Potential protective role of parsley on induced tongue carcinogenesis in albino rats

Parsley has been traditionally used as a food additive and herbal medicament. The flavonoid apigenin and its glycosides constitute the most abundant phenolic compounds found in parsley. They exhibit numerous pharmacological effects, including antioxidant, anti-inflammatory, antitoxic, and anticancer properties.

The aim of the study was to evaluate the potential chemopreventive effect of orally administered parsley extract on tongue cancer induced by 7,12-dimethylbenz[a]anthracene (DMBA) and formaldehyde in rats.

A total of 36 adult male albino rats were randomly allocated into 3 equal groups: the parsley group was administered 2 g/kg body weight parsley extract through oral gavage 3 times per week; the carcinogenesis group received a topical application of 0.5% DMBA in acetone and formaldehyde to the tongues; and the parsley-treated carcinogenesis group was administered parsley extract combined with a topical application of DMBA and formaldehyde. Additionally, a group of 5 rats served as a negative control group. After 8 weeks, the tongues of the rats were dissected and subjected to histopathological, immunohistochemical, histomorphometric, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses.

Histopathologically, the tongues from the carcinogenesis group revealed several signs of hyperplasia, dysplasia and the invasion of dysplastic cells into the underlying connective tissue. The tongues of the parsley-treated carcinogenesis group exhibited a reduction in dysplastic changes and almost regained their normal architecture, as observed in both the control and parsley groups. The immunohistochemical analysis of the area percentage of caspase-3 immunoexpression revealed a significant increase in the parsley-treated carcinogenesis group compared to the carcinogenesis group, which approached the results observed in both the control and parsley groups. The qRT-PCR results of tumor necrosis factor-alpha (TNF-α) expression displayed a significantly decreased expression in the parsley-treated carcinogenesis group as compared to the carcinogenesis group. These findings were comparable to those observed in the control and parsley groups.

In a rat model, oral administration of parsley extract has been shown to impede the initiation of several cellular carcinogenic changes in tongue tissues.