Therapeutic effects of proanthocyanidins on the pathogenesis of periodontitis— An overview.

Periodontitis is a bacterially induced chronic inflammatory disease that destroys the connective tissue and bone that support teeth. Bacteria initiates periodontitis and destruction of the alveolar bone and periodontal connective tissue is clearly observed. But, the events occuring between these two points of time remain obscure and this study focusses on these aspects. The proanthocyanidins (PC) have variable pharmacological and nutraceutical benefits including improvement of ischemic cardiovascular disease, prevention of atherosclerosis and antiarthritic, anticancer and antimicrobial activities. The benefits associated with the antioxidant activity of PC have been evaluated both in vivo and in vitro. But, reports on the ameliorative effects of PC on oral diseases and specifically on periodontitis are very few. Hence, a novel attempt is made to review the possible protective effects of PC and its mechanism of action in periodontitis and also to show whether PC could be developed as a therapeutic agent for periodontitis.

In vitro studies on inhibitory effect of proanthocyanidins in modulation of neutrophils and macrophages.

The role of proanthocyanidins (PC), a novel flavonoid extracted from grape seeds was studied in vitro in the modulation of neutrophil and macrophage function. We attempted to assess the levels of non-enzymatic and enzymatic mediators in the presence or absence of PC in 4-phorbol-12--myristate-13-acetate (PMA)-stimulated neutrophils isolated from humans and rats, E. coli endotoxin-stimulated macrophages and macrophages isolated from E. coli endotoxin-induced experimental periodontitis in rats. Addition of PC at a concentration of 50 µg/ml effectively blocked the release of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and exhibited a marked inhibition of myeloperoxidase (MPO) and lysosomal enzymes (p<0.001), as compared to PMA-stimulated neutrophils (human and rats) and neutrophils isolated from experimental periodontitis in rats. The levels of ROS, RNS and lysosomal enzymes were found to be elevated (p<0.001) and addition of PC significantly (p<0.001) reduced these levels as compared to those from E. coli endotoxin-stimulatedmacrophages from rats and macrophages isolated from experimental periodontitis in rats (p<0.001). Thus, the study demonstrated that PC decreased the levels of ROS and RNS and also inhibited the MPO and lysosomal enzymes activities in experimental periodontitis in rats. In addition, this study clearly indicated that PC could be developed as an effective antiinflammatory agent.

Protective effect of proanthocyanidins on endotoxin induced experimental periodontitis in rats.

The pathogenesis of periodontitis involves anaerobic oral bacteria as well as the host response to infection and several drugs have been developed which can curtail these deleterious effects. Proanthocyanidin, a novel flavanoid extracted from grape seeds, has been shown to provide a significant therapeutic effect on endotoxin (Escherichia coli) induced experimental periodontitis in rats. In this study, protective action of different doses of proanthocyanidins was investigated in blood by assaying the reactive oxygen species such as hydrogen peroxide, superoxide anion, myeloperoxidase and lipid peroxides, lysosomal enzyme activities such as cathepsin B, cathepsin D, β-glucuronidase and acid phosphatase, nonenzymatic antioxidants such as ascorbic acid, -tocopherol, ceruloplasmin, reduced glutathione and antioxidant enzymes such as catalase, superoxide dismutase, glutathione peroxidase and glutathione-s-transferase. Experimental periodontitis rats showed a reduction in body weight and body weight gain could be noticed when they were administered proanthocyanidins. The levels of reactive oxygen species and lysosomal enzymes were found to increase whereas antioxidant levels were decreased significantly in experimental periodontitis. Proanthocyanidins at an effective dose of 30mg / kg body weight, sc, for 30 days effected a decrease in serum reactive oxygen species, lipid peroxides, lysosomal enzymes, acute phase proteins and an increase in antioxidant levels. Histopathological evidence of experimental periodontitis showed cellular infiltration of inflammatory cells while proanthocyanidin treated groups demonstrated only scattered inflammatory cells and blood vessels. Thus, the results showed that dietary supplementation of proanthocyanidin enhanced the host resistance as well as the inhibition of the biological and mechanical irritants involved in the onset of gingivitis and the progression of periodontal disease.