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Figure 1.
(a) Gas ion chromatogram of CAEO. (b) Mass spectrum of thymol.
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Figure 2.
Comparative 2D and 3D interactions of thymol and standard drugs with different target proteins used in the study. 6XYS: PBD ID for the crystal structure of enzyme acetylcholinesterase from the gut of Meloidogyne incognita larvae, 5IVH: PDB ID for the crystal structure of enzyme carboxylesterase from the head capsule of Spodoptera litura larvae, 1YHZ: PDB ID for the crystal structure of enzyme acetohydroxyacid synthase (AHAS) from the weed Raphanus raphanistrum sub sativus, amino acid residues in green rings are showing van der Waals interactions, amino acid residues in pink rings are showing pi-alkyl interactions, amino acid residues in purple rings are showing pi-sigma interactions, amino acids in red rings are showing unfavorable bumps.
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S.N. Compound R.I. Lit R.I. Exp % Mol. formula M.F.P. Monoterpene hydrocarbon 1. α-thujene 931 929 3.2 C10H16 M+ = 136; m/z: 121, 119, 105, 93 (100%), 91, 77, 65, 53, 51, 43, 41, 27 2. p-cymene 1022 1023 3.9 C10H14 M+ = 134; m/z: 132, 120, 119 (100%), 103, 91, 77, 65, 55, 41, 39 3. γ-terpinene 1054 1054 2.9 C10H16 M+ = 136; m/z: 121, 119, 107, 105, 93 (100%), 91, 79, 77, 65, 43, 41, 39, 27 Total (%) 10.0 Monoterpene oxygenated 4. Thymol 1288 1283 69.6 C10H14O M+ = 150; m/z: 136, 135 (100%), 115, 91, 79, 77, 65, 51, 39 5. carvacrol 1296 1297 3.2 C10H14O M+ = 150; m/z: 136, 135 (100%), 117, 107, 91, 77, 65, 51, 39, 27 Total (%) 72.8 Sesquiterpene hydrocarbon 6. Bicyclogermacrene 1502 1501 2.5 C15H24 M+ = 204;
m/z: 189, 176, 161, 147, 136, 133, 121, 107, 93 (100%), 79, 67, 53, 41, 39, 297. (E)-caryophyllene 1421 1423 3.7 C15H24 M+ = 204; m/z: 175, 147, 133, 120, 107, 93 (100%), 91, 79, 69, 55, 41, 39, 27 Total (%) 6.2 Sesquiterpene oxygenated 8. β-eudesmol 1648 1645 1.1 C15H26O M+ = 222; m/z: 189, 175, 141, 131 (100%), 79, 75, 73, 55 Total (%) 1.1 Others 9. 1-(3-ethyloxiranyl)-ethanone − − 2.6 C6H10O2 M+ = 114; m/z: 85, 71, 57, 44, 43 (100%), 38, 31 10. Carvacrol methyl ether 1247 1251 2.3 C11H16O M+ = 164; m/z: 161, 149 (100%), 91, 79, 71, 53 11. Thymyl acetate 1355 1355 1.3 C12H16O2 M+ = 192; m/z: 150, 136, 135 (100%), 91,43 12. Carvacrol ethyl ether 1456 1457 1.2 C12H24O M+ = 184; m/z: 138, 124, 109, 95, 82, 67, 57 (100%), 55, 43, 41, 39, 29 Total (%) 7.4 Total Composition (%) 97.5 CAEO: Coleus aromaticus essential oil; R.T.: Retention time; R.I. Lit.: Retention index (DB-5 column) acquired from literature; R.I. Exp.: Retention index acquired from experimental data; M.F.P.: Mass Fragmentation Pattern. Table 1.
Chemical composition of CAEO.
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Dose (µL/mL) Number of eggs hatched in time Mean % Egg hatchability 24 h 48 h 72 h 96 h 0.25 4.66 5.66 7.33 11.33 7.25 95.39 0.50 4.66 5.66 6.66 8.66 6.42 95.92 1.00 3.33 5.00 5.66 5.66 4.92 96.87 Control 106.00 143.00 173.66 207.66 157.58 ± 43.35 S.E.M 0.34 0.29 0.59 C.D. 1% 1.35 1.17 2.34 C.D. 5% 0.99 0.86 1.73 C.V. 56.90 CAEO: Coleus aromaticus essential oil; C.D.: Critical Difference; C.V.: Coefficient of Variance, ** p < 0.05. Table 2.
% Egg hatchability inhibition of CAEO against M. incognita in laboratory conditions.
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Dose (µL/mL) Number of larvae dead in time Mean
larvae dead% Mortality 24 h 48 h 72 h 0.25 9.33 27.33 28.33 21.66 ± 10.69 13.47 0.50 25.00 38.33 39.33 34.22 ± 8.00 27.78 1.00 55.66 66.00 66.33 62.66 ± 6.06 52.32 Control 2.00 8.66 11.66 7.44 ± 4.94 S.E.M. 2.05 2.05 3.55 C.D. 1% 8.34 8.34 14.45 C.D. 5% 6.09 6.09 10.55 C.V. 15.56 CAEO: Coleus aromaticus essential oil; C.D.: Critical Difference; C.V.: Coefficient of Variance, ** p < 0.05. Table 3.
% Mortality of 2nd stage larvae of M. incognita in different concentrations of CAEO.
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Dose (µL/mL) Number of seeds germinated in different time intervals Mean seed germinated % Growth inhibition % Root growth inhibition % Shoot growth inhibition 24 h 48 h 72 h 96 h 108 h 250 1.66 2.66 3.33 3.66 4.66 3.20 ± 1.12 63.70 74.79 91.93 500 0.66 1.00 1.66 2.33 3.00 1.73 ± 0.95 80.34 85.91 94.99 750 0.00 0.66 1.00 1.33 2.00 1.00 ± 0.74 88.66 97.36 98.76 1000 0.00 0.00 0.33 0.33 0.33 0.20 ± 0.18 97.75 98.11 100 Control 7.00 7.00 10.00 10.00 10.00 8.80 ± 1.64 0.0 0.0 0.0 Pendimethalin 0.0 0.0 0.0 0.0 0.0 0.0 100.0 100.0 100.0 C.D. 1% 0.53 C.D. 5% 0.39 C.V. 18.13 CAEO: Coleus aromaticus essential oil; C.D.: Critical Difference; C.V.: Coefficient of Variance, ** p < 0.05. Table 4.
% Phytotoxic activity of CAEO against R. raphanistrum seeds in laboratory conditions.
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Dose
(µL/mL)Insects observed alive at different time intervals Mean insect survival % mortality 12 h 24 h 36 h 10 5.00 5.00 5.00 5.00 ± 0.0 0 20 5.00 4.33 4.00 4.44 ± 0.51 11.13 30 4.66 3.66 3.33 3.88 ± 0.69 22.33 40 4.00 4.00 3.33 3.77 ± 0.38 24.46 50 2.00 1.33 1.00 1.44 ± 0.51 71.13 Control 5.00 5.00 5.00 5.00 ± 0.0 0 Permethrin 0.0 0.0 0.0 0.0 100.0 C.D. 1% 0.5 0.7 1.3 C.D. 5% 0.4 0.5 0.9 C.V. 14.7 CAEO: Coleus aromaticus essential oil; C.D.: Critical Difference; C.V.: Coefficient of Variance, ** p < 0.05. Table 5.
% Mortality of S. litura against CAEO in laboratory conditions.
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Major compounds Predicted biological activities Anti-helminthic (nematodes) Insecticidal Anti-fungal Anti-bacterial α-thujene 0.388 > 0.047 − 0.337 > 0.067 0.130 > 0.098 p-cymene 0.633 > 0.005 0.391 > 0.006 0.368 > 0.058 − γ-terpinene 0.642 > 0.005 − 0.443 > 0.041 0.325 > 0.051 thymol 0.569 > 0.008 0.323 > 0.013 0.464 > 0.037 0.336 > 0.047 carvacrol 0.722 > 0.004 0.351 > 0.010 0.449 > 0.039 0.319 > 0.053 bicyclogermacrene 0.520 > 0.014 0.350 > 0.010 0.439 > 0.042 − (E)-caryophyllene 0.333 > 0.080 0.368 > 0.008 0.582 > 0.020 0.437 > 0.023 β-eudesmol − − 0.401 > 0.049 0.302 > 0.059 carvacrol methyl ether 0.622 > 0.005 0.388 > 0.007 0.362 > 0.059 − thymyl acetate 0.775 > 0.003 0.327 > 0013 0.456 > 0.038 0.324 > 0.052 dodecanal 0.458 > 0.025 0.368 > 0.008 0.314 > 0.075 0.280 > 0.068 Pa > Pi, Pa = Probable activity and Pi = Probable inactivity. Table 6.
In silico PASS prediction bioactivities of major compounds in CAEO.
Figures
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Tables
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