Inhibition of 4-Nitroquinoline-1-Oxide-Induced Oral Carcinogenesis by Plant Products.

Abstract

SummaryThe modifying effects of naturally occurring plant products such as neem leaf and turmeric extracts on 4-nitroquinoline-l-oxide (4NQO)-induced oral carcinoma were investigated in male Wistar strain rats. All the animals painted with 4NQ0 on their cheek mucosa for 20 weeks developed oral neoplasms identified histologically as squamous cell carcinoma. The oral tumor tissue showed a decrease in lipid peroxidation with concomitant changes in antioxidant activity. In groups of animals painted with 4NQ0 and simultaneous oral administration of neem leaf and turmeric extract, respectively, no tumors were observed; and the lipid peroxidation and antioxidant levels showed a pattern similar to that of untreated controls. Thus, the anticarcinogenic effect of neem leaf and turmeric extract appears to be related to their antioxidant function.We envisage that measurement of lipid peroxidation and antioxidant status with histological changes could be used to biomonitor tumor progression and evaluate the therapeutic response.

Biomonitoring the Chemopreventive Potential of the Plant Products Neem and Turmeric in 4-Nitroquinoline 1-Oxide-Induced Oral Carcinogenesis.

“…In contrast to the diminished lipid peroxidation in oral tumor tissue reported by us previously [4], lipid peroxidation was found to be enhanced in liver, plasma, and erythrocytes of rats bearing the oral tumors. Thus, the tumor and host tissue appear to comprise two separate metabolic compartments.…”

“…accompanied by changes in lipid peroxidation and antioxidants in the oral mucosa [4]. This prompted us to examine whether the chemopreventive potential of these plant products is mediated by modulation of antioxidant defense mechanisms in the host tissues of the tumor-bearing animals.…”

Medicinal Properties of Neem Leaves: A Review

“…Yadav and Rathore [62] observed inhibition of mitotic activity by neem leaf extract. Studies from this laboratory have demonstrated the chemopreventive potential of neem leaf extracts on MNNG-induced forestomach tumours and 4-nitroquinoline 1-oxide induced oral carcinogenesis [63][64][65][66][67][68]. Aqueous as well as alcoholic extracts of neem leaf effectively suppressed DMBA-induced HBP carcinogenesis by modulating the cellular redox status as well as carcinogen-metabolizing enzymes in the target organ, as well as in host liver and blood [61,[69][70][71].…”

Chemoprotective Effects of Neem Leaf Extract on 7,12-Dimethylbenz(a)anthracene (DMBA)-Induced Hamster Buccal Pouch Carcinogenesis.

“…The anti-mutagenic and anti-carcinogenic properties of neem preparations have been documented [3][4][5]. In a previous report from this laboratory, we demonstrated the inhibition of 4-nitroquinoline 1-oxide (4NQ0)-induced oral carcinogenesis by neem leaf extract [6].Hamster buccal pouch carcinogenesis induced by 7,12-dimethylbenz [ a ] an- …”