A phytosome is a molecular complex designed to improve the body’s absorption of beneficial plant compounds. The term combines “phyto,” meaning plant, with “some,” referring to a cell-like structure. This technology addresses a major limitation in herbal medicine, where many powerful natural compounds, such as polyphenols and flavonoids, exhibit poor absorption after being taken orally.
These beneficial plant extracts often have a chemical structure that prevents them from efficiently crossing the fatty barriers of the human digestive system. Phytosome technology overcomes this challenge by creating a specialized molecular complex that enhances the uptake and effectiveness.
Defining the Phytosome Structure
The core of a phytosome lies in its unique chemical architecture, which is a standardized plant extract complexed with a phospholipid molecule. This process typically involves reacting the herbal constituent with phosphatidylcholine, a main component of human cell membranes. Unlike a simple mixture, the active plant compound forms a specific chemical bond with the polar head of the phospholipid molecule.
This bond anchors the plant compound to the lipid structure. The resulting entity is a lipid-compatible molecular complex, where the active ingredient is chemically integrated, not merely encapsulated. This precise structural arrangement means the plant constituent becomes an integral part of the lipid complex, creating a hybrid molecule that the body’s digestive system recognizes as fat-like. The ratio of the active plant compound to the phospholipid is often stoichiometric, such as a 1:1 or 2:1 ratio.
The Mechanism of Enhanced Bioavailability
The structural transformation into a phytosome directly addresses the challenge of low oral bioavailability faced by many plant extracts. Most cell membranes in the human body are lipophilic because they are composed of a phospholipid bilayer. Plant compounds that are water-soluble struggle to pass through this fatty barrier in the digestive tract to enter the bloodstream.
By chemically binding the plant compound to phosphatidylcholine, the phytosome significantly increases the lipophilicity of the combined molecule. This new lipid-compatible structure is far better equipped to interact with and seamlessly integrate into the intestinal cell membranes. The phytosome acts as a biological ferry, carrying the poorly absorbed active ingredient across the gastrointestinal wall.
Once the phytosome complex crosses the membrane, the active plant constituent is delivered into the circulation, resulting in a significantly higher concentration in the plasma compared to the free, uncomplexed extract. This enhanced absorption rate allows for a lower required dosage to achieve the desired therapeutic effect.
How Phytosomes Differ from Liposomes
Phytosomes and liposomes are both lipid-based delivery systems, but they differ in their molecular organization. Liposomes are microscopic, spherical vesicles formed when phospholipids self-assemble into one or more concentric bilayers in an aqueous environment. They function by physically encapsulating the active ingredient, which resides either within the central water-filled core or between the lipid layers.
The defining difference is that liposomes do not form a chemical bond with the ingredient they carry; the relationship is one of physical entrapment. In contrast, a phytosome forms a specific molecular complex where the active plant compound is chemically linked to the phospholipid head. This makes the plant compound an integral structural component of the phytosome, not just cargo trapped within a vesicle. This tighter chemical association contributes to their superior stability and enhanced ability to pass through biological membranes compared to simple lipid encapsulation.
Common Herbal Extracts Utilizing Phytosomes
Plant extracts that traditionally suffer from poor absorption benefit significantly from phytosome technology. A prominent example is the compound curcumin, the polyphenol responsible for the vibrant color in turmeric. Curcumin is notoriously poorly absorbed, but when formulated as a phytosome, its absorption and bioavailability are dramatically increased.
Milk Thistle, specifically its active component silybin, is another compound whose efficacy is limited by low oral absorption. Studies have demonstrated that silybin complexed into a phytosome is absorbed into the bloodstream up to seven times more readily than the standard milk thistle extract. Green tea catechins, which include the potent antioxidant EGCG, are also frequently prepared as phytosomes to overcome their rapid metabolism and poor permeability.
Other extracts, such as those from Ginkgo biloba and grape seed, which contain flavonoids and proanthocyanidins, also see improved delivery. By complexing these compounds, which are often large and water-soluble, with phospholipids, the resulting phytosome formulation ensures that a greater quantity of the beneficial plant compound reaches the target tissues.