## 3 Results and Discussion
### Metal Content  
The presence of metals in essential oils is influenced by various factors such as plant species, climatic conditions, soil composition, age of the plant, harvesting period, and geographical origin. The primary source of these metals is the soil, which the plants absorb through their root system [101]. According to the literature, elements such as Fe, Cu, \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & & \multicolumn{3}{c}{**MIC ug/mL**} \\ \hline
**Compound** & _Escherichia coli_ & _Enterococcus faecalis_ & _Klebsiella pneumoniae_ & _Pseudomonas aeruginosa_ & _Staphylococcus aureus_ \\ \hline Lemon peel & \textgreater{}512 & \textgreater{}512 & 128 & 256 & 128 \\ Bay leaf & 64 & 256 & 32 & 128 & 16 \\ Clove & 128 & \textgreater{}512 & 256 & \textgreater{}512 & \textgreater{}512 \\ Star anise & \textgreater{}512 & 256 & 128 & \textgreater{}512 & \textgreater{}512 \\ Oregono & \textgreater{}512 & 256 & 64 & 64 & 32 \\ Nutmeg & \textgreater{}512 & 256 & 256 & \textgreater{}512 & \textgreater{}512 \\ CAZ & 0.5 & 256 & 256 & 4 & 64 \\ CIP & \textless{}0.125 & 0.5 & 256 & \textless{}125 & 0.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Antimicrobial activities of selected compounds, lemon, laurel, clove, nutmeg, anise and oregano, against Gram-positive bacteria _S aureus_ and _E. faecalis_, and Gram-negative bacteria including _E. coli_, _K,pneumoniae_ and _P. aeruginosa_. Ag, and Zn are associated with antimicrobial, antioxidant, and other beneficial biological activities [102]. The mechanism of antimicrobial action of these ions can destroy the cell walls and membranes of microbes, leading to leakage of cell contents and eventual cell death. They can also generate reactive oxygen species in microbial cells, further damaging cell structures, proteins and DNA. Antioxidant mechanisms such as antioxidants play a role in reducing oxidative stress in human cells by supporting enzymes such as superoxide dismutase that neutralize harmful free radicals. This helps to protect cellular components from oxidative damage and maintain cellular health. In summary, they support immune defense through their antimicrobial action and help control oxidative damage, which promotes overall cellular resilience [103]. Conversely, elements such as As, Cd, Pb, and Hg are known to have toxic effects, even at relatively low concentrations [11]. The general principles of chemical risk assessment came out of four steps: hazard identification, hazard characterization, exposure assessment, risk characterization, and toxicokinetic and toxicity aspects [104]. The potential health risks associated with these elements have been evaluated using the methodology proposed by the US-EPA [105]. The non-carcinogenic risk was estimated based on the target hazard quotients (THQs), calculated using the formula THQ = CDI/RfD, where CDI represents the chronic daily intake and RfD represents the chronic reference dose for each heavy metal. The RfDs are as follows: 1000 (Al), 3 (CrVI), 140 (Mn), 43 (Co), 20 (Ni), 40 (Cu), 300 (Zn), 0.304 (As), 1 (Cd), 0.571 (Hg), and 3.57 (Pb) \(\upmu\)g/kg body weight/day [10]. On the other hand, Mg and Na in these quantities and concentrations are not toxic and only have positive effects on human health. The content of metals in the essential oils is shown in Table 8.  
The RfD indicates the level of exposure at which harm is unlikely, with lower RfDs reflecting higher toxicity. The results show that elements with greater toxicity (lower RfD) typically have concentrations below 1.00 mg/kg, while elements with potential antioxidant properties, such as Cu, Zn, and Al, are found at higher concentrations (above 10 mg/kg) in the selected essential oils. Other trace elements are also present in very low concentrations in the essential oils. Several metals and their compounds are known to possess both antimicrobial and antioxidant activities [106; 107; 108].