The chemopreventive activity of apple against carcinogenesis: antioxidant activity and cell cycle control.

Apples and their derivatives are rich in phytochemicals, including flavonoids (catechins, flavonols, quercetin) and phenolic acids (quercetin glycosides, catechin, epicatechin, procyanidins), vitamins, and fibers, that confer an important antioxidant property. Chemoprevention is defined by the use of natural or synthetic agents to interfere with the progression, reverse, or inhibit carcinogenesis, thereby reducing the risk of developing clinically invasive disease. The aim of this article is to present data generated from the use of apples as a chemopreventive agent in carcinogenesis using in-vivo and in-vitro test systems. Apple and its bioactive compounds can exert chemopreventive properties as a result of antioxidant activity and cell cycle control. However, future focus of research on apple such as identifying the specific phytochemical responsible for the anticarcinogenic effect, timing of consumption, and adequate amount of apples to achieve the best preventive effect using human large randomized-controlled trials is needed. Furthermore, animal studies are also relevant for better understanding the role of this fruit in human health as well as modulation of degenerative diseases such as cancer. Therefore, this area warrants further investigation as a new way of thinking, which would apply not only to apples but also to other fruit used as promising therapeutic agents against human diseases.

Polyphenols as a chemopreventive agent in oral carcinogenesis: putative mechanisms of action using in-vitro and in-vivo test systems.

Polyphenols are present in foods and beverages, being related to sensorial qualities such as color, bitterness, and astringency, which are relevant in products such as wine, tea, and grape juice. These compounds occur naturally in forms varying from simple phenolic acids to complex polymerized tannins. Oral cancer is the most common head and neck cancer, and it often has a poor prognosis owing to local tumor invasion and frequent lymph node metastasis. Nowadays, chemoprevention is considered as a promising approach for controlling cancer as a result of specific natural products or synthetic agents able to suppress, reverse, or even prevent premalignancy before transformation into invasive cancer. The use of polyphenols as a chemopreventive agent is a suitable tool for modulation of the oral carcinogenesis process. The aim of this article is to present data generated from the use of polyphenols as a chemopreventive agent in oral carcinogenesis using in-vivo and in-vitro test systems. These results have shown that polyphenols are able to exert some chemopreventive action as a result of inducing cellular death, apoptosis, inhibition of tumor growth, and antioxidative properties. Therefore, this area warrants further investigation as a new approach that would apply not only to polyphenols but also to other phytochemicals used as promising therapeutic agents against oral human diseases, especially cancer.