Evaluatıon Of The Effects Of Hyperıcum Perforatum Extract On 7,12-Dımethylbenzanthracene-Induced Experımental Oral Cancer Model


Thesis Type: Doctorate

Institution Of The Thesis: Gazi University, Sağlık Bilimleri Enstitüsü, AĞIZ, DİŞ VE ÇENE CERRAHİSİ ANABİLİM DALI, Turkey

Approval Date: 2019

Thesis Language: Turkish

Student: DİLARA NUR ÖZTÜRK

Supervisor: İnci Rana Karaca

Abstract:

Oral cancers may emerge from anywhere in the oral cavity and unless diagnosed at an early stage

and treatment is initiated immediately they demonstrate high mortality rates. Nearly 90% of all oral

cancers are oral squamous cell carcinomas. Today, there are many ongoing studies in order to find

alterative curative agents against cancer. There are many studies investigating the chemopreventive

properties of various plants, plant extracts and plant-deried chemicals, especially in developing

countries. H. perforatum is known to have many beneficial properties for the organism and has

been used for traditional medicine in various cultures. The purpose of this study was to investigate

the chemopreventive properties of H. perforatum on 7,12-dimethylbenz(a)anthracene-induced rat

oral squamous cell carcinoma model and the plant’s effects on the antioxidant defence

mechanisms. In the study, the in vitro antioxidant efficacy, radical scavenging activity and phenolic

compound content of H. perforatum was determined and an extract was prepared to be used in the

in vivo part of the study. In the in vivo study protocol, 30 Wistar male rats were divided randamly

into 4 groups as 6 in the control and 8 in each of the other groups (Group 1: control, Group 2:

DMBA group, Group 3: HP+DMBA group, Group 4: HP group). The antioxidant defence

mechanisms in tissue and blood samples were evaluated biochemcally and

immunohistochemically, the cancerous changes in connective tissue were investigated

immunohistochemically and epithelial changes in the tissue samples were evaluated

histopathologically. The extract revealed an inhibitory effect on some antioxidant enzymes

especially when it is applied together with the carcinogen. Immunohistochemical evaluations

revealed no invasive changes in the connective tissue. According to the histopathological resuts, H.

perforatum showed chemoprevetive effects although it did not prevent carcinomatous changes in

the epithelium to 100%. The results of this study shows that H. perforatum is a promising

chemopreventive agent and furthes studies without the limitations of this one and dose

determination studies may be able to evaluate the full potential of this plant.

Key Words : H y p ericum perforatum, antioxidant, oral cancer, oral squamous cell

carcinoma