Synthesis and antifungal activity of chalcone derivatives

Article abstract of DOI:10.1080/14786419.2015.1007973

In the present study, using chalcone as a lead compound, a series of its derivatives (compounds 1-30) were designed and synthesised. Their activity of anti-pathogenic fungi of plants has been evaluated. It is found that these compounds have good antifunga

Full text of DOI:10.1080/14786419.2015.1007973

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Synthesis and antifungal activity of
chalcone derivatives
Yuanyuan Zhenga, Xuesong Wanga, Sumei Gaoa, Min Maa, Guiming
Rena, Huabing Liua & Xiaohong Chena
a School of Physics and Chemistry, Xihua University, Chengdu
610039, P.R. China
Published online: 12 Feb 2015.
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To cite this article: Yuanyuan Zheng, Xuesong Wang, Sumei Gao, Min Ma, Guiming Ren, Huabing Liu
& Xiaohong Chen (2015): Synthesis and antifungal activity of chalcone derivatives, Natural Product
Research: Formerly Natural Product Letters, DOI: 10.1080/14786419.2015.1007973
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Natural Product Research, 2015
http://dx.doi.org/10.1080/14786419.2015.1007973
Synthesis and antifungal activity of chalcone derivatives
Yuanyuan Zheng, Xuesong Wang, Sumei Gao, Min Ma, Guiming Ren, Huabing Liu and
Xiaohong Chen*
School of Physics and Chemistry, Xihua University, Chengdu 610039, P.R. China
(Received 30 October 2014; final version received 9 January 2015)
In the present study, using chalcone as a lead compound, a series of its derivatives
(compounds 1–30) were designed and synthesised. Their activity of anti-pathogenic
fungi of plants has been evaluated. It is found that these compounds have good
antifungal activity against Sclerotinia sclerotiorum, Helminthosprium maydis, Botrytis
cinerea, Rhizoctonia solani and Gibberella zeae. Among them, the inhibition of growth
for compound 30 against S. sclerotiorum showed 89.9%, with the median effective
concentrations (EC50) of 15.4 mg mL21. The inhibition of growth for compounds 28, 29
and 30 at a concentration of 100 mg mL21 against H. maydis is 90.3%, 90.7% and
91.1%, with EC50 of 15.1, 18.3 and 18.1mg mL21, respectively.
Keywords: antifungal activity; chalcone derivatives; inhibition of growth
1. Introduction
Chalcones represent an important group of natural compounds with a variety of biological
activities including antibacterial and antifungal ones. They have numerous applications as
pesticides, photo-protectors in plastics, food additives as well as anti-inflammatory and
anticancer agents (Anto et al. 1995; Iwata et al. 1997; Dimmock et al. 1999; Go et al. 2005;
Nowakowska 2007). Therefore, in the present study, chalcone derivatives were synthesised
based on it. In the meantime, their antifungal activity has been evaluated in the laboratory to find
new fungicides with high efficacy and low toxicity.
Sclerotinia sclerotiorum, Helminthosprium maydis, Botrytis cinerea, Rhizoctonia solani and
Gibberella zeae are harmful pathogenic fungi of crops or vegetables (Li et al. 2007; Liu & Chen
2007; Chen et al. 2009). Over the past decades, synthetic fungicides including carbendazim have
been used to prevent them. However, in recent years, they have developed resistance to the
fungicides (Egashira et al. 2000; Ignatova et al. 2000; Guimara˜es et al. 2004; Ten Have et al.
2007). Moreover, their scope of resistance continues to expand and has already included many
*Corresponding author. Email: zhengyuan408@163.com
q 2015 Taylor & Francis

2
Y.y. Zheng et al.
new fungicides (Finkers, Bai, et al. 2007; Finkers, van den Berg, et al. 2007; Finkers, et al. 2008).
Therefore, new fungicides are continually required.
2. Results and discussion
All the synthesised derivatives in Table 1 of chalcone were screened for their activity against
S. sclerotiorum, H. maydis, B. cinerea, R. solani and G. zeae. The results are presented in
Table 2.
These compounds showed good antifungal activity (Tables 2–6) against S. sclerotiorum,
H. maydis, B. cinerea, R. solani and G. zeae. Among them, the inhibition of growth for
compound 30 against S. sclerotiorum exhibited 89.9%, with the median effective concentrations
(EC50) of 15.4 mg mL21. The inhibition of growth for compounds 28, 29 and 30 at a
concentration of 100 mg mL21 against H. maydis showed 90.3%, 90.7% and 91.1%, with EC50 of
15.1, 18.3 and 18.1 mg mL21, respectively. From Table 2, compounds 28, 29 and 30 (having
CH3, OCH3 and CH2CH2CH3 substituents, respectively) with pyridine rings exhibit better
activity than the others having the same substituents but without pyridine rings. It seems that
pyridine rings may enhance biological activity of these compounds.
The preliminary results suggested that the design and synthesis of these compounds may be
instructive to the investigations of the antifungal activity of derivatives of chalcone. It is also
promising and beneficial to further studies in developing new and more effective fungicides in
Table 1. Structure of target compounds 1–30.
Compounds
R1
4–F
4–OCH3
4–CH3
2–Cl
2–NO2
2,4-Cl
H
4–Br
4–OCH3
4–CH3
4–Cl
3–Cl
3–Br
2,4–Cl
3,4–Cl
4–C6H5
2–C4H3O
4–F
4–Br
4–Cl
2–Cl
4–OCH3
3–Cl
3–Br
3,4–Cl
–
R2
R3
Yield (%)
1
2
3
4
5
6
7
8
2,4–Cl
2,4–Cl
2,4–Cl
2,4–Cl
2,4–Cl
2,4–Cl
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
75.0
60.2
67.8
72.0
79.1
68.4
73.0
65.0
85.7
86.0
88.3
84.5
79.6
83.5
77.9
72.8
56.5
68.4
65.7
70.3
81.4
73.4
67.4
71.6
69.0
84.7
84.7
83.3
76.3
76.8
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
4–OCH3
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
3,4–(OCH3)
–
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
–
4–Cl
4–Br
–
–
–
–
–
–
–
–
4–CH3
4–OCH3
4–(CH2) 2CH3

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3
Table 2. Antifungal activity of compounds 1–30 against S. sclerotiorum, H. maydis, B. cinerea, R. solani
and G. zeae at 100 mg mL21
.
Inhibition of growth (%)a
Compounds
S. sclerotiorum
H. maydis
B. cinerea
R. solani
G. zeae
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
54.0 ^ 0.01
19.2 ^ 0.23
53.2 ^ 0.15
59.1 ^ 0.03
53.6 ^ 0.02
23.7 ^ 0.05
35.6 ^ 0.02
38.5 ^ 0.04
58.1 ^ 0.34
35.3 ^ 0.06
14.4 ^ 0.52
33.3 ^ 0.17
25.5 ^ 0.21
38.4 ^ 0.08
32.4 ^ 0.06
34.3 ^ 0.03
26.5 ^ 0.01
19.3 ^ 0.26
23.6 ^ 0.06
24.4 ^ 0.17
28.7 ^ 0.03
30.1 ^ 0.05
33.5 ^ 0.13
36.7 ^ 0.26
38.9 ^ 0.03
68.8 ^ 0.07
69.3 ^ 0.13
63.9 ^ 0.03
46.3 ^ 0.06
89.9 ^ 0.48
100
48.9 ^ 0.15
48.9 ^ 0.04
59.1 ^ 0.03
43.5 ^ 0.21
52.1 ^ 0.06
54.1 ^ 0.08
58.6 ^ 0.05
47.9 ^ 0.12
23.1 ^ 0.19
38.5 ^ 0.38
40.1 ^ 1.08
45.6 ^ 0.32
52.3 ^ 0.07
49.8 ^ 0.02
54.8 ^ 0.15
39.4 ^ 0.33
52.3 ^ 0.53
57.8 ^ 0.05
54.3 ^ 0.03
47.2 ^ 0.23
48.3 ^ 0.32
49.2 ^ 0.03
51.6 ^ 0.33
56.7 ^ 0.13
44.2 ^ 0.06
70.9 ^ 0.03
62.9 ^ 0.05
90.3 ^ 0.18
90.7 ^ 0.56
91.1 ^ 0.03
87.5
66.9 ^ 0.05
36.9 ^ 0.03
47.9 ^ 0.13
40.6 ^ 0.06
51.9 ^ 0.02
54.3 ^ 0.07
58.5 ^ 0.41
46.7 ^ 0.02
38.6 ^ 0.25
42.4 ^ 0.16
47.3 ^ 0.62
58.6 ^ 0.54
48.9 ^ 0.49
47.7 ^ 0.34
28.1 ^ 1.04
34.6 ^ 0.06
38.9 ^ 0.02
41.3 ^ 0.01
42.6 ^ 0.08
49.3 ^ 0.07
51.7 ^ 0.63
56.6 ^ 0.24
42.7 ^ 0.27
48.3 ^ 0.33
52.9 ^ 0.05
46.4 ^ 0.04
45.3 ^ 0.08
42.3 ^ 0.09
65.4 ^ 0.81
43.6 ^ 0.56
91.3
44.3 ^ 0.11
37.3 ^ 0.07
52.6 ^ 0.04
47.3 ^ 0.01
18.1 ^ 0.04
27.3 ^ 0.04
18.3 ^ 0.23
27.4 ^ 0.33
31.8 ^ 0.14
32.1 ^ 0.27
43.8 ^ 0.45
39.7 ^ 0.03
51.2 ^ 0.07
49.7 ^ 0.22
54.3 ^ 0.28
58.7 ^ 0.05
55.6 ^ 0.02
57.9 ^ 0.13
61.2 ^ 0.61
59.3 ^ 0.47
51.4 ^ 0.04
56.8 ^ 0.01
49.1 ^ 0.05
48.9 ^ 0.09
57.6 ^ 0.39
33.3 ^ 0.45
25.5 ^ 0.51
42.4 ^ 0.43
40.4 ^ 0.09
60.3 ^ 0.04
100
37.7 ^ 0.02
48.2 ^ 0.01
57.9 ^ 1.01
56.7 ^ 0.13
45.3 ^ 0.31
18.1 ^ 0.01
27.9 ^ 0.13
48.9 ^ 0.14
37.7 ^ 0.37
39.6 ^ 0.21
43.2 ^ 0.44
21.6 ^ 0.02
27.9 ^ 0.14
31.5 ^ 0.19
37.6 ^ 0.36
39.3 ^ 0.11
42.5 ^ 0.27
38.8 ^ 0.04
34.8 ^ 0.54
51.2 ^ 0.29
48.8 ^ 0.13
40.7 ^ 0.04
52.3 ^ 0.03
41.9 ^ 0.05
54.7 ^ 0.28
70.1 ^ 0.17
60.9 ^ 0.37
63.9 ^ 0.28
70.1 ^ 0.38
63.5 ^ 0.62
100
25
26
27
28
29
30
Carbendazim
aBased on the mean of triplicates.
the agricultural chemistry field. However, there is more work to be done. Of course, a number of
derivatives of chalcone should be further synthesised for screening and surveying quantitative
structure–activity relationships so as to find novel fungicides with high effect and low toxicity.
Meanwhile, the mechanisms of activity of compounds 28, 29 and 30, and their safety to human
being and non-target organisms also need to be investigated.
2.1. Antifungal activity against H. maydis
Compared with the efficient fungicide carbendazim, the synthesised compounds were submitted
to laboratorial bioassay. The results are presented in Tables 3–5. They had good antifungal
activity against H. maydis. The EC50 value of these compounds reached 15.1, 18.3 and
18.1 mg mL21, respectively. The results of regressive and correlative analyses indicated that the
correlation was significant between concentration and efficacy. The correlative coefficient of
compound 28 was 0.9020. The x 2 test demonstrated that the results were reliable (x 2 ¼ 3.842,
df ¼ 3, p . 0.05). The correlative coefficient of compound 29 was 0.9061. The x 2 test
demonstrated that the results were reliable (x 2 ¼ 4.367, df ¼ 3, p . 0.05). The correlative

4
Y.y. Zheng et al.
Table 3. Antifungal activity of compound 28 against H. maydis.
Compound 28
Carbendazim
Concentration (mg mL21
)
200
100
50
25
12.5
100
50
25
12.5
94.5 90.3 70.2 59.7 49.4 87.5 70.8 57.5 41.5 35.5
6.3
Inhibition of growtha (%)
Regressive equation
(Y ¼ aX þ b)
Y ¼ 1.3728 X þ 3.8382
Y ¼ 1.2373 X þ 3.5189
EC50 (mg mL 21
(95% CL)
Correlative coefficient (r)
x 2
15.1
(10.5–19.5)
0.9020
15.7
(12.1– 19.6)
0.9808
3.842
2.862
aBased on the mean of triplicates.
Table 4. Antifungal activity of compound 29 against H. maydis.
Compound 29
Carbendazim
Concentration (mg mL 21
)
200
100
50
25
12.5
100
50
25
12.5
6.3
97.6 90.7 70.3 56.7 43.6 87.5 70.8 57.5 41.5 35.5
Inhibition of growtha (%)
Regressive equation
(Y ¼ aX þ b)
Y ¼ 1.6684 X þ 2.8927
Y ¼ 1.2373 X þ 3.5189
EC50 (mg mL 21
(95% CL)
Correlative coefficient (r)
x 2
18.3
(14.2–22.4)
0.9061
15.7
(12.1–19.6)
0.9808
4.367
2.862
aBased on the mean of triplicates.
Table 5. Antifungal activity of compound 30 against H. maydis.
Compound 30
Carbendazim
Concentration (mg mL 21
)
200
100
50
25
12.5
100
50
97.4 91.1 71.2 55.1 44.4 87.5 70.8 57.5 41.5 35.5
25
12.5
6.3
Inhibition of growtha (%)
Regressive equation
(Y ¼ aX þ b)
Y ¼ 1.6654 X þ 2.9040
Y ¼ 1.2373 X þ 3.5189
EC50 (mg mL 21
(95% CL)
Correlative coefficient (r)
x 2
18.1
(13.9–22.2)
0.9026
15.7
(12.1–19.6)
0.9808
4.318
2.862
aBased on the mean of triplicates.
coefficient of compound 30 was 0.9026 and the x 2 test demonstrated that the results were
reliable (x 2 ¼ 4.318, df ¼ 3, p . 0.05).
2.2. Antifungal activity against S. sclerotiorum
As shown in Table 6, using the efficient fungicide carbendazim as the comparative standard, the
synthesised compound was subjected to laboratorial bioassay. Its EC50 value reached
15.4 mg mL21. The results of regressive and correlative analyses revealed that the correlation
was significant between concentration and efficacy. The correlative coefficient was 0.9090.
As for the results of S. sclerotiorum, the x 2 test also showed that the results were reliable
(x 2 ¼ 3.522, df ¼ 3, p . 0.05).

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Table 6. Antifungal activity of compound 30 against S. sclerotiorum.
Compound 30
Carbendazim
Concentration (mg mL 21
Inhibition of growtha (%)
Regressive equation
(Y ¼ aX þ b)
200
100
50
25
12.5
100
50
25
12.5
6.3
96.5 89.9 73.3 57.8 49.7 94.1 85.5 74.9 61.1 49.5
Y ¼ 1.4777 X þ 3.2434
Y ¼ 1.2683 X þ 4.3132
EC50 (mg mL 21
(95% CL)
22.4
(11.1–19.7)
0.9090
3.5
(2.4–(4.6)
0.9614
0.605
Correlative coefficient (r)
x 2
3.522
aBased on the mean of triplicates.
3. Experimental
3.1. General
S. sclerotiorum, H. maydis, B. cinerea, R. solani and G. zeae were obtained from the Chinese
Academy of Agricultural Sciences. They were preserved at 48C. All chemicals and solvents were
purchased from commercial sources unless specified otherwise. IR spectra were recorded on a
Thermofisher Nicolet-6700 spectrophotometer (Thermo Fisher Scientific, MA, USA). 1H NMR
spectra were taken on a Varian Unity Inova-400 instrument (Varian Medical Systems, Palo Alto,
CA, USA) using deuteron-chloroform and DMSO-d6 as the solvent. The NMR data were
provided in the supplementary materials.
3.2. Synthesis of target compounds
The target compounds were synthesised in accordance with the reaction shown in Figures 1 and 2.
Appropriate aldehyde (0.01 mol) and acetophenone derivatives (0.01 mol) were dissolved in
anhydrous ethanol (15 mL). The reaction mixture was stirred at 08C for 8 h. Then, 10% NaOH
(5 mL) was slowly added to the above mixture under stirring until the reaction was complete.
The precipitate was filtered and washed with still water. The pure compounds were obtained by
re-crystallisation in acetone and water.
3.3. Assay of antifungal activity
The antifungal activity of the synthesised compounds against S. sclerotiorum, H. maydis, B.
cinerea, R. solani and G. zeae were determined using the plate growth rate method (Huang &
Yang 2006).
O
O
O
CH
NaOH/CH3CH2OH
R1
R2
+
R1
R2
Figure 1. Synthetic method of target compounds 1–25.
O
O
O
NaOH/CH3CH2OH
H
N
+
N
R3
R3
Figure 2. Synthetic method of target compounds 26–30.

6
Y.y. Zheng et al.
The synthesised compounds and carbendazim (purity 90%) were dissolved in dimethyl
sulphoxide, respectively. They were added to the sterile culture medium (PDA) at 458C, mixed
to homogeneity and transferred to sterile Petri dishes to solidify. A mycelium agar disc (5 mm in
diameter) of the target fungi was placed in the center of PDA plates. They were incubated at
288C in the dark until the target fungi used as controls covered the surface of these plates.
Control groups were treated with the corresponding solutions without the synthesised
compounds or carbendazim. Each experiment was replicated three times. The diameter of the
fungi in the cultures was measured and the inhibition of growth was calculated according to the
formula of Abbott. EC50 values were calculated with the Statistics Package for the Social
Sciences (SPSS) based on probit analysis.
4. Conclusions
A series of derivatives of chalcone have been successfully synthesised in this work, and were
tested for their antifungal activity against S. sclerotiorum, H. maydis, B. cinerea, R. solani and
G. zeae for the first time. It is found that these compounds have good antifungal activity against
S. sclerotiorum, H. maydis, B. cinerea, R. solani and G. zeae. Among them, the inhibition of
growth for compound 30 against S. sclerotiorum showed 89.9%, with the median effective
concentrations (EC50) of 15.4 mg mL21. The inhibition of growth for compounds 28, 29 and 30
at a concentration of 100 mg mL21 against H. maydis exhibited 90.3%, 90.7% and 91.1%, with
EC50 of 15.1, 18.3 and 18.1 mg mL21, respectively.
Supplementary material
Experimental details relating to this paper are available online, alongside Figures S1–S60.
Funding
This project was supported by the Scientific Research Fund of Sichuan Provincial Education Department
[grant number 14ZA0113], the Innovation Fund of Postgraduate, Xihua University [grant number
YCJJ2014127] and the Research Center for Advanced Computation, Xihua University.
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