While we would all love to use natural products as preservatives, we are confusinig antioxidants with preservatives.
According to the Merriam - Webster Dictionary, preservatives are "an additive used to protect against decay, discoloration, or spoilage". The only way to do that with certainty is to add a chemical agent.
However, there are natural items that can reduce microbial activity (such as essential oils) and can have some preservative qualities.
Technically, the following items are antioxidants and not preservatives. Oxidation occurs when light and air hits oils and turns them rancid. Antioxidants are designed to protect the oils from spoiling and opening the door to other contaminants. This process cannot be stopped completely, but using an antioxidant considerably slows down the process. Using an antioxidant will increase the shelf life of natural products and are still safe for your skin. The top three natural antioxidants used in natural skin care are listed below:
Rosemary Extract (INCI Nomenclature: Rosmarinus Officinalis (Rosemary) Leaf Extract) Also known as rosemary oleoresin.
Distilled from rosemary leaves, rosemary extract is perhaps the most effective of this antioxidant class. It is not the same as rosemary essential oil. Rosemary Extract (ROE) is a stronger formulation and includes more of the products of distillation. Using ROE will give off a slight herbaceous smell, but it can be covered or enhanced by other fragrances. In fact, many manufacturers create formulas that highlight the rosemary scent. ROE is oil soluble and should be blended in the oil stage of making lotions and creams.
Vitamin E (INCI Nomenclature: Tocopherols)
The oldest and most well known of all antioxidants. Vitamin was the first to be introduced to the market and was not only used as an antioxidant, but as a moisturizer. Like ROE, Vitamin E is oil soluble. Not only can vitamin E add to the creaminess of a blend it does provide protection. There are 2 types of vitamin E oil available: natural (d-tocopherol) and synthetic (dl-tocopherol). Only the natural vitamin E has antioxidant value. If you wish to use vitamin E for its protection qualities you can find NATURAL Vitamin E in capsules from health food stores.
Grapefruit Seed Extract (INCI: Citrus Grandis and Glycerin)
A newcomer to the natural preservative category, grapefruit seed extract is just that – the extract from pulverized grapefruit seeds. Many people use GSE for its anti-fungal properties and some antimicrobial activity. Due to these qualities, it is suggested GSE may be more powerful than ROE or Vitamin E.
However, there is some debate as to the efficacy of using GSE. Again, GSE is not a true preservative, but an antioxidant. The other major downfall of GSE is that it is also extracted with synthetic compounds, including methylparaben.http://caren-young.suite101.com/natural-preservatives-a65795