Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds consisting of two or more fused aromatic rings. Most of them are formed during incomplete combustion of organic materials such as wood and fossil fuels, petroleum products, and coal. The composition of PAH mixtures varies with the source and is also affected by selective weathering effects in the environment. PAHs are ubiquitous pollutants frequently found in a variety of environments such as fresh water and marine sediments, the atmosphere, and ice. Due to their widespread distribution, the environmental pollution due to PAHs has aroused global concern. Many PAHs and their epoxides are highly toxic, mutagenic and/or carcinogenic to microorganisms as well as to higher forms of life including humans. The main aim of this review is to provide contemporary information on PAH sources, route of exposure, worldwide emission rate, and adverse effects on humans, especially with reference to cancer.

Colon cancer is considered as the precarious forms of cancer in many developed countries, with few to no symptoms; the tumor is often diagnosed in the later stages of cancer. Monoterpenes are a major part of plant essential oils found largely in fruits, vegetables and herbs. The cellular and molecular activities show therapeutic progression that may reduce the risk of developing cancer by modulating the factors responsible for colon carcinogenesis. Colon cancer was induced with DMH with a dose of (20 mg/Kg/body weight) for 15 weeks by subcutaneous injection once in a week. Myrtenal treatment was started with (230 mg/Kg/body weight) by intragastric administration, one week prior to DMH induction and continued till the experimental period of 30 weeks. The Invivo results exhibit the elevated antioxidant and lipid peroxidation levels in DMH treated animals. The Histopathological analysis of colon tissues well supported the biochemical alterations and inevitably proves the protective role of Myrtenal. Treatment with myrtenal to cancer bearing animals resulted in a remarkable increase in the inherent antioxidants and excellent modulation in the morphological and physiological nature of the colon tissue. It is thus concluded that myrtenal exhibits excellent free radical scavenging activity and anticancer activity through the suppression of colon carcinoma in Wistar albino rats.
Animals* ; Antioxidants ; Carcinogenesis ; Colon* ; Colonic Neoplasms* ; Developed Countries ; Dimenhydrinate ; Fruit ; Injections, Subcutaneous ; Lipid Peroxidation ; Monoterpenes ; Oils, Volatile ; Plants ; Rats ; Vegetables

Objective: To evaluate the antioxidant and antidiabetic mechanism(s) of ethyl acetate extract fraction of Moringa oleifera (M. oleifera) leaves on streptozotocin-induced diabetes in male Sprague-Dawley rats. Methods: A total of 24 adult male rats were segregated randomly into four groups (6 rats each group). Streptozotocin-induced diabetes rats were given (oral gavage) ethyl acetate extract fraction of M. oleifera (200 mg/kg b.w.) for 30 d. The rats of control and experimental groups were sacrificed after 24 hours of final dose of treatment, to extract blood and pancreatic tissue for biochemical and histopathological analysis. Results: The ethyl acetate extract fraction of M. oleifera significantly reversed (P<0.05) the manifestation of streptozotocin on the levels of serum glucose & insulin, lipid profile, hepatic damage markers (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase), malondialdehyde formation, antioxidants (glutathione, Vitamin C & Vitamin E), antioxidant enzymes (superoxide dismutase, glutathione S-transferase, glutathione peroxidase and catalase) and pro-inflammatory cytokines (IL-1 β , TNF- α & IL-6). Histopathological analysis of pancreatic tissues was in concurrence with the biochemical results. Conclusions: These findings support that M. oleifera leaves have potent therapeutic effect on diabetes mellitus via increasing antioxidant levels and inhibition of pro-inflammatory mediators.