## 3 Results and Discussion
### The Effect of Essential oils on the Viability of Bifidobacterium in In Vitro Conditions
\begin{table}
\begin{tabular}{l l l l l l l l l l l l l} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**KI 1**} & \multicolumn{4}{c}{**Content (\%) 2**} & \multicolumn{2}{c}{**Content (\%)**} \\ \cline{5-11}  & & & **Lemon Peel** & **Clove Bud** & **Juniper Berry** & \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Compound**} & \multirow{2}{*}{**KI**} & \multicolumn{2}{c}{**Lemon Peel**} & \multicolumn{2}{c}{**Clove Bud**} & \multicolumn{2}{c}{**Juniper Berry**} \\ \cline{4-11}
4. & \multirow{2}{*}{Myrreal} & 1193 & - & - & 0.67 & 104. & Germacene B & 1556 & - & - & 1.76 \\ \hline
45. & Decanal & 1203 & 0.13 & - & - & 105. & Spathulenol & 1576 & - & - & 0.67 \\ \hline
46. & Octyl acetate & 1210 & 0.04 & - & - & 106. & Caryophyllee oxide & 1581 & - & 0.96 & 0.68 \\ \hline
47. & Verbenone & 1214 & - & - & 1.42 & 107. & Humulene epoxide & 1606 & - & 0.09 & 0.51 \\ \hline
48. & Chrysanthenyl acetate & 1232 & - & - & 0.12 & 108. & Depi-1,10-cubenol & 1614 & - & - & 0.70 \\ \hline
49. & Cumin aldehyde & 1238 & - & - & 0.28 & 109. & e-Cadined & 1653 & - & - & 2.83 \\ \hline
50. & Neral (E-Citral) & 1239 & 2.74 & - & - & 110. & Cadalene & 1674 & - & - & 0.39 \\ \hline
51. & Carvone & 1239 & 0.46 & 0.13 & 0.52 & 111. & Oxplononance & 1733 & - & - & 1.02 \\ \hline
52. & Chavicol & 1253 & - & 1.36 & - & 112. & Benzylbenzamide & 1762 & - & 0.34 & - \\ \hline
53. & Ceranol & 1253 & 3.38 & - & - & 113. & e-Copper-11-0 & 1891 & - & - & 0.15 \\ \hline
54. & Methyl dironellate & 1261 & - & - & 0.62 & 114. & Biformene & 1979 & - & - & 0.16 \\ \hline
55. & Ceranial (Z-Citral) & 1266 & 4.05 & - & - & 115. & m-Camphorene & 1944 & - & - & 0.39 \\ \hline
56. & Perilla aldehyde & 1268 & 0.31 & - & - & 116. & p-Camphorene & 1977 & - & - & 0.19 \\ \hline
57. & Bornyl acetate & 1280 & 0.07 & - & 0.78 & 117. & 13-Eprimanol & 2056 & - & - & 0.65 \\ \hline
58. & Thymol & 1290 & 0.05 & - & - & 118. & Squalene & 2790 & - & 0.08 & - \\ \hline
59. & 2-Undecanone & 1291 & - & 0.09 & 0.85 & 119. & Heptacosane & 2705 & & 0.09 & - \\ \hline
60. & Undecanal & 1309 & 0.10 & - & - & 120. & Octacosane & 2804 & & 0.21 & - \\ \hline \multicolumn{8}{c}{Monotrepene hydrocarbons (\%)} & \multicolumn{4}{c}{68.53} & 0.26 & 39.58 \\ \multicolumn{8}{c}{Oxygenated monoterpenes (\%)} & \multicolumn{4}{c}{24.78} & 0.66 & 15.08 \\ \hline  & & & & & & 4.09 & 10.71 & 31.69 \\ \hline  & & & & & & - & 1.05 & 6.56 \\ \multicolumn{8}{c}{Other (\%)} & \multicolumn{4}{c}{2.14} & 83.91 & 5.56 \\ \hline  & Total Identified (\%) & & & & 99.54 & 96.59 & 98.47 \\ \hline  & Oil yield (\%) & & & & & 6.63 & 3.65 & 0.95 \\ \hline \hline \end{tabular} \({}^{1}\) Kovats’ Retention Index on DB-SMs column, 2 radiative content expressed as percentage of the total oil composition obtained by CC/MS.3 not identified.  
\end{table} 
Table 1: _Cont._[PERSON] and [PERSON] [41] showed that the essential oils obtained from sweet oranges and lemons exhibited effective antibacterial activities compared to bergamot oil, citral, and linalool. The lemon essential oil contained the largest amount of limonene, but the lowest amount of citral compared to the essential oils obtained from sweet oranges and bergamot. Limonene did not show antibacterial action. The authors also stated that the Gram-positive bacteria were more sensitive to the antibacterial action of essential oils compared to the Gram-negative bacteria. Among the studied Gram-positive bacteria, _S. aureus_ was found to be the most resistant. The results of previous research [41] confirmed that of our work, which showed that the lemon oil was characterized by weak antibacterial action. [PERSON] et al. [42] tested the effect of 21 different essential oils on four species of Gram-negative bacteria (_E. coli_, _Klebsiella pneumoniae_, _Pseudomonas aeruginosa_, and _Proteus vulgaris_) and two species of Gram-positive bacteria (_Bacillus subtilis_ and _S. aureus_) and showed that lemon oil moderately inhibited the growth of the tested bacteria.