4/26/09

Addictive substances and medicinal plants

I will only mention in this post addictive behaviours to chemical substances and not those involving customs. Addictions are cases of obsession and compulsion to use substances that produce apparent pleasure and tranquility. Their continued use promote brain changes as tolerance, physical dependence, uncontrollable desire, and if their comsumption is stopped, characteristic symptoms of withdrawal come out. 

The most common addictive substances are alcohol, nicotine, benzodiazepines, opioids and stimulants. The body becomes addicted to the neurological changes that substances produce. Characteristic behaviorial changes are also present. 

Apparently the diverse addictions have similar physiological mechanisms. They act over substances involved in communication between different parts of the brain that released in specific brain sites produce pleasure, or wellness, or over other that are involved in  biological cycles regulation. These substances are neurotransmitters (dopamine, serotonin, GABA) and hormones (melatonin). 

Addictive substances alter hormones and neurotrasmitters production levels and physiological thresholds sensitivity of receptors to these compounds and cause damage to some tissues exposed (eg. Lung tissue or liver cells). 

Both genetics and environment have a direct influence. Researchers have discovered genes directly involved in the mentioned processes  and when there are gene deviations or alterations, the possibility of being addicted is higher. Exposure to environmental factors determines the possibility of addiction, stress and exposure to drugs at an early age and access to substance abuse risk factors are preponderant. 

There are several plants that have been used successfully  in reducing consumption of chemicals and reducing withdrawal symptoms. I will mention the most known and that have been scientifically tested. 

Korean Angelica (Angelica gigas), apparently the essential oil of this plant has successfully modulate the release of dopamine in certain areas of the brain. 

St. John's wort (Hypericum perforatum) modulates several neurochemical pathways. This explains its activity in depression, abstinence from alcohol and not smoking. The hyperacine and hyperforine appear to be the most active compounds. Depression and alcoholism have some neurochemical similarities, such as low activity of serotonin in the brain. 

St. John's wort extract compared with other antidepressants, and there are differences. Has been shown that hypericine stimulates dopamine extracellular levels, also norepinephrine and serotonin as well as glutamate levels, aminoacid responsible for the reactions to panic and stress brain site. It has been evaluated for quitting smoke because of the link between smoking and depression. Primary successes have been achieved. 

Iboga (Tabernanthe iboga) a shrub of equatorial Africa, is used to treat addiction to stimulants. It contains an alkaloid, iboganina, which has shown positive effects on the consumption of nicotine, alcohol, morphine and cocaine in animal trials . Apparently iboganina and some of its derivatives are promising agents for  addiction treatment. 

Kava (Piper methysticum) binds to brain sites associated with addiction and compulsive desire to alcohol, smoking, cocaine and heroin. It has been reported a decline in the desire of those substances consumption. Kavapironas supplementation decreased the effects of abstinence. 

Kudzu (Pueraria lobata) has succeeded in reducing alcohol consumption and the symptoms outcoming. The most important active ingredients are  isoflavones puerarin, daizina and daidzeina. This plant also has anxiolytic effects in several ways and act accordingly. In China its use is widespread both alone and with other natural medicines. 

Lobelia (Lobelia inflata) and other plants like marshmallow (Althaea officinalis) comprise the so-called herbal cigarettes. Lobeline physiologically tends to replace the nicotine, so the body reduces the dependence feeling. 

Nescafe (Mucuna pruriens) has significant levels of levodopa (L-dopa), the dopamine precursor, making it possible to increase levels of neurotrasmitters associated with abstinence. 

Passionflower (Passiflora incarnata) contains a chemical fraction, the benzoflavona that appears to be responsible for most  plant medicinal activity. It has achieved success in reversing tolerance and dependence to psychotropic drugs such as morphine, nicotine and alcohol in animals. 

4/17/09

Medicinal plants chemicals

Medicinal plants chemicals are substances present in plants for specific activities in plants life. Respond to millions years of evolution, different plant species interacting with the environment.

Many compounds are necessary for protection against climate and pollutants agressions (sun, cold, heat, etc.) against predators (herbivores, insects), parasites (worms, insect larvae) or infections (bacteria, fungi, virus). Other compounds are involved in plant reproduction and growth, such as hormones or growth factors, or are used to attract birds and insects to carry out pollen and seeds, thus ensuring reproduction and dispersal of these species. Some compounds are also involved in plants structure to keep them upright and for humidity maintenance. Other compounds are intermediate metabolites of normal chemical reactions.

The main concept is that herbal substances with medicinal activity are vital components of the normal plants physiology and were discovered along many years by human communities that lived in close relationship with nature. Without the aim to classify the active ingredients, it can be said that medicinal actions are fulfilled by chemical reactions, mechanical and physical effects or as nutritional supplementation.

Chemical groups such as alkaloids, saponins, essential fatty acids and glycosides are the most important, with a special remark on subgroups as flavonoids, polyphenols and bitter substances. Fiber, both soluble and insoluble, acts in a mechanical way. The vitamins, minerals and water are nutrients.

Major chemical reactions are: antioxidant activity, performed by a large amount of chemicals (polyphenols, carotenoids), hormonal activity (isoflavones), enzyme regulation (indoles, terpenes), interference with gene replication (saponins), antiparasitic and antimicrobial activity (terpenes) and anti-inflammatory activity.

In another entry I will give examples of activities to make the subject a little more understandable and enjoyable.

4/10/09

Cholesterol metabolism

Ultra simplified explanation of the regulation of cholesterol in the organism. 

The objective is quite straightforward, the process aims to keep cholesterol levels at figures commensurate with the body requirements.

Therefore, as provided by the diet (external cholesterol ) is what is consumed daily and, depending on the food type, mobilizes a very complex mechanism that regulates the formation of cholesterol from the body (synthesis) and the removal of cholesterol excess, if any. 

Cholesterol that is consumed passes from the intestine to the liver, transported as lipid or fat particles, through special vessels and is released from the liver into the blood, where is carried by special proteins that form the complexes known as lipoproteins (LDL and VLDL) . Another complex, the HDL leads cholesterol  back to the liver for disposal. 

Organic synthesis (less than half of total cholesterol) is carried out in cells of the liver, intestine and to a lesser extent in cells of other organs, based on what is known as the energy cycle. Within these cells, at specialized sites in the cytoplasm. Part of the cholesterol produced turns to blood and the rest is stored in the cytoplasm, free or in capsules. 

Excess cholesterol is eliminated from the body through just an unique path, the bile, either as free cholesterol or converted into biliar acids. 

The amount of cholesterol in blood is regulated, as noted earlier, by several parallel mechanisms involved, blood level receptors or detectors, endocrine glands, hormones, special genes, enzymes and small intracellular organs. 

The outer surface of the cell membrane, in contact with bloodstream, has special extensions (like tiny wires) that "measure" continuously blood cholesterol level. These sensors give notice to the involved endocrine glands, pancreas and adrenal, which, depending on the situation, release hormones to increase or decrease cholesterol production in the cells (synthesis). To emphasize that, owing to its importance, one of the hormones involved is insulin. 

These hormones control the exposure of specific genes and the reading of genetic information (transcription) that stimulate (if necessary) enzymes production, which act as accelerators for the 
cholesterol production and its precursors or promoting HDL to remove cholesterol from the bloodstream. 

The reading of genetic information and the production of these enzymes, is carried out in small organs of the cytoplasm and the nucleus almost permanently, something very difficult to imagine, as a factory with an enormous amount of workers that do not stop at any time. They have periods of greater and lesser activity, but the alert and the mechanisms are always active. 

A similar but somewhat simpler mechanism, occurs in the liver for bile formation and cholesterol incorporation. 

I ask the scientists' indulgence and the readers' understanding due to that to write this post on the metabolism of cholesterol, I have had to shorten explanations so its accuracy and clarity are not the best.