CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.11 No.09, pp 308-321, 2018
12 31
Abstract : The plant source based on natural material products cover a major sector of the biomedical and medical field then the focus on plant research has been increased worldwide. We have performed a structural investigation and spectroscopic studies of a natural plant material product cyclitol: D-Pinitol. The spectroscopic properties of D-Pinitol were analyzed in the present study using FT-IR, FT-Raman spectra in the region of FT-IR (4000-400cm-1and FT-Raman cm-1). The vibrational frequencies were obtained by DFT-B3LYP/-311++G(d,p) as a basis set. The optimized geometry of D-Pinitol has been elucidated using, vibrational assignment and calculation of potential energy distribution (PED). The charges of atoms and electronic structural system NBO/NLMO. The molecular electrostatic surface and reactivity of this natural molecule have been calculated. The UV-Vis spectrum has been recorded in methanol solvent (MeOH) and electronic properties such as frontier orbitals (FMOs) calculated HOMO-LUMO is measure by the TD-DFT approach. Docking simulation is powerful way to figure out the binding structure of a substrate in its receptor. Key Words : PED, NBO, FMOs, Docking Study.
D-Pinitol, IUPAC name D-3-O-methyl-chiro-inositol, is a cyclitol occurring in nature compound. The cyclitols are extensively distributed in the plant kingdom. The D-pinitol(C7H14O6) in especially 3-O-methyl ether is widely distributed but D-Chiro-inositol is originated in plants. In the occurrence of most great quantities of myo-inositol, inconsequential amount of D-Chiro-inositol have been indicated in animal and human tissue. Inositol stands for 1,2,3,4,5,6-cyclohexanehexol and consists of nine discrete stereoisomers, namely, cis-, myo,allo-, muco-, neo-, epi-, scyllo-, optical isomer p-chiro -, and L-chiro-inositol. D-Pinitol is one of the naturally occurring inositol derivatives[1]. This lower-molecular-weight, non-toxic, sugar like compound is biodegradable[2,3] and has the food supplement because of its reported effectiveness in lowering blood glucose level. The worldwide total number of people with diabetes is projected to upswing from 171 million in 2000 to 366 million in 2030.
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
DOI= http://dx.doi.org/10.20902/IJCTR.2018.110937
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321. 309
D-Pinitol is a bioactive compound re-counted to have important biological and medical activities. The secondary metabolism exerts medical activities on insulin-like, human metabolism [4], antitumor, antiinflammatory[5,6], osmoprotectant[7], embryo development[8], cardioprotectivc[9], antihyperlipidemic[10]. This compound also has some bio control effect on lardvicidal activities, mothy ovipositor attraction butterfly. Literature survey reveals that so far there is no completespectroscopic study FT-IR, FT-Raman, and quantum chemical calculation study for tittle compound D-Pinitol. In this study, we set out the experimental and theoretical investigation of the conformation, vibrational and electronic transition of D-Pinitol. The optimized geometry parameters, fundamental frequencies, molecular frontier orbitals surfaces(FMOs), molecular electrostatic potential (MEP) of the tittle compound have been calculated by using DFT–B3LYP method 6311++G(d,p) basis set to explore the molecular dynamics and structural parameters that govern the chemical calculations behavior and to compare predictions made from theory with experimental observations.
2. Experimental Details
The compound D-Pinitol(> 90 % (HPLC), powder)was purchased from Sigma–Aldrich Chemical Company, USA and used as such without further purification to record FT-IR and FT-Raman spectra. The FTIR spectrum of the title compound was recorded in the 4000–400 cm -1 region with a BRUKER IFS 66 V spectrometer using KBr pellets. The FT-Raman spectrum was also recorded in the region 4000 -100 cm-1 with BRUKER IFS 100/s Raman molecule equipped with Nd: YAG laser source operating at 1064 nm line width 150mWpower. The ultraviolet absorption spectrum of sample solved in methanol was examined in the range 200–400 nm by using Cary 5E UV–Vis NIR recording spectrometer.
3. Quantum Chemical Calculations
Calculations of the title compound were carried out with Gaussian03W software program [11] using the B3LYP/6-311++G(d,p)quantum chemical calculation methods to predict the molecular structure and vibrational wavenumbers. Calculations were accepted out with Becke’s three parameter hybrid model using the Lee–Yang– Parr correlation functional (B3LYP) method. In order to interpret various second order interaction between the filled and empty orbitals, NBO calculations are doneby Gaussian03W package at the DFT/B3LYP/6311++G(d,p) level. NBO analysis provides an efficient method for studying inter and intramolecular bonding and interaction among bonds. The UV–Vis range, electronic transitions, vertical excitation energies and absorbance of the title molecule are calculated with the TD-DFT. The electronic transitions such as the highest occupied molecular orbital (HOMO) and lowestlying unoccupied molecular orbital (LUMO) energies are computed with DFT method. The assignments of each vibration were examined on the basis of the measured data and potential energy distribution (PED) of the vibrational modes that carried out by VEDA 4.0 program [12]. The assignment of the calculated wavenumbers is aided by the animation option of Gauss view program, which gives a visual presentation of the vibrational modes [13].
The optimized molecular structure of D-Pinitol belongsto C1 point group symmetry. The optimized parameters such as bond length and bond angle are compared with the obtainable experimental X-ray diffraction (XRD) data of the tittle compound structure so as to calculate the close consistency of those parameters [14] and show good agreement with each other parameters are presented of tittle compound calculated by B3LYP/6-311++G(d,p) basis set Table 1.The magnitude of a bond length of D-pinitol follows C1
00 0
C2=C1-C6=C2-C3=1.53A, C1-O7=C2-O8=1.41A, C3-C4=C4-C5=C5-C6=1.52A,C3-O9=C4-O10=C5-O11=O12C13=1.42A0and C6-O12= 1.43A0 from the show results, it is clear that an excellent agreement with the experimental data. The hexagonal bond angle of the benzene ring of C2-C1-C6=110.31A0, C2-C1-O7 = 109A0,
0000 0
C6-C1-O7=111A,C2-C3-O9=106A,C5-C4-O10=112A,C4-C5-O11=107A, C6-O12-C13=114Afrom showing results, it is clear that an excellent agreement with that experimental data. The dissimilarity in bond angle may be observed due to the atoms which involve in bonding are presented Fig 1.
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Fig.1 Optimized structure of D-pinitol Table1. Optimized geometrical parameters like bond length and bond angles of D-Pinitol
Bond length | B3LYP/6311++G(d,p) | Bond angle | B3LYP/6311++G(d,p) |
C1 –C2 | 1.5308 | C6 -C1 -O7 | 111.9114 |
C1 -C6 | 1.5343 | C1 -C2 -C3 | 109.5766 |
C1 -O7 | 1.4168 | C1 -C2 -O8 | 109.4778 |
C2 -C3 | 1.5380 | C3 -C2 -O8 | 109.7989 |
C2 -O8 | 1.4198 | C2 -C3 -C4 | 111.2568 |
C3 -C4 | 1.5299 | C2 -C3 -O9 | 106.8939 |
C3 -O9 | 1.4236 | C4 -C3 -O9 | 110.2086 |
C4 -C5 | 1.5247 | C3 -C4 -C5 | 111.3494 |
C4 -O10 | 1.4237 | C3 -C4 -O10 | 106.8448 |
C5 -C6 | 1.5285 | C5 -C4 -O10 | 112.1628 |
C5 -O11 | 1.4238 | C4 -C5 -C6 | 105.8109 |
C6 -O12 | 1.4341 | C4 -C5 -O11 | 107.8447 |
O12 -C13 | 1.4241 | C6 -C5 -O11 | 112.1075 |
Bond angle | C1 -C6 -C5 | 109.7651 | |
C2 -C1 -C6 | 110.3152 | C1 -C6 -O12 | 110.1545 |
C2 -C1 -O7 | 109.7217 | C6 -O12 -C13 | 114.1673 |
The area of the vibrational analysis is to find vibrational assignments connected with specific molecular structures of a calculated compound. Entirely the vibrations are active in FT-IR and FT-Raman.The molecule has 27 atoms, hence, which possess75 normal modes of vibrations. The B3LYP\6-311++G(d,p) calculated frequencies along with experimentally obtained FT-IR and FT-Raman spectral measurements are tabulated in Table 2.The observed and calculated frequencies using B3LYP/6-311++G(d,p) along with their relative, probable assignments and potential energy distribution (PED) of the title compound are condensed in Table 2. The maximum number of values determined by B3LYP\6-311++G(d,p) method are in good agreement with the experimental values. The observed and experimental FT-IR and FT-Raman spectra of D-pinitol are shown in the Fig.2 and 3 respectively.
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
Fig.2FT-IR spectrum of D-pinitol
Fig. 3 FT-Raman spectrum of D-pinitol
C-H Vibrations
The aromatic and hetro aromatic structures such as pyridine, pyrilium, thiapprilium show C-H stretching vibrations act as fingerprint spectral region between 3100 -2900cm-1[15,16]. In this spectral region, bands are not pretentious noticeably by the nature of the functional groups experimentally in the title molecule
-1 -1
of C-H vibration are observed at 2998, 3040,3055 and 3086 cmin FT-IR and 3000, 3043, 3056 and 3075 cmin FT-Raman. The theoretical vibrations by B3LYP method also view clearly show good agreement with experimental.The vibration data involving C-H in-plane-bending in strongest absorptions for aromatic
-1 -1
compounds occur in the spectral region 1300-1000cmand 1000-650cmdue to the C-H out of plane bending[17-19 ] respectively and very useful for characterization purpose when there is in-plane interaction above 1200cm-1C-H usually move in opposite direction[17]. For our title molecule, the C-H in-plane bending
vibration is found at 1020 and 1206 cm-1in FT-IR and at 1026 and 1203 cm -1 in FT-Raman. The
theoreticalcalculation vibrations by B3LYP method also show good agreement with experimental data. The out-of-plane bending spectral vibration is observed at 656, 748,775 and 823 in FT-IR, and at 639, 753, 780 and 837cm-1 in FT-Raman. This theoreticalcalculation vibration in B3LYP/6-311++G(d,p) method also show good agreement with experimental data, with these vibrational modes, are also confirmed by their PED values.
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C-C Vibrations
The ring C-C stretching vibration is very important in the spectrum and highly characteristic vibrations stretching give rise to a characteristic peak in the spectral region of 1600-1000 cm -1 and are not significantlyinfluenced by the nature of the replacement about the ring[20]. In the present study C-C stretching vibrationsare observed at 1020,1070,1080,1013, 1126 1159,1242,1306,1378,1410, and 1426 cm -1in FT-IR spectrum and FT-Raman bands were observed at 1026,1082,1113,1126,1162,1301,1381,1412 and 1427cm-1 . The theoretical values calculated were obtained in the range 1023 to 1421 cm -1 by B3LYP/6-311++G(d,p) method and shows clearly that the theoretical values are in very good agreement with experimental values in give Table 2.
C-O Vibrating
The title compound method methoxy group in aromatic ring includes C-O band, where two different types of carbon are calculated are attached to oxygen and visible in two different regions C-O vibration is with high sensitivity and strong intensity of absorption to moderately minor changes in its environment. Intra and intermolecular factors affected C-O absorptions inorganic compounds due to inductive, field effects, conjugation effects and mesmeric effects[21]. The C-O stretching vibration occurs with strong band spectral region 1000-1230[22]. In the title compound C-O vibrations are observed of which 1070,1082,1113,1126,1159,
-1 -1
1187 and 1206 cm in FT-IR and at 1082, 1111, 1126,1162,1191,and 1203 cm in FT-Raman showing
excellent dependability with theoretical values at 1076, 1085,1117,1121,1160,1111 and 1207 cm-1 B3LYP/6311++ method. In tittle compound of in-plane and out-plane, the vibration generally occurs in 670 to 330cm 1[23-27]. In the present molecule 332,356,414,444,472,501 in FT-IR and FT-Raman 329,352,394, 419,438,468,479,511 and 528 in both spectra in meantime, theoretical values are slightly levels than the expected, while,experimental values agree with spectral data recordedin literature.
CH3Vibrations
The title of molecules D-Pinitonl, possess a CH3 group in the hetro aromatic ring shown in Fig 2 and3. For the vibration assignment of CH3 group one can expect nine fundamentals, namely CH3ss – symmetric stretch, CH3Sb-symmetric bending, CH3 ips–in-plane stretch (in-plane hydrogen stretching mode); CH3ipb –inplane bending (i.e-in-plane hydrogen deformation mode); CH3 t –twisting mode, CH3opb – out-of-plane bending modes, CH3ipr – in-plane rocking, CH3 – opr-out-of-plane rocking. The C-H vibration stretching in methyl occurs at lower frequencies than those of aromatic ring (3000-3100 cm-1)[28,29] and in the present
-1 -1
study, the vibration mode observed at 3022 cmin the FT-IR spectrum at 3019 cmin FT-Raman spectrum and 3027cm-1 theoretically are vibration assigned. The asymmetric bending vibrations mode of CH3 group typically
-1 -1
appear in the spectral region 1465-1440 cm and 1390-1370cm[30,31]. In this study, the calculated asymmetric bending vibrations of CH3obtained at 1465, in FT-IR and 1470 in FT-Raman respectively the experiment symmetric bonding of CH3 vibration were 7modes of CH3 observed at 166 cm-1 by the DFT/6311++ calculation and 155cm-1 in FT-Raman which coincides very most with calculated and literature [32,33].
O-H Vibrations
The O-H functional group there are three vibrations stretching in-plane bending and out-of-plane bending bands due to O-H stretching vibration medium to strong intensity in FT-IR spectrum band is generally weak inFT-Raman spectrum[34]. The O-H –in-plane, and O-H out of plane bending vibration is observed 1440
-1 -1-1
1260cmand 875-960 cm[35]. TheO-H groups strongly in the spectral region 3700-3400cm[36,37]. In D-Pinitol, the O-H stretching vibration.Observed at 3543,3596,3606, 3617,3623 inFT-IR at 3537 as very most, 3586,3608,3613 and 3622 FT-Raman spectra. The theoretical values 3538,3594, 3600,3616 and 3619 are also O-H stretching of D-Pinitolvibrational by B3LYP/6-311++G(d,p). The O-H in-plane bending spectralvibration as the very most band at 1338,1378,1410, 1426 in the FT-IR spectrum and 1338,1350,1381,1412 in the FT-Raman spectra. The O-H out of plane bending spectral vibrations observed at 915 in FT-IR, at 922 FT-Raman. The theoretical values 921 are also assigned to O-H out of plane bending by B3LYP/6-311++G(d,p), Table 2.
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Table 2Vibrational assignments of D-Pinitol
Experimental | Calculated | Vibrational Assignments+PED (%) | |
---|---|---|---|
FT-IR cm -1 | FT-R cm -1 | B3LYP/6311++G(d,p) cm -1 | |
- | 80 | 83 | τ HCOC(47) |
- | 103 | 98 | τ COCC(38) +τ CCCC(31) |
- | 116 | 118 | τ COCC(53) +τ CCCC(12) |
- | 155 | 166 | δ OCC(54)+ τ CH3(57) |
- | 185 | 171 | δ OCC(21)+ τ HCOC(37) |
- | 204 | 200 | δ OCC(13)+ γ OCCC(24) |
- | 215 | 222 | δ OCH(45) |
- | 259 | 261 | δ OCC(50) |
- | 263 | 269 | δ OCC(50) |
- | - | 276 | δ OCC(50) |
- | 289 | 287 | δ OCC(54)+ τ HCOC(36) |
- | 314 | 310 | δ OCC(59) |
- | 332 | 329 | δ OCC(27) |
- | 356 | 352 | δ COC(54)+τ HCOC(10) |
- | 381 | 394 | γ COCC(30) |
- | 414 | 419 | δ OCC(20)+τ HOCC(22) |
- | 444 | 438 | τ HOCC(39) |
- | 472 | 468 | τ HOCC(79)+ γ OCCC(10) |
- | 465 | 479 | τ HCCO(69) |
- | 501 | 511 | τ HOCC(76) |
- | - | 528 | δOCC(10)+ τ OCCC(10) |
656 | 639 | 642 | δCCH(35) |
674 | 669 | 669 | γ OCCC(11) |
694 | 694 | 680 | τ HOCC(79) |
748 | 753 | 736 | γCCCH(31) |
775 | 780 | 780 | γCCCH (37) |
823 | 837 | 838 | δCCH (12) + γ CCCH (11) |
857 | 856 | 849 | γ CCOC(17) |
915 | 922 | 921 | δCCH(58) |
975 | 978 | 981 | γ CCCH(28) |
1020 | 1026 | 1023 | γ CCCH(22) |
1055 | 1052 | 1061 | δCH2 (37) |
1070 | 1082 | 1076 | υOC(46)+γ OCCC(16) |
1082 | - | 1085 | γ OCCC(42) |
- | - | 1097 | υOC(42)+ γ OCCC(36) |
1013 | 1111 | 1117 | υOC(27)+ γ OCCC(46) |
1126 | 1126 | 1121 | γ OCCC(38) |
- | - | 1134 | γ OCC(40) |
1159 | 1162 | 1160 | υOC(32)+ γ OCC(22) |
1187 | 1191 | 1181 | τCH3(35) |
1206 | 1203 | 1207 | δHCH(10)+ τ CH3(29) |
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- | - | 1213 | δHOC(14) |
---|---|---|---|
1239 | 1241 | 1234 | υOC(39)+ δHOC(23) |
1242 | - | 1257 | γ CCCH(12) |
1275 | 1277 | 1277 | γ CH3(21) |
- | - | 1293 | υOC(42)+ τ HCCO(20) |
1306 | 1301 | 1308 | γ CCCH(11) |
- | - | 1321 | δHOC(12) |
1338 | 1338 | 1334 | δOCH(35) |
- | 1350 | 1362 | δHCO(11) |
1378 | 1381 | 1383 | δHCO(15)+ γ CCCH(17) |
- | - | 1399 | δHCO(40) |
1410 | 1412 | 1408 | δHCO(11)+ γ CCCH(14) |
1426 | 1427 | 1421 | υCC(33)+δHOC(10)+δHCO(28) + γ CCCH(16) |
- | 1442 | 1440 | δHOC(53)+ υCH(31) |
1449 | - | 1447 | δHOC(35)+δHCO(14)+γ CCCH(12) |
- | 1457 | 1451 | υCH(42)+δHOC(54) |
1465 | 1470 | 1469 | δHOC(48)+ γ CH3(32) |
- | 1491 | 1489 | δCH3(46)+ δHOC(18) |
1501 | - | 1499 | δCH3(72) |
1531 | 1532 | 1532 | δHCH(54) |
2998 | 3000 | 3002 | υCH()4 |
3022 | 3019 | 3027 | υCH3(89) |
3040 | 3043 | 3038 | υCH(86) |
3055 | 3056 | 3054 | υCH(94) |
- | - | 3059 | υCH(91) |
3086 | 3075 | 3080 | υCH(93) |
- | - | 3104 | υCH(94) |
3111 | - | 3108 | υCH(97) |
3139 | - | 3146 | υCH(99) |
3543 | 3537 | 3538 | υOH(88) |
3596 | 3586 | 3594 | υOH(98) |
3606 | 3608 | 3610 | υOH(100) |
3617 | 3613 | 3616 | υOH(100) |
3623 | 3622 | 3619 | υOH(100) |
υ–stretching;δ–in-plane-bending;τ–torsion;γ–out-of-plane-bending
Natural bond analysis has been achieved extensive usage in dynamic behaviors of community and electronic structure system [38,39]. The NBO analysis is an efficient method to investigate the intra and intermolecular interactions and charge transfer or conjugative from the filled (Bonding or lone pair) to virtual orbital spaces (antibonding and Rydberg)[40]. The NBO procedure uses mainly information pertaining to the atomic orbital overthe lab and density matrices. The natural atomic orbitals (NAOs) transformation to the orthogonalization which is followed by a bond orbital transformation to get the NBOs[41]
Second Order Perturbation Analysis
The NBO analysis carried out second-order perturbation theory helps to detect the role of all possible
interaction between filled donor Lewi’s type NBOs and estimating they are energetic. The occupied and
unoccupied NBO undergo a delocalization of electron density corresponding to an electron donor to electron
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
can of acceptors interaction and have the degree of conjugation of the system is measured by the hyper conjugative interaction energyE(2)[41]. NBO calculations were performed using Gaussian NBO version.For each donor(i) and acceptor (j), the stabilization energy associated with idelocalization.
ଠ!ଠ!ଠ ! !
E2= -n0 = -nଉ
௺ି
NBO results presented in Table 3, aresignificant in order to conclude whether some variation of ions increase or decrease the electrostatic nature of interaction from the Table 3. In D-pinitol interaction between the first lone pair of O10 and antibonding ofଉ௺12-H23 has the highest E(2) value around 11.05Kcal/Mol. The other important interaction giving stronger stabilization energy value of 8.43 Kcal/Mol to antibondingo ଉ௺ୄ12
– C6 between the lone pair of oxygen O8 and occupancy of electrons and P-character. The natural localized molecular orbital (NLMO) study has been carried out since they expression how bonding in a molecule is composed of orbitals localized on different atoms. The origin of NLMOs from NBOs gives direct insight into the nature of the localized molecular orbital’s ‘‘delocalization tails’’ [42,43]. Table 3, shows significant NLMO's occupancy, the percentage of parent NBO and atomic hybrid contributions of D-pinitol calculated at the B3LYP level using 6-31++G(d, p) basis set. The NLMO of a second lone pair of Oxygen atom O10 is the most delocalized NLMO and has only 96% contribution from the localized LP(2) O10 parent NBO, and the delocalization tail (3%) consists of the hybrids of O12 and H23.
Table 3 NBO/NLMO analysis of D-Pinitol
Donor | Acceptor | E(2)Kj/Mol | Hybrid | ED(e) | %From Parent Nbo | Hybrid Atom | Cont Atom | Atom | Percentage |
---|---|---|---|---|---|---|---|---|---|
LP(2) O8 | σ*C5 –C6 | 8.34 | P1.00 | 1.95342 | 97.647 | C5,C6 | 1.973 | O8 | 99.98 |
LP(2)O9 | σ*C4 -C5 | 6.62 | P1.00 | 1.95577 | 97.769 | C4,C6 | 1.587 | O9 | 99.99 |
LP(2)O10 | σ*O12 -H23 | 11.05 | P1.00 | 1.92942 | 96.458 | O12,H23 | 3.220 | O10 | 99.99 |
LP(2)O11 | σ*C3 -C4 | 7.71 | P1.00 | 1.95391 | 97.678 | C3,C4 | 1.606 | O11 | 99.99 |
LP(2)O12 | σ*C1 -C2 | 6.93 | P1.00 | 1.93934 | 96.949 | C1,C2 | 2.862 | O12 | 99.99 |
LP(2)O13 | σ*C1 -C6 | 4.70 | P1.00 | 1.95350 | 97.660 | C1,C6 | 1.949 | O13 | 99.99 |
The molecule electrostatic potential (MEP) at a point in force acting on a proton located in the space around a molecule given an electrical charge clouded generated, electron and nuclei provide[44]. The molecular electrostatic potential (MEP) surface map is plotted over the optimized structure of D-Pinitol in order to investigative the polarity of the charged molecule and mapping an electron density isosurface with electrostatic potential surface, shape, size negative, the positive and physic-chemical reactivity of mentioned molecules. It is recognized as a supportive parameter which characterizes [45,46]. In different values of the MEP, at the surface are represented by different colors, the maximum negative region represents the site for electrophilic attack indicated by red colors while the maximum positive region represents nucleophilic attacked in indicated region represents green. The 3D diagram of MEP for the D-Pinitol compound at B3LYP/6-311++G(d,p) basis set is shown in Fig 4, the color codes region represented maps are in the range from -0.0409 au (deepest red) to 0.05000 au (deepest blue) for D-pintol respectively.
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
Fig.4 Molecular electrostatic potential of D-pinitol
Molecular orbital theory approaches, the energy gap between HOMO-LUMO is an important in chemical reactivity of the molecules such as hardness, softness, electronegativity and electrophilicity index as well as all local reactivity and formative molecular electrical transport properties, of kinetic stability, optical polarizability[47-51] are shown in Fig 5.The highest occupied molecular orbitals (HOMOs) and lowest lying unoccupied molecular orbitals (LUMOs) are named as frontier molecular orbital (FMOs). The quantum bonding features of D-Pinitolis depicted by a plot of the HOMO-LUMO.Progress, the parameters
likeHardness (), the chemical potential () and electronegativity () and softness (S), electrophilicity index () were well-defined using the above mentioned energy values. Which are defined follow.
= ( )ୗ(ள) ( )ୗ(୭)
୕୕
= ( )ୗ(୭)
= = ( )ୗ(ள)
ି ି( ଢ଼) ଢ଼
S= , = , = , = , =
୕୕ ୕୕
Using the above equations, the chemical potential, hardness, and electrophilicity index, electronegativity and softness are being calculated for D-Pinitol and their values as shown in Table 4. The functionality of this new reactivity quantity has been recently demonstrated in mastery the toxicity of various pollutants in terms of their reactivity and site selectivity [52–54].
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
Fig. 5 Frontier molecular orbital of D-pinitol Table 4 Molecular properties of D-Pinitol
Molecular properties | B3LYP\6-31G(d,p) | Molecular properties | B3LYP\6-31G(d,p) |
---|---|---|---|
EHOMO(eV) | 6.8175 | Chemical Hardness() | 7.2708 |
ELUMO(eV) | -0.9064 | Softness(S) | 0.1375 |
E Homo-Lumogap(eV) | 7.7240 | Chemical Potential() | -6.3643 |
Ionisation | -6.8175 | Electronegativity() | 6.36438 |
Electron affinity (A) | 0.9064 | Electrophilicity | 20.2526 |
4.6Molecular Docking Studies of (compound name) Against Myeloperoxidase
Oxidative stress is mostly associated with inflammation. This is particularly dominated by neutrophils, which has a huge capacity to generate reactive oxygen species (55-57). It uses hydrogen peroxide to catalyze the production of hypohalous acids as well as an excess of free radicals (58). These reactive intermediates readily oxidize lipids, proteins, and DNA (59,60). Hypochlorous acid and hypobromous acid are kinetically the most reactive two-electron oxidants produced in vivo (60). Hypochlorous acid is a potent toxin, and at low levels, it activates stress response pathways within cells (62). Identification of specific biomarkers of hypochlorous acid at sites of inflammation has confirmed that MPO contributes to protein damage in cystic fibrosis (63), atherosclerosis (64), and atrial fibrillation (65). The convincing evidence that MPO produces damaging oxidants at sites of inflammation has focused attention on it as a pharmacological target. Currently, there is no effective inhibitor of the enzyme and limited appreciation of the best routes to block its activity. The present study is to find the better inhibitor for this enzyme.
The O2 atom of the hydroxyl group of the co-crystal ligand Fig 6 interacts with the N2 atom of the amide group of PHE147 at a distance of 3.0 Å. It also interacts with the O2 atom of the GLU 102 at a distance of
2.5 Å with the glide score of -5.14 and glides energy of -26.22 kcal/mol.
In the (D-Pinitol) the three hydroxyl group interacts with the N2 atom of amide group of the ARG 124, N2 atom of amide group of PHE 147 and with the O2 atom of GLU 102 at a distance of 3.0Å, 3.0Å, 3.0Å, 2.5Å and 2.8Å, respectively. The docking results obtained the glide score of -5.29 and glide energy of -26.59 kcal/molis shown in Table 5. The D-Pinitol shows the good H-bond interaction, glide score and glide energy than the existing co-crystal ligand is shown in the Fig.6 & 7. It may act as an inhibitor of the inflammation disease.
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
Fig. 6PVW (Co-crystal) of D-pinitol
Fig. 7 Molecular docked model of o of D-pinitol Table 5 Molecular Docking Studies Of (D-Pinitol) Against Myeloperoxidase
Compounds | H-bond interactions D-H...A | Distance (Å) | Glide score | Glide energy (kcal/mol) |
---|---|---|---|---|
(PVW) Cocrystal | (PHE 147)N-H...O O-H...O(GLU 102) | 3.0 2.5 | -5.14 | -26.22 |
Compound name | (ARG424)N-H...O (ARG 424)N-H...O (PHE 147)N-H...O O-H...O(GLU 102) O-H...O(GLU 102) | 3.0 3.0 3.0 2.5 2.8 | -5.29 | -26.59 |
To understand nature of electronic transitions of D-Pinitol molecule has been recorded within 200-800 nm for discovered in methanol solvent fig 8. The obtained UV radiation was electronic absorption wavelength by molecules passes from a state of the ground to the excited state. There are one excitation transitions of UV-Visible spectra of D-Pinitol. These bands are reported at 239 nm and electronic transitions of the title molecule of D-Pinitol was studied using time-dependent DFT (TD-DFT) calculation 239 nm in the methanol solvent was theoretically analysis using in present Table 6. Electronic transition from HOMO->LUMO (96%), HOMO>L+1 (56%) and H-1->LUMO (63%), HOMO->L+1 (31%) with contribution. The observed transition from HOMOLUMO is n*.
A. Manikandan et al /International Journal of ChemTech Research, 2018,11(09): 308-321.
Fig.8 UV-Spectrum of D-pinitol Table 6The UV–vis excitation energy of D-Pinitol
States | TD-B3LYP/6-31G(d,p) | Expt. obs | Major Contributions | |
---|---|---|---|---|
Methanol | ||||
cal | E(eV) | |||
S1 | 241.09 | 7.2466 | 239 | HOMO->LUMO (96%) |
S2 | 216.20 | 7.4601 | 214 | HOMO->L+1 (56%) |
S3 | 212.43 | 7.6333 | 213 | H-1->LUMO (63%), HOMO>L+1(31%) |
The prophesied structural of the D-Pinitol were investigated thoroughly and analyzed using high-level quantum chemistry calculation. The optimized geometrical parameters and vibrational frequencies FT-IR, FT-Raman calculated of the fundamental modes of D-Pinitol have been obtained from DFT/B3LYP/6311++G(d,p). Experimentally observed frequencies assignment is in very good agreement with quantum chemical theoretical calculation. The NBO analysis conforms, the interaction energy formed by the orbital overlaps LP(2) O10and ଉ * O12-H23 and E(2) = 11.05Kal/molan actual close to pure P-type lone pair orbital participates in the electron donation to the LP(2) O8 accept ଉ * C5-C6 and E(2) =8.34Kal/mol. The MEPs and electron densities of D-Pinitol lie in the range from -0.0409 au (deepest red) to 0.0500 au(deepest blue) respectively for D-Pinitol. Finally, HOMO-LUMO energy gap discloses that charge transfer occurs in the molecules, which are responsible for the bioactive property of the biomedical compound D-Pinitol.
References
W. H., WenzelU., Lewalter T., NickenigG., ZimmermannW. H., MeinertzT., BogerR. H., ReichenspurnerH., FreemanB. A., EschenhagenT., EhmkeH., HazenS. L., WillemsS., BaldusS.. Nat. Med. 2010, 16,s 470–474.
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