Application of UV–Vis spectrophotometric process for the assessment of indoloacridines as free radical scavenger

Article abstract of DOI:10.1016/j.jphotobiol.2016.07.026

A conventional approach has been used to synthesis Indole fused acridine, 4a–e. In this paper to achieve the target molecule, 4 the reaction was performed via two steps. In step 1, there was a reaction between Carbazolone, 1 and benzophenone, 2 to get dih

Full text of DOI:10.1016/j.jphotobiol.2016.07.026

Journal of Photochemistry & Photobiology, B: Biology 162 (2016) 641–645
Contents lists available at ScienceDirect
Journal of Photochemistry & Photobiology, B: Biology
journal homepage: www.elsevier.com/locate/jphotobiol
Application of UV–Vis spectrophotometric process for the assessment of
indoloacridines as free radical scavenger
b,
c
Makuteswaran Sridharan a, , K.J. Rajendra Prasad , G. Madhumitha ,
⁎
⁎
Naif Abdullah Al-Dhabi d, Mariadhas Valan Arasu d
Department of Chemistry, R.V. College of Engineering, Mysore Road, Bangalore 560059, Karnataka, India
Department of Chemistry, Bharathiar University, Coimbatore 641049, Tamil Nadu, India
Chemistry of Heterocycles & Natural Product Research Laboratory, Department of Chemistry, School of Advanced Sciences, VIT University, Vellore 632 014, Tamil Nadu, India
a
b
c
d
Department of Botany and Microbiology, Addiriyah Chair for Environmental Studies, College of Science, King Saud University, P. O. Box 2455, Riyadh 11451, Saudi Arabia
a r t i c l e i n f o
a b s t r a c t
Article history:
A conventional approach has been used to synthesis Indole fused acridine, 4a–e. In this paper to achieve the tar-
get molecule, 4 the reaction was performed via two steps. In step 1, there was a reaction between Carbazolone, 1
and benzophenone, 2 to get dihydroindoloacridine, 3. In step 2, compound, 3 was treated with 5% Palladium/Car-
bon in the presence of diphenyl ether for 5 h to give a dark brown product, 4. The column chromatography was
used to purify final product, 4. All the synthesized compounds such as 3 and 4 were characterized by melting
point, FTIR, 1H NMR, and Mass spectra. Further to check the purity of the compounds it was subjected to CHN an-
alyzer. The target molecules such as 3 and 4 were screened for antimicrobial studies against bacteria such as Ba-
cillus subtilis (B. subtilis), Staphylococcus aureus (S. aureus), Klebsiella pneumonia (K. pneumonia), Salmonella typhi
(S. typhi); and fungi like Aspergillus niger (A. niger), Aspergillus fumigatus (A. fumigatus). The obtained results clear-
ly proves that the target molecules shown reasonable activity against K. pneumonia and A. niger. Further the com-
pounds were screened for free radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH). The free
radical scavenging property was performed using UV–Visible spectroscopy. The results were compared with the
standard BHT (Butylated Hydroxy Toluene). Compounds, 4a and 4e were shown higher percentage of inhibition
when compare to the standard. The result confirms that further research on indoloacridine will leads effective
drug to the market.
Received 29 June 2016
Accepted 21 July 2016
Available online 26 July 2016
Keywords:
Benzophenone
Carbazolone
Indoloacridine
Antibacterial
Antifungal
Free radical scavenger
© 2016 Elsevier B.V. All rights reserved.
1. Introduction
various phytoconstituents which will not suit for drastic conditions for
several human beings. So to overcome these drawbacks we have fo-
Mostly due to presence of mismatched electrons free radicals are un-
stable in nature, which can be manufactured by various steps like stress
due to oxidation, and natural metabolic disorder [1]. If suddenly our
body temperature were high all free radicals lead to act as toxins
which can eradicate through anti-oxidants or else known as free radical
scavengers [2]. Recently most of the researchers focused their research
progress towards nitrogen containing heterocyclic compounds [3–11].
It is consider as one of the best natural products which score better re-
sults against various pharmacological and biological applications. The
continuous increase of natural products as well as pharmacological ac-
tion of these molecules has generated synthetic interest. Nowadays
most of the free radical scavengers available in all over the globe
which can be attain easily by various green approaches were studied
and reported [12], but it contains some side effects due to presence of
cused towards synthetic free radical scavenger. In this manuscript au-
thors synthesize Indoloacridine molecule to treat against free radicals
which can be monitored by UV–Visible spectroscopy at the wavelength
of 515 to 520 nm [13]. Also we have processed anti-microbial activity for
various pathogens like bacteria, fungi and yeast.
Acridine is a molecule which contains nitrogen molecule with sys-
tem of heterocycles [5] which plays a major role in medicinal chemistry
field as scavenger of free radicals [14]. An Indolo molecule is stated to be
a glycosidic product which occurs naturally and plays a several biologi-
cal role as anti-cancer agents. Also it has high binding affinity to any
other molecules [15–20]. So with this high affinity of binding indole
molecule was binded with acridine and subjected to various pharma-
ceutical and biological applications. Already some researchers focused
on synthetic anti-oxidants which lead to better anti-oxidant activity
with BHT (butylated hydroxyl toluene) as standard [21] and also stud-
ied for various biological applications [22–24]. Most of the articles stated
about larvicidal and anti-oxidant properties; but there are very few re-
ports on synthetic microbial agents. So in this manuscript we process
⁎
Corresponding authors.
E-mail addresses: sridharanm@rvce.edu.in (M. Sridharan), kjrprasad@gmail.com
(K.J.R. Prasad).
http://dx.doi.org/10.1016/j.jphotobiol.2016.07.026
1011-1344/© 2016 Elsevier B.V. All rights reserved.

642
M. Sridharan et al. / Journal of Photochemistry & Photobiology, B: Biology 162 (2016) 641–645
Scheme. 1. Conventional approach for the synthesis of compounds, 4a–e.
to study the synthetic compound against various pathogenic bacteria
such as B. subtilis, S. aureus, K. pneumonia, S. typhi; and fungi like A.
niger, A. fumigatus were tested by agar well diffusion method and
reported.
the pure product column chromatography technique was adopted with
the help of petroleum ether and ethyl acetate system using 98:2 solvent
system. The spectral data and physical constants of the compounds are
reported in Tables 1-3.
2. Experimental Parts
2.3. Antimicrobial Activity of the Synthesized Compounds, 4a–e
2.1. Materials and Methods
2.3.1. Source of Microorganism
In order to find the antimicrobial activity for the synthesized com-
pounds the following microorganisms were used
Chemicals and solvents which we have used for this experiment has
been used without any further purification. Melting point was recorded
with standard benzoic acid for the calibration. Bruker Avance 400 MHz
spectrometer was used to record 1H and 13C NMR in CDCl3 or DMSO-d6.
➢ S. aureus (ATCC 700699) and B. subtilis (ATCC 11778) - Gram positive
bacteria.
➢ K. pneumonia (ATCC 2719) and S. typhi (ATCC 700931) - Gram nega-
tive bacteria.
2.2. General Procedure for the Preparation of Indolo Fused Acridines, 4a–e
➢ niger and A. fumigatus-Yeast like fungi.
Compounds, 3a–e were prepared as per the earlier report [6] and the
corresponding melting point, 1H and 13C NMR were matched with the
literature. Further compounds, 4a–e were prepared as follows: About
1 mmol of dihydroindoloacridine, 3 and 50 mg of Palladium/Carbon was
refluxed in the presence of diphenyl ether (3 mL) for 5 h (Scheme 1).
The reaction progress was noted by Thin Layer Chromatography.
After the reaction completion, it was filtered through Whatman-41
paper to remove Palladium/Carbon. From the reaction mixture the excess
solvent was removed. Then the residue was transferred into crushed ice.
The product is the form of crude as separated with ethyl acetate. To get
2.3.2. Standardization of Microorganism and Culture Media
About 0.2 mL cultures (overnight) of all organisms were dispended
into 20 mL of sterile nutrient broth and then incubated for about 5 h
to standardize the culture to 106 cfu/mL. A loopful of standard culture
was used for antimicrobial assay. The solid growth of medium used
for bacteria was nutrient agar and for fungi was sabouraud dextrose
agar.
Table 2
Table 1
Physical constants of the synthesized compounds, 4a–e.
Physical constants of the synthesized compounds, 3a–e.
Compounds
Nature
Yield (%) MP (°C)
Reference
Compounds
Nature
Yield (%) MP (°C) [literature
report]
Reference
[6]
Pale yellow
prisms
67
74
71
251–253 NA
Orange
crystals
84
230–232 [231]
Yellow prisms
Yellow prisms
282–284 NA
Yellow
solid
81
250–252 [250]
[6]
248–250 NA
Orange
solid
82
75
282–284 [282]
231–233
[6]
NA
Yellow solid
64
62
274–276 NA
269–271 NA
Orange
solid
Pale yellow
powder
Orange
crystals
66
207–209
NA
Note: NA – not reported earlier in the literature.
Note: NA – not reported earlier in the literature.

M. Sridharan et al. / Journal of Photochemistry & Photobiology, B: Biology 162 (2016) 641–645
643
Table 3
Spectral characterizations of compounds, 3d, 3e, and 4a–e.
Compounds
FTIR
1H NMR
Mass
CHN
(Cm−1
)
[actual/observed] analysis
(%)
3414,
2923,
2854,
1643,
11.75 (b s,
1H, N\\H),
8.20–7.04
(m, 12H),
382/380
418/416
392/394
C,
78.61;
H, 4.40;
N, 7.22
1596, 1029 3.08–2.89
(m, 4H)
3445,
2925,
2818,
1641,
11.95 (b s,
1H, N\\H),
8.05–7.15 (
m, 11H),
C,
72.11;
H, 3.71;
N, 6.59
1592, 1060 2.97–2.88
(m, 4H)
3431,
2922,
2855,
1648,
1592,
11.67 (b s,
1H, N13\\H),
8.10–7.01
(m, 13H),
C,
79.04;
H, 4.17;
N, 7.24
2.51 (s, 3H,
Fig. 1. Free radical activity measured by time vs absorbance.
1044, 820, CH3)
768
3434,
2921,
2862,
1646,
1592,
1046, 701
3446,
2881,
2858,
1672,
1591,
1028, 763
3362,
2923,
2871,
1640,
1593,
1028, 735
3365,
11.52 (b s,
392/394
392/394
380/378
C,
mother bacterial suspension. The bacterial swabs were streaked on all
directions firmly inside the test tube above the level of fluid to remove
excess of bacterial residue. The petriplates which is already prepared
was taken and then swabbed on the surface. Later a sterile well borer
was punched on the agar rim to make well of 8 mm size. The agar plates
were then dried for few min to which 100 μL of compounds, 4a–e con-
trol and standards where dispersed into well by using micropipette. The
test samples were prepared in 1 mg/1 mL of DMSO as solvents. For 24 h
the petriplates with the sample were incubated at 37 °C for the growth
of microorganism. Later the petriplates were examined for the inhibi-
tion zone around the well. It was measured and compared with the
standard compounds in mm which was discussed in Table 4. The proce-
dure was repeated twice to confirm the reciprocation of the results.
The standard used for determining bacteria was 1 mg of Penicillin in
DMSO (5 mL) and for antifungal activity was 1 mg of Oflaxacin in DMSO
(5 mL). The solvent, DMSO was used as a control. The synthesized com-
pounds, 4a–e were tested for antimicrobial activity. The results obtained
are tabulated in Table 4.
1H, N\\H),
8.12–6.93
(m, 13H),
2.52 (s, 3H,
CH3)
79.84;
H, 4.52;
N, 7.01
11.57 (b
C,
s,1H, N\\H),
8.02–6.72
(m, 13H),
2.58 (s, 3H,
CH3)
11.72 (b s,
1H, N\\H),
8.04–7.01
(m, 14H)
79.20;
H, 4.10;
N, 7.07
C,
79.14;
H, 4.06;
N, 7.29
11.55(b s,1H, 414/412
N\\H),
8.02–7.05
C,
2927,
2889,
1643,
1593,
72.44;
H, 3.27;
N, 6.64
(m, 13H)
1477,
1067,
2.4. Free Radical Scavenging Property of the Synthesized Compounds, 4a–e
1054, 767
The antiradical scavenging assay of indole fused acridine, 4a–e was
measured by DPPH method [21,26,27]. Stable radical DPPH used as a re-
agent. The DPPH (0.01 mM) was mixed in absolute ethanol which is
named as stock solution. From the stock 1 mL of the DPPH solution
was added to 3 mL of compounds, 4a–e prepared in pure ethanol.
BHT, ascorbic acid and compounds, 4a–e (100 μg/mL) in absolute etha-
nol was used for this study. The absorbance (Fig. 1) was measured at
517 nm at time interval of 5 min for half an hour (Table 5). The
2.3.3. Test for Antimicrobial Property
Agar well diffusion procedure [25] were utilized to evaluate antimi-
crobial studies of compounds, 4a–e. The medium used for the growth
for bacteria and fungi were nutrient and sabouraud's agar respectively.
Around 24 h broth cultures of all mentioned test organism were used
for the assay. Sterilized applicator stick was used to inoculate into the
Table 4
Antimicrobial activity of target molecules, 4a–e.
Table 5
Name of the organisms
Zone inhibition (mm)
UV–Visible absorbance of target compounds, 4a–e.
4a
4b
4c
4d
4e
DMSO
Standard
Time (min)
Absorbance of the compoundsa (nm)
Gram positive bacteria
S. aureus
B. subtils
Ascorbic acid
BHT
14a
14b
14c
14d
14e
4
4
4
3
2
1
2
2
3
5
---
---
7
8
0
5
0.111
0.121
0.118
0.115
0.113
0.110
0.104
0.107
0.077
0.076
0.075
0.059
0.058
0.058
0.047
0.048
0.048
0.047
0.047
0.047
0.047
0.143
0.133
0.133
0.133
0.133
0.133
0.133
0.100
0.089
0.083
0.078
0.075
0.074
0.074
0.090
0.080
0.077
0.077
0.076
0.076
0.075
0.071
0.052
0.049
0.045
0.043
0.042
0.042
Gram negative bacteria
K. pneumonia
S. typhi
10
15
20
25
30
5
---
4
---
3
---
2
---
6
---
7
7
---
---
Yeast like fungi
A. niger
A. fumigatus
5
---
5
2
2
---
2
---
6
---
8
5
BHT, ascorbic acid, DPPH, 14(b–e), (each one is 1.5 × 10−4 mM in ethanol solution) at
a
Note: “—“ represents negative results.
517 nm.

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M. Sridharan et al. / Journal of Photochemistry & Photobiology, B: Biology 162 (2016) 641–645
3. Results and Discussion
3.1. Chemistry of Compounds, 3 and 4
1-Carbazolone, 1a on treatment with benzophenone, 2 in glacial
acetic acid yielded an orange solid. Its IR spectrum showed a strong
NH band at 3279 cm−1 and νC_N at 1643 cm−1. Its 1H NMR spectrum
ν
of carbazole -NH proton at δ 11.58 as singlet, eleven aromatic protons
as a cluster from δ 8.02–7.10, a four proton multiplet in the region δ
2.92–2.66, and a three-proton singlet at δ 2.48 for the CH3 group. In
mass analysis 392 corresponds to the molecular ion peak of compound,
4a. These spectral details and also the CHN report were matched with
the molecular formula C26H19N2Cl, corresponding to the structure
dihydroindoloacridine, 3a.
Compound, 4a FTIR spectrum showed a strong νNH band at
3431 cm−1, and a νC_N band at 1648 cm−1. Its 1H NMR spectrum
showed carbazole NH proton at δ 11.67 as a singlet, thirteen aromatic
protons as a cluster from δ 8.10–6.98, and a three-proton singlet at δ
2.51 for the CH3 group. The molecular ion peak appeared at m/z 392 in
the MS. The spectral and analytical details attest the compound as in-
dole fused acridine, 4a.
Fig. 2. Percentage inhibition of free radical scavenger.
Table 6
3.2. Antimicrobial Proerty of Target Compounds, 4a–e
Percentage inhibition of target compounds, 4a-e.
Time (min)
% inhibition
The microbial activity of the synthesized compounds, 4a–e as fol-
lows from the Table 5.
Ascorbic acid
BHT
14a
14b
14c
14d
14e
0
5
90.70
89.87
90.12
90.37
90.54
90.79
91.04
91.04
93.55
93.63
93.72
95.01
95.14
95.14
96.06
95.98
95.98
96.06
96.06
96.06
96.06
88.02
88.86
88.86
88.86
88.86
88.86
88.86
91.62
92.55
93.05
93.47
93.72
93.80
93.80
92.46
93.29
93.55
93.55
93.63
93.63
93.70
94.05
95.64
95.89
96.23
96.39
96.48
96.48
➢ Compound, 4a and 4b exhibited vital antibacterial property against
S. aureus.
➢ Compound, 4a and 4e showed significant antibacterial activity
against B. subtilis and K. pneumonia.
➢ Neither of the compounds showed activity against S. typhi.
➢ Compounds, 4a, b, and 4e showed significant antifungal activity
against A. niger.
10
15
20
25
30
➢ A weak activity against A. fumigatus was shown only by compound,
14b.
percentage of radical scavenging (Fig. 2, Table 6) was calculated with
the following equation
3.3. Free Radical Scavenging Proerty of Target Compounds, 4a–e
%DPPHradicalscavenging ¼ ½AD−Asꢀ=AD X 100
The result suggests that out of five compounds, 4a–e examined,
compound, 4a showed a decrease in the absorbance (Fig. 1) and in-
crease in percentage inhibition (Fig. 2) whereas compound, 4e showed
a moderate absorbance and moderate percentage inhibition. But
where, AD - absorbance taken only for DPPH in absolute ethanol.
As - absorbance taken for compound, 4 with DPPH in absolute
ethanol.
Fig. 3. Free radical scavenging mechanism for the compound, 4.

M. Sridharan et al. / Journal of Photochemistry & Photobiology, B: Biology 162 (2016) 641–645
645
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To conclude from the all the synthesized compounds, compound, 4a
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In this present work, the synthesized compound 4 has been proved
as good antimicrobial agent. Further it was acting as a good free radical
scavenger, when compared to the standard antioxidant. These results
will turn the young researcher to find further view on indoloacridines.
[15] S.M. Roopan, F.R. Nawaz Khan, SnO2 nanoparticles mediated nontraditional synthe-
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Acknowledgments
[16] M. Sridharan, K.J.R. Prasad, A.E. Kotheimer, T. Wagner, M. Zeller, Whole molecule
disorder in a solid solution of two indoloacridines, J. Chem. Crystallogr. 39 (2009)
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Author Dr. M. Sridharan thank to the management of R.V. College of
Engineering for their support and encouragement. Naif Abdullah Al-
Dhabi and Valan Arasu extend their sincere thankfulness to the Dean-
ship of Scientific Research, King Saud University for its funding to Prolif-
ic Research Group (PRG-1437-28). Dr. K J Rajendra Prasad thanks UGC
for Emeritus Professorship.
[17] M. Sridharan, K.J.R. Prasad, A. Ngendahimana, M. Zeller, Structural investigations of
novel indoloacridines, J. Chem. Crystallogr. 39 (2009) 270–278.
[18] M. Sridharan, K.J.R. Prasad, M. Zeller, 9-Chloro-1-methyl-7-phenyl-5,6-dihydro-
13H-indolo[3,2-c]acridine, Acta Cryst E65 (2009) o1064.
[19] E. Yamuna, M. Sridharan, K.J.R. Prasad, M. Zeller, Structural investigations on 4-
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novel indolo[2,3 a]pyrimido[5,4-c]carbazoles as a new class of anti-cancer agents,
Eur. J. Med. Chem. 56 (2012) 292–300.
[21] S.M. Roopan, T. Maiyalagan, F. Nawaz Khan, Solvent free synthesis of some
quinazolin-4(3H)-ones derivatives, Can. J. Chem. 86 (2008) 1019–1025.
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some 2-and 3-substituted isoquinolinones, Indian J. Heterocycl. Chem. 19 (2009)
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