Table 1: Essential oils bearing plants and main constituents with targeted cancer cell cytotoxicity in in vitro studies.

SpeciesMajor EO constituent(s)Cancer cell linesNoncancer cell linesMajor findings and EO concentrationsMechanismsREF

Thymus fallaxCarvacrol, p-cymene, thymol and γ-terpineneDLD-1 (CRc)Mouse fibroblast (L.929)Cytotoxic to cancer cells (IC50 0.347 mg/mL) and noncytotoxic to normal cells (IC50 22 mg/mL)Antioxidant activity[13]

Boswellia sacraα-pinene, α-thujene, β-pinene, myrcene and boswellic acidT47D, MCF7, MDA-MB-231 (Bc)Immortalized normal human breast (MCF10-2A)Cytotoxic to cancer cells (EO dilution IC50 1 : 900 for TD47, 1 : 1000 for MCF7, 1 : 950 for MDA-MB-231) and noncytotoxic to immortalised normal cells (EO dilution IC50 1 : 680)Antiproliferative[14]

Amomum tsaoko1,8-cineole, ρ-propylbenzaldehyde, geraniol, geranial, α-terpineol, α-phellandrene, neral and β-pineneHepG2 and Bel-7402 (Lc) HeLa
(Cc), A549 (Lc), SGC-7901 (GAC), PC-3 (Pc)
Hepatocyte (HL-7702) and umbilical vein endothelial (HUVEC)Cytotoxic to cancer cells, particularly HepG2 (IC50 31.8 μg/mL), Hela (IC50 66.46 μg/mL) and Bel-7402 (IC50 96.08 μg/mL), with less cytotoxicity towards HL-7702 (IC50 272.4 μg/mL) and HUVEC (IC50 163.91 μg/mL). No cytotoxicity towards A549Antiproliferative[15]

Lippia alba (Citral chemotype)Geranial, neral, geraniol, trans-β-caryophyllene, 6-methyl-5-hepten-2-one, limonene, linaloolHeLa (Cc)African green monkey kidney (Vero)Cytotoxic to cancer cells (CC50 3.5 μg/mL) and noncytotoxic to normal cells (CC50 > 100 μg/mL)Citral-dependent cytotoxicity[16]

Boswellia sp. (1,200 mg/ml frankincense gum resin)Duva-3,9,13-trien-1,5alpha-diol-1-acetate, octyl acetate, o-methyl anisole, naphthalene decahydro-1,1,4a-trimethyl-6-methylene-5-(3-methyl-2-pentenyl), thunbergol (Mikhaeil et al., 2003)J82 (Blc)Human urothelium (UROtsa)Cytotoxic to cancer cells (no viable cells after EO dilution 1 : 1,100 after 24 hours) and noncytotoxic to normal cells (no viable cells after EO dilution 1 : 400)Antiproliferative[17]

Casearia sylvestrisBicyclogermacrene, β-caryophyllene, spathulenol, α-humulene, α-pineneHeLa (Cc), A549 (Lc) HT-29 (CRc)Monkey kidney (Vero) and mice macrophagesCytotoxic to HeLa (CD50 63.3 µg·ml−1), A549 (CD50 60.7 µg·ml−1) and HT-29 (CD50 90.6 µg·ml−1) with less cytotoxicity to Vero (CD50 210.1 µg·ml−1) and macrophages (CD50 234.0 µg·ml−1)Cytotoxicity[18]

Zanthoxylum rhoifolum Lamß-caryophyllene, α-humulene, α-pinene, myrcene and linaloolHeLa (Cc), A549 (Lc) HT-29 (CRc)Monkey kidney (Vero) and mice macrophagesCytotoxic to HeLa (CD50 90.7 µg/ml), A549 (CD50 82.3 µg/ml), and HT-29 (CD50 113.6 µg/ml) and noncytotoxic to normal cells (CD50 > 600 µg/ml)Cytotoxicity[19]

Commiphora gileadensisSabinene, ß-caryophyllene, germacrene D, α-pinene BS-241 (Mouse T-cell lymphoma)
MoFir
(Epstein Barr virus transformed human B lymphocytes)
Normal human skin fibroblasts (FB)EO dilution of 1 : 5000 killed 87% of BS-24-1 cells and 40% of MoFir cellsAntiproliferative[20]

Aniba rosaeodoraRosewood essential oil (REO), linaloolA431 (Ec), HaCaT (pre-cancerous)Epidermal keratinocytes (HEK001, NHEK)Cytotoxicity to cancer cells A431 and HaCaT (<20% viability) and minor cytotoxicity to normal cells HEK001 and NHEK (>70% viability)Cytotoxicity[21]

Note. Cytotoxicity is expressed as the concentration of the essential oils inhibiting cell growth by 50%; CRc: colorectal cancer; Bc: breast cancer; Lc: lung cancer; Cc: Cervical cancer; GAC: gastric adenocarcinoma; Pc: prostate cancer; BLc: bladder carcinoma; Ec: epidermoid carcinoma; IC50: inhibitor concentration 50; CC50: cytotoxic concentration.