Association of Phytol with Toxic and Cytotoxic Activities in an Antitumoral Perspective: A Meta-Analysis and Systemic Review

BACKGROUND

Phytol have various pharmacological activities such as antimicrobial, cytotoxic, antitumoral, antimutagenic, anti-atherogenic, antidiabetic, lipid-lowering, antispasmodic, antiepileptic, antinociceptive, antioxidant, anti-inflammatory, anxiolytic, antidepressant and immunoadjuvant. Several studies point to an association of phytol with implications for apoptosis and necrosis at cellular levels in cancer, yet no clear conclusions were drawn.

METHOD

To clarify this, we conducted a meta-analysis of non-clinical studies of phytol and its associations with toxicity and cytotoxicity emphasizing the mechanisms of apoptosis and necrosis induction and its importance in tumor therapy. Relevant studies were systematically searched in PubMed and Web of Science. The association between phytol and cyto-/toxicity was assessed by odds ratio (ORs) and 95% confidence intervals (CI). Twentythree studies were finally included in the meta-analysis. A significant association between phytol and toxicity (OR: 1.47; 95% CI = 0.86-2.48) was found among in vivo studies and cytotoxicity (OR: 1.81; 95% CI = 1.12- 2.65, p<0.05) in in vitro and ex vivo studies. In in vitro studies, 24% of them indicate that phytol at high doses induces apoptosis by several mechanisms; while about 40% of ex vivo studies indicate that phytol induces reactive oxygen species generation. But, Phytol does not act as a direct oxidant, unlike its metabolite phytanic acid. The 24% of in vivo studies also highlighted the mechanisms for apoptosis-like including expression of Bcl2 protein or mutations in pro-apoptotic protein Bax. Of them, 8% studies show necrosis and hepatotoxicity. However, in 24% of the articles, the mechanisms of toxicity and cytotoxicity are still not well elucidated.

CONCLUSION

This study confirms that the association between phytol and cyto-/toxicity depends on the dose/concentration used in the given experimental conditions. Thus, there are still great prospects for new research aimed at the use of phytol and its metabolite as anticancer agents.

Effect of Diterpenes on Hepatic System

Complication in the hepatic system is a major concern for human being. To control and keep the hepatic system healthy, a number of measures, including drug treatments are considered. Diterpenes are essential oils having promising antioxidant and cytotoxic properties along with their genotoxic and mutagenic effects. These agents are good targets for health promotion, especially in the light of their potential organo-protectivity. We searched in the databases, PUBMED and SCIENCE DIRECT from June 2011 to June 2016 for publishing evidence on diterpenes and their effects on hepatic system. After sorting the data, activity-wise findings are discussed in this current article. The results suggest that diterpenes have hepatoprotectivity property via antioxidant and anti-inflammatory, antimicrobial, anticancer/antitumor, hypolipidemic, anti-apoptosis, autophagic, antimetastasize, anti-proliferating, anti-fibrosis as well as receptor and serum biomarkers mediated pathways. On the other hand, hepatoxic effects of diterpenes are also accounted with cytotoxicity, apoptotic cell death and downregulation of cytochrome P450 systems. A number of important diterpenes have been reported in the literatures that act on the hepatic system. Some of them exert toxic effects on the liver, especially in rodent model. Hence, more extensive researches are recommended that will highlight their mechanism of action on the liver.

Genotoxic and Mutagenic Activity of PT-31

Toxicity assessment is an important tool in drug discovery and development. PT-31 (3-(2-chloro-6-fluorobenzyl)-imidazolidine-2,4-dione) is an imidazolidine- 2,4-dione analogue of clonidine that displays a dose-dependent analgesic profile and synergism with morphine. This study investigated genotoxic and mutagenic effects of PT-31 in Swiss mice. For this, ten mice (M1:F1) per group were treated with PT-31 intraperitoneally (i.p.) at 0.5, 1.0 and 5.0 mg/kg. The dimethyl sulfoxide (0.5%) and 50 mg/kg cyclophosphamide (i.p.) were taken as negative (NC) and positive controls, respectively. The bone marrow cells were collected after 24 h, while peripheral blood after 30 min, 12 h and 24 h of the treatment for the comet assay. Micronucleus (MN) test was performed only on bone marrow cells collected after 24 h of i.p. treated animals. A hundred cells were considered for the comet assay and quantification of the index of damage and frequency of damage. Lack of genotoxicity with 0.5 mg/kg of PT-31 and DNA repair ability with 0.5 and 1.0 mg/kg doses at 12 h and 24 h in comparison to NC group was observed (P<0.05). There was an increase in MN formation by PT-31 1.0 and 5.0 mg/kg treated female and male mice, respectively. PT-31 induced genotoxic and mutagenic effects only in higher doses.