The Role of Vitamins, Magnesium, and Trace Elements in COVID-19 Treatment and Post-COVID-19 Rehabilitation: An Updated Overview.

This review summarizes the scientific knowledge concerning the impact of vitamins, magnesium, and trace elements on various mechanisms contributing to the possible treatment and prevention of COVID-19, including its delayed consequences. A search was conducted in various databases, including PubMed, Scopus, ClinicalTrials.- gov, and Web of Science. Among the main mechanisms involved in the effects of the studied micronutrients, immune-boosting, antioxidant and anti-inflammatory effects were also highlighted. The analyzed clinical trials confirmed that supplementation with higher daily doses of some micronutrients can reduce SARS-CoV-2 viral load and hospitalization time. The potential role of most known vitamins in preventing, treating COVID-19, and rehabilitating patients was considered. The most promising agents for combating COVID-19 and its consequences might be the following vitamins: vitamin D, ascorbic acid, polyunsaturated fatty acids (PUFAs), and some B complex vitamins. Inorganic elements deserving attention include magnesium and trace elements, such as zinc, selenium, copper, and iron. Some associations were found between micronutrient deficiencies and COVID-19 severity in children, adults, and older people. Patients can obtain the aforementioned micronutrients from natural food sources or as supplements/- drugs in various dosage forms. The reviewed micronutrients might be considered adjunctive treatment strategies for COVID-19 patients.

Alpha-lipoic Acid: An Antioxidant with Anti-Aging Properties for Disease Therapy.

The anti-aging effects of alpha-lipoic acid (αLA), a natural antioxidant synthesized in human tissues, have attracted a growing interest in recent years. αLA is a short- -chain sulfur-containing fatty acid occurring in the mitochondria of all kinds of eukaryotic cells. Both the oxidized disulfide of αLA and its reduced form (dihydrolipoic acid, DHLA) exhibit prominent antioxidant function. The amount of αLA inside the human body gradually decreases with age resulting in various health disorders. Its lack can be compensated by supplying from external sources such as dietary supplements or medicinal dosage forms. The primary objectives of this study were the analysis of updated information on the latest two-decade research regarding the use of αLA from an anti-aging perspective. The information was collected from PubMed, Wiley Online Library, Scopus, ScienceDirect, SpringerLink, Google Scholar, and clinicaltrials.gov. Numerous in silico, in vitro, in vivo, and clinical studies revealed that αLA shows a protective role in biological systems by direct or indirect reactive oxygen/nitrogen species quenching. αLA demonstrated beneficial properties in the prevention and treatment of many age-related disorders such as neurodegeneration, metabolic disorders, different cancers, nephropathy, infertility, and skin senescence. Its preventive effects in case of Alzheimer's and Parkinson's diseases are of particular interest. Further mechanistic and clinical studies are highly recommended to evaluate the wide spectrum of αLA therapeutic potential that could optimize its dietary intake for prevention and alleviation disorders related to aging.

Ayurvedic and Chinese Herbs against Coronaviruses.

COVID-19 is a viral disease that infects the lower airways, causing severe acute respiratory syndrome (SARS) and fatal pneumonia. The ripple effect of the COVID-19 outbreak has created serious problems in the healthcare systems of many countries and had far-reaching consequences for the global economy. Thus, effective control measures should be implemented for this coronavirus infection in the future. The ongoing episode of the SARS-CoV-2 sickness, COVID-19, in China, and the subsequent irregular spread of contamination to different nations, has alarmed the clinical and academic community primarily due to the deadly nature of this disease. Being a newly identified virus in the viral classification and having the highest mutation rate, rapid therapeutics are not readily available for treating this ailment, leading to the widespread of the disease and causing social issues for affected individuals. Evidence of Ayurveda and traditional Chinese medicine (TCM) has been found in ancient civilizations, such as those of the Hindus, Babylonians, Hebrews, and Arabs. Although TCM and Ayurvedic herbs do not promise to be very effective treatments for this pandemic, they can reduce infectivity and virulence by enhancing immunity and showing effectiveness in rehabilitation after COVID-19 disease. Thus, they could be used as sources of inhibitor molecules for certain phenomena, such as viral replication, attachment to the host, 3CL protease inhibition, 3a ion channel inhibitors, and reverse transcription inhibition. Medicinal plants from TCM and Ayurveda and their biologically active phytoconstituents can effectively modulate the targets and pathways relevant to inflammation and immune responses in human bodies. The present review analyzes the role of certain TCM and Ayurvedic medicinal plants in healing COVID-19 infection. Medicinal plants such as Glycyrrhiza glabra (licorice), Curcuma longa (turmeric), and Zingiber officinale (ginger) are regarded as the main antiviral herbs. Their extracts and individual bioactive compounds could be used as potential substances for developing remedies to prevent or cure the coronavirus disease. Generally, antiviral phytochemicals obtained from natural sources are considered potent candidates for fighting COVID-19 infection and rehabilitation after it.

The Possible Roles of ß-alanine and L-carnosine in Anti-aging.

alanine (BA), being a non-proteinogenic amino acid, is an important constituent of L-carnosine (LC), which is necessary for maintaining the muscle buffering capacity and preventing a loss of muscle mass associated with aging effects. BA is also very important for normal human metabolism due to the formation of a part of pantothenate, which is incorporated into coenzyme A. BA is synthesized in the liver, and its combination with histidine results in the formation of LC, which accumulates in the muscles and brain tissues and has a well-defined physiological role as a good buffer for the pH range of muscles that caused its rapidly increased popularity as ergogenic support to sports performance. The main antioxidant mechanisms of LC include reactive oxygen species (ROS) scavenging and chelation of metal ions. With age, the buffering capacity of muscles also declines due to reduced concentration of LC and sarcopenia. Moreover, LC acts as an antiglycation agent, ultimately reducing the development of degenerative diseases. LC has an anti-inflammatory effect in autoimmune diseases such as osteoarthritis. As histidine is always present in the human body in higher concentrations than BA, humans have to get BA from dietary sources to support the required amount of this critical constituent to supply the necessary amount of LC synthesis. Also, BA has other beneficial effects, such as preventing skin aging and intestinal damage, improving the stress-- fighting capability of the muscle cells, and managing an age-related decline in memory and learning. In this review, the results of a detailed analysis of the role and various beneficial properties of BA and LC from the anti-aging perspective.

An Update on Glutathione's Biosynthesis, Metabolism, Functions, and Medicinal Purposes.

Glutathione (GSH) has been the focus of increased scientific interest in the last decades. It plays a crucial role in all major physiological processes by supplying antioxidant defenses through participating in cellular redox reactions in the human body and other living organisms. GSH also participates in detoxifying xenobiotics, protecting protein thiols from crosslinking and oxidation, regulating the cell cycle, storing cysteine, etc. The significant role of GSH in the most important physiological processes has been highlighted, such as maintaining the redox balance and reducing oxidative stress due to its ability to inactivate the reactive oxygen, nitrogen, and sulfur species. It can also enhance metabolic detoxification and regulate the function of the immune system. All of these characteristics make it a universal biomarker since its proper balance is essential for improving health and treating some age-related disorders. This review presents a current concept of the synthesis and metabolism of GSH; its main functions in a living organism, and as a precursor and cofactor; data on the use of GSH for medicinal purposes in the prevention and treatment of some diseases, as well as a nutritional strategy to maintain a normal pool of GSH in the body. The data were gathered by searching relevant information in multiple databases, such as PubMed, Scopus, ScienceDirect, and Google Scholar.

Medicinal Plant-Derived Phytochemicals in Detoxification.

The average worldwide human life expectancy is 70 years, with a significantly higher value in Western societies. Many modern diseases are not associated with premature mortality but with a decreased quality of life in aged patients and an excessive accumulation of various toxic compounds in the human body during life. Today, scientists are especially interested in finding compounds that can help increase a healthy lifespan by detoxifying the body. Phytotherapy with specific approaches is used in alternative medicine to remove toxins from the body. Worldwide, research is conducted to identify medicinal plant-derived molecules that, with few or no side effects, may protect the liver and other organs. This review provides updated information about the detoxification process, the traditional and modern use of the most effective medicinal plants, their active metabolites as detoxifying agents, and the mechanisms and pathways involved in the detoxification process. Among medicinal plants with substantial detoxifying properties, a major part belongs to the Asteraceae family (Silybum marianum, Cynara scolymus, Arctium lappa, Helichrysum spp, Inula helenium, and Taraxacum officinale). The most widely used hepatoprotective phytocomponent is silymarin, a standardized extract from the Silybum marianum seeds containing a mixture of flavonolignans. Many polysaccharides, polyphenols, and terpenoids have a detoxifying effect. Overall, scientific data on medicinal plants used in phytotherapeutic practice worldwide provides an understanding and awareness of their efficacy in detoxification.

Anticancer activity of broccoli, its organosulfur and polyphenolic compounds.

The use of natural bioactive constituents from various food sources for anticancer purposes has become increasingly popular worldwide. Broccoli (Brassica oleracea var. italica) is on the top of the consumed vegetables by the masses. Its raw matrix contains a plethora of phytochemicals, such as glucosinolates and phenolic compounds, along with rich amounts of vitamins, and minerals. Consumption of broccoli-derived phytochemicals provides strong antioxidant effects, particularly due to its sulforaphane content, while modulating numerous molecules involved in cell cycle regulation, control of apoptosis, and tuning enzyme activity. Thus, the inclusion of broccoli in the daily diet lowers the susceptibility to developing cancers. Numerous studies have underlined the undisputable role of broccoli in the diet as a chemopreventive raw food, owing to the content in sulforaphane, an isothiocyanate produced as a result of hydrolysis of precursor glucosinolates called glucoraphanin. This review will provide evidence supporting the specific role of fresh florets and sprouts of broccoli and its key bioactive constituents in the prevention and treatment of different cancers; a number of studies carried out in the in vitro and in vivo conditions as well as clinical trials were analyzed.

Natural Compounds Used for Treating Hair Loss.

Hair loss or alopecia is a common dermatological condition affecting up to 2% of the world population. It is often caused by hereditary factors, such as male or female pattern baldness, but it can also result from various environmental factors, an unbalanced diet, or chronic illness. While hair loss is not life-threatening, it can cause significant anxiety, depression, and other psychological problems, ultimately impacting an individual's quality of life. Various treatments for hair loss, including both synthetic drugs, such as minoxidil and finasteride, or medicinal herbs, have been approved by the Food and Drug Administration. Despite synthetic drugs' effectiveness, they may come with potential side effects. Natural remedies have been proposed as a viable option for treating hair loss because many chronic disorders can cause alopecia. As such, this review focuses on identifying alternative, efficient treatment agents with limited side effects. Specifically, it looks into medicinal plants as potential healing agents for treating hair loss. To gather relevant information for the study, multiple databases were searched, including Scopus, PubMed, and Google Scholar. A comprehensive search was conducted using a range of search terms, such as "hair loss", "alopecia", "natural remedies for hair loss", "herbal treatments for hair loss", and others to extract relevant scientific articles. Many medicinal plants and natural compounds have shown potential in reducing hair loss, thanks to their anti-inflammatory and antioxidant properties and the ability to improve local metabolism when applied externally. According to existing literature, herbal extracts and formulations derived from plants, such as Urtica dioica, Humulus lupulus, Serenoa repens, Vitis vinifera, Pygeum africanum, Cucurbita pepo, etc., as well as certain individual herbal compounds, micronutrients, bee products, and keratin, may be effective in reducing hair loss directly or indirectly. Research suggests that medicinal plants and a variety of natural compounds hold promise in promoting hair growth and preventing alopecia.

Pharmacological Treatments and Natural Biocompounds in Weight Management.

The obesity pandemic is one of society's most urgent public health concerns. One-third of the global adult population may fall under obese or overweight by 2025, suggesting a rising demand for medical care and an exorbitant cost of healthcare expenditure in the coming years. Generally, the treatment strategy for obese patients is largely patient-centric and needs dietary, behavioral, pharmacological, and sometimes even surgical interventions. Given that obesity cases are rising in adults and children and lifestyle modifications have failed to produce the desired results, the need for medical therapy adjunct to lifestyle modifications is vital for better managing obesity. Most existing or past drugs for obesity treatment target satiety or monoamine pathways and induce a feeling of fullness in patients, while drugs such as orlistat are targeted against intestinal lipases. However, many medications targeted against neurotransmitters showed adverse events in patients, thus being withdrawn from the market. Alternatively, the combination of some drugs has been successfully tested in obesity management. However, the demand for novel, safer, and more efficacious pharmaceutical medicines for weight management does exist. The present review elucidates the current understanding of the available anti-obesity medicines of synthetic and natural origin, their main mechanisms of action, and the shortcomings associated with current weight management drugs.

Natural Ingredients to Improve Immunity.

The immune system protects the body from infectious agents such as bacteria, viruses, or fungi. Once encountered with pathogens or antigens, the innate and adaptive arms of the immune system trigger a strong immune response to eliminate them from the system and protect the body. Thus, well-balanced immunity is pivotal for maintaining human health, as an insufficient level of immune defense leads to infections and tumors. In contrast, the excessive functioning of the immune system causes the development of autoimmune diseases and allergies. Strong immunity requires adequate nutrition, dietary interventions, and sufficient intake of certain vitamins (vitamin C, vitamin D, and folic acid) and minerals (magnesium, zinc, and selenium). Therefore, nutritional and micronutrient deficiencies lead to compromised immunity. Several natural ingredients have shown potent immunomodulatory properties. The immune-enhancing properties of many plants and fungi are due to containing bioactive phytoconstituents such as polyphenols, terpenoids, ß-glucans, vitamins, etc. Probiotics and prebiotics can be used as innovative tools to reduce intestinal inflammation and downregulate hypersensitivity reactions. Plant sources of melatonin, a multifunctional molecule with proven anti-inflammatory and immunomodulatory properties, have been discovered relatively recently. The bioactive compounds augment the immune response by directly increasing the cytotoxic activity of natural killer cells, macrophages, and neutrophils. Many phytoconstituents prevent cell damage due to their powerful antimicrobial, antioxidant, and anti-inflammatory properties. The present review attempts to understand the molecular mechanisms underlying the immune-enhancing properties of some bioactive compounds from plants, fungi, animals, microorganisms, and other natural sources.

Traditional Chinese Medicine as the preventive and therapeutic remedy for COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic still has tremendous impacts on the global socio-economy and quality of living. The traditional Chinese Medicines (TCM) approach showed encouraging results during previous outbreaks of Severe Acute Respiratory Syndrome-related coronavirus (SARS-CoV) and the Middle East Respiratory Syndrome Coronavirus (MERS-CoV). With limited treatment availability, TCM herbs and formulations could be viable to reduce COVID-19 symptoms and potential sources for discovering novel therapeutic targets. We reviewed 12 TCM herbs and formulations recommended for COVID-19 management by the National Health Commission and National Administration of Traditional Chinese Medicine, the People's Republic of China. This article explored the Chinese national authorities' guidelines from 2003 to 2020, the scientific data in public databases for the recommended TCM remedies, and their potential mechanistic actions in COVID-19 management. Several TCM herbs and formulations could potentially benefit COVID-19 management. The recommended TCM oral preparations list are Huoxiang zhengqi, Jinhua Qinggan, Lianhua Qingwen, and Shufeng jiedu; the recommended injection preparations comprise Xiyanping Xuebijing, Re-Du-Ning, Tanreqing, Xingnaojing, Shenfu, Shengmai, and Shenmai. TCM remedies are viable options for symptom alleviation and management of COVID-19. The current SARS-CoV-2 pandemic presents an opportunity to find novel therapeutic targets from TCM-active ingredients. Despite the recommendations in Chinese National guidelines, these remedies warrant further assessments in well-designed clinical trials for their efficacies in COVID-19.

The Role of Astaxanthin as a Nutraceutical in Health and Age-Related Conditions.

The current review provides an up-to-date analysis of scientific data on astaxanthin (ASX) sources and experimental studies on its health benefits as a potent antioxidant in the aging process. ASX is a liposoluble carotenoid nutrient and reddish-orange pigment, naturally synthesized by numerous microalgae, yeasts, and bacteria as secondary metabolites. Provides a reddish hue to redfish and shellfish flesh that feed on ASX-producing microorganisms. The microalga Haematococcus pluvialis is the most important source for its industrial bioproduction. Due to its strong antioxidant properties, numerous investigations reported that natural ASX is a more significant antioxidant agent than other antioxidants, such as vitamin C, vitamin E, and ß-carotene. Furthermore, several data show that ASX possesses important nutraceutical applications and health benefits, especially in healthy aging processes. However, further studies are needed for a deeper understanding of the potential mechanisms through which ASX could lead to its effective role in the healthy aging process, such as supporting brain health and skin homeostasis. This review highlights the current investigations on the effective role of ASX in oxidative stress, aging mechanisms, skin physiology, and central nervous system functioning, and shows the potential clinical implications related to its consumption.

Polyphenols in Metabolic Diseases.

Polyphenols (PPs) are a large group of phytochemicals containing phenolic rings with two or more hydroxyl groups. They possess powerful antioxidant properties, multiple therapeutic effects, and possible health benefits in vivo and in vitro, as well as reported clinical studies. Considering their free-radical scavenging and anti-inflammatory properties, these substances can be used to treat different kinds of conditions associated with metabolic disorders. Many symptoms of metabolic syndrome (MtS), including obesity, dyslipidemia, atherosclerosis, elevated blood sugar, accelerating aging, liver intoxication, hypertension, as well as cancer and neurodegenerative disorders, are substantially relieved by dietary PPs. The present study explores the bioprotective properties and associated underlying mechanisms of PPs. A detailed understanding of these natural compounds will open up new opportunities for producing unique natural PP-rich dietary and medicinal plans, ultimately affirming their health benefits.

Selenium: An Antioxidant with a Critical Role in Anti-Aging.

Aging is characterized by an imbalance between damage inflicted by reactive oxygen species (ROS) and the antioxidative defenses of the organism. As a significant nutritional factor, the trace element selenium (Se) may remodel gradual and spontaneous physiological changes caused by oxidative stress, potentially leading to disease prevention and healthy aging. Se is involved in improving antioxidant defense, immune functions, and metabolic homeostasis. An inadequate Se status may reduce human life expectancy by accelerating the aging process or increasing vulnerability to various disorders, including immunity dysfunction, and cancer risk. This review highlights the available studies on the effective role of Se in aging mechanisms and shows the potential clinical implications related to its consumption. The main sources of organic Se and the advantages of its nanoformulations were also discussed.

Natural Compounds and Products from an Anti-Aging Perspective.

Aging is a very complex process that is accompanied by a degenerative impairment in many of the major functions of the human body over time. This inevitable process is influenced by hereditary factors, lifestyle, and environmental influences such as xenobiotic pollution, infectious agents, UV radiation, diet-borne toxins, and so on. Many external and internal signs and symptoms are related with the aging process and senescence, including skin dryness and wrinkles, atherosclerosis, diabetes, neurodegenerative disorders, cancer, etc. Oxidative stress, a consequence of the imbalance between pro- and antioxidants, is one of the main provoking factors causing aging-related damages and concerns, due to the generation of highly reactive byproducts such as reactive oxygen and nitrogen species during the metabolism, which result in cellular damage and apoptosis. Antioxidants can prevent these processes and extend healthy longevity due to the ability to inhibit the formation of free radicals or interrupt their propagation, thereby lowering the level of oxidative stress. This review focuses on supporting the antioxidant system of the organism by balancing the diet through the consumption of the necessary amount of natural ingredients, including vitamins, minerals, polyunsaturated fatty acids (PUFA), essential amino acids, probiotics, plants' fibers, nutritional supplements, polyphenols, some phytoextracts, and drinking water.

Quercetin in the Prevention and Treatment of Coronavirus Infections: A Focus on SARS-CoV-2.

The COVID-19 outbreak seems to be the most dangerous challenge of the third millennium due to its highly contagious nature. Amongst natural molecules for COVID-19 treatment, the flavonoid molecule quercetin (QR) is currently considered one of the most promising. QR is an active agent against SARS and MERS due to its antimicrobial, antiviral, anti-inflammatory, antioxidant, and some other beneficial effects. QR may hold therapeutic potential against SARS-CoV-2 due to its inhibitory effects on several stages of the viral life cycle. In fact, QR inhibits viral entry, absorption, and penetration in the SARS-CoV virus, which might be at least partly explained by the ability of QR and its derivatives to inhibit 3-chymotrypsin-like protease (3CLpro) and papain-like protease (PLpro). QR is a potent immunomodulatory molecule due to its direct modulatory effects on several immune cells, cytokines, and other immune molecules. QR-based nanopreparations possess enhanced bioavailability and solubility in water. In this review, we discuss the prospects for the application of QR as a preventive and treatment agent for COVID-19. Given the multifactorial beneficial action of QR, it can be considered a very valid drug as a preventative, mitigating, and therapeutic agent of COVID-19 infection, especially in synergism with zinc, vitamins C, D, and E, and other polyphenols.

Natural Dietary Compounds in the Treatment of Arsenic Toxicity.

Chronic exposure to arsenic (As) compounds leads to its accumulation in the body, with skin lesions and cancer being the most typical outcomes. Treating As-induced diseases continues to be challenging as there is no specific, safe, and efficacious therapeutic management. Therapeutic and preventive measures available to combat As toxicity refer to chelation therapy, antioxidant therapy, and the intake of natural dietary compounds. Although chelation therapy is the most commonly used method for detoxifying As, it has several side effects resulting in various toxicities such as hepatotoxicity, neurotoxicity, and other adverse consequences. Drugs of plant origin and natural dietary compounds show efficient and progressive relief from As-mediated toxicity without any particular side effects. These natural compounds have also been found to aid the elimination of As from the body and, therefore, can be more effective than conventional therapeutic agents in ameliorating As toxicity. This review provides an overview of the recently updated knowledge on treating As poisoning through natural dietary compounds. This updated information may serve as a basis for defining novel prophylactic and therapeutic formulations.

Nano-Silica Carriers Coated by Chloramphenicol: Synthesis, Characterization, and Grinding Trial as a Way to Improve the Release Profile.

Silica nanoparticles were applied as the carrier of chloramphenicol (2,2-dichloro-N-[(1R,2R)-1,3-dihydroxy-1-(4-nitrophenyl)propan-2-yl]acetamide), and were loaded in a 1% carbopol-based gel (poly(acrylic acid)), which allowed obtainment of an upgraded drug form. The samples of silica materials were obtained by means of modified Stöber synthesis, and their morphological properties were analyzed using Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) method, elemental analysis (EA), thermogravimetric analysis (TGA), analysis of the specific surface properties, X-ray diffraction study (XRD), scanning electron microscope (SEM), and dynamic light scattering (DLS) methods, which permitted the selection of the drug carrier. The two obtained silica carriers were coated with chloramphenicol and loaded into 1% carbopol gel. The release studies were then performed. The release results were evaluated using mathematical models as well as model-independent analysis. It was found that the modification of the synthesis of the silica by the sol-gel method to form a product coated with chloramphenicol and further grinding of the silica material influenced the release of the active substance, thus allowing the modification of its pharmaceutical availability. The change in the parameters of silica synthesis influenced the structure and morphological properties of the obtained silica carrier. The grinding process determined the way of adsorption of the active substance on its surface. The studies showed that the proper choice of silica carrier has a considerable effect on the release profile of the prepared hydrogel formulations.

Chemical Variability and Pharmacological Potential of Propolis as a Source for the Development of New Pharmaceutical Products.

This review aims to analyze propolis as a potential raw material for the development and manufacture of new health-promoting products. Many scientific publications were retrieved from the Scopus, PubMed, and Google Scholar databases via searching the word "propolis". The different extraction procedures, key biologically active compounds, biological properties, and therapeutic potential of propolis were analyzed. It was concluded that propolis possesses a variety of biological properties because of a very complex chemical composition that mainly depends on the plant species visited by bees and species of bees. Numerous studies found versatile pharmacological activities of propolis: antimicrobial, antifungal, antiviral, antioxidant, anticancer, anti-inflammatory, immunomodulatory, etc. In this review, the composition and biological activities of propolis are presented from a point of view of the origin and standardization of propolis for the purpose of the development of new pharmaceutical products on its base. It was revealed that some types of propolis, especially European propolis, contain flavonoids and phenolic acids, which could be markers for the standardization and quality evaluation of propolis and its preparations. One more focus of this paper was the overview of microorganisms' sensitivity to propolis for further development of antimicrobial and antioxidant products for the treatment of various infectious diseases with an emphasis on the illnesses of the oral cavity. It was established that the antimicrobial activity of different types of propolis is quite significant, especially to Gram-negative bacteria and lipophilic viruses. The present study could be also of interest to the pharmaceutical industry as a review for the appropriate design of standardized propolis preparations such as mouthwashes, toothpastes, oral drops, sprays, creams, ointments, suppositories, tablets, and capsules, etc. Moreover, propolis could be regarded as a source for the isolation of biologically active substances. Furthermore, this review can facilitate partially overcoming the problem of the standardization of propolis preparations, which is a principal obstacle to the broader use of propolis in the pharmaceutical industry. Finally, this study could be of interest in the area of the food industry for the development of nutritionally well-balanced products. The results of this review indicate that propolis deserves to be better studied for its promising therapeutic effects from the point of view of the connection of its chemical composition with the locality of its collection, vegetation, appropriate extraction methods, and standardization.

A review on natural teeth whitening.

BACKGROUND: Discoloration of teeth occurs for various reasons. Common ingredients like substances from tea and coffee, as well as antibiotics like tetracycline, or food dyes, can percolate into the teeth, and, as such, these stains may persist in the porous structure of the enamel. Smoking is also contributory to dental discoloration, with toxins of tobacco smoke accumulating in a similar way. With aging, teeth tend to be discolored with accumulation of various stains in addition to the enamel gradually eroding to expose the yellow dentin. HIGHLIGHT: This review focused on the effect of several natural ingredients with teeth-whitening properties and their daily clinical application. Metabolic dental bleaching mechanisms, as well as tooth discoloration and decay, were also reviewed. The current scientific literature (mostly from 2000 to 2020) was consolidated from manuscripts retrieved from Scopus, PubMed, ResearchGate, and Google Scholar. CONCLUSION: Natural teeth whitening effectively lightens the natural color of teeth without eroding dental surfaces. On the other hand, commercially available whiteners containing hydrogen peroxide and carbamide peroxide, in high concentrations, can lead to deproteinization and demineralization of teeth through oxidation processes. If used extensively, these compounds may cause a number of adverse effects. Alternative natural teeth-whiteners include ingredients like lemons, strawberries, oranges, papaya, and other fruits. Such natural ingredients offer a milder and safer way of whitening teeth than whiteners containing hydrogen peroxide or carbamide peroxide.