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Juglone, a naphthoquinone from walnut, exerts cytotoxic and genotoxic effects against cultured melanoma tumor cells
Author(s) -
Aithal Kiran B.,
Kumar Sunil M.R.,
Rao Nageshwar B.,
Udupa Nayanabhirama,
Rao Satish B.S.
Publication year - 2009
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2009.06.018
Subject(s) - juglone , micronucleus test , genotoxicity , apoptosis , oxidative stress , microbiology and biotechnology , cytotoxicity , population , dichlorofluorescein , biology , comet assay , dna damage , micronucleus , glutathione , mtt assay , programmed cell death , cytotoxic t cell , chemistry , biochemistry , toxicity , medicine , in vitro , dna , environmental health , organic chemistry , enzyme
This study demonstrates cytotoxic and genotoxic potential of juglone, a chief constituent of walnut, and its underlying mechanisms against melanoma cells. MTT assay and clonogenic assay were used to study cytotoxicity, micronucleus assay to assess genotoxicity, glutathione (GSH) assay and 2′,7′‐dicholorofluorescein diacetate (DCFH‐DA) assay to evaluate the oxidative stress induction. Apoptosis/necrosis induction was analysed by flow cytometry. We observed a concentration‐dependent decrease in cell survival with a corresponding increase in the lactate dehydrogenase levels. A dose‐dependent increase in the frequency of micronucleated binucleate cells indicated the potential of juglone to induce cytogenetic damage in melanoma tumor cells. Moreover, results of the micronuclei study indicated division delay in the proliferating cell population by showing decrease in the cytokinesis blocked proliferation index. Further, juglone‐induced apoptosis and necrosis could be demonstrated by oligonucleosomal ladder formation, microscopic analysis, increase in the hypodiploid fraction (sub Go peak in DNA histogram), as well as an increased percentage of AnnexinV(+)/PI(+) cells detected by flow cytometry. A significant concentration‐dependent decrease in the glutathione levels and increase in dichlorofluorescein (DCF) fluorescence after juglone treatment confirmed the ability of juglone to generate intracellular reactive oxygen species. The cytotoxic effect of juglone can be attributed to mechanisms including the induction of oxidative stress, cell membrane damage, and a clastogenic action leading to cell death by both apoptosis and necrosis.