The isolation and potential use of glycolic acid present in the local plant Erica multiflora L.

Abstract

Erica multiflora L. 1753 is a perennial, evergreen shrub widely distributed in the lowlands of the Mediterranean Basin. Literature was reviewed for the medicinal properties and constituents of the plant. Not much information was gathered but it was found out that Erica multiflora L. has been used in traditional medicine as an astringent, urinary antiseptic and diuretic. Glycolic acid (alpha-hydroxyacetic acid) was the active component responsible for this diuretic potential (Balansard, 1951). Other constituents of the shrub are tannins, concrete oil and cyanogenic glycosides. The botanical aspect and habitat of the plant were also reviewed. Glycolic acid was extracted by the following procedure adapted from that described originally by Balansard (1951). Decoctions were prepared from the plant, which were then precipitated by lead II acetate to remove the tannins. 96% ethanol was added to the filtrates and any excess lead was decomposed by sodium phosphate. The solutions were filtered and then bleached by activated carbon. After evaporation, the residues were extracted with a mixture of diethyl ether and petroleum ether. The solvent was evaporated and the residues were collected. Titrations were performed for quantitative determination of the acid. The residues were dissolved in distilled water and to each of the above solution, potassium iodate solution was added and after half an hour, the solutions were titrated with 80% 10 Molar hydrochloric acid. The percentage content of glycolic acid in the decoctions and the percentage recovery of the acid from the residues were calculated. A cream containing 2% glycolic acid was formulated, using the residues as a source of the acid and Aqueous Cream (also prepared by myself) as the base. The cream was tested for its irritancy/intolerability on five volunteers. In only one case, a slight prickling sensation was felt. No visible hypersensitivity reactions were observed. Therefore from the results obtained, it was concluded that the cream can be used safely for topical application. Erica multiflora L qualifies as. a good source of glycolic acid and can be incorporated in topical formulations. The plant can substitute the synthetically produced acid or glycolic acid-containing plants which do not grow in the Maltese Islands, that are currently being incorporated in commercially available skin care products.