Introduction: The number of molecules in nature can be considered virtuallyunlimited, thanks to the various possible combinations of the arrangement andrearrangement of the atoms.
Since the year 1800 thru the first half of 2015,over 101 million organic and inorganic molecules have been discovered andcataloged worldwide, many of which produced by natural, synthetic andbiosynthetic mechanisms of chemical engineering (1). This number, however,seems to be only a fraction of the molecular universe, yet unexplored, of ourplanet. Throughout the ages mankind has benefited from natural medicines totreat or prevent a broad spectrum of diseases. Indeed, secondary metabolitesfrom plants, microorganisms and marine products have been long considered asvaluable sources of novel molecules with potential for drug development innumerous biomedical areas (2). To date, a very high number of conditionsaffecting the oral health can be prevented, ameliorated and/or treated with theuse of natural product (NP)-based drugs or formulations. There is a long listof NP-derived and NP-inspired drugs (3), mouthwashes, and toothpastes etc.
thathave been available over the counter or under prescription. Longer yet is thelist of reasons why the search for novel treatment modalities should not cease.Microbial resistance, short- and long-term toxicity, adverse and side effects,high costs for the end user, compromised sustainability of industriallarge-scale production, among many others. Furthermore, the consumer demand for nutritional,medicinal and cosmetic products derived from natural sources has beenincreasing in last decade.
Accordingly, the industry of natural products hasconsecutively been growing. Back the middle 1970s, natural products industryrepresented an estimated US $2.4 billion/year. In 2011, it was value at US $91billion/year with a growth rate of 7.
4% from the previous year in the globalsales 8, 9. Particularly, natural cosmetic products has an annual growingof 9-10% across Europe, North America and Asia Pacific regions with US $8.2billion in sale in 2013 10, 11. The renewed consumer interest in natural cosmeticproducts has also sparked the increase of research in field of medicinal,aromatic and cosmetic (MAC) plants extracts to use and/or take advantages fromthem in health and cosmetic care products 12. The discovery of the biologicalproperties of natural sources and derivatives allows the formulation of newbioactive products that contribute to health, beauty and wellness of humans,and add value to products marketed 12–14. According to the European Union (EU) Cosmetics Regulation,anything which can perform the followings for external parts of the human body(epidermis, hair system, nails, lips and external genital organs), teeth andmucous membranes of the oral cavity in order to cleaning them, perfuming them,changing their appearance and/or correcting body odors and/or protecting themor keeping them in good condition can be classified as cosmetic products 15.
Opposing to the European legislation, Food and Drug Administration (FDA) considersthat sunbath products, moisturizers and makeup marketed with sun-protectionclaims, skin-whitening products, anti-wrinkle products, antidandruff shampoos,toothpastes that contain fluoride, deodorants that are also antiperspirants,and cosmetic textiles are drugs, since these products include one or morecompounds with biological activity and/or affect the body’s structure orfunctions 16, 17. Cosmetics can be grouped in 7 categories: skin care andmaintenance; cleansing; odor improvement; hair removal; hair care andmaintenance; care and maintenance of mucous membranes; and decorative cosmetics18. Though not consensual, textile cosmetics can be a skin care cosmetic19, 20. The cosmetic properties of aromatic plants, especially asfragrance, are attributed to essential oils (EOs) and extracts. Hence, EOs arenormally an ingredient present in all categories of cosmetic products 21.
Herbs have been used in medicines andcosmetics from centuries. Their potential to treat different skin diseases, toadorn and improve the skin appearance is well-known. As ultraviolet (UV)radiation can cause sunburns, wrinkles, lower immunity against infections,premature aging, and cancer, there is permanent need for protection from UVradiation and prevention from their side effects. Herbs and herbal preparationshave a high potential due to their antioxidant activity, primarily.Antioxidants such as vitamins (vitamin C, vitamin E), tannin, flavonoids, andphenolic acids play the main role in fighting against free radical species thatare the main cause of numerous negative skin changes.
Although isolated plantcompounds have a high potential in protection of the skin, whole herbs extractsshowed better potential due to their complex composition. Earlier studies hadshown that green and black tea (polyphenols) ameliorate adversative to the skinreactions for UV exposure. The gel from aloe vera is believed to stimulate skinand assist in new cell growth. Extract of Krameria triandra has a majorcomponent octyl methoxycinnamate which can absorbs 25 to 30% of the amount ofUV radiation.
Sesame oil resists 30% of UV rays, while coconut, peanut, olive,and cottonseed oils block out about 20%. A “sclerojuglonic” compound can beformed from naphthoquinone and it can produce keratin in the reaction thatprovides UV protection. Traditional use of plant in medication orbeautification is the basis for researches and making new trends in cosmetics.
This review covers all essential aspects of potential of herbs as radioprotectiveagents and its future prospects 7. Phenoliccompounds are secondary plant metabolites, produced in response to differentstresses such as infections, wounding, ultraviolet (UV) irradiation, ozone,pollutants, etc. Theanti-inflammation, inhibit tumor growth, pro-apoptotic and anti-angiogenicactions, antimicrobial, antiviral, and antiaging properties, modulate theimmune system, increase capillary resistance, protect the cardiovascular andneurological systems, limit weight gain, promote wound healing, etc can beachieved by using single type of secondary metabolite ie flavonoids. Polyphenolicsare used in numerous sectors of the food and cosmetic industry as naturaladditives (natural coloring agents, conservative agents, natural antioxidants,nutritional additives) 24. Polyphenols currently contributes on their bioavailability, antioxidative and anticarcinogenicproperties. Polyphenols protective role can be seen against reactive oxygen andnitrogen species, UV light, plant pathogens, parasites and predators. Itresults in several beneficial biological activities giving rise to prophylaxisor possibly even to a cure for several prevailing human diseases, especiallyvarious cancer types.
Omnipresence, specificity of the response and the absenceof or low toxicity is crucial advantages of polyphenols as anticancer agents.The main problem represents their low bioavailability and rapid metabolism. Oneof the promising solutions lies in nano-formulation of polyphenols thatprevents their degradation and thus enables significantly higher concentrationsto reach the target cells. A very common process of solution is the use ofmixtures of various polyphenols that bring synergistic effects, resulting inlowering of the required therapeutic dose and in multi targeted action. Existingdrug and polyphenols combination therapies also shown a promising output withsignificantly lower toxicity 25.
EOs are a complex liquid mixture of volatile, lipophilicand odoriferous compounds bio synthesized by living organisms, predominantlyaromatic plants 29. The major plants families from which EOs are extractedinclude Asteraceae, Myrtaceae, Lauraceae, Lamiaceae, Myrtaceae, Rutaceae andZingiberaceae, the dicotyledonous angiosperm plant families. They are secondarymetabolites produced in cytoplasm and plastids of plant cells 22 and storedin secretory cells, cavities, canals, epidemic cells or glandular trichomes 27.Present in different parts of the plants (buds, flowers, leaves, stems, twigs,seeds, fruits, roots, wood, bark, or rhizome), EOs are usually extracted byprocesses of steam distillation, solid phase extraction, cold pressing, solventextraction, supercritical fluid extraction, hydro distillation 13, 23, 27,or simultaneous distillation-extraction 28, 30. Among cosmetics, the EO aremainly used in perfumes, and skin and hair care products 23. In the globalbeauty market, skin care products, mostvaluable category, accounting for 23% value share of total sales in 2009 34.
However, EOs have a short shelf life, since they are volatile and reactive inpresence of light, heat, moisture, and oxygen. To overcome these challenges,microencapsulation has been considered as one of the most effective techniques26. Furthermore, microencapsulation provides the controlled-release deliveryand improves the handling of the EOs 35. Although EOs include substances with distinct organicfunctional groups, such as alcohols, aldehydes, esters, phenols, hydrocarbons,EOs are mostly monoterpenes, sesquiterpenes and diterpenes 31.
300 ofapproximately 3000 EOs produced by using about 2000 plant species arecommercially important. Their characteristic flavor and fragrance properties,as well as various biological activities, have been increasingly studied andreported in the scientific literature. In cosmetic products, EOs play a major ruleas fragrance ingredients 32. However, additional properties of EOs may bevery capable and fascinating for cosmetics products, for example EOs withantibacterial or antifungal activities countenance reducing the use ofpreservatives components in a product 33. However, a systematic review undertaken by Freires IA group (4)revealed that 22 and 40% of the studies on the anti-caries activity ofessential oils, natural products and their isolated constituents do not reportany chemical and botanical characterization data, respectively.This issue has raised concerns not only about the scientificvalidation of the findings reported but also because this could create a gapbetween the in vitro and in vivo bioactivity identified and an effective use ofthat information to develop novel drugs or formulations with advantageous clinicalefficacy and safety in humans. Although 49% of the new chemotherapeutic drugsand 73% of the new antibacterials approved by the US Food and DrugAdministration are NP or NP-derived drugs (3), a tremendous number of herbalmolecules do not reach the minimum requirements to be tested in and used byhumans, particularly for oral care product development. Apart from thebiological effectiveness of the molecule itself, in several cases this is aresult of poorly designed, superficial basic research that does not provideconsistent evidence to support the clinical testing of NP and derivedmolecules.
Jeon et al. (5) pointed out that most studies in caries researchhave focused on general aspects (microbial inhibitory effects) rather thanaddressing the actual pathophysiological aspects of the disease, which isbiofilm-dependent and involves physicochemical processes of tooth de- andremineralization. It seems consensual that there is a persistent need for morepotent, effective, low-cost, safe and well tolerated drugs and oral careformulations in dentistry, skin care formulations in cosmetics. As the years goby, a high number of studies concerning bioactivity of plant extracts andisolated molecules with clinical interest have been published worldwide.
Therehave been reports on antibacterial, antifungal, anti-inflammatory,antinociceptive, saliva stimulant, anti-halitosis, anti-caries, anti ageing,anti elastase, low telomerase affectivity etc properties of the most diverseplant materials and molecules nature can provide.Hence, the precise mechanisms of action and effectiveness of thetested extracts/compounds remain fatally unknown until further research—ifrelevant—is carried out. Another critical limitation lies in the non-use of modernmethods and technology, including bioinformatics, identification of moleculartargets in the human genome (6), high-throughput screening and appropriatestatistical models, among others. These tools allow the researcher tocomprehensively characterize the extract, fraction or molecule prior to clinicaltesting concerning bioactivity, local or systemic toxicity, pharmacokineticsand pharmacodynamics. As such, they may provide consistent evidence on naturalproduct effectiveness and safety along with reduced financial burden and riskof failure at further stages. Given these limitations, what has been the real impact of naturalproduct research on the oral health care and cosmetic industry over the last 15years? How far has research led to novel NP-based therapeutic modalities toguide decision-making in dentistry and cosmetic product, is still unknown tothe scientific world.
Here I propose my thesis work to bridge the gap betweenknowledge and formulation of Indian Traditional Medicinal plants in oralhealthcare and cosmetics.