Tissue damage, chemical mediators

Natural products are fundamental to pain treatment. They yield new analgesics and play an important role in the study of pain mechanisms [for review see 1,2]. Pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Alternatively, it can be described in terms of such damage [3]. The sensory component of pain (nociception) is triggered by mechanical, thermal, or chemical noxious stimuli at the free ends of small diameter primary afferent fibres (nociceptors) present in practically all body tissues [4,5]. After tissue damage, several mediators, such as bradykinin,... 

Immunoenhancement, which, as adverse effect, may lead to immune-mediated diseases such as hypersensitivity reactions and autoimmune diseases. Hypersensitivity reactions are the result of normally beneficial immune responses acting inappropriately, causing inflammatory reactions and tissue damage. The two most frequent manifestation of chemical-induced allergy are contact hypersensitivity and respiratory sensitization, both of which can have a serious impact on quality of life and represent a common occupational health problem. Hypersensitivity reactions are often considered to be increased at such a rate to become a major health problem in relation to environmental chemical exposure. 

Classically, inflammation is a protective reaction of the body in response to some physical, chemical, or microbial injury and insult of the cells. Acute inflammation, rapid onset and shorter duration, is considered as a healthy response. However, when inflammation continues for prolonged period of time, it becomes detrimental and may raise the first step of a chronic disease (Medzhitov, 2008). Arachidonic acid/COX and nuclear factor- (NF- ) are well known inflammatory pathways which induce production of inflammatory mediators such as prostaglandins, thromboxanes, leukotrienes, and cytokines. Most commonly accepted mechanism of anti-inflammation is inhibition of cyclooxygenase (COX) activity. There are two kinds of cyclooxygenases COX-1 is natural protective enzyme of intestinal mucosa while COX-2 is induced by tissue damage as an inflammatory mediator (Maroon et al., 2006). NF- is a recently identified... 

When cells are damaged they release a variety of chemical mediators, which can activate or sensitize nociceptors to other chemicals. This explains acute pain. Chronic pain is more difficult to explain, especially if it goes on beyond the initial tissue damage. Chronic pain is thought to be associated with changes to the normal physiological pain pathway. 

All extracts and their fractions showed HjOj-scavenging ciqiacity in a concentration-dependentmaimer. The values were lower for lOOppmasconqiared to those for 200 ppm level of extracts. The scavei ing of HjOj by extracts and their fractions is attributed to dieir phenolics udiich could donate electrons to HjOj, thus neutralizing it to water. The efficacy of the fractions of each extract was dependent on die chemical nature of phenolic conqiounds involved. Hius, crude extracts, their fractions or purified conqxHinds thereof may be incorporated into foods to minimize free radical-mediated l id peroxidation. They may also be used as alternative drugs/supplements to treat human diseases associated with free radical-mediated tissue damage. 

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