Extraction and isolation of gallic acid from Rhuscoriaria and preparation of silyl ether derivatives for analytical application

Rhuscoriaria Linn (Anacardiacea), commonly known as sumac, is an important crop widely used in iran as a food spice, and also in folk medicine, due to its health-promoting properties. Sumac has been used as a spice, condiment, appetizer, and as a souring agent for centuries. A broad range of nutritionally and medicinally significant phytochemical components have been identified from various parts of sumac as tannins, flavonoids, anthocyanins, organic acids, flavones, proteins, fiber, volatile oils, nitrates and nitrites. The plants also possesses minerals which are beneficial in the treatment of different disorders and contribute to various biological processes. Antioxidant activity and phenolic compounds of sumac extracts were investigated. Sumac was extracted in methanol and subjected to solvent–solvent partitioning to yield two fractions as ethyl acetate and aqueous. While Gallic acid was the main phenolic acid in the extracts.Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. One of the main features of the silicon-containing material is a dramatic increase in their lipophilic properties. silyl ethers of polyphenols such as Galic acid provide stable and volatile derivatives useful in the gas chromatography.There action in the synthesis of silyl ethers is as follows:The introduction of a silyl group(s) gives derivatives of enhanced volatility, making the derivatives suitable for analysis by gas chromatography and electron-impact mass spectrometry (EI-MS).