Abstract
Two sets of structurally different jatrophanes (
Some degenerative illnesses such as Alzheimer’s and Parkinson’s disease manifest in higher level of micronuclei (MN) as products of chromosome breakage or loss in peripheral blood lymphocytes. 1,2 The cytokinesis-block micronucleus (CBMN) assay, based on cytokinesis inhibition by cytochalasin B (Cyt-B), has facilitated MN analysis exclusively in binucleate (BN) cells that have completed their first in vitro division after treatment with the test agent or following culture initiation. 3-7 The CBMN assay in peripheral blood lymphocytes has been used to detect DNA and chromosome damage as a consequence of an autoimmune disease, 8 chronic kidney disease, 9 type 2 diabetes, 10 metabolic syndrome, 11 head and neck cancer, 12 and other illnesses, or to evaluate the presence and extent of chromosomal damage in human populations that are exposed to genotoxic agents. 13
Natural phenolic compounds from medicinal herbs and dietary plants play an important role in cancer prevention and treatment. 14 CBMN assays have shown that treatment of human lymphocytes with natural phenolic compounds, such as flavonoids, 15,16 diarylheptanoids, 17,18 or seeds extracts from grape, 19 raspberry, blackberry, and currant, 20-22 induced decrease in the frequency of micronuclei and manifested protective effect on human lymphocytes DNA, compared to the action of alkylating agent mitomycin C (MMC) (negative control) and/or amifostine WR-2721 (positive control).
Genus Euphorbia (family Euphorbiaceae) is a rich source of jatrophanes, macrocyclic diterpenoids with trans-bicyclo[10.3.0.]pentadecane structure characterized by a flexible 12-membered ring. Jatrophanes may perform different biological activities such as cytotoxic, 23 antimicrobial, 24 antiviral, 25,26 and lipid-lowering activity, 27 or may modulate overexpression of P-glucoprotein (P-gp) in order to overcome multidrug resistance to anticancer drugs. 28,29 Several jatrophanes exhibit microtubule (MT) interacting activity and induce paclitaxel-like microtubules. 30,31 Compounds that stabilize MT represent potential therapeutic approach for the treatment of Alzheimer’s disease and related tauopathies. 32
In this study 16 jatrophane diterpenoids isolated from Euphorbia dendroides 33,34 and latex extracts from E. dendroides and Euphorbia nicaeensis induced decrease in the frequency of MN and manifested protective effect on human lymphocytes DNA.
Jatrophanes
Incidence of MN, Distribution MN Per Cells, CBPI, and Frequency of MN Measurement in Cell Cultures of Human Lymphocytes Treated With Different Concentration of 1-18.
Abbreviations: CBPI, cytokinesis-block proliferation index; MMC, mitomycin C.
MN/Bn cells: incidence of micronuclei in binucleated cells.
% Bn cells with MN: binucleated cells with micronuclei.
MN/1000 Bn cells: incidence of micronuclei in 1000 binucleated cells (examined for each concentration).
Frequency of MN: incidence of MN present like % from control groups in cell cultures of human lymphocytes treated with different concentration of jatrophanes or plant extracts.
The statistical significance of difference between the data pairs was evaluated by one-way analysis of variance followed by the Tukey test. Statistical significance at P < 0.01.
aCompared with control groups, statistically significant at P < 0.01.
a*Compared with control groups, statistically significant at P < 0.05.
bCompared with amifostine WR 2721, statistically significant at P < 0.01.
b*Compared with amifostine WR 2721, statistically significant at P < 0.05.
cCompared with MMC, statistically significant at P < 0.01.
c*Compared with MMC, statistically significant difference P < 0.05.
In the course of a structure-activity relationship (SAR) study, jatrophanes were classified into 2 groups. The first group (

Structures of the tested jatrophanes isolated from Euphorbia dendroides and Euphorbia nicaeensis.
Jatrophanes
Weaker protective effect but still higher than positive control was observed when the highest dose (4 µg/mL) of
Among the tested jatrophanes of the second group the most effective was
The tested hexane extracts of lyophilized latex of E. dendroides (
Antioxidant potential of heterocyclic compounds using CBMN assay has been summarized in a review. 35 Polyphenols could reduce the incidence of single-strand breaks in double-stranded DNA, as well as radical-induced base damage. 36
MT stabilizing drugs may be utilized in treatment of neurodegenerative diseases to compensate for the loss of tau function and to maintain or restore effective axonal transport. Although a growing number of MT stabilizing natural products continue to be discovered, only a few selected compounds, such as paclitaxel and epothilone, have been characterized as potential candidates for the treatment of neurodegenerative diseases. 32
Jatrophanes isolated from Euphorbia semiperfoliata Viv. stimulated purified tubulin assembly in vitro. The rearrangement of MT was in contrast to the bundling produced by paclitaxel.
30
In another study, nontoxic jatrophane
As revealed in a previous SAR study on P-gp inhibition of 11 jatrophanes (
Compounds that stabilize MT may offer therapeutic approach for the treatment of Alzheimer’s disease and related tauopathies. So far, several jatrophanes exhibited MT interacting activity and induced paclitaxel-like MTs. On the other hand detection of DNA and chromosomal damage through the elevated level of MN using in vitro CBMN assay in peripheral blood lymphocytes may be an indication of several diseases, such as Alzheimer’s and Parkinson’s.
Therefore a set of jatrophanes (
Experimental
Subjects
Venous blood samples were withdrawn into heparinized sterile vacutainers (Becton Dickinson, Bradford, MA) from 6 healthy nonsmoking male volunteers who had not been exposed to chemicals, drugs, or other substances. A safety protocol concerning blood-borne pathogen/biohazard was taken. The volunteers consented to use their blood for the experiment. From each subject, 2 aliquots of blood, 5 mL each were obtained. The study complied with the code of ethics of the World Medical Association (Helsinki Declaration of 1964, as revised in 2002). The blood samples were obtained at the Medical Unit in accordance with current Health and Ethical regulations in Serbia, Law on Health Care (2005).
Cytokinesis-Block Micronucleus Assay
Jatrophanes
Statistical Analysis
The statistical analysis was performed using Origin software package version 7.0. The statistical significance of difference between the data pairs was evaluated by one-way analysis of variance followed by the Tukey test. Statistical difference was considered significant at P < 0.01. The index calculating is presented as the percent of change comparing different groups.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was financially supported by Ministry of Science and Education of the Republic of Serbia, (Project 172053).
