Friday, July 31, 2009



Ever wonder what natural compounds account for the aroma, flavor and color of vegetables and fruits?

The answer is flavonoids. Thousands of them.

How do we get them? Choose foods by the colour code

Interest by the public in flavonoids has been increasing due to the growing reputation of food antioxidant that can have beneficial roles in disease prevention.


Five Fun Flavonoid Facts


#1. Flavonoids are a large subfamily of phenolic compounds synthesized by plants as pigments that attract pollinators, repel pests and protect plant cells both from ultraviolet radiation and internal production of reactive oxygen species during photosynthesis.

#2. As a group, flavonoids are the most associated
phytochemical class with antioxidant values in plant foods.

Scientists are keenly pursuing numerous potential health effects of flavonoids associated with colorful fruit and vegetable-rich diets. Even in people without disease, benefits may occur for the cardiovascular system, brain, joints, skin, urinary trac
t and healthy aging.

#3. Many of the biological effects of flavonoids seem to come from their ability to modulate communication between cells, a newly discovered mechanism of flavonoid action in

addition to the more traditionally accepted antioxidant role. Read more about potential flavonoid actions in humans, click!

#4. Scientists are examining flavonoids as “biological response modifiers”, a role where they may alter the body's responses to viruses, allergens, bacteria, carcinogens (cancer agents), inflammatory agents, and oxygen radicals.

#5. There are 6 major groups of dietary flavonoids. Although flavonoids are related by a common chemical structure (called in chemistry, a “phenolic ring”), at least 4,000 variations in flavonoid structure occur, and therefore more than 4,000 individual flavonoids in the plant kingdom!

BONUS! If you are interested, the 6 groups are

i) Anthocyanidins. Also called flavonals. Parent structure to anthocyanins found in red, blue, purple and black berries and grapes. Present in dark wines. Examples: cyanidin, delphinidin.

ii) Flavanols. Found in black and green teas, berries, dark chocolate.

Single structures (“monomers”) are called catechins

whereas

multiple-unit structures (“polymers”) are called proanthocyanidins.

iii) Flavanones. Characteristic of citrus fruits (oranges, grapefruit, lemons),

members of this group include naringenin, silybin and hesperidin.

iv) Flavonols. Found in all plants with bright colors, such as berries, kale (dark green),

broccoli and bell peppers, this group includes quercetin and kaempferol.

v) Flavones. Represented by apigenin and luteolin, flavones are found

in herbs (chamomille, parsley) and subterranean plants like celery and radishes.

vi) Isoflavones. The signature group from soybeans and soy products

(tofu, soy milk), isoflavone members include genistein and daidzein.


Flavonoids in plants

What are Flavonoids?

Flavonoids are a diverse group of chemicals found in all plants. About 4000 phytochemicals belong to the flavonoids group. Examples of flavonoids are luteolin, quercetin, blumeatin, tetrahdrooxyflavanone, epigallocatechin gallate, anthocyanins, and tamarixetin. Flavonoids are secondary metabolite products from the phenylpropanoid biosynthetic pathway. All Flavonoids are derived from a chalcone precursor.

Function of Flavonoids in plants

Flavonoids play a variety of roles in plants. Below are some of their important functions:

Plant-microorganism interactions : Flavonoids play roles as signal molecules, phytoalexins, detoxifying agents, and stimulants for germination of spores. Flavonoids may have defensive or stimulant role depending on the microorganisms role in the plant.

Pigments : Anthocyanins give the colors of flowers, fruits, and leaves of plants.

Flavor : Flavonoids are among an array of the chemicals in plants that give the rich taste of plant products. The flavor may act as repellant or attractant to microorganisms or pests or pollinators.

Flavonoids are powerful antioxidants and scanvengers of free radicals. Free radicals cause cellular, and DNA damage in our body and consequently induce age-related diseases suchs as dementia and cancer.

Flavonoids: Antioxidant Activity and Health Benefits

What are flavonoids?

Flavonoids are polyphenols abundantly found in fruits, vegetables, and herbs (eg. tea, ginger root). Flavonoids are synthesized only in plants. They are a diverse group of phytochemicals, exceeding four thousand in number. From human nutrition perspective, flavonoids are important components of a healthy diet because of their antioxidant activity. Nevertheless, the antioxidant potency and specific effect of flavonoids in promoting human health varies depending on the flavonoid type (chemical, physical, and structural properties). Among the potent antioxidant flavonoid types are quercetin, catechins and xanthohumol. Flavonoid science is a research area rapidly gaining deeper insight on the health benefit and chemical property of flavonoids.

Flavonoids and Their Food Sources

Example of dietary flavonoid sources include:

Tea: Green, white or black tea are a rich source of flavonoids, especially flavonols (catechin, epicatechin, epigallocatechin, epicatechin gallate). Tea is a good source of quecertin.

Onions: The major flavonoid in onions is quercetin. Other flavonoids in onion are kaempferol and myricertin.

Honey: Depending on the flower type the bees feed on, honey contains myricertin, and quercetin.

Other dietary flavonoid sources are beans, spinach, buckwheat, strawberry, blueberry, rooibos plant. The concentration and composition of flavonoids in plants may vary depending on the growing condition, maturity, plant part, and variety.

Health Benefits of Flavonoids

Beneficial effects of flavonoids on human health are partly explained by their antioxidant activity. Because of the antioxidative property, it is suggested that flavonoids may delay or prevent the onset of diseases (such as cancer) induced by free radicals. They also inhibit low density lipoprotein (LDL) oxidation by free radicals. Flavonoids have been reported to have negative correlation with incidence of coronary heart disease. Furthermore, flavonoids have anti-bacterial, anti-viral, anti-tumor, anti-inflammatory, antiallergenic, and vasodilatory effect. They also inhibit platelet aggregation.




Wednesday, July 29, 2009

Chemicals used in healthcare

Steroid used in medicine and health care
Steroids are natural substances with many different effects in the human body, which begin over several days. The primary use of steroids in health care is to reduce inflammation and other disease symptoms. Steroid skin creams for example cause thinning and weakness of the skin, while steroids also cause calcium to leak out of bones so that they weaken and fracture spontaneously. Steroids also make people feel very hungry and cause blood sugar to rise.
People on steroids can gain weight and often develop a typical "moon face" as well as getting diabetes. We all need aggressive immune systems to fight infections and cancers, but steroids knock that out. People on high doses of steroids for medical reasons can die from chest infections and cancers of many kinds. We see these patterns in those who receive organ transplants, who need often need huge doses of steroids to stop the body from destroying the donated tissue. Cancers often develop, which shows us how important our white cells are in keeping us cancer-free, and how often all of us develop cancer in our daily lives. Most of us may have two or three tiny cancers inside us at any time. Taking high dose steroids makes it more likely one of these will develop rapidly.
People on high dose steroids are immune-deficient in every way so that many organisms that rarely cause problems can overgrow, totally upsetting the normal balance of mircobes in the body. An example is candida yeast which can grow rapidly in the mouth causing painful thrush.

Chemistry in vehicles

Plastic in cars
Plastic has benefited the society in many ways. Plastic has contributed a lot in aeronautics technology over the past 50 years, including advancements in satellites, shuttles, aircraft, and missiles. As a result, civilian air travel has improved, and military air power and space exploration. Among all that, transportation industries have benefited widely from plastics.Plastic is a popular choice when making modes of transportation because of its features:-
  • tough
  • resistant to corrosion
  • durable
  • lightweight
  • easy to colour


For these reasons, plastic is found in the fenders, bumpers, trunk lids, housings for headlights and sideveiw mirrors, grilles, hoods, doors, and wheel covers.
Through the use of plastic, the average passenger car has lost 145 pounds since 1988. The lighter weight translates to better fuel efficiency and has saved approximately 21 million barrels of oil.

Trains and busses also take advantage of plastic. Modern designs use plastic in the window and door frames and in the seating. Subway cars use plastic for the seats, the seat covers, in making the carpeting, in creating the handles, in the interior panels, and even in the polycarbonate windows. Of course, other means of transportation, such as bicycles, roller skates, kayaks, canoes, skateboards, snowboards, surfboards, motorcycles, and even some athletic shoes anf football players take full advantage of plastic in their creation.

Tuesday, July 28, 2009

ChEmICaLs UsEd In LaBoRaToRaToRy

Laboratory chemicals, solids, liquids or gases have discrete molecular composition and are used extensively in clinical and research laboratories. As temperature changes, these solid or liquids or gases may change into other states or phases. Chemicals utilized in laboratories have numerous uses. For instance, in chromatography, electrophoresis or life sciences research as bio reagents, biological buffers, inhibitors, stains and tracking dyes. Chemical solutions are used as indicators, reagents for testing and analysis for preparation of volumetric solutions. Similarly, amino acids and derivatives, inorganic compounds, solvents, and biopharmaceutical agents have countless applications in laboratories.

Solvents

Solvents, clear and colourless are of 2 types which are organic and inorganic. In general, solvents have low boiling point and evaporate quickly leaving the soluble matters behind. Solvents are used in range of applications such as dry cleaning, nail polish removers, glue solvents, spot removers, paint thinners, perfumes, detergents, chemical synthesis, and research chemistry. Solvents require careful handling as they pose serious dangers to human lives. These chemicals should be stored in tightly closed containers in a well-ventilated area. They should never be flushed down the drain and used near the open flames.



Reagents
Are the substances or indicators used for detecting, analyzing and identifying chemical processes? Fundamental types of reagents used in chemical reaction are acetal, acetyl, benzyl, methyl agents, methyl esters and other more. More accurately, these chemicals are added in order to trigger chemical change. The reagents industry is worth US$382 million, which has the enormous potential to reach US $ 400 million by the end of 2011.


HPLC Solvents
HPCL: high performance liquid chromatography -
Are solvents that are used in many application areas including process control, forensic analysis, environmental monitoring, clinical testing and quality control. These solvents are mainly used for separating, identifying and measuring components presented in a mixture of chemical substances. The widely used HPLC solvents are formic acid, pyridine, trifluroacetic acid, acetonitrile, dimethylsulfoxide, heptafluorobutyric acid and dimethylformamide.

Sunday, July 26, 2009

Are Leading Brand Laundry Detergents Environmentally Friendly?


Consumers have become concerned about the products they use that produce impacts towards the environment lately. Unfortunately, it can be difficult for consumers to find out just what ingredients are in certain products and to which extend they are environmental friendly. For instance, the leading one: Laundry detergents. You certainly won’t figure out just by looking at the contents, where you normally find the following puzzling message: “Ingredients include surfactants (anionic and nonionic) and enzymes.”

First of all, companies are not required by law to list their ingredients, and claim that their formulations are confidential. Secondly, the ingredients they use change over time, whether due to reformulation or simply the use of alternative ingredients to reduce costs. List of ingredients commonly used in the leading brands, and the way they impact the environment, a good idea of tells us what’s really inside:


Artificial fragrances
Artificial fragrances are made from petroleum. Many do not degrade in the environment, and may have toxic effects on both fish and mammals. Additionally, they often can cause allergies and skin or eye irritation.

Optical brighteners
Optical brighteners of many different synthetic chemicals when applied to clothing, convert UV light wavelengths to visible light, thus making laundered clothes appear "whiter." This does not enhance the product's performance in any way but they simply trick the eye. Optical brighteners do not readily biodegrade. They are toxic to fish when washed into the general environment and can create bacterial mutations. They can cause allergic reaction when in contact with skin that is then exposed to sunlight. Most optical brighteners are given trade names which consumers are unlikely to see on a label.

Phosphates
Phosphates are natural minerals and their role in laundry detergents is to remove hard water minerals and thus increase the effectiveness of the detergents themselves. They are also a deflocculating agent; that is, they prevent dirt from settling back onto clothes during washing. While relatively non-irritating and non-toxic in the environment, they nonetheless contribute to significant eutrophication of waterways and create unbalanced ecosystems by fostering dangerously explosive marine plant growth. For these reasons they are banned or restricted in many states and should be considered offensive.

Alkyl phenoxy polyethoxy ethanols
Synthetic surfactants that are slow to biodegrade in the environment and have been implicated in chronic health problems. Researchers in England have found that in trace amounts they activate estrogen receptors in cells, which in turn alters the activity of certain genes. For example, in experiments they have been found to stimulate the growth of breast cancer cells and feminize male fish. One member of this family of chemicals is used as a common spermicide, indicating the general level of high biological toxicity associated with these compounds.

Friday, May 29, 2009

For centuries, chemistry have always been evolving in human lives. Every invention somehow related to chemistry in daily life; be it from the day cave man invented fire through friction between rocks up to today's findings on antidode for A H1N1 virus. This assignment has given me a chance to find chemistry in my daily life.