Chemical Analysis of Essential Oils of Cymbopogon schoenanthus (L.) Spreng. and Nepeta azurea R.Br. ex Benth from Djbouti, In-Vitro Cytotoxicity against Cancer Cell Lines and Antibacterial Activities

Abstract

The aim of this research was to evaluate the essential oils of two medicinal plants from Djibouti: Cymbopogon schoenanthus (L.) Spreng. and Nepeta azurea R.Br. ex Benth. in cytotoxic activity against thirteen (13) cancer cell lines (A2780, A549, HCT116, HEK-293, JIMT-T1, K562, MIA-Paca2, MRC5, NCI-N87, PC3, RT4, U2OS and U87-MG) and antibacterial activity against seven (7) Gram (−) strains (Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella enterica sv. Typhimurium and Shigella sonnei) and five (5) Gram (+) strains (Corynebacterium sp., Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus agalactiae). The plants were extracted by hydrodistillation and were analyzed by GC-MS. The main components of Cymbopogon schoenanthus essential oil (CSEO) were 3-isopropenyl-5-methyl-1-cyclohexene (32.3%) and D-Limonene (11.3%), and the main component of Nepeta azurea essential oil (NAEO) was methyl (2E)-2-nonenoate (53.2%). The two essential oils showed inhibitory cytotoxicity activities of all the cancer cells tested; on the other hand, the antibacterial activities are only well-noticed for the CSEO oil at a concentration of 5% against Klebsiella pneumoniae, Pseudomonas aeruginosa, Corynebacterium sp., Enterococcus faecalis and Staphylococcus aureus. Our results demonstrated that the two essential oils could be effective natural anticancer agents, in addition to an antibacterial character for Cymbopogon schoenanthus essential oil.

1. Introduction

Noncommunicable diseases have a considerable impact on human health, as well as on the economy [1]. They decrease the quality of life of patients and increase the causes of premature death and lead to other harmful consequences [2]. Among these diseases is cancer, which is the second leading cause of death in the world after heart disease. Cancer is a large group of chronic diseases and can target tissues or organs in the human body [3,4]. Currently, cancer treatments are based on several methods, generally based on chemotherapy, radiotherapy, surgery and the use of active ingredients [5,6]. The latter have high costs given the stage and grade of the cancer. However, the use of traditional herbal treatments has gained attention in recent years [7].

Medicinal plants have played a transversal role in the treatment of cancer. Several authors have reported over 3000 species that possess anticancer activities [8,9,10,11,12]. The study of anticancer agents from natural sources began in the early fifties, when medicinal plants were exploited as a focal point of bioactive molecules and, at the same time, the production of new molecules similar to natural chemical compounds for cancer with different reactions in organic synthesis and sometimes by computer modeling [13,14]. The different parts of plants contain a set of low molecular weight substances called secondary metabolites such as terpenoids, phenolic compounds, flavonoids, alkaloids and other organic compounds substituted by other elements such as sulfur and phosphorus [15,16,17,18].

Djibouti is a developing country facing socioeconomic problems with infectious diseases, particularly certain types of cancerous diseases, in addition to the lack of medical technology for screening and diagnosis, which are mostly unaffordable for the population, and the execution preventive and awareness programs in marginal areas [19]. Djibouti is known for its wide variety of climatic conditions, including a tropical desert on the coast and in the north, while it becomes a semi-desert at the central heights. The Djiboutian flora is one of the few species studied in the world, and a large number of medicinal plants have been used by the local population to fight against diseases, particularly cancer [20,21,22].

The current study was conducted in the regions of Mouloud and Day in Djibouti, from where the populations of these suburbs claim that cancer has been treated using dozens of medicinal plants since antiquity. The present study therefore has to evaluate two medicinal plants: Cymbopogon schoenanthus and Nepeta azurea used in the treatment of cancer and in the treatment of other pathogenic diseases, because they have the potential to be evaluated and used in the development of pharmaceutical products useful for the future.

2. Material and Methods

2.1. Collection and Identification of Vegetable Material

The collection of plant materials took place in two different areas of Djibouti: the first plant of Cymbopogon schoenanthus was collected from the Mouloud region (south-west of Djibouti; 11°10′18.3″ N 42°30′01.4″ E), and the second plant of Nepeta azurea was collected from the Day region (north of Djibouti; 11°44′46.6″ N 42°41′03.5″ E) (Figure 1). The collection period included February and March. The two species were identified by the first author, and they are classified in an herbarium of the Medicinal Research Institute of Djibouti (CERD) with the respective access numbers CS4-2019 and NA3-2019.

2.2. Extraction of Essential Oils

Both CSEO and NAEO essential oils from Cymbopogon schoenanthus and Nepeta azurea were extracted by the Clevenger apparatus. The dried aerial parts were cut into small pieces, and 50 g of each species were immersed in 400 mL of distilled water and heated under reflux for 4 h. After dehydration of the organic phase with anhydrous sodium sulphate, the volumes of the essential oils were determined, and the viscous liquids were stored in amber glass bottles wrapped in aluminum foil at 4 °C [23]. All experiments were performed in triplicate.

The yields of NOEC and NAEO were determined by the following formula:

$$Y\left(\%\right)=\left(\frac{V}{W}\times 100\right)\pm \left(\frac{∆V}{W}\times 100\right)$$

with

V: volume of essential oil collected;

∆V: volume uncertainty;

W: weight of dry vegetable matter.

2.3. GC-MS Analyses

The identification of the chemical composition of two essential oils CSEO and NAEO was made using an apparatus of gas chromatography coupled to a mass spectrometer equipped with a flame ionization detector (FID) (Agilent Technologies 7820, Santa Clara, CA, USA). All the components and the properties of use are mentioned in Figure 2 [24].

2.4. Cytotoxicity Assay

All cancer cell lines (

Table 1. The origin, source and growth medium of 13 cancer cell lines used in the cytotoxicity test.

Cell Lines	Origin	Source	Growth Medium
A2780	Ovarian carcinoma	ECACC-93112517	Gibco RPMI 1640
A549	Lung carcinoma	ATCC®-CCL-185TM	Gibco RPMI 1640
HCT116	Colorectalcarcinoma	ATCC®-CCL-247TM	Gibco McCoy’s 5A
HEK-293	Embryonic kidney	ATCC®-CRL-1573TM	Gibco RPMI 1640
JIMT-T1	Breast carcinoma	DSMZ-ACC 589	Gibco DMEM
K562	Myelogenous leukemia	ATCC®-CCL-243TM	Gibco RPMI 1640
MIA-Paca2	Pancreas carcinoma	ATCC®-CRL-1420TM	Gibco DMEM
MRC5	Lung normal	ATCC®-CCL-171TM	Gibco DMEM
NCI-N87	Gastric carcinoma	ATCC®-CRL-5822TM	Gibco RPMI 1640
PC3	Prostate carcinoma	ATCC®-CRL-1435TM	Gibco RPMI 1640
RT4	Urinary bladder	ATCC®-HTB-2TM	Gibco McCoy’s 5A
U2OS	Bone osteosarcoma	ATCC®-HTB-96TM	Gibco McCoy’s 5A
U87-MG	Brain glioblastoma	ATCC®-HTB-14TM	Gibco DMEM

) were obtained from the American Type Culture Collection (ATCC, Rockville, MD, USA), the German Collection of Microorganisms and Cell Cultures of the Leibniz Institute (DSMZ, Braunschweig, Germany) and the European Collection of Authenticated Cell Cultures (ECACC, England). Each cell type was cultured in its appropriate medium and supplemented with 10% fetal bovine serum, 1% glutamine and 1% penicillin/streptomycin. Additionally, the cell lines were maintained at 5% CO₂. The cultures were periodically examined under an inverted microscope to assess the absence of microbial contaminants and the amount of confluence.

Both CSEO and NAEO essential oils were tested in ELISA microplates at different concentrations (10, 5, 1, 0.5, 0.1, 0.05, 0.01 and 0.005 μg/mL; solvent DMSO 5%), where 10 µL of each concentration was added to 90 µL of culture medium, which contained 3.10³ cells/wells. After the incubation of microplates for 72 h, 100 μL of CellTiter Glo Reagent was added to each well for 15 min before recording the luminescence with a spectrophotometric plate reader. The dose–response curves were plotted with Excel software, and the 50% inhibition concentration values (IC₅₀) were determined from the polynomial trend curves [25].

2.5. Antibacterial Activity

The antibacterial activity was studied according to the effect of the essential oils against Gram-negative and Gram-positive bacteria (

Table 2. The strains used during the antibacterial test.

Gram Negative		Gram Positive
Strains	Code/Source	Strains	Code/Source
Acinetobacter baumannii Enterobacter cloacae Escherichia coli Klebsiella pneumoniae Pseudomonas aeruginosa Salmonella enterica Shigella sonnei	ATCC 19606 Clinical isolate ATCC 25922 ATCC 700603 ATCC 27853 ATCC 13311 ATCC 9290	Corynebacterium sp. Enterococcus faecalis Staphylococcus aureus Staphylococcus epidermidis Streptococcus agalactiae	Clinical isolate ATCC 29212 ATCC 29213 Clinical isolate ATCC 27956

) by determining the diameters of inhibition using the agar well diffusion test [26]. This method is widely used for the evaluation of the antibacterial activity of essential oils. In this manipulation, the surfaces of the petri dishes were inoculated by spreading 100 μL of the bacterial suspension over the entire surface of the Mueller-Hinton Medium agar. Then, four perforations were made (diameter: 6 mm; depth: 5 mm), one for the negative control (dimethylsulfoxide DMSO 5%), one for the positive control (commercial antibiotics + DMSO 5%), one for CSEO and the last for NAEO. It is noted that the two essential oils were tested at a concentration of 5% in DMSO, and three repetitions were made per test and for each strain. The antibacterial activity was evaluated according to the zone of inhibition visualized after incubation of the petri dishes for 24 h at 37 °C.

3. Statistical Analysis

The data from all tests were statistically evaluated using XLSTAT software. The values were presented as the mean ± uncertainty at 95% of the three replicates of each experiment using Student’s Law.

4. Results

After the harvesting of the medicinal plants C. schoenanthus and N. azurea, the subject of this research in the two regions of Djibouti, extractions by hydrodistillation using a Clevenger apparatus, was carried out to obtain, respectively, the two essential oils CSEO and NAEO. The yields of these two essential oils obtained were, respectively, 1.16% and 1.25% (

Table 3. Yields of both essential oils.

Essential Oil	Yield (%)
CSEO	1.16 ± 0.22
NAEO	1.25 ± 0.25

).

The chemical compositions of the CSEO and NAEO were determined by gas chromatography (GC) coupled with a flame ionization detector (FID); all the data found are mentioned in

Table 4. Chemical compositions of CSEO and NAEO.

Pic	RT (*)	Compounds	CSEO	NAEO
1	6.35	3-Isopropenyl-5-methyl-1-cyclohexene	32.3	-
2	6.51	α-Phellandrene	0.2	-
3	7	β-Phellandrene	0.5	-
4	7.1	D-Limonene	11.3	-
5	7.3	β-trans-Ocimene	1.7	-
6	7.54	Ocimene	1.1	-
7	8.15	4-Nonanone	2.1	-
8	8.49	L-Fenchone	0.5	-
9	8.75	Linalol	-	0.4
10	9.24	2-p-Menthen-1-ol	5.1	-
11	9.49	cis-p-menth-2-en-1-ol	0.2	-
12	9.6	Terpineol, cis-.beta.-	3.5	-
13	10.21	Cyclohexene, 3-acetoxy-4-(1-hydroxy-1-methylethyl)-1-methyl-	0.8	-
14	10.39	Anethofuran	0.7	-
15	10.58	α-Terpineol	8.5	-
16	10.7	α-Phellandren-8-ol	0.7	-
17	10.823	cis-Piperitol	2.1	-
18	10.9	trans-Piperitol	1.4	-
19	11.09	gamma.-Isogeraniol	0.6	-
20	11.22	cis-Geraniol	0.4	-
21	11.55	piperitone	-	1.7
22	11.85	4-Undecanone	0.3	-
23	11.95	2-Caren-10-al	0.3	-
24	12.13	2-Undecanone	-	0.8
25	12.14	Cyclohexene, 2-ethenyl-1,3,3-trimethyl-	0.2	-
26	12.27	1-Tetradecyne	0.3	0.8
27	12.34	2-Acetoxy-1,8-cineole	0.4	-
28	12.56	Boschnialactone	-	3.6
29	12.87	Isogeraniol	-	1.7
30	12.95	Neryl acetate	0.5	-
31	13.07	Geraniol acetate	3.7	-
32	13.31	Limonene oxide	-	1
33	13.43	β-Bourbonene	-	0.6
34	13.5	Elemene	0.8	0.5
35	13.68	1-Methyl-2-decalone	-	6.1
36	13.81	Oplopanone	-	1.8
37	13.93	Cis-caryophyllene	0.8	5.7
38	13.99	Cyclohexanol, acetate	-	5
39	14.09	α-Bergamotene	0.2	-
40	14.57	Inknown	-	0.9
41	14.63	4-Dodecanone, 11-methyl-	0.3	-
42	14.74	Phellandral	-	8.6
43	14.74	Germacrene D	0.3	-
44	14.86	β-eudesmene	0.2	-
45	14.94	Methyl (2E)-2-nonenoate	0.2	53.2
46	15.15	τ-cadinene	0.3	-
47	15.2	δ-cadinene	0.6	-
48	15.25	L-calamenene	-	2
49	15.59	β- elemol	7.8	-
50	16.03	Caryophyllene oxide	1.2	2.8
51	16.31	Cis-carveol	0.2	-
52	16.41	Cubenol	-	1.5
53	16.52	Eudesm-7(11)-en-4-ol	1.4	-
54	16.61	γ-eudesmol	0.7	-
55	16.72	τ-cadinol	0.6	-
56	16.89	10-epi-β-eudesmol	3	-
57	16.97	Viridiflorol	0.7	1.3
58	17.18	Trans-2-Hydroxy-1,8-cineole	0.2	-
59	17.49	Eudesma-4,11-dien-2-ol	0.3	-
60	17.68	longipinocarveol	0.3	-
61	18.69	Eudesm-5-en-11-ol	0.4	-
Total (%)			99.9	99.1

(*) RT: Retention time.

. The analyses made allowed us to identify 47 compounds for CSEO with a total percentage of 99.9%; among them, two (2) major compounds were visualized: 3-isopropenyl-5-methyl-1-cyclohexene (32.3%) and D-limonene (11.3%) and seven (7) compounds with moderate concentrations between 2% and 8%, such as: β-elemol (7.8%), 2-p-menthen-1-ol (5.1%), geraniol acetate (3.7%), terpineol, cis-beta.- (3.5%), 10-epi-β-eudesmol (3.0%), 4-Nonanone (2.1%) and cis-piperitol (2.1%). In addition, the NAEO analysis identified 20 compounds with a percentage of 100%, hence a single major compound, methyl (2E)-2-nonenoate (53.2%), and seven (7) compounds with concentrations moderate between 2% and 9%, such as: phellandral (8.6%), 1-methyl-2-decalone (6.1%), cis-caryophyllene (5.7%), cyclohexanol acetate (5.0%), boschnialactone (3.6%), caryophyllene oxide (2.8%) and L-calamenene (2.0%). The two oils have compounds in common with different concentrations; we noted: 1-tetradecyne, elemene, cis-caryophyllene, methyl (2E)-2-nonenoate, caryophyllene oxide and viridiflorol.

The results of the in vitro cytotoxicity test against the thirteen (13) cancer cell lines (A2780, A549, HCT116, HEK-293, JIMT-T1, K562, MIA-Paca2, MRC5, NCI-N87, PC3, RT4, U2OS and U87-MG) are expressed by the 50% inhibition concentrations (IC₅₀) in

Table 5. IC₅₀ (µg/mL) values for the evaluation of CSEO and NAEO in the cytotoxicity test against the cancer lines.

Cell Line	CSEO	NAEO	Vinblastine	Doxorubicie	Combrestatin A4	MMAE (*)
A2780	0.14 ± 0.03	0.62 ± 0.09	-	-	-	0.45 ± 0.01
A549	0.49 ± 0.23	0.07 ± 0.01	-	56.60 ± 0.84	20.00 ± 0.10	0.46 ± 0.05
HCT116	0.65 ± 0.03	0.11 ± 0.01	35.00 ± 0.84	-	2.00 ± 0.10	2.07 ± 0.02
HEK293	0.19 ± 0.05	0.83 ± 0.11	-	-	-	-
JIMT-T1	1.50 ± 0.30	2.07 ± 0.20	-	-	-	-
K562	0.99 ± 0.01	1.00 ± 0.01	20.00 ± 0.12	-	5.00 ± 0.30	3.12 ± 0.20
MIA-Paca2	0.55 ± 0.02	0.86 ± 0.01	-	-	-	4.36 ± 0.20
MRC-5	0.83 ± 0.09	0.09 ± 0.01	-	39.88 ± 1.22	-	-
NCI-N87	3.26 ± 1.52	0.90 ± 0.27	-	-	-	1.65 ± 0.07
PC3	0.29 ± 0.01	0.80 ± 0.07	-	2.09 ± 0.03		0.36 ± 0.03
RT4	4.75 ± 1.24	0.53 ± 0.01	-	36.29 ± 1.20	-	0.50 ± 0.01
U2OS	0.24 ± 0.02	0.67± 0.05	-	-	-	-
U87-MG	0.59 ± 0.09	1.13 ± 0.22	2.00 ± 0.04	99.61 ± 2.34	9.00 ± 0.50	0.21 ± 0.03

(*) MMAE: Monomethyl Auristatin E.

. After reading the values obtained and comparing them with positive standards such as: Vinblastine, Doxorubicie, Combrestatin A4 and Monomethyl Auristatin E, the two essential oils have interesting activities against all the cell lines tested, and in many cases, were more effective than the standards tested.

The additional antibacterial activity in this work against twelve (12) bacterial strains of two oils: CSEO and NAEO are mentioned in

Table 6. Antibacterial activity of the CSEO and NAEO.

Gram	Bacterial Strain	CSEO (*)	NAEO (*)
Gram +	Corynebacterium sp.	+	-
	Enterococcus faecalis	-	-
	Staphylococcus aureus	+	-
	Staphylococcus epidermidis	-	-
	Streptococcus agalactiae	-	-
Gram −	Acinetobacter baumannii	-	-
	Enterobacter cloacae	-	-
	Escherichia coli	-	-
	Klebsiella pneumoniae	+	-
	Pseudomonas aeruginosa	+	-
	Salmonella enterica sv. Typhimurium	-	-
	Shigella sonnei	-	-

(*) Both essential oils tested at 5%. (+) Activity. (-) No activity

. The data set obtained did not give good results. All bacteria were resistant to NAEO at a concentration of 5%; however, CSEO showed activity against only four (4) bacteria: Corynebacterium sp., Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa.

5. Discussion

To reduce the risk of chronic diseases with regards to the research of treatments based on medicinal plants, essential oils have been explored in recent decades as a natural and safe alternative [27]. In addition to being more expensive, the available treatments also have side effects. The in vitro biological activities of several essential oils in diverse applications have been well-documented by various researchers, particularly anticancer and antimicrobial tests [28,29,30].

A number of plant species, including C. schoenanthus and N. azurea, are traditionally used for the treatment of various diseases in Djibouti. In this context, the objective of this study was to evaluate the two essential oils of these two plants using two different in vitro tests: the first concerns the cytotoxicity test of the cancerous cell lines, and the second test targets the antibacterial activities against clinical strains.

The chemical compounds identified in the two essential oils CSEO and NAEO are totally different compared to other previous studies made (

Table 7. Investigation on the chemical compositions of CSEO and NAEO.

Essential Oils	Investigator	Place	Major Constituents
CSEO	Shahi and Tava (1993) [31]	Jaisalmer (India)	Limonene (19.54%) and 2-undecanone (14.68%)
	Ketoh et al. (2005) [32]	Kozah (Togo)	Piperitone (61.01%) and Carene-2 (23.4%)
	Katiki et al. (2012) [33]	Sao Paulo (Brazil)	Geraniol (59.42%) and Geranial (13.49%)
	Watheq Malti et al. (2020) [34]	Bechar–Ghardaia (Algeria)	Cis-p-menth-2-en-1-ol (22.6-28.5%), trans-p-menth-2-en-1-ol (15.4–16.3%)
	Sawadogo et al. (2022) [35]	Ouagadougou (Burkina Faso)	Piperitone (59.8%) and 2-carene (16.4%)
NAEO	Simiyu (2004) [36]	Central (Kenya)	nepetalactone (14.67%) and β-cubebene (10.52%)

) [31,32,33,34,35,36]. Several molecules are determined as major compounds in CSEO, particularly piperitone, which presented percentages of 61.01% and 59.80% in the CSEO of African countries such as Togo and Burkina Faso, respectively [32,35]; on the other hand, our study presented 3-isopropenyl-5-methyl-1-cyclohexene (32.3%) and D-limonene (11.3%) as major compounds. Moreover, limonene has been listed as one of the major compounds of CSEO from India, with a percentage of 19.54% [31]. Subsequently, only one search was found on NAEO in Kenya, from where the composition of this oil gave two major compounds, such as: nepetalactone (14.67%) and β-cubebene (10.52%) [36], which are different from our study, which gave methyl (2E)-2-nonenoate (53.2%). These differences in the chemotypes observed in all these studies are due to several factors, among them the meteorological parameters and soil type [37].

In vitro tests against the cancer cell lines of two essential oils: CSEO and NAEO gave promising results, which confirms the traditional use of two medicinal plants Cymbopogon schoenanthus and Nepeta azurea in Djiboutian herbal medicine. The antitumor properties of essential oils from different species of Cymbopogon spp. and Nepeta spp. have been the subject of a large number of publications, which have been confirmed by in vitro studies, including Cymbopogon nardus, Cymbopogon flexuosus, Cymbopogon citratus, Nepeta schiraziana, Nepeta sibirica, Nepeta rtanjensis, Nepeta curviflora and Nepeta curvidens (

Table 8. Investigation of the anticancer activity of some essential oils of Cymbopogon and Nepeta species.

Essential Oil of Plant	Cancer Cell Lines Tested	Reference
Cymbopogon nardus	Oral (KB) and blood (P388)	Manosroi et al. (2006) [38]
Cymbopogon flexuosus	Colon (HT-29, HCT-15, SW-620, 502713), lung (A549, HOP-62, H-226), cervix (SiHa), oral (KB), prostate (DU-145) and promyelocytic leukemia (HL-60)	Sharma et al. (2009) [39]
Cymbopogon citratus	Head and neck (HTB43)	Yen et al. (2016) [40]
Cymbopogon nardus	Breast (MCF-7), Cervic (HeLa) and myelogenous leukemia (K562).	Sujatha et al. (2019) [41]
Cymbopogon citratus	Kidneys (VERO) and Cervic (SiHa)	Pan et al. (2022) [42]
Nepeta schiraziana	Liver tissue (Hep-G2) and breast (MCF-7).	Sharifi-rad et al. (2017) [43]
Nepeta sibirica	Stomach (HL60, Kato III)	Tsuruoka et al. (2012) [44]
Nepeta rtanjensis	Cervic (HeLa), myelogenous leukemia (K562), Lung (A549), colon (LS-174) and breast (MDA-MB-231).	Skorić et al. (2017) [45]
Nepeta curviflora	Cervic (HeLa)	Jaradat et al. (2020) [46]
Nepeta curvidens	Lung (A549), oral (KB) and prostate (C450).	Ashrafi et al. (2020) [47]

) [38,39,40,41,42,43,44,45,46,47]. The cytotoxic actions of essential oils against tumor cell lines depend on different types of cancer. Several molecules are endowed with antitumor properties, particularly phenols, alcohols and aldehydes [48]. It is generally the essential oils rich in such molecules that exhibit the greatest cytotoxic efficacy against cancer cell lines. Several mechanisms have been proposed to explain the reactions involved. Generally, two hypotheses are confirmed for the actions of these compounds by several authors, such as: the power to activate apoptosis in tumor cells and the power to disrupt the mitochondrial membrane potential [49,50].

Finally, the in vitro antibacterial tests of the two essential oils did not show any activity, except the CSEO, which has an activity against the four bacterial strains Corynebacterium sp., Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. These results have been proven by several authors who confirmed the absence of antimicrobial activities of species of the genera Cymbopogon spp. and Nepeta spp. [51,52].

6. Conclusions

Essential oils obtained from Cymbopogon schoenanthus and Nepeta azurea can be used in the medical field as a natural alternative to replace or reduce the use of synthetic drugs, as they exhibit significant anticancer properties alone and/or in pharmaceutical formulations. These essential oils have shown promising results against dozens of cancer cell lines, as well as Cymbopogon schoenanthus essential oil showing antibacterial activity against some clinical strains. The results of the reported studies can be considered as the basis for further in vivo studies.