Table 2.
Essential oils bearing plants and major constituents with targeted cytotoxicity to cancer cells in in vitro studies.
| Species | Major EO Constituent(s) | Cancer Cell Lines | Noncancer Cell Lines | Major Findings and EO Concentrations | Mechanisms | Reference |
|---|---|---|---|---|---|---|
| Thymus fallax | Carvacrol, p-cymene, thymol, γ-terpinene | DLD-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 | [93] |
| Boswellia sacra | α-pinene, α-thujene, β-pinene, myrcene, boswellic acid | T47D, 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 immortalized normal cells (EO dilution IC50 1:680) | Antiproliferative | [77] |
| Amomum tsaoko | 1,8-cineole, ρ-propylbenzaldehyde, geraniol, geranial, α-terpineol, α-phellandrene, neral, β-pinene | HepG2 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 A549 | Antiproliferative | [94] |
| Lippia alba (Citral chemotype) | Geranial, neral, geraniol, trans-β-caryophyllene, 6-methyl-5-hepten-2-one, limonene, linalool | HeLa (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 | [95] |
| Boswellia sp. (1200 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 1:1100 after 24 h) and noncytotoxic to normal cells (no viable cells after EO dilution 1:400) | Antiproliferative | [96] |
| Casearia sylvestris | Bicyclogermacrene, β-caryophyllene, spathulenol, α-humulene, α-pinene | HeLa (Cc), A549 (Lc) HT-29 (CRc) | Monkey kidney (Vero) and mice macrophages | Cytotoxic 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 | [97] |
| Zanthoxylum rhoifolum Lam | ß-caryophyllene, α-humulene, α-pinene, myrcene, linalool | HeLa (Cc), A549 (Lc) HT-29 (CRc) | Monkey kidney (Vero) and mice macrophages | Cytotoxic 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 | [98] |
| Commiphora gileadensis | Sabinene, 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 cells | Antiproliferative | [99] |
| Aniba rosaeodora | Rosewood essential oil (REO), linalool | A431 (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 | [100] |
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.