**4. Optimization of the EOs' use against BC**

Nanoemulsions (NEs) can work as an ally to reduce some problems associated with Eos such as sensibility and lability. That is what happened with the use of *Zataria multiflora* EO loaded into chitosan (CS) nanoparticles. This combination improved the proliferation inhibition rate of BC cells as well as apoptosis, generation of ROS, trigger of mitochondrial membrane permeabilization and DNA damage, with high selectivity to human cancer cells of breast adenocarcinoma MCF7, T47D, and MDA-MB-231 [98].

Another study made with CS and N,N,N-trimethyl chitosan (TMC) also increased the toxicity of another EO from *Ocimum gratissimum*, when loaded with TNC nanoparticles on MDA-MB-231 BC cell lines [99]. A similar result was found using *Cyperus articulatus* EO loaded with CS nanoparticles [100].

*Nigella sativa* L. has been used in traditional medicine for about 1400 years and it grows in countries bordering the Mediterranean Sea and India [101]. Its EO has properties such as anti-inflammatory and anticancer. *N. sativa*-EO-NE increased the apoptosis of MCF7 [102].

Mitomycin C (MTC) was solubilized in NEs of EO from ginger (EOG) and from frankincense, which was shown to increase the toxicity for MCF7 cells when compared with the use of MMC alone. EOG had the strongest apoptotic effect [103]. The same effect was seen when MTC was combined with chamomile NE oil [104].

Sandal wood EO (SEO), extracted from *Santalum* trees, was encapsulated into liposomes composed of 15% SEO, 78.5% water, 4% enzyme modified lecithin, and 2.5% polysorbate. This combination provoked DNA damage and cytotoxicity and genotoxicity against MCF7 cells [105].

## **5. EOs as an alternative for side effects reduction during BC treatment**

**63**

**7. Conclusions**

*Essential Oils' Potential in Breast Cancer Treatment: An Overview*

affordability of new medications [106]. Women suffering from BC received 5-day aroma therapy treatment using either ginger EO or a placebo. Nausea score was significantly lower after ginger EO inhalation but was not sustained for the overall treatment effect. Overall, the EO improved health-related quality of life [107]. Symptoms of urogenital atrophy (UA) are common in BC survivors [108]. The cause is due to systemic treatments as a side effect of endocrine therapies and topical estrogen is usually used to reduce the symptoms. Other alternatives are being sought and could be valid to improve life quality of the patients with BC. EO of *Cymbopogon martini* and *Pelargonium graveolens* affected the cell grown in hormone-dependent MCF7 and hormone-independent MDA-MB-231 cell lines with pronounced estrogenicity, but clinical trials are necessary to better understand these effects [109]. Reaction on the skin can happen in BC patients under radiotherapy treatment. Twenty four patients received an EO mixture with 32.5% of jojoba (*Simmondsia chinensis*), 30% *Aloe vera* (*Aloe barbadenisis*), 10% of Tamanu (*Calophyllum inophyllum*), 10% primrose *Oenothera biennis*), 5% frankincense (*Boswellia carteri*), 5% geranium (*Pelargonium graveolens*), 5% lavender (*Lavandula angustifolia*), and 2.5% helichrysum (*Helichrysum angustifolium*) this EO mixture had a similar result as a medication used for treating this side effect and therefore can be used as an alternative treatment [110].

Some EOs used in research were not able to have satisfactory in vitro anticancer effects on MCF7 as EO from *Sideritis perfoliata*, *Satureja thymbra*, *Salvia officinalis*, *Laurus nobilis*, *Pistacia palaestina* [111], *Nepeta cataria* L. [112], *Nectandra leucantha* [113], *Laurus nobilis* L, *Origanum syriacum* L, *Origanum vulgare* L, *Salvia triloba* L. [37], *Salvia officinalis* [114], grapefruit (*Citrus paradisi*), ginger (*Zingiber officinale*) [83],

*Origanum vulgare* EO, composed mostly of 4-terpineol, induced cell proliferation of MCF7, although at the concentration of 50 mg/mL opposite effect was found, but still with minor effect when compared to the result in other cancer cells [116]. *Aloysia citriodora, Boswellia sacra, Boswellia serrata, Cistus ladanifer, Citrus × aurantium, Citrus limon, Citrus sinensis, Cymbopogon citratus, Foeniculum vulgar, Illicium verum, Satureja montana, Syzygium aromaticum, Thymus capitatus, and Thymus vulgaris* presented minor effects in MCF7, T47D, and MDA-MB-231 [94]. EO of *Semenovia suffruticosa* grown in Kerman, Iran, induced cell death in MCF7, but it also had the same effect on normal cell line [117]. EO from the leaves of *Solanum macranthum* did not show anticancer properties in Hs578T [90].

This information is helpful to elucidate some effects of EOs that are used by the population. Some EOs may not have any effect for BC or can even help stimulate BC cells or have toxic action. Due to this, it is important to determinate if they are safe for common use. Furthermore, it is worth mentioning that the results show unsatisfactory effects in regard to concentrations used, which does not prevent the

Sesquiterpenes and monoterpenes are part of the main components of essential oils, some of them already being isolated and with actions described, although it is

A large number of essential oils from different plants have been described in the literature with promising in vitro effect in a variety of breast cancer cells and even

important to establish the force of the use of multiple compounds together.

use of these EOs in other researches with different outcomes.

*DOI: http://dx.doi.org/10.5772/intechopen.91781*

**6. Unsatisfactory EOs results for BC**

and *Anemopsis californica* [115].

Chemotherapy-induced nausea and emesis are one of the most common problems in BC patients and they can be inappropriately managed due to low *Essential Oils' Potential in Breast Cancer Treatment: An Overview DOI: http://dx.doi.org/10.5772/intechopen.91781*

*Essential Oils - Bioactive Compounds, New Perspectives and Applications*

MCF7, T47D and MDA-MB-231 [94].

terpinen-4-ol only had mild action [96].

**4. Optimization of the EOs' use against BC**

T47D, and MDA-MB-231 [98].

apoptosis of MCF7 [102].

genotoxicity against MCF7 cells [105].

[91]. Similar effect was obtained with EO from leaves of *Solanium spirale* Roxb containing 48.10% of diterpene alcohol (E)-Phytol [92], with EO from leaf, stem, stem bark, and root of *Uvariodendron angustifolium* with the presence of citral (a mixture of

*Litsea cubeba*, composed by 68.9% of MT citral, and *Cinnamomum zeylanicum*, mainly composed by (E)-cinnamaldehyde, also had inhibitory action on BC cells

EO from *Erigeron acris* root showed higher antiproliferative activity for MCF7 and MDA-MBA-231 than *E. annuus*, which may be due to polyacetylenic compounds, matricaria and lachnophyllum ester [95], while *Waldheimia glabra* from the Himalayan Mountains, composed mainly of ST spathulenol and thujopsene, fatty alcohol 9-tetradecenol, MT α-thujone, santolina alcohol, and MT tertiary alcohols

EO obtained from the seeds of onion *Afro styrax lepidophyllus* and garlic tree *Scorodophloeus zenkeri* are usually used as spices in Africa. It exhibited a strong inhibitory effect on MDA-MB 231. The predominant compound in both oils was the terpenoid 2,4,5,7-tetrathiaoctane [97]. EO of aerial parts, branches and leaves, of *Glandora rosmarinifolia* (Ten.) D.C. Thomas is composed mostly of aliphatic alkanes and diterpene hydrocarbons; it induces cell growth inhibition at triple negative-breast cancercell lines SUM 149 and MDA-MB-231 in part due to a pro-oxidant mechanism [5].

Nanoemulsions (NEs) can work as an ally to reduce some problems associated with Eos such as sensibility and lability. That is what happened with the use of *Zataria multiflora* EO loaded into chitosan (CS) nanoparticles. This combination improved the proliferation inhibition rate of BC cells as well as apoptosis, generation of ROS, trigger of mitochondrial membrane permeabilization and DNA damage, with high selectivity to human cancer cells of breast adenocarcinoma MCF7,

Another study made with CS and N,N,N-trimethyl chitosan (TMC) also increased the toxicity of another EO from *Ocimum gratissimum*, when loaded with TNC nanoparticles on MDA-MB-231 BC cell lines [99]. A similar result was found

*Nigella sativa* L. has been used in traditional medicine for about 1400 years and it grows in countries bordering the Mediterranean Sea and India [101]. Its EO has properties such as anti-inflammatory and anticancer. *N. sativa*-EO-NE increased the

Mitomycin C (MTC) was solubilized in NEs of EO from ginger (EOG) and from frankincense, which was shown to increase the toxicity for MCF7 cells when compared with the use of MMC alone. EOG had the strongest apoptotic effect [103]. The same effect was seen when MTC was combined with chamomile NE oil [104]. Sandal wood EO (SEO), extracted from *Santalum* trees, was encapsulated into liposomes composed of 15% SEO, 78.5% water, 4% enzyme modified lecithin, and 2.5% polysorbate. This combination provoked DNA damage and cytotoxicity and

**5. EOs as an alternative for side effects reduction during BC treatment**

Chemotherapy-induced nausea and emesis are one of the most common problems in BC patients and they can be inappropriately managed due to low

using *Cyperus articulatus* EO loaded with CS nanoparticles [100].

terpenoids) [93] and with EO from *Syzygium aromaticum*, a source of TT [4].

**62**

affordability of new medications [106]. Women suffering from BC received 5-day aroma therapy treatment using either ginger EO or a placebo. Nausea score was significantly lower after ginger EO inhalation but was not sustained for the overall treatment effect. Overall, the EO improved health-related quality of life [107].

Symptoms of urogenital atrophy (UA) are common in BC survivors [108]. The cause is due to systemic treatments as a side effect of endocrine therapies and topical estrogen is usually used to reduce the symptoms. Other alternatives are being sought and could be valid to improve life quality of the patients with BC. EO of *Cymbopogon martini* and *Pelargonium graveolens* affected the cell grown in hormone-dependent MCF7 and hormone-independent MDA-MB-231 cell lines with pronounced estrogenicity, but clinical trials are necessary to better understand these effects [109].

Reaction on the skin can happen in BC patients under radiotherapy treatment. Twenty four patients received an EO mixture with 32.5% of jojoba (*Simmondsia chinensis*), 30% *Aloe vera* (*Aloe barbadenisis*), 10% of Tamanu (*Calophyllum inophyllum*), 10% primrose *Oenothera biennis*), 5% frankincense (*Boswellia carteri*), 5% geranium (*Pelargonium graveolens*), 5% lavender (*Lavandula angustifolia*), and 2.5% helichrysum (*Helichrysum angustifolium*) this EO mixture had a similar result as a medication used for treating this side effect and therefore can be used as an alternative treatment [110].
