Every day, science is validating and explaining the actions of the great tonic herbs. Most of the researchers are not seeking to validate old theories. Instead they are seeking new discoveries and new paths to healing and to promoting healthy functioning. Many of the scientists are wise enough to be looking into Nature as a source of inspiration and resources. By combining the older wisdom with cutting edge theory and technology, they are discovering that science and Nature can be blissfully blended. Thousands of research projects are under way at any one time around the world, in virtually every university, examining the nature and actions of herbs and their constituents. This is a revolutionary time in the evolution of herbology and in the search for radiant health, well being and longevity, as scientists and clinicians verify and acknowledge the traditional benefits of the tonic herbs and discover the mechanisms and new uses for these miraculous gems of creation.
Protection against cerebral ischemia by TSG, a polyphenol from the Chinese tonic herb He Shou Wu (Polygonum multiflorum)
By Ron Teeguarden
©Dragon Herbs 2009
Ischemic brain injury is one of the leading causes of adult disability and death. A transient or permanent reduction of cerebral blood flow often initiates brain ischemia. Ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. When this occurs in the brain, it usually leads to neuronal cell death in the brain due to lack of oxygen and nutrients and due to initial inflammatory responses. When blood supply returns to the tissue after a period of ischemia, the damage is actually increased. This damage is called reperfusion injury. The restoration of circulation results in inflammation and oxidative damage through the induction of oxidative stress rather than restoration of normal function. Even transient (temporary) ischemia produces large amounts of free radicals and causes severe neurotoxicity in the brain during reperfusion.
The ischemia-induced free radical expression appear to be mediated by the activation of NF-κB, (nuclear factor kappa B) a key signaling molecule in the cell apoptotic (programmed death) process. NF-κB is at the center of all inflammation in the body, acute and chronic. It is central to the process of inflammaging, by which humans become chronically inflamed as they age, leading to degenerative disease and finally death.
NF-κB has been shown to be activated during brain ischemia by increased oxidative stress. Reactive oxygen species (ROS) such as the hydroxyl radical are considered important mediators of the brain damage after ischemia/reperfusion injury. ROS are a major form of free radical. The intracellular ROS generation during ischemia and reperfusion contributes to a severely disturbed membrane function, triggering various critical cellular signal transduction pathways. This results in a critical intracellular calcium accumulation that leads to cell self destruction (apoptosis – programmed cell death) and, if unchecked, to death.
A molecule known as JNK is activated by oxidative stress and mediates ROS-induced cell apoptosis. Reactive nitrogen species (RNS) such as nitric oxide (NO) are another key factor in the pathophysiological response of the brain after ischemia/reperfusion injury. There is an increase of NO production, along with other free radicals which have been implicated in ischemia-induced apoptotic cell death.
Because intracellular ROS/RNS play such important roles in the cerebral ischemia/reperfusion injury, many antioxidants have been studied for their potential ability to attenuate ROS/RNS formation and protect against ischemia/reperfusion injury.
Ischemia is not only caused by trauma to the head. It may occur on a more limited, chronic basis simply as a result of aging and degenerative diseases. Small brain lesions known as cerebral microbleeds are now recognized to be relatively common among baby boomers. Dutch researchers recently found that nearly 20% of people aged 60-69 had noticeable lesions and 38% of people who have survived to the age 80 had such lesions. Microbleeding results in brain lesions that are marked by iron deposits that result from red blood cells that have leaked out of the small blood vessels in the brain. Research indicates that people who smoke, those with high blood pressure, and those with risk markers for Alzheimer’s disease and amyloid angiopathy are at higher risk to have these lesions due to cerebral microbleeding (April 1 issue of Neurology, 2008).
It has been recently affirmed that men and women suffering from coronary heart disease seem to fare worse on measures of cognitive function. The longer the person had heart disease, the worse their performance in such mental processes as reasoning, vocabulary and verbal fluency, according to a study in the July 23 issue of the European Heart Journal. Men who experienced their first CHD more than a decade prior had even lower scores for reasoning, vocabulary and semantic fluency. The risk of declining performance in the realm of reasoning went down by about 30 percent for every five years after a diagnosis of coronary heart disease. There seems little doubt that blood supply to the brain is involved in mental decline as one ages.
The authors suggest that people should focus on preventing coronary heart disease by not smoking and avoiding or controlling diabetes, high cholesterol and high blood pressure. And the focus should start early, before it’s too late. Read the rest of this entry »
