About 12,000 years ago, agriculture began. This development, known as the Neolithic Revolution, triggered major changes in human society and to how humans lived. The traditional hunter-gatherer lifestyles that had sustained humans since their evolution were replaced by permanent settlements with reliable food supplies. When crops and animals could be farmed to meet increasing demands, cities and civilizations grew, and global population increased from around five million people 10,000 years ago to more than seven billion people today.

The essence of agriculture is humans obtaining energy by intaking and oxidizing carbohydrates, which are photosynthesized by plants using sunlight as a key component. However, burning carbohydrates for energy produces unwanted oxidative stresses in our body. As such, we have been trying to find ways to combat such excessive oxidative stresses. One proven approach is to seek food rich in antioxidants.

Deeply rooted in plant evolution, antioxidant molecules are produced in all farm plants and are plentiful in many agricultural food sources. This is because the plants, like us, rely on antioxidants. Plants use antioxidants to overcome two major sources of threats: solar oxidative stresses and biological stresses.

Solar oxidative stresses originate from sunlight, the very source of all energy on earth.  Sunlight is not a light source of constant intensity; we are all part of a moving universe, and such movements cause fluctuations in the intensity of the sunlight reaching a particular plant. To protect themselves against excessive sunlight and the associated oxidative stresses, plants produce antioxidative molecules. These molecules work using three different mechanisms:

• Some molecules start to absorb sunlight energy directly when it becomes too strong for the photosynthesis unit. These molecules function like smart umbrellas for chlorophylls and start to work whenever chlorophylls are overloaded by sunlight.
• Other antioxidants work by receiving (quenching) excited state energy from chlorophylls, preventing the chlorophylls from suffering injuries caused by excess energy.
• When the first two mechanisms fail to protect the chlorophylls and free radicals are produced as a consequence of oxidative stress in the photosynthesis unit, antioxidants that neutralize the free radicals effectively protect the plant from unintended solar oxidative stresses.

The most common antioxidants with these functions are beta-carotene and lycopene.

Biological stresses are commonly presented by animals, despite plants relying on them for help with pollination. A major reason why plants produce aromatic components is so they can attract animals to help them; however, animals may overeat plant fruits, and herbivores and pathogens may attack leaves and fruits, stopping the plants’ normal life cycles. Therefore, plants produce antioxidants so that they are less attractive to herbivores and pathogens. They also produce antioxidants with high chemical oxygen demand (COD) so that things cannot grow on them. Vitamin E is one example of such an antioxidant, and a lot of phenolic antioxidants function this way as well.

Human beings have been absorbing and using these plant antioxidants by eating the plants. We are all aware of the importance of a balanced diet rich in antioxidants; we live in an oxidizing environment, and our body produces life-sustaining energy by burning carbohydrates. Balancing the resulting oxidative stresses is critical to human health.

Skin is the largest human organ, and it is often subjected to both solar and biological stresses. While some of the antioxidants we consume can end up in our skin, there are many reasons why we should explore better ways to deliver antioxidants to the skin. The major reason is that not all antioxidants can be eaten. They may be too unattractive to our taste buds (Recall that this is one of the design principles of plant antioxidants!) or too difficult to absorb through our digestive system.

Even after decades of food industrialization, many plant antioxidants still go to waste. Often the food processing technology is not capable of picking up all the antioxidants. Other times, we do not want to include some valuable antioxidants in our food because they are difficult to swallow.

Therefore, agriculture-based cosmetic active ingredients are a promising technology for humans to further enhance their overall health. Developing this technology will also result in more comprehensive utilization of plant resources. Key areas for technological advancement include:

• Better harvesting of plant antioxidants through researching innovative extraction methods and utilizing plant materials that are unsuitable for the food industry.
• Better delivery of plant actives to human skin through innovative cosmetic and delivery system formulation. One of the recent key advancements is to formulate a homogenous and uniform cosmetic layer on the skin surface to serve as a steady administrating reservoir of these actives during the entire time the cosmetic product is on the skin.

We will further expand on some of these topics in our future contributions to this forum.

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