2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and their applications

Abstract

The present invention discloses 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and applications thereof. The 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone of the present invention can significantly inhibit the main post-harvest pathogens of citrus green mold, citrus penicillium and citrus acid rot fungi, and its effect is higher than that of the commercial fungicide prochloraz. Therefore, the present invention provides candidate compounds for the research and development of new antibacterial drugs, and also provides a new approach for the development and utilization of new fruit preservatives.

Description

Technical Field

[0001] The invention belongs to the field of freshness preservation, and specifically relates to 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and applications thereof. Background Art

[0002] Citrus is the world's largest category of fruit, and my country is one of the world's major citrus producing areas. In view of current consumer demand and the current development status of my country's citrus industry, my country's citrus is mainly sold fresh. Fresh citrus is very prone to diseases from picking to consumption, causing huge economic losses, and there is an urgent need for safe and efficient post-harvest disease prevention and control technologies. For a long time, chemical fungicides have been the main means of preventing and controlling post-harvest rot in citrus, but existing chemical fungicides have poor safety and are prone to produce drug-resistant strains, which are not in line with the future development direction of fruit preservation. Therefore, it is of great significance to develop new and efficient antibacterial agents.

[0003] Flavonoids are a type of green and safe fruit preservatives. They have good effects in preventing and controlling fruit diseases and maintaining the quality of fruit storage, and meet the development needs of green fruit preservation technology. Isopentenyl flavonoids are a relatively rare natural structure type among flavonoids. The presence of isopentenyl side chains can significantly enhance the targeting of flavonoids and improve the biological activity of the compounds. Isopentenyl flavonoids have the characteristics of high efficiency and low toxicity, showing potential development prospects as green and safe preservatives. Summary of the invention

[0004] To this end, the first object of the present invention is to provide 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs having good inhibitory effect on the growth of citrus green mold, penicillium or acid rot fungi.

[0005] The 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogue of the present invention has a structure as shown in formula (I):

[0006]

[0007] The 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analog is preferably any compound of formula (I), namely compound C7, C8 or C9.

[0008] More preferably, the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analog is compound C7, whose structural formula is shown in formula (II).

[0009]

[0010] The second object of the present invention is to provide the use of the above-mentioned compound C7, C8 or C9 or its pharmaceutically acceptable salt in the preparation of drugs for preventing and controlling post-harvest diseases of fruits.

[0011] A drug for preventing and treating post-harvest fruit diseases, comprising the above compound C7, C8 or C9 or its pharmaceutically acceptable salt as an active ingredient.

[0012] Preferably, the post-harvest disease of fruit is a post-harvest disease of citrus.

[0013] More preferably, the post-harvest disease of citrus is citrus green mold, citrus penicillium or citrus acid rot.

[0014] The third object of the present invention is to provide the use of the above-mentioned compound C7, C8 or C9 or its pharmaceutically acceptable salt in the preparation of a fruit preservative.

[0015] A fruit preservative contains the above compound C7, C8 or C9 or its pharmaceutically acceptable salt as an active ingredient.

[0016] Preferably, the fruit preservative is a citrus preservative.

[0017] The fourth object of the present invention is to provide a method for preventing and controlling post-harvest diseases of fruits, which comprises soaking the fruits in the above-mentioned preservative and drying them.

[0018] Preferably, the fruit is citrus.

[0019] Preferably, the preservative is an aqueous solution of compound C7, the concentration of which is 100 mg / L, and the citrus fruits are soaked for 3 minutes.

[0020] The present invention provides a class of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs with significant inhibitory activity against citrus green mold, penicillium or acid rot. Since the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs of the present invention have good anti-citrus green mold, penicillium and acid rot activities and citrus fruit preservation effects, wherein the compound C7 (chemical structure is shown in formula (II)) has significantly higher effects on anti-citrus penicillium, citrus green mold and citrus acid rot than the commercial fungicide prochloraz, and therefore can be used for the preparation of antibacterial drugs, especially for the application in the prevention and treatment of citrus post-harvest diseases. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The inhibitory effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and prochloraz on citrus green mold.

[0022] Figure 2The inhibitory effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and prochloraz on Penicillium citrinum.

[0023] Figure 3 The inhibitory effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and prochloraz on citrus acid rot fungi.

[0024] Figure 4 The effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone (compound C7) treatment on punctured citrus fruits inoculated with green mold pathogen.

[0025] Figure 5 The effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone (compound C7) treatment on punctured citrus fruits inoculated with Penicillium spp. DETAILED DESCRIPTION

[0026] The experimental methods in the following examples of the present invention, where no specific conditions are specified, are usually carried out under conventional conditions or under conditions recommended by the manufacturers. The various commonly used chemical reagents used in the examples are all commercially available products.

[0027] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] The terms "including" and "having" and any variations thereof of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment comprising a series of steps is not limited to the listed steps or modules, but may optionally include steps not listed, or may optionally include other steps inherent to these processes, methods, products or equipment.

[0029] The present invention is further described in detail below in conjunction with specific examples, but the embodiments of the present invention are not limited thereto.

[0030] Example 1: Preparation of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs and their spectral data

[0031] The synthesis process of the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogue of the present invention is shown in formula (III):

[0032]

[0033] The specific synthesis steps are as follows:

[0034] 1. Synthesis of Compound C2

[0035] Take 3,5-dihydroxybenzaldehyde (compound C1, 3.6 g, 15 mmol) and dissolve it in 50 mL of anhydrous N, N-dimethylformamide (DMF), place it in an ice bath and stir for 10 min, add NaH (1.2 g, 30 mmol), slowly add chloromethyl methyl ether (MOMCl, 2.4 mL, 30 mmol) dropwise while stirring in an ice bath, continue to react in the ice bath for 30 min, remove the ice bath, and react the mixture at room temperature for 55 min, immediately add ice water (100 mL) to terminate the reaction, extract with ethyl acetate (100 mL×3), combine the organic phases, and then wash with distilled water and saturated brine respectively, dry with anhydrous Na2SO4 and concentrate in vacuo. By silica gel column chromatography (V 石油醚 :V 乙酸乙酯 =10:1) to purify the crude product to obtain compound C2 with a yield of 90%. 1 H-NMR(500MHz,Acetone-D6)δppm:3.47(6H,s,-OCH3×2),5.28(4H,s,-OCH2×2),7.00(1 H,t,J=2.5,5.0Hz,),7.25(2H,d,J=2.5Hz),9.95(1H,s,-C=O.MS(ESI),m / z:225.1[MH] - ,265.3[M+K] + .

[0036] 2. Synthesis of Compound C4

[0037] Take 2,4,6-trihydroxyacetophenone (compound C3, 5.04g, 30mmol) and dissolve it in 60mL tetrahydrofuran. After it is completely dissolved, add 1,8-diazabicycloundec-7-ene (DBU, 4.50g 30mmol), stir for 10min, add 1-bromo-3-methyl-2-butene (4.46g, 30mmol) dropwise under ice bath, continue stirring and reacting under ice bath for 30min, then transfer to room temperature and stir and react for 18h, terminate the reaction with 1mol / L HCl (90mL), extract with ethyl acetate (100mL×3), combine the organic phases, and then wash with distilled water and saturated brine respectively, dry with anhydrous NaSO4 and concentrate in vacuo. By silica gel column chromatography (V 石油醚 :V 乙酸乙酯 =4:1) to obtain pale yellow solid C4 with a yield of 45%. 1H-NMR(500MHz,Acetone-D6)δppm:1.63(3H,s,-CH3),1.75(3H,s,-CH3),2.62(3H,s,-COCH3),3.25(2H,d,J=7.0Hz,-CH2),5.23(1H ,t,J=7.0,14.5Hz,-C=H),6.08(1H,s,Ar-H),9.10(1H,s,Ar-OH),9.49(1H,s,Ar-OH),13.96(1H,s,Ar-OH).MS(ESI),m / z:235.0[MH] - ,259.1[M+Na] + .

[0038] 3. Synthesis of Compound C5

[0039] Compound C4 (1.89 g, 8 mmol) was dissolved in 50 mL of anhydrous acetonitrile, placed in an ice bath and stirred for 10 min, anhydrous K2CO3 (4.146 g, 30 mmol) was added, MOMCl (1.28 mL, 16 mmol) was slowly added dropwise under stirring in an ice bath, the reaction was continued for 30 min in an ice bath, and then reacted at room temperature for 45 min, ice water (100 mL) was added to terminate the reaction, and the mixture was extracted with ethyl acetate (100 mL × 3), the organic phases were combined, and then washed with distilled water and saturated brine respectively, dried over anhydrous NaSO4, and concentrated in vacuo. A pale yellow liquid compound C5 was isolated by silica gel column chromatography (V petroleum ether: V ethyl acetate = 8:1), with a yield of 83%. 1 H-NMR (500MHz, Acetone-D6) δppm: 1.64(3H,s,-CH3),1.77(3H,s,-CH3),2.66(3H,s,-COCH3),3.29(2H,d,J=7.0Hz,-CH2),3.46(3H,s,-OCH3),3 .53(3H,,s,-OCH3),5.19(1H,m,-C=H),5.32(2H,s,-OCH2),5.36(2H,s,-OCH2),6.50(1H,s,Ar-H),13.97(1H,s,Ar-OH).MS(ESI),m / z:323.1[MH] - ,347.2[M+Na] + .

[0040] 4. Synthesis of Compound C6

[0041] Potassium hydroxide (0.84 g, 15 mmol) was dissolved in 20 mL of anhydrous ethanol, and compound C5 (1.62 g, 5 mmol) was added dropwise under stirring. After reacting for 5 min, compound C2 (1.13 g, 5 mmol) was gradually added dropwise. The reaction was continued at room temperature for 20 h, and ice water (50 mL) was added to terminate the reaction. The pH value was adjusted to 2.0 with hydrochloric acid, and extracted with dichloromethane (50 mL × 3). The organic phase was washed with distilled water and saturated brine, respectively, dried over anhydrous NaSO4, and concentrated in vacuo. Silica gel column chromatography (V 石油醚 :V 乙酸乙酯 =20:3) to obtain yellow solid compound C6 with a yield of 70%. 1 H-NMR (500MHz, Acetone-D6) δppm: 1.65(3H,s,-CH3),1.79(3H,s,-CH3),3.33(2H,d,J=7.0Hz,-CH2),3.48(6H,s,-OCH3×2),3.49(3H,s,-OCH3),3 .58(3H,s,-OCH3),5.22(1H,m,-C=H),5.27(4H,s,-OCH2×2),5.35(2H,s, -OCH2),5.42(2H,s,-OCH2),6.54(1H,s,Ar-H),6.79(1H,t,J=2.0,4.0Hz Ar-H),7.10(2H,d,J=2.5Hz,Ar-H),7.70(1H,d,J=15.5Hz,C=H),8.03(1H,d,J=15.5Hz,C=H),13.96(1H,s,Ar-OH).MS(ESI),m / z:531.3[MH] - ,532.4[M+H] + ,555.4[M+Na] + .

[0042] 5. Synthesis of Compound C7

[0043] Compound C6 (1.60 g, 3 mmol) was dissolved in 50 mL of CH3OH-HCl (1 mol / L), refluxed at 55°C for 50 min, and water (100 mL) was added to terminate the reaction. After vacuum concentration to remove methanol, ethyl acetate was added for extraction (100 mL×3), the organic phase was washed with distilled water, dried over anhydrous NaSO4, and concentrated in vacuum. Yellow solid compound C7 was isolated by silica gel column chromatography (V petroleum ether: V ethyl acetate = 1:1) with a yield of 89%. 1H-NMR(500MHz,Acetone-D6)δppm:1.67(3H,s,-CH3),1.79(3H,s,-CH3),3.30(2H,dd ,J=7.0Hz,H-1”),5.26(1H,m,H-2”),6.13(1H,s,H-5’),6.47(1H,t,J=2.0Hz,H-4),6 .71(2H,d,J=2.0Hz,H-2,6),7.65(1H,d,J=15.5Hz,H-1α),8.18(1H,d,J=15.5Hz,H-1 β),8.46(s,2H,Ar-OH),9.17(s,1H,Ar-OH),9.68(s,1H,Ar-OH),14.31(s,1H,Ar-OH). 13 C-NMR (125MHz, Acetone-D6) δppm: 18.7 (CH3), 26.7 (CH3), 22.8 (C-1”), 125. 0(C-2”),131.7(C-3”),106.6(C-1'),166.6(C-2'),109.0(C-3'),163.9(C-4 '),96.2(C-5'),161.1(C-6'),139.2(C-1),108.5(C-2,6),160.6(C-3,5),10 6.3(C-4),194.2(C=O),129.4(C-1α),143.7(C-1β).MS(ESI),m / z:355.2[MH] - ,357.1[M+H] + ,379.1[M+Na] + .

[0044] 6. Synthesis of compounds C8 and C9

[0045] Compound C7 (0.71 g, 2 mmol) was dissolved in 20 mL of CH3OH-HCl (1.5 mol / L), refluxed at 55°C for 30 min, and water (30 mL) was added to terminate the reaction. After vacuum concentration to remove methanol, ethyl acetate was added for extraction (50 mL×3), the organic phase was washed with distilled water, dried over anhydrous NaSO4, and vacuum concentrated. Yellow solid compound C8 was obtained by separation through silica gel column chromatography (V petroleum ether: V ethyl acetate = 3:2); yellow solid compound C9 was obtained by separation through (V petroleum ether: V ethyl acetate = 2:3). The yields of compounds C8 and C9 were 38% and 55%, respectively.

[0046] The spectral data of C8 are as follows:

[0047] 1H-NMR (500 MHz, Acetone-D6) δ ppm: 1.36 (6H, s, -CH3×2), 1.83 (2H, m, H-2”), 2.61 (2H, m, H-3”), 5.94 (1H, s, H-5’), 6.47 (1H, t, H-4), 6.71 (2H, d, J=2.5 Hz, H-2,6), 7.67 (1H, d, J=15.5 Hz, H-1α), 8.20 (1H, d, J=15.5 Hz, H-1β), 8.47 (s, 2H, Ar-OH), 9.74 (s, 1H, Ar-OH), 14.55 (s, 1H, Ar-OH). 13 C-NMR (125 MHz, Acetone-D6) δ ppm: 27.7 (CH3×2), 77.4 (C-1”), 33.5 (C-2”), 17.6 (C-3”), 106.4 (C-1’), 166.7 (C-2’), 102.5 (C-3’), 162.7 (C-4’), 97.0 (C-5’), 160.8 (C-6’), 139.3 (C-1), 108.5 (C-2,6), 160.6 (C-3,5), 106.4 (C-4), 194.1 (C=O), 129.2 (C-1α), 143.9 (C-1β). MS (ESI), m / z: 355.1 [M-H] - , 357.4 [M+H] + , 379.1 [M+Na] + .

[0048] The spectral data of C9 are as follows:

[0049] 1 H-NMR (500 MHz, Acetone-D6) δ ppm: 1.21 (6H, s, -CH3×2), 1.68 (2H, m, H-2”), 2.63 (2H, m, H-1”), 3.24 (3H, s, -OCH3), 6.11 (1H, s, H-5’), 6.46 (1H, m, H-4), 6.69 (2H, d, J=2.0 Hz, H-2,6), 7.64 (1H, d, J=15.5 Hz, H-1α), 8.16 (1H, d, J=15.5 Hz, H-1β), 8.39 (s, 2H, Ar-OH), 9.80 (s, 1H, Ar-OH), 14.15 (s, 1H, Ar-OH). 13C-NMR (125MHz, Acetone-D6) δppm: 25.7 (CH3×2), 49.9 (OCH3), 18.2 (C-1”), 39 .9(C-2”),76.4(C-3”),106.6(C-1'),167.6(C-2'),109.7(C-3'),165.0(C-4 '),96.3(C-5'),161.2(C-6'),139.4(C-1),108.5(C-2,6),160.6(C-3,5),10 6.3(C-4),198.9(C=O),129.4(C-1α),143.7(C-1β).MS(ESI),m / z:387.2[MH] - ,389.3[M+H] + ,411.1[M+Na] + .

[0050] Example 2: 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs inhibit citrus green mold

[0051] The agent (compound C7, C8 or C9, prochloraz) was dissolved in dimethyl sulfoxide (DMSO), diluted to 25, 50 and 100 μg / mL respectively with potato dextrose agar (PDA) medium, poured into a 9 cm culture dish, and inoculated with citrus green mold in the center of the culture dish after cooling and solidification. The reaction was observed for 9 days, and the solvent group (1% DMSO by volume) was used as a control. The inhibition rate was calculated according to the following formula.

[0052]

[0053] ODc represents the mycelial growth diameter of the control group, and ODs represents the mycelial growth diameter of the treatment group.

[0054] The results are as follows Figure 1 As shown, compound C7, C8 or C9 can significantly inhibit the growth of citrus green mold, showing a concentration-inhibitory activity effect; among them, compound C7 has the most significant activity, and its effect in inhibiting citrus green mold is significantly higher than that of the commercial fungicide prochloraz.

[0055] Example 3: 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs inhibit Penicillium citrinum

[0056] The drug (compound C7, C8 or C9, prochloraz) was dissolved in dimethyl sulfoxide (DMSO), diluted to 25, 50 and 100 μg / mL respectively with PDA culture medium, poured into a culture dish with a diameter of 9 cm, and after cooling and solidification, inoculated with citrus Penicillium in the center of the culture dish. The culture was observed for 7 days, and the solvent group (1% DMSO) was used as a control. The inhibition rate was calculated according to the following formula.

[0057]

[0058] ODc represents the mycelial growth diameter of the control group, and ODs represents the mycelial growth diameter of the treatment group.

[0059] The results are as follows Figure 2 As shown, compound C7, C8 or C9 can significantly inhibit the growth of citrus Penicillium, showing a concentration-antibacterial activity effect; among them, compound C7 has the most significant activity, and its antibacterial activity is significantly higher than that of the commercial fungicide prochloraz.

[0060] Example 4: 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs inhibit citrus acid rot fungi

[0061] The agent (compound C7, C8 or C9, prochloraz) was dissolved in dimethyl sulfoxide (DMSO), diluted to 25, 50 and 100 μg / mL respectively with PDA culture medium, poured into a culture dish with a diameter of 9 cm, and after cooling and solidification, citrus acid rot fungus was inoculated in the center of the culture dish. The reaction was observed for 7 days, and the solvent group (1% DMSO) was used as a control. The inhibition rate was calculated according to the following formula.

[0062]

[0063] ODc represents the mycelial growth diameter of the control group, and ODs represents the mycelial growth diameter of the treatment group.

[0064] The results are as follows Figure 3 As shown, compound C7, C8 or C9 can significantly inhibit the growth of citrus acid rot fungi, showing a concentration-antibacterial activity effect, among which compound C7 has the most significant activity, and its antibacterial activity is significantly higher than that of the commercial fungicide prochloraz.

[0065] Example 5: Effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone (Compound C7) on the preservation of citrus fruits

[0066] Treatment group: Compound C7, whose chemical structure is shown in formula (II), was prepared into a saturated solution with anhydrous ethanol, and diluted with water to a final concentration of 100 mg / L to obtain a preservative solution. Summer oranges were soaked in the preservative solution for 3 minutes, taken out and dried, and citrus green mold pathogens were inoculated on the dried summer oranges using the live injury inoculation method, and placed in a constant temperature and humidity incubator for 6 days.

[0067] Control group: Add an equal amount of anhydrous ethanol to the treatment group into the aqueous solution, soak the summer oranges in the aqueous solution for 3 minutes, take them out and dry them, inoculate citrus green mold pathogen on the dried summer oranges using the live injury inoculation method, and place them in a constant temperature and humidity incubator for 6 days.

[0068] The results are as follows Figure 4 As shown, citrus green mold pathogens are highly pathogenic, causing severe fruit rot, which will quickly spread to the entire fruit after the disease occurs (control group); and compound C7 pretreatment of citrus fruits can significantly inhibit the occurrence of citrus green mold disease.

[0069] Example 6: Effect of 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone (Compound C7) on the preservation of citrus fruits

[0070] Treatment group: Compound C7, whose chemical structure is shown in formula (II), was prepared into a saturated solution with anhydrous ethanol, and diluted with water to a final concentration of 100 mg / L to obtain a preservative solution. Summer oranges were soaked in the preservative solution for 3 minutes, fished out and dried, and the dried summer oranges were inoculated with citrus penicillium by the live injury inoculation method, and placed in a constant temperature and humidity incubator for 6 days.

[0071] Control group: Add an equal amount of anhydrous ethanol to the treatment group into the aqueous solution, soak the summer oranges in the aqueous solution for 3 minutes, take them out and dry them, inoculate the dried summer oranges with citrus penicillium using the live injury inoculation method, and place them in a constant temperature and humidity incubator for 6 days.

[0072] The results are as follows Figure 5 As shown, after the control group was inoculated with citrus Penicillium spp., the fruits suffered severe rot; while pretreatment of citrus fruits with compound C7 could significantly inhibit the occurrence of citrus Penicillium spp.

[0073] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogs, the compound having a structural formula as shown in formula (I), Formula (I).

2. Use of the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogue according to claim 1 in the preparation of a drug or preservative for preventing and treating postharvest diseases of fruits; The preservative is a citrus preservative; The post-harvest fruit diseases are citrus green mold, citrus penicillium or citrus acid rot.

3. Use of the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogue according to claim 1 in the preparation of a method for preventing and controlling postharvest pathogens of fruits; The fruit post-harvest pathogens are citrus post-harvest pathogens, including green mold fungi, penicillium fungi or sour rot fungi.

4. A drug or preservative for preventing and treating post-harvest fruit diseases, characterized in that: The invention contains the 2',3,4',5,6'-pentahydroxy-3'-isopentenyl chalcone analogue described in claim 1 as an active ingredient, the preservative is a citrus preservative; and the post-harvest fruit disease is citrus green mold, citrus penicillium or citrus sour rot.

5. A method for preventing and controlling post-harvest diseases of fruits, characterized in that: The citrus is soaked in a preservative and then air-dried. The preservative is the preservative according to claim 4.

6. The method according to claim 5, characterized in that The preservative is an aqueous solution of compound C7, the concentration of which is 100 mg / L, and the citrus is soaked for 3 minutes.

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