“Dr. Rana has a wealth of knowledge in phytochemistry. This topic is of interest to cosmetic scientists, formulators, analytical scientists, chemists and biochemists who want to enhance their knowledge and capabilities using botanical ingredients in product development,” said event organizer and NYSCC board member Suzanne Davis in her introduction.
The seminar spanned from an introduction to plant materials and their compounds to the development of skin lightening products using botanical ingredients.
Rana is no stranger to nature. Raised in the foothills of the Himalayas, he is now the director of technical services and product development at Innophos Nutrition, Inc. Cranbury, NJ and previous worked in R&D at Amway. Rana is an active member of Society of Cosmetic Chemists (SCC), International Association of Analytical Communities (AOAC), member of American Chemical Society (ACS) and Asian Congress of Nutrition (ACN). He has chaired many scientific sessions at the national and international level.
So, what exactly is a natural product? According to Rana, it is a chemical compound or substance produced by a living organism that is found in nature.
“When a chemical compound is obtained from the plant, the term ‘phytochemical’ is implied,” he said. “Organic compounds in nature are produced by the pathways of primary or secondary metabolism by a process called biosynthesis, which is the entry of inorganic carbon dioxide (CO2) and its conversion into important compounds. This happens in all living systems to produce natural products.”
Acetogenins, a class of polyketide natural products found in plants of the family Annonaceae, were also a topic on hand. They are otherwise known as “natural and safe chemicals” utilized in nutraceuticals. They are characterized by linear 32- or 34-carbon chains containing oxygenated functional groups including hydroxyls, ketones, epoxides, tetrahydrofurans and tetrahydropyrans. They are often terminated with a lactone or butenolide.
Meanwhile, flavonoids are groups of aromatic plant pigments, which are biosynthesized via a confluence of the acetate/malonate and shikimate pathways. They are found virtually in all land-based green plants.
Another category of acetogenins are lipids (fats and oils, waxes and phospholipids). According to Rana, “Typically, people mean fat when they refer to lipids, but this is incorrect. Lipids are molecules that are soluble in fat. So, all fats are lipids, but not all lipids are fats!”
For the application of lipid nanoparticles in skin care, there are many different techniques described in literature for the production of lipid nanoparticles. Commonly, lipid nanoparticles are obtained by mixing the melted lipid with an aqueous medium containing a surfactant, followed by application of mechanical forces (ultrasounds or high pressure) to break the oil droplets at a nanometer size. When cooled to room temperature, these droplets solidify into nanoparticles. The final product is a milky dispersion, containing the lipid nanoparticles dispersed into the aqueous medium.
Saponifiable lipids are common in the personal care industry. Saponification is the process that produces soaps from the reaction of fats and a strong base. The saponifiable lipids contain long chain carboxylic acids, or fatty acids, esterified to a “backbone” molecule, which is normally glycerol.
The subsequent issue was quinones—in particular, Chinese rhubarb for skin care application.
“The antioxidant activity of quinone and its derivatives are well documented,” said Rana.
Phenolic compounds are important for the quality of plant-based foods; they are responsible for the color of red fruits, juices and wines and substrates for enzymatic browning, and are also involved in flavor properties.
Finally, polyphenolic compounds play an important role in health and beauty applications, noted Rana. These compounds combat “free radicals” and act as an antioxidant.
What are free radicals? According to Rana, free radicals are produced through:
• Inflammatory responses,
• Immune functions, and
Free radical sources include pollution, sunlight, smoke, X-rays, fried foods and even exercise, according to the speaker.
The skin uses a series of “intrinsic antioxidants” to protect itself from free radical damage. These are natural defenders for healthy cells in the body.
Unlike sunscreens, which have an SPF rating system to guide consumers in their purchases, there is no widely accepted method to choose antioxidant anti-aging products, said Rana. Several biological assays are used to assess the ability of natural ingredients to protect skin aging.
If we don’t know which compounds are specifically responsible for the biological activity, one or more natural constituents present in the plant material, referred to as “marker compounds” are selected and used to test for quality. If therapeutic effects can be assigned to the activity of one, or even a few, well-defined constituents—those can be labelled as “active markers.”
The following imperative issue was tyrosinase inhibitors for skin-lightening application.
“Many tyrosinase inhibitors, such as hydroquinone, kojic acid, azelaic acid, electron rich-phenols and arbutin, have been tested in pharmaceuticals and cosmetics for their capability of preventing overproduction of melanin,” said Rana. “Meanwhile, their structure-activity relationship analysis has been widely discussed.”
Hydroquinone is one of the most frequently prescribed ingredients among the conventional skin-whitening agents. However, hydroquinone causes skin irritation, said Dr. Rana.
“This leads to the use of kojic acid and arbutin as alternative agents, but these agents show poor efficacy in vivo,” he said. “In addition, due to their adverse side effects, low formulation stability and poor skin penetration, their use is still limited. Japanese officials also spurred to ban the use of kojic acid in skin treatment due to its carcinogenicity.”
Rana concluded that there is a great need for developing new tyrosinase inhibitors from different sources such as plants.
“Natural products, especially botanicals, have been extensively utilized in the cosmetics industry. Botanical ingredients, in general, offer lower adverse side effects than synthetic ingredients.”