# Lemongrass Essential Oil Components with Antimicrobial and Anticancer Activities
## 3 LEO Therapeutics
### Anticancer Activity
Geraniol has been reported to induce the expression of pro-apoptotic proteins Bcl-2, Bax, Bak, and caspase3/8/9 in several human cancer cell lines [128; 133]. Moreover, the considerable increase in these proteins indicates that geraniol induces apoptosis through the mitochondrial intrinsic pathway [134]. The antiangiogenic activity of geraniol has been confirmed by both in-vivo and in-vitro studies. Geraniol suppresses the endothelin cell line and reduces Ki67-positive cells and CD3-microvesela by suppressing the expression of VEGFR-2 in Balb/c mice [135]. This activity might play a role in reducing tumour growth, as the tumour needs a new blood vessel to grow. Geraniol arrested the proliferation of two pancreatic cancer cell lines, MIA PaCa-2 and BxPC, in hamsters when injected with PC-1 pancreatic ductal adenocarcinoma cells. In both the cell lines, it arrested the G1 phase of the cell cycle along with increasing the expression of the cyclin kinase inhibitor proteins p21 cip1 and p27 kip1 while suppressing those of cyclin A, B1, and CDK2 [136; 137]. Figure 4 indicates a series of distinctive signalling pathways activated in cancer cells via different components of LEO. D-limonene, another constituent of LEO, was also reported to possess antineoplastic activity. D-limonene enhances the activity of carcinogen metabolizing enzymes, such as cytochrome P450, responsible for the conversion of carcinogens into less harmful forms and blocks their interaction with DNA [138]. Treatment of D-limonene on LS174T human colon cancer cells inhibited the P13K/Akt pathway and induced cell apoptosis. An increase in PARP cleavage and activation of caspase-3 indicates the involvement of the mitochondrial apoptotic pathway [139]. Limonene-mediated induction of apoptosis via increased expression of Bax and caspase-3 and decreased Bcl-2 expression has been reported in T24 bladder cancer cells. Moreover, limonene arrested the cell cycle in the G2/M phase and wound healing and transwell assay using Matrigel has confirmed the limonene mediated suppression of cancer cell migration and invasion [140]. Another component of the EO of lemongrass, citronellol, is also found to exert cytotoxic effects on several cancer cell lines [141; 142; 143]. Citronellol showed its anticancer activity via increased reactive oxygen species production, alterations in mitochondrial permeability, DNA fragmentation, changes in cytochrome c activities, and activation of caspase, against the MCF-7 human mammary tumour cell line [144]. The cytotoxicity of \(\alpha\)-bisabolol has been reported against human and rat malignant glioma cancer cell lines. In \(\alpha\)-bisabolol-treated cell lines, the rapid loss of inner transmembrane potential and an increase in cytochrome-c translocation indicate that \(\alpha\)-bisabolol can trigger apoptosis through mitochondrial intrinsic pathway [145]. Another experimental study has confirmed the cytotoxic effect of \(\alpha\)-bisabolol against several cancer cell lines. \(\alpha\)-bisabolol arrested cell cycle and initiated cancer cell death via a BID (BH3-only  
Figure 4: Distinctive signalling pathways activated in cancer cells via different components of LEO. Every component acts differently against cancer cells and involves diverse signalling pathways. All the involved pathways lead to inhibition of cell migration, cell cycle, and DNA synthesis. All these events eventually cause cell death (apoptosis).