chemistry

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Example and Guide.

Types of Lipids, their Structures, Functions in the Body, and Health Effects

Lipids are a group of biomolecules that have the property of not being soluble in water but yes in organic solvents. The origin of the word lipid is Greek word lipos, that means fat. (Timberlake, 2017). They play vitals roles in our bodies such as immune regulation, inflammation, and maintenance of homeostasis, and act as intercellular and intracellular signaling mediators that bear many cell functions. Lipids can interact with the aggregation and propagation of many pathogenic proteins that are visible signs of several neurodegenerative disorders, including Alzheimer's (AD) and Parkinson's (PD) diseases (Chiurchiù. et al 2022).

Types of Lipids

Structures

Lipids have distinctive structures that are special for each kind. For example, waxes, triacylglycerols, glycerophospholipids, and sphingolipids are esters that can be hydrolyzed to produce fatty acid and other molecules. Triacylglycerols and glycerophospholipids contain the alcohol glycerol, but sphingolipids contain the amino alcohol sphingosine. On the other side, steroids have a unique structure because they contain a steroid nucleus of four fused carbon rings, do not possess fatty acids and cannot be hydrolyzed (Timberlake, 2017).

Fatty Acids

Contains a long, unbranched carbon chain with a carboxylic acid at one end which is hydrophobic, so it makes fatty acids insoluble in water. Most of fatty acids have between 12 and 20 atoms of carbon. Lauric acid, founded in coconut oil is an example of fatty acid. There are different types of fatty acids: saturated, unsaturated, monounsaturated and polyunsaturated. The saturated (SFA) contains only carbon- carbon single bonds (similar to alkanes), the unsaturated (UFA) contains one or more carbon- carbon double bonds, in the monounsaturated (MUFA) the carbon chain has one double bond (similar to alkene), and a polyunsaturated (PUFA) has at least two carbon-carbon double bonds. The human body is capable of synthesizing some fatty acids from carbohydrates or other fatty acids. However, humans cannot synthesize sufficient amounts of polyunsaturated fatty acids such as linoleic acid, linolenic acid, and arachidonic acid. Because they must be obtained from the diet, they are known as essential fatty acids (EFAs). The treatment of pain, fever, and inflammation is based on inhibiting the enzymes that convert arachidonic acid to prostaglandins., Several nonsteroidal and anti-inflammatory drugs (NSAIDs) such as aspirin, block the production of prostaglandins; doing this, they reduce pain, inflammation ad fever (antipyretics) Diet has changed in America to include more unsaturated fat and less saturated fatty acids for an increasing fear of atherosclerosis and heart disease associated with high levels of fat. However, fish and vegetable oils have unsaturated fatty acids, for example, Omega-3 fatty acids that lowers the tendency of blood platelets to stick together, thereby reducing the possibility of blood clots, However, high levels of omega-3 fatty acids can increase bleeding if the ability of the platelets to form blood clots is reduced too much. It does seem that a diet that includes fish such as salmon, tuna, and herring can provide higher amounts of omega-3 fatty acids, which help lessen the possibility of developing heart disease (Timberlake, 2017). Most The Government has been asked to set a law that will eliminate trans-fatty acids from the food value chains. Trans-fatty acids are manufactured fats that prevent products from melting at room temperature. They can be found in variety of food products such as margarine, cooking oil, baked goods like cakes, cookies, fried foods like French fries, doughnuts, fried chicken, among others. According to Moses Talibata, the Legal Officer Uganda National Health Consumer Organization (UNHCO), Ugandan products will not compete in the regional market if government does not move to eliminate the trans-fatty acids from the value chain. “We want a law which requires of Uganda Bureau of Standards (UNBS) to adopt mandatory standards from eliminating trans-fatty acids from our food chain that manufacturers must a bid by standard”, he said. “In the study that we conducted, we found that there is a legislative gap. Trans-fatty acids are not regulated, even the UNBS do not at all condemn or punish whoever includes trans-fatty acids in their processes of making oils and fats,” he explained ( The New Vision, 2022).

Waxes

Natural waxes are found in the surface of fruits, and on the leaves and stems of plants where they help prevent loss of water and damage from pests. They provide a waterproof coating on the skin, fur, and feathers of animals. Contains 14 to 30 carbon atoms. Beeswax from honeycombs and carnauba wax from palm trees give a protective coat to furniture, cars, and floors. Jojoba wax is used in making candles and cosmetics. Lanolin, a mixture of waxes obtained from wool, is used in by its softener properties in hand and facial lotions. (Timberlake, 2017). Simmondsia chinensis (jojoba) is the only plant known to store wax esters instead of triacylglycerols in its seeds. Wax esters are composed of very-long-chain monounsaturated fatty acids and fatty alcohols and constitute up to 60% of the jojoba seed weight (Kawiński et al. 2021)

Triacyclglycerols

Also called triacylglycerides, are triesters of glycerol (a trihydroxy alcohol), which are stored in the body as fatty acids. Three hydroxyl groups of glycerol form ester bonds with the carboxyl groups of the fatty acids. Most naturally occurring triacylglycerols contain glycerol bonded to two or three different fatty acids, like palmitic acid, oleic acid and stearic acid. Triacylglycerols are the mayor form of energy storage for animals. Animals that hibernate eat large quantities of plants, seeds, and nuts high in calories. The body temperature drops to nearly freezing, and cellular activity, respiration, and heart rate are drastically reduced. During this time, stored fat is the only source of energy (Timberlake, 2017). Triacylglycerols, or TAGs, are a class of lipids which form the backbone to biofuels. The molecules are comprised of glycerol attached to three fatty acid chains. In Japan, Hiroyuki Ohta at Tokyo Institute of Technology, together with scientists based at institutions across Tokyo, Japan, have uncovered a way of enhancing the production triacylglycerols in the Nannochloropsis algal strain NIES-2145, thereby increasing oil synthesis from the microalgae (Newstex, 2015).

Phospholipids

Are similar in structure to triacylglycerols; they include glycerophospholipids and sphingomyelins. In glycerophospholipids, two fatty acids form ester bonds with the first and second hydroxyl groups of glycerol. The third hydroxyl group forms an ester with phosphoric acid, which forms another phosphoester bond with an amino alcohol. In sphingomyelins, sphingosine replaces glycerol. Poisonous snake venom contains phospholipases that hydrolyze phospholipids in red blood cells. In multiple sclerosis, the sphingomyelin is lost from the myelin sheath, scars form on the neurons, causing muscle weakness sand loss of vision. The production of pulmonary surfactant, a mixture of phospholipids produced by lung cells, occurs in a fetus after 24 to 28 weeks of pregnancy. If the infant is born before this time, the immature lungs and the low level of surfactant will lead to a high chance of infant respiratory distress syndrome (IRDS). Once the infant is born, treatments including steroids are used to help the maturation of the lungs (Timberlake, 2017). Whey Protein Phospholipid Concentrate (WPPC), a low-value coproduct, is currently being examined as a source of nutritional and functional ingredients. WPPC contains high-value components, such as various types of proteins and phospholipids.

The phospholipids found in WPPC are also of high nutritional Interest. Potentially, the phospholipids from WPPC could be utilized to fortify high value products like Infant formula and nutritional products. There are also minor bioactive components of WPPC that are worth exploring (Lucey, 2022)

Steroids: Cholesterol, Bile Salts and Steroid Hormones

Steroids are compounds containing the steroid nucleus, which consist of three cyclohexane rings and one cyclopentane ring fused together. The four rings in the steroid nucleus are designated A, B, C, and D. The carbon atoms are numbered beginning with the carbons in ring A, and in steroids like cholesterol, ending with two methyl groups.

Cholesterol, which is one of the most important and abundant steroids in the body, is a

sterol because it contains an oxygen atom as a hydroxy1 group (- OH) on carbon 3. Like

many steroids, cholesterol has a double bond between carbon 5 and carbon 6, methyl groups

at carbon 10 and carbon 13, and a carbon chain at carbon 17. In other steroids, the oxygen

atom forms a carbonyl group (C=0) at carbon 3. is a component of cellular membranes, myelin sheath, and brain and nerve tissue. It is also found in the liver and bile salts; large quantities of it are found in the skin, and some of it becomes vitamin D when the skin is exposed to direct sunlight. In the adrenal gland, cholesterol is used to synthesize steroid hormones. The liver synthesizes cholesterol for the body from fats, carbohydrates, and proteins. Additional cholesterol is obtained from meat, milk, and eggs in the diet. There is no cholesterol in vegetable and plant products. The American Heart Association has recommended that we consume no more than 300 mg of cholesterol a day. Research suggest that saturated fats and cholesterol are associated with diseases such as diabetes, cancer, and atherosclerosis. Clinically, cholesterol levels are considered elevated if the total plasma cholesterol level exceeds 200 mg/dL.

Bile Salts in the body is synthesized from cholesterol in the liver and stored in the gallbladder. When bile is secreted into the small intestine, the bile salts mix with the water- insoluble fats and oils in our diets. They act much like sops due to its polar and non-polar regions, breaking down large globules of fat into smaller droplets. They help with the absorption of cholesterol into the intestinal mucosa. When large amounts of cholesterol accumulate in the gallbladder, cholesterol can become solid, which forms gallstones. Gallstones are composed of almost 100% cholesterol, with some calcium salts, fatty acids, and glycerophospholipids. Normally, small stones pass through the bile duct into the duodenum, the first part of the small intestine immediately beyond the stomach. If a large stone passes into the bile duct, it can get stuck, and the pain can be severe. If the gallstone obstructs the duct, bile cannot be excreted. Then bile pigments known as bilirubin will not be able to pass through the bile duct into the duodenum. They will back up into the liver and be excreted via the blood, causing jaundice (hyperbilirubinemia), which gives a yellow color to the skin and the whites of the eyes.

Steroid hormones are chemical messengers that serve as a communication system from one body part to another. Include sex hormones and the adrenocortical hormones and are closely related in structure to cholesterol and depend on it for their synthesis. Two of the male sex hormones, testosterone and androsterone, promote the growth of muscle and facial hair, and the maturation of the male sex organs and of sperm. The estrogens, a group of female sex hormones, direct the development of female sexual characteristics: the uterus increases in size, fat is deposited in the breasts, and the pelvis broadens. Progesterone prepares the uterus for the implantation of a fertilized egg. If an egg is not fertilized, the levels of progesterone and estrogen drop sharply, and menstruation follows. Synthetic forms of the female sex hormones are used in birth control pills. As with other kinds of steroids, side effects include weight gain and a greater risk of forming blood clots (Timberlake, 2017).

Health Effects

The optimal levels for the four standard tests in a lipid panel are:

* Total cholesterol: below 200 mg/dL.

*  High-density lipoprotein (HDL) cholesterol: above 60 mg/dL.

* Low-density lipoprotein (LDL) cholesterol: below 100 mg/dL (less than 70 mg/dL in diabetics).

*  Triglycerides: below 150 mg/dL.

Lipid levels usually tend to be on the higher side. Abnormally low levels are extremely rare. However, they can arise with severe liver disease or severe malnutrition. In adults, risk factors are obesity, lack of physical activity, diabetes and high blood pressure. In addition, certain

diseases such as hypothyroidism, chronic kidney disease and pancreatitis can also elevate lipid levels. Once the lipid levels have been found to be elevated, intervention is required. High cholesterol and triglycerides, if neglected, tend to get deposited on the walls blood vessels. Sometimes the vessel may get blocked completely. This can cause heart attacks and strokes, which can prove to be fatal. If the initial lipid profile is normal, it needs to be rechecked every four to five years. If the results are abnormal or there are other risk factors involved, such as diabetes or obesity or a family history of premature strokes and death, then lipids should be rechecked every year. Lipids may become controlled rapidly on medication, but that does not mean the patient has recovered. It is the medication that is keeping cholesterol and triglycerides low. Discontinuing the medication can lead to rising values once again and cause dangerous side effects (Mathai, 2022). New research finds that certain types of lipids in the blood play a role in how the apolipoprotein E (APOE) gene influences Alzheimer's disease risk. A recently published study in Alzheimer's & Dementia: The Journal of the Alzheimer's Association takes a closer look at the connection among blood lipids, two forms of APOE, and Alzheimer's. This study suggests that specific blood lipids could potentially be new targets for Alzheimer's prevention ( Asia News, 2022). Lipids, especially essential fatty acids play an important role in the health and development of humans and play a critical role in the prevention of disease by altering their composition. Lipids are a source of energy and the structure of cell membranes and polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential fatty acids to regulate the inflammatory responses on the macrophage cells, which are considered anti-inflammatory agents. Moreover, they can inhibit the activation of the pro-inflammatory transcription factor and suppress the activation of mitogen-activated protein kinases (MAPKs) signaling pathway. These pathways involved inflammatory responses, which produce inflammatory cytokines and inflammatory mediators. In addition, high levels of EPA and DHA were reported from the lipid extracts including from total lipids, neutral lipids, and polar lipids of various ascidian species. The lipid extracts from ascidians have improved beneficial health effects, such as anti-diabetic and antioxidant effects (A-yeong, 2022). Cardiovascular diseases associated with high cholesterol (hypercholesterolemia) and low-density lipoproteins (LDL) levels are significant contributors to total mortality in developing and developed countries. Mathematical modeling of LDL metabolism is an important step in the development of drugs for hypercholesterolemia (Efremov et al. 2022). Bacterial bile salt hydrolysis is considered a risk factor for the development of colon cancer because of the risk of forming harmful secondary bile salts after an initial deconjugation step. In this study, the influence of enhanced bacterial bile salt transformation by the bile salt hydrolase-active Lactobacillus reuteri was studied in batch culture using the microbial suspension of the Simulator of the Human Intestinal Microbial Ecosystem. Although there have been advances in radiotherapy, chemotherapy and surgery, mortality caused by colorectal cancer remains very high and has decreased only slightly. Thirty percent of all colon cancer deaths can be linked to diet. Probably one of the most cited mechanisms is that of a high-fat diet. To resorb the increased amount of dietary fat, more conjugated primary bile salts are secreted in the small intestine. This leads to an increased of bile salts to the colon and an increased metabolism of the bile salts. Some of the bile salts generated by the micro-organisms have been incriminated in colonic carcinogenesis One of the most important bacterial bile salt trans- formations is bile salt hydrolysis, which is mediated by a wide range of colon anaerobes. The bile salt hydrolase enzyme releases the glycine and/or taurine moiety from the side chain of the bile salt steroid core and generates deconjugated primary bile salts, which are less water-soluble and are excreted more easily via the faeces. The principle of bile salt hydrolysis was used to decrease the serum cholesterol in pigs through interaction with the host's bile salt metabolism. In the latter, the bacterial bile salt hydrolase activity in pigs was enhanced by oral administration of Lactobacillus reuteri. This caused a greater drain on the bile salt pool, resulting in a loss of feedback inhibition on bile salt synthesis and an increased conversion of cholesterol into bile salts. Because of this, the serum cholesterol levels in the pigs were lowered (De Boever, 2000) . There is considerable concern about the increasing incidence of endocrine-related cancer and deteriorating reproductive health in humans. A large number of natural and man-made chemicals have the ability to mimic the action of the endogenous steroid hormone 17b-estradiol by binding to and activating the estrogen receptor. In this matter, there is no consensus regarding the role of xenoestrogens in these effects and no conclusive studies demonstrating that xenoestrogens initiate or contribute to the development of these effects. The molecular structure of exogenous natural and synthetic estrogens may be very similar to, or strikingly different from the natural hormone (Cabaravdic, 2010).

Conclusions

As a conclusion, we can affirm that lipids are extremely important in our world. Fatty acids contribute to the treatment of pain, fever, and inflammation, waxes provide a waterproof coating on the skin, fur, and feathers of animals, triacyclglycerols help animals to storage energy on hibernation time, phospholipids allow the formation of pulmonary surfactant in the fetus, the cholesterol has a huge impact in human health, increasing the chance of mortal diseases, bile salts help with the absorption of cholesterol into the intestinal mucosa, and steroid hormones are chemical messengers that serve as a communication system from one body part to another. Lipids play an important role in the health and development of humans and play a critical role in the prevention of diseases by altering their composition. Lipids are a source of energy and the structure of cell membranes and polyunsaturated fatty acids that regulate the inflammatory responses on the macrophage cells, which are considered anti-inflammatory agents.

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References

Chiurchiù, V., Tiberi, M., Matteocci, A., Fazio, F., Siffeti, H., Saracini, S., Nicola, B. M., & Sancesario, G. (2022). Lipidomics of Bioactive Lipids in Alzheimer’s and Parkinson’s Diseases: Where Are We?  International Journal of Molecular Sciences, 23(11), 6235. https://doi.org/10.3390/ijms23116235

Mathai, G. (2022, Apr 13). Keep lipid levels in line.  The Telegraph (India)https://www.proquest.com/newspapers/keep-lipid-levels-line/docview/2649432557/se-2

Timberlake, K. C. (2017). Chemistry: An Introduction to General, Organic, and

Biological Chemistry. Thirteen Edition. Pearson Education, Inc.

Kawiński, A., Miklaszewska, M., Stelter, S., Głąb, B., & Banaś, A. (2021). Lipases of germinating jojoba seeds efficiently hydrolyze triacylglycerols and wax esters and display wax ester-synthesizing activity.  BMC Plant Biology, 21, 1-13. https://doi.org/10.1186/s12870-020-02823-4

Biofuels Digest: Japanese researchers enhance triacylglycerols production in algae(2015). . Newstex.

Lucey, J. (2022). A closer look at Whey Protein Phospholipid Concentrate.  Dairy Foods, 123(8), 21. https://www.proquest.com/trade-journals/closer-look-at-whey-protein-phospholipid/docview/2702262443/se-2

Efremov, Y., Contributed equally to this work with:,Yuri Efremov, Ermolaeva, A., Gordleeva, S., Svistunov, A., Zaikin, A., & Timashev, P. (2022). A mathematical model of 0RW1S34RfeSDcfkexd09rT2in vitro1RW1S34RfeSDcfkexd09rT2 hepatocellular cholesterol and lipoprotein metabolism for hyperlipidemia therapy.  PLoS One, 17(6)https://doi.org/10.1371/journal.pone.0264903

De Boever, P., Wouters, R., Verschaeve, L., Berckmans, P., Schoeters, G., & Verstraete, W. (2000). Protective effect of the bile salt hydrolase-active Lactobacillus reuteri against bile salt cytotoxicity.  Applied Microbiology and Biotechnology, 53(6), 709-14. https://doi.org/10.1007/s002530000330

Cabaravdic, M. (2010). The Xenoestrogen Effects of Polycyclic Aromatic Hydrocarbons and Organochlorines Compounds: Historical Perspective and Update.  Materia Socio-Medica, 22(2), 105. https://www.proquest.com/scholarly-journals/xenoestrogen-effects-polycyclic-aromatic/docview/1170602076/se-2

Stakeholders want law to eliminate trans-fatty acids from food. (2022, Feb 01).  The New Vision https://www.proquest.com/newspapers/stakeholders-want-law-eliminate-trans-fatty-acids/docview/2624217749/se-2

United States: Blood lipids involved with the protective effect of an Alzheimer's disease gene suggest new targets for prevention. (2022, Jul 04).  Asia News Monitor  https://www.proquest.com/newspapers/united-states-blood-lipids-involved-with/docview/2683579556/se-2

A-yeong, J., Contributed equally to this work with: A-yeong Jang, Weerawan Rod-in Weerawan Rod-in, Weerawan Rod-in, C. M., Choi, G. S., & Woo, J. P. (2022). Anti-inflammatory effects of neutral lipids, glycolipids, phospholipids from 0RW1S34RfeSDcfkexd09rT2Halocynthia aurantium1RW1S34RfeSDcfkexd09rT2 tunic by suppressing the activation of NF-κB and MAPKs in LPS-stimulated RAW264.7 macrophages.  PLoS One, 17(8)https://doi.org/10.1371/journal.pone.0270794