian J. Org. Chem. 2023, 12, e202300369. [Google Scholar] [CrossRef]
  34. Bhakuni, B.S.; Kumar, A.; Balkrishna, S.J.; Sheikh, J.A.; Konar, S.; Kumar, S. Kotbu Mediated Synthesis of Phenanthridinones and Dibenzoazepinones. Org. Lett. 2012, 14, 2838–2841. [Google Scholar] [CrossRef]
  35. Meseroll, L.M.N.; McKee, J.R.; Zanger, M. Synthesis of 5,6-Dihydrophenanthridine (Dhpa) Sulfonamides and Subsequent Acid-Catalyzed Rearrangement to Diaryl Sulfones. Synth. Commun. 2011, 41, 2557–2568. [Google Scholar] [CrossRef]
  36. Pan, H.L.; Fletcher, T.L. 6(5h)-Phenanthridinones. Iii. Halo-6(5h)Phenanthridinones. J. Heterocycl. Chem. 1970, 7, 597–605. [Google Scholar] [CrossRef]
  37. Baechler, S.A.; Fehr, M.; Habermeyer, M.; Hofmann, A.; Merz, K.-H.; Fiebig, H.-H.; Marko, D.; Eisenbrand, G. Synthesis, Topoisomerase-Targeting Activity and Growth Inhibition of Lycobetaine Analogs. Bioorg. Med. Chem. 2013, 21, 814–823. [Google Scholar] [CrossRef]
  38. Fujita, R.; Yoshisuji, T.; Wakayanagi, S.; Wakamatsu, H.; Matsuzaki, H. Synthesis of 5(6h)-Phenanthridones Using Diels–Alder Reaction of 3-Nitro-2(1h)-Quinolones Acting as Dienophiles. Chem. Pharm. Bull. 2006, 54, 204–208. [Google Scholar] [CrossRef]
  39. Hoffmann-Emery, F.; Jakob-Roetne, R.; Flohr, A.; Bliss, F.; Reents, R. Improved Synthesis of (S)-7-Amino-5H,7H-Dibenzo[b,d]Azepin-6-One, a Building Block for γ-Secretase Inhibitors. Tetrahedron Lett. 2009, 50, 6380–6382. [Google Scholar] [CrossRef]
  40. Casida, J.E. Curious About Pesticide Action. J. Agric. Food Chem. 2011, 59, 2762. [Google Scholar] [CrossRef] [PubMed]
  41. Butler, P.J. Self-Assembly of Tobacco Mosaic Virus: The Role of an Intermediate Aggregate in Generating Both Specificity and Speed. Phil. Trans. R. Soc. Lond. B 1999, 354, 537–550. [Google Scholar] [CrossRef]
  42. Chen, W.; Chen, C.; Chen, Y.; Hsieh, J. Hydride-Induced Anionic Cyclization: An Efficient Method for the Synthesis of 6-H-Phenanthridines Via a Transition-Metal-Free Process. Org. Lett. 2015, 17, 1613–1616. [Google Scholar] [CrossRef] [PubMed]
  43. Tummatorn, J.; Krajangsri, S.; Norseeda, K.; Thongsornkleeb, C.; Ruchirawat, S. A New Synthetic Approach to 6-Unsubstituted Phenanthridine and Phenanthridine-Like Compounds under Mild and Metal-Free Conditions. Org. Biomol. Chem. 2014, 12, 5077–5081. [Google Scholar] [CrossRef] [PubMed]
  44. Ghosh, M.; Ahmed, A.; Singha, R.; Ray, J.K. Domino Suzuki Coupling and Condensation Reaction: An Efficient Strategy Towards Synthesis of Phenanthridines. Tetrahedron Lett. 2015, 56, 353–355. [Google Scholar] [CrossRef]
  45. Lu, A.; Wang, T.; Hui, H.; Wei, X.; Cui, W.; Zhou, C.; Li, H.; Wang, Z.; Guo, J.; Ma, D.; et al. Natural Products for Drug Discovery: Discovery of Gramines as Novel Agents against a Plant Virus. J. Agric. Food Chem. 2019, 67, 2148–2156. [Google Scholar] [CrossRef] [PubMed]
  46. Leberman, R. The Isolation of Plant Viruses by Means of “Simple” Coacervates. Virology 1966, 30, 341–347. [Google Scholar] [CrossRef]
  47. Fraenkel-Conrat, H.; Williams, R.C. Reconstitution of Active Tobacco Mosaic Virus from Its Inactive Protein and Nucleic Acid Components. Proc. Natl. Acad. Sci. USA 1955, 41, 690–698. [Google Scholar] [CrossRef]
  48. Zimmern, D. The 5′ End Group of Tobacco Mosaic Virus Rna Is M7g5′Ppp5′Gp. Nucleic Acids Res. 1975, 2, 1189–1202. [Google Scholar] [CrossRef]
  49. Yang, S.; Wang, T.; Lu, A.; Wang, Q. Discovery of Chiral Diamine Derivatives Containing 1,2-Diphenylethylenediamine as Novel Antiviral and Fungicidal Agents. J. Agric. Food Chem. 2023, 71, 10989–11000. [Google Scholar] [CrossRef] [PubMed]
  50. Li, L.; Xu, C.; Zou, J.; Deng, Z.; You, S.; Wang, Q. Novel Cyclopenta[C]Pyridine Derivatives Based on Natural Cerbinal as Potential Agrochemical Anti-Tmv Agents and Insecticides. J. Agric. Food Chem. 2024, 72, 6684–6690. [Google Scholar] [CrossRef] [PubMed]
  51. Bhyravbhatla, B.; Watowich, S.J.; Caspar, D.L.D. Refined Atomic Model of the Four-Layer Aggregate of the Tobacco Mosaic Virus Coat Protein at 2.4-Å Resolution. Biophys. J. 1998, 74, 604–615. [Google Scholar] [CrossRef]
  52. Forli, S.; Huey, R.; Pique, M.E.; Sanner, M.F.; Goodsell, D.S.; Olson, A.J. Computational Protein–Ligand Docking and Virtual Drug Screening with the Autodock Suite. Nat. Protoc. 2016, 11, 905–919. [Google Scholar] [CrossRef] [PubMed]
  53. Chen, Y.-F.; Wu, Y.-S.; Jhan, Y.-H.; Hsieh, J.-C. An Efficient Synthesis of (Nh)-Phenanthridinones Via Ligand-Free Copper-Catalyzed Annulation. Org. Chem. Front. 2014, 1, 253–257. [Google Scholar] [CrossRef]
  54. Liu, F.; Venter, H.; Bi, F.; Semple, S.J.; Liu, J.; Jin, C.; Ma, S. Synthesis and Antibacterial Activity of 5-Methylphenanthridium Derivatives as Ftsz Inhibitors. Bioorg. Med. Chem. Lett. 2017, 27, 3399–3402. [Google Scholar] [CrossRef]
  55. Ferraccioli, R.; Carenzi, D.; Motti, E.; Catellani, M. A Simple Catalytic Synthesis of Condensed Pyridones from O-Bromoarylcarboxamides Involving Ipso Substitution Via Palladacycles. J. Am. Chem. Soc. 2006, 128, 722–723. [Google Scholar] [CrossRef] [PubMed]
  56. Cookson, R.F.; James, J.W.; Rodway, R.E.; Simmonds, R.G. Synthesis of Some Phenanthridone Derivatives. J. Heterocycl. Chem. 1972, 9, 475–480. [Google Scholar] [CrossRef]
  57. Lu, C.; Dubrovskiy, A.V.; Larock, R.C. Palladium-Catalyzed Annulation of Arynes by O-Halobenzamides: Synthesis of Phenanthridinones. J. Org. Chem. 2012, 77, 8648–8656. [Google Scholar] [CrossRef]
  58. Tabata, H.; Suzuki, H.; Akiba, K.; Takahashi, H.; Natsugari, H. Atropisomeric Properties of 7-, 8-, and 9-Membered-Ring Dibenzolactams: Conformation, Thermal Stability, and Chemical Reactivity. J. Org. Chem. 2010, 75, 5984–5993. [Google Scholar] [CrossRef]
Ijms 26 01103 g001
Figure 1. Structures of compounds 1a, 1b, 2a, 2b, 3a~5a, and 6~9.
Figure 1. Structures of compounds 1a, 1b, 2a, 2b, 3a~5a, and 6~9.
Ijms 26 01103 g001
Ijms 26 01103 sch001
Scheme 1. Synthetic route of the target compounds 3, 4, and 5.
Scheme 1. Synthetic route of the target compounds 3, 4, and 5.
Ijms 26 01103 sch001
Ijms 26 01103 sch002
Scheme 2. Synthetic route of the target compounds 13~18.
Scheme 2. Synthetic route of the target compounds 13~18.
Ijms 26 01103 sch002
Ijms 26 01103 g002
Figure 2. Results of in vitro 20S disk inhibition reaction under transmission electron microscope: (A) blank; (B) DMSO; and (C) compound 18 and the aggregates indicated by yellow circles.
Figure 2. Results of in vitro 20S disk inhibition reaction under transmission electron microscope: (A) blank; (B) DMSO; and (C) compound 18 and the aggregates indicated by yellow circles.
Ijms 26 01103 g002
Ijms 26 01103 g003
Figure 3. Results of in vitro TMV nanorod assembly reaction under transmission electron microscope: (A) 20S disk without RNA; (B) 20S disk with RNA; (C) 20S disk with RNA and DMSO; and (D) 20S disk with RNA and compound 18.
Figure 3. Results of in vitro TMV nanorod assembly reaction under transmission electron microscope: (A) 20S disk without RNA; (B) 20S disk with RNA; (C) 20S disk with RNA and DMSO; and (D) 20S disk with RNA and compound 18.
Ijms 26 01103 g003
Ijms 26 01103 g004
Figure 4. Molecular docking results of compound 18 with the TMV coat protein.
Figure 4. Molecular docking results of compound 18 with the TMV coat protein.
Ijms 26 01103 g004
Table 1. In vivo antiviral activities (inactivation effect) of phenanthridin-6(5H)-one analogs (3a~i, 13a~e, and 16~18), phenanthridine analogs (4a~i), 5-methylphenanthridinium chloride analogs (5a~i), compound 2, ribavirin, and ningnanmycin (NN) against TMV at 500 mg/L.
Table 1. In vivo antiviral activities (inactivation effect) of phenanthridin-6(5H)-one analogs (3a~i, 13a~e, and 16~18), phenanthridine analogs (4a~i), 5-methylphenanthridinium chloride analogs (5a~i), compound 2, ribavirin, and ningnanmycin (NN) against TMV at 500 mg/L.
SampleInhibition Rate (%) aSampleInhibition Rate (%) aSampleInhibition Rate (%) aSampleInhibition Rate (%) a
3a19.5 ± 1.74b25.3 ± 0.65c37.2 ± 2.613d37.8 ± 1.1
3b31.8 ± 2.44c40.9 ± 1.15d19.2 ± 4.513e31.6 ± 1.1
3c33.7 ± 1.84d34.9 ± 3.55e31.1 ± 0.21641.2 ± 3.5
3d31.9 ± 3.34e43.0 ± 2.55f36.8 ± 0.81732.5 ± 1.9
3e29.2 ± 1.14f30.9 ± 4.85g38.4 ± 0.31849.2 ± 1.6
3f41.3 ± 0.24g33.5 ± 1.45h26.3 ± 2.1244.7 ± 0.5
3g35.1 ± 2.44h21.5 ± 3.45i35.2 ± 1.1ribavirin39.5 ± 0.3
3h46.8 ± 0.24i45.9 ± 4.313a27.0 ± 4.0NN58.8 ± 2.4
3i37.5 ± 1.05a34.0 ± 4.413b59.4 ± 1.8
4a35.2 ± 2.65b49.7 ± 0.813c42.9 ± 1.9
a The effect (inhibition rate) is presented as the mean ± SD (%). The deep blue color emphasizes an inhibition rate greater than 39.5% (ribavirin).
Table 2. In vivo antiviral activities of phenanthridin-6(5H)-one analogs (3a~i, 13a~e, and 16~18), phenanthridine analogs (4a~i), 5-methylphenanthridinium chloride analogs (5a~i), compound 2, ribavirin, and ningnanmycin (NN) against TMV.
Table 2. In vivo antiviral activities of phenanthridin-6(5H)-one analogs (3a~i, 13a~e, and 16~18), phenanthridine analogs (4a~i), 5-methylphenanthridinium chloride analogs (5a~i), compound 2, ribavirin, and ningnanmycin (NN) against TMV.
SampleConc. (mg/L)Inhibition Rate (%) aSampleConc. (mg/L)Inhibition Rate (%)
Inactivation
Effect 		Curative
Effect 		Protection
Effect		Inactivation
Effect 		Curative
Effect 		Protection
Effect
3f50041.3 ± 0.246.9 ± 1.838.1 ± 2.313c50042.9 ± 1.935.4 ± 3.644.7 ± 1.1
1005.8 ± 0.511.5 ± 2.77.4 ± 0.91007.2 ± 0.76.0 ± 0.413.5 ± 0.2
3h50046.8 ± 0.242.1 ± 1.441.7 ± 0.61650041.2 ± 3.544.4 ± 2.037.9 ± 1.2
1009.3 ± 0.712.5 ± 2.001005.3 ± 1.08.6 ± 0.60
4c50040.9 ± 1.136.7 ± 1.347.0 ± 3.81850049.2 ± 1.647.3 ± 0.254.4 ± 2.5
10015.1 ± 0.69.6 ± 1.817.9 ± 2.010016.7 ± 1.119.2 ± 0.822.0 ± 2.1
4e50043.0 ± 2.540.1 ± 3.435.6 ± 4.5250044.7 ± 0.540.9 ± 3.339.1 ± 2.9
1009.8 ± 0.911.0 ± 0.77.8 ± 1.31006.6 ± 0.100
4i50045.9 ± 4.341.7 ± 2.047.8 ± 0.6ribavirin50039.5 ± 0.337.2 ± 1.440.2 ± 0.8
10012.1 ± 0.718.6 ± 3.59.1 ± 1.010011.3 ± 0.913.6 ± 0.89.5 ± 1.2
5b50049.7 ± 0.847.1 ± 2.951.3 ± 3.7NN50058.8 ± 2.455.9 ± 0.757.1 ± 0.6
10017.6 ± 1.49.4 ± 2.515.2 ± 0.510026.4 ± 0.924.0 ± 1.227.2 ± 1.5
13b50059.4 ± 1.855.6 ± 1.052.3 ± 2.5
10015.8 ± 3.618.0 ± 0.421.5 ± 2.0
a The effect (inhibition rate) is presented as mean ± SD (%).
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Hu, Z.; Guo, J.; Ma, D.; Wang, Z.; Liu, Y.; Wang, Q. Discovery of Crinasiadine, Trisphaeridine, Bicolorine, and Their Derivatives as Anti-Tobacco Mosaic Virus (TMV) Agents. Int. J. Mol. Sci. 2025, 26, 1103. https://doi.org/10.3390/ijms26031103

AMA Style

Hu Z, Guo J, Ma D, Wang Z, Liu Y, Wang Q. Discovery of Crinasiadine, Trisphaeridine, Bicolorine, and Their Derivatives as Anti-Tobacco Mosaic Virus (TMV) Agents. International Journal of Molecular Sciences. 2025; 26(3):1103. https://doi.org/10.3390/ijms26031103

Chicago/Turabian Style

Hu, Zhan, Jincheng Guo, Dejun Ma, Ziwen Wang, Yuxiu Liu, and Qingmin Wang. 2025. "Discovery of Crinasiadine, Trisphaeridine, Bicolorine, and Their Derivatives as Anti-Tobacco Mosaic Virus (TMV) Agents" International Journal of Molecular Sciences 26, no. 3: 1103. https://doi.org/10.3390/ijms26031103

APA Style

Hu, Z., Guo, J., Ma, D., Wang, Z., Liu, Y., & Wang, Q. (2025). Discovery of Crinasiadine, Trisphaeridine, Bicolorine, and Their Derivatives as Anti-Tobacco Mosaic Virus (TMV) Agents. International Journal of Molecular Sciences, 26(3), 1103. https://doi.org/10.3390/ijms26031103

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop