Rosmarinic acid
Synonyms:Rosemary acid; Benzenepropanoic acid, alpha-((3-(3,4-dihydroxyphenyl)-1-oxo-2-propenyl)oxy)-3,4-dihydroxy-;(2S)-3-(3,4-dihydroxyphenyl)-2-[3-(3,4-dihydroxyphenyl)prop-2-enoyloxy]propanoic acid
CAS No.: 20283-92-5
Molecular formula: C18H16O8
Molecular weight: 360.33
Botanical Source: Rosmarinus officinalis
Solubility: slightly soluble in water, but well soluble in most organic solvents.
Appearance: brown yellow powder

Function of Rosmarinic acid:

a.A natural antioxidant,which is widely used in food, functional foods, spices and condiments and daily chemical industries.
b.Anti-aging effect.
c.Strong weight-losing effect.
d.Anti-cancer effect and can be used in the treatment of cardiovascular diseases.

Applications of Rosmarinic acid:

a. In Food industry
1). High-efficient antioxidant;
2). Antibacterial;
3). Restrain growing of colon bacillus and staphylococcus aureus.
b. In Pharmaceuticals and Health Care industry 
1). Reduces activity of hyaluronidase, then keep hyaluronic acid living for a long time in epidermal cell;
2). Antineoplastic effect;
3). Anti-hepatitis effect, protect liver from damnification;
4). Anti-nephritis;
5). Anti-thrombus;
6). Anti-platelet-aggregation;
7). Refreshing, strengthening memory, improving strain and hypersomnia, anti-depressant.
c. In Cosmetic industry
1). Intensify constringency;
2). Eliminate freckle, strengthen skin elasticity and slow aging;
3). Accelerate blood circulation of scalp;
4). Improve phalacrosis, reduce scurf and embellish hair;
5). Stimulate hair and nail growing.

Rosmarinic acid, C18H16O8, is a natural polyphenol antioxidant carboxylic acid found in many Lamiaceae herbs used commonly as culinary herbs such as lemon balm, rosemary, oregano, sage, thyme and peppermint. Chemically, rosmarinic acid is an ester of caffeic acid with 3,4-dihydroxyphenyl lactic acid. It is a red-orange powder that is slightly soluble in water, but well soluble in most organic solvents.

Biological importance
Because of the antioxidant activity of Lamiaceaeous herbs in laboratory test models they have been suggested to have beneficial effects in humans. Rosmarinic acid has a number of interesting biological activities, e.g. antiviral, antibacterial, antiinflammatory and antioxidant. The presence of rosmarinic acid in medicinal plants, herbs and spices has beneficial and health promoting effects. In plants, rosmarinic acid is supposed to act as a preformed constitutively accumulated defense compound.

Metabolism
Rosmarinic acid is known to undergo metabolism in humans and rats to methylated rosmarinic acid, coumaric acid, ferulic acid and caffeic acid.