# Anti-Breast Cancer Activity of Essential Oil:
## 3 Result
### Bioactivity of Essential Oils as Anti-Breast Cancer Agents
#### 3.4.1 Monoterpenes  
Nearly all essential oils contain monoterepenes, which have a structure of 10 carbon atoms with at least one double bond [59]. Monoterpene has been linked to breast cancer in numerous studies. The oxygenated monoterepene 1,8-cineole is a major component of the oil from _L. nobilis_ fruits and leaves. The leaves and fruits' crude ethanol fractions, including solvent extracts, show strong antiproliferative activity. However, the fruits are more potent against both breast cancer cell models (MCF7 and T47D). At the IC\({}_{50}\) value, the mechanisms of apoptosis are different when the proapoptotic efficacy of _L. nobilis_ fruits is not regulated by p53 or p21, and the component of the leaves extract substantially increased p53 level. In both extracts, apoptosis is independent of caspase-8 or Fas ligand [110]. Essential oils derived from _Zataria multifora_ were investigated using MCF-7 and MDA-MB-231 cells. It is known that the main component of these essential oils are monoterepenes. The mechanism of monoterepenes is apoptosis by inducing reactive oxygen species (ROS), mitochondrial membrane potential (MMP) disruption, DNA damage, G2 and S-phase [122]. The essential oils were also investigated in vitro using cell lines of 4T1 and TC1 and tested on white winstar mice. As compared to controls, the results showed that the tested essential oils were effective at reducing tumor weight and inhibiting 4T1 and TC1 cell growth and death. They also enhanced the secretion of TNF-, IFN-, and IL-2 while decreasing IL-4. During the treatment with _Zataria multifora_ oil, the biochemical factors of mice did not change significantly [94]. In addition, _Cymbopogon citratus_ essential oils include monoterepenes which reduce tumors, necrosis, and mitosis. Carvacrol-treated test animals did not exhibit necrosis, mitosis, or infiltration. The cumulative tumor volume was significantly reduced by carvacrol at a dose of 100 mg/kg/day BW, dropping to 0.11-0.05 cm\({}^{3}\) from 0.38-0.04 cm\({}^{3}\) in the DMBA group (_p_ 0.01). Thus, it may be concluded that carvacrol and _Cymbopogon citratus_ extracts exhibited antitumor effects on female rats having DMBA-induced breast cancer [95]. Anti-breast cancer activity was also analyzed by in vitro and in vivo for _Oliveria decumbens_ essential oils by enhancing apoptotic and immunomodulatory effects. Based on the MTT test, _Oliveria decumbens_ essential oils inhibit viability on 4T1 cancer cells without significant effects on normal cells L929 in 2D analysis, as well as the anti-proliferative effect on 4T1 spheroid (3D analysis). The results showed that _Oliveria decumbens_ essential oils induce apoptosis through ROS generation, mitochondrial membrane potential disruption, caspase-3 activations, and DNA damage. On in vivo testing, the effectiveness of _Oliveria decumbens_ essential oils were evaluated in tumor-induced 4T1 mice and cytokine to confirm the antitumor effect and development of immune response associated with Th1 expansion [38]. The monoterepene of _Pinus sylvestris_' essential oils demonstrated minimal inhibitory doses of 0.125, 0.1, 3.0, and 10.0 \(\upmu\)g/mL, against _B. subtilis_, _S. cerevisiae_, _S. aureus_, and _E. coli_, respectively. The proliferation of MCF-7 cells was decreased by 45.3% and 99.7% by the oils at 50 \(\upmu\)g/mL and 100 \(\upmu\)g/mL, respectively, and 14.36 \(\pm\) 0.28 \(\upmu\)g/mL was the inhibitory concentration of DPPH (2,2-diphenyl-1-picryhydrazyl) for radical scavenging [96]. Additionally, the essential oils from the leaves of _Erythrina corallodendron_ L. reduced the growth, migration, and invasion of breast cancer cells in a dose-dependent manner. Further research on the essential oils from leaves of _E. corallodendron_ should be performed to elucidate their potential as a clinical drug or adjuvant to treat migration and invasion of breast cancer [97]. Moreover, essential oils from the _Oxycedrus_ L. fruit showed higher efficacy against MCF-7 cells as compared to the extract derived from the leaves.