Table 2.
Yield, chemical constituents and their percentage variation in the essential oils of Lippia thymoides leaves after the drying process at 40, 50, and 60 °C.
| Fresh | 40 °C | 50 °C | 60 °C | |||
|---|---|---|---|---|---|---|
| Yield * (%) | 0.53 a ± 0.01 | 0.72 b ± 0.01 | 0.76 b ± 0.00 | 0.46 a ± 0.09 | ||
| RIL | RIC | Compound | Area % | Area % | Area % | Area % |
| 924 | 927 | α-thujene | - | 0.78 ± 0.04 | 0.27 ± 0.38 | 0.62 ± 0.23 |
| 988 | 985 | Myrcene | 0.52 ± 0.62 | 2.46 ± 1.39 | 2.10 ± 1.15 | 2.16 ± 0.48 |
| 1002 | 1005 | α-phellandrene | - | 0.26 ± 0.00 | 0.11 ± 0.15 | 0.23 ± 0.02 |
| 1014 | 1012 | α-terpinene | 0.37 ± 0.45 | 1.70 ± 0.97 | 1.39 ± 0.76 | 1.40 ± 0.13 |
| 1020 | 1019 | p-cymene | 2.97 ± 2.79 | 8.75 ± 3.08 | 8.36 ± 3.54 | 8.97 ± 0.64 |
| 1022 | 1025 | o-cymene | 0.04 ± 0.05 | 0.35 ± 0.49 | 2.28 ± 0.57 | - |
| 1044 | 1042 | E-β-ocimene | - | 0.04 ± 0.05 | 0.08 ± 0.11 | 0.12 ± 0.01 |
| 1054 | 1056 | γ-terpinene | 2.75 ± 3.55 | 9.54 ± 0.59 | 12.36 ± 4.64 | 8.19 ± 0.28 |
| 1065 | 1064 | cis-sabinene hydrate | 0.05 ± 0.06 | 0.02 ± 0.03 | - | 0.18 ± 0.00 |
| 1086 | 1088 | Terpinolene | - | 0.08 ± 0.12 | 0.20 ± 0.04 | 0.17 ± 0.01 |
| 1095 | 1099 | Linalool | 0.03 ± 0.04 | 0.13 ± 0.18 | 0.27 ± 0.07 | 0.19 ± 0.00 |
| 1098 | 1104 | trans-sabynene hydrate | - | 0.05 ± 0.07 | 0.04 ± 0.05 | - |
| 1141 | 1146 | Camphor | - | 0.02 ± 0.00 | 0.03 ± 0.00 | - |
| 1167 | 1175 | Umbellulone | 0.88 ± 0.04 | 1.48 ± 2.02 | 0.06 ± 0.02 | 0.28 ± 0.36 |
| 1174 | 1180 | Terpinen-4-ol | 0.73 ± 0.13 | 1.05 ± 1.01 | 1.44 ± 0.10 | - |
| 1232 | 1237 | Thymol methyl ether | 1.28 ± 0.30 | 2.69 ± 1.54 | 1.47 ± 0.09 | 1.28 ± 0.03 |
| 1289 | 1297 | Thymol | 62.78 ± 0.63 | 49.21 ± 11.46 | 53.03 ± 11.76 | 59.29 ± 2.89 |
| 1349 | 1356 | Thymyl acetate | 7.22 ± 2.30 | 6.46 ± 0.72 | 5.25 ± 0.45 | 4.92 ± 0.10 |
| 1374 | 1379 | α-copaene | - | 0.02 ± 0.02 | 0.04 ± 0.01 | 0.07 ± 0.00 |
| 1387 | 1388 | β-bourbonene | - | 0.02 ± 0.00 | 0.02 ± 0.02 | 0.03 ± 0.00 |
| 1417 | 1425 | E-caryophyllene | 8.84 ± 1.10 | 8.08 ± 0.26 | 7.46 ± 0.56 | 5.21 ± 0.44 |
| 1432 | 1439 | α-trans-bergamotene | 0.23 ± 0.04 | 0.39 ± 0.34 | 0.13 ± 0.01 | - |
| 1452 | 1458 | α-humulene | 1.49 ± 0.22 | 1.75 ± 1.00 | 0.89 ± 0.09 | 0.79 ± 0.07 |
| 1484 | 1486 | Germacrene D | 0.59 ± 0.13 | 0.79 ± 0.26 | 0.37 ± 0.07 | 0.40 ± 0.02 |
| 1495 | 1499 | γ-amorphene | - | 0.05 ± 0.06 | 0.09 ± 0.00 | 0.24 ± 0.00 |
| 1500 | 1504 | α-muurolene | - | 0.20 ± 0.17 | 0.07 ± 0.01 | 0.14 ± 0.01 |
| 1513 | 1519 | γ-cadinene | 0.42 ± 0.14 | 0.36 ± 0.28 | 0.15 ± 0.02 | 0.22 ± 0.01 |
| 1522 | 1528 | δ-cadinene | 0.78 ± 0.24 | 0.77 ± 0.63 | 0.30 ± 0.03 | 0.41 ± 0.04 |
| 1582 | 1589 | Caryophillene oxide | 1.09 ± 0.40 | 1.01 ± 0.86 | 0.30 ± 0.07 | 1.06 ± 0.05 |
| 1608 | 1615 | Humulene epoxide II | - | 0.02 ± 0.03 | 0.01 ± 0.01 | 0.14 ± 0.01 |
| 1640 | 1646 | epi-α-murrolol | - | 0.02 ± 0.02 | - | 0.07 ± 0.02 |
| 1652 | 1659 | α-cadinol | - | 0.02 ± 0.03 | - | 0.07 ± 0.01 |
| Monoterpene hydrocarbons | 6.70 ± 7.49 | 23.95 ± 4.35 | 27.14 ± 11.35 | 21.85 ± 1.80 | ||
| Oxygenated monoterpenes | 72.95 ± 2.89 | 61.1 ± 7.50 | 61.56 ± 11.08 | 66.14 ± 1.38 | ||
| Sesquiterpene hydrocarbons | 12.35 ± 1.91 | 12.41 ± 2.32 | 9.49 ± 0.85 | 7.5 ± 0.59 | ||
| Oxygenated sesquiterpene | 1.1 ± 0.42 | 1.07 ± 0.78 | 0.31 ± 0.06 | 1.33 ± 0.09 | ||
| Total ** | 90.07 ± 3.11 | 98.53 ± 0.05 | 98.49 ± 1.17 | 96.79 ± 0.26 |
Notes: * Columns with the same letter did not differ by the Tukey test at 5% probability; RI(L): Retention index from literature [52,53]; RI(c): Retention index calculated using an n-alkane standard solutions (C8–C40) in column DB5-MS; ** Relative percentage areas calculated based on the peak areas.