Natural Antioxidants, Antibacterials From Olive Leaf Extracts Used In Cosmetics, Pharmaceutical, And Food Industries

Abstract

Olive leaves are rich with polyphenolic compounds which exhibit many activities like antimicrobial, antioxidant activities. Natural compounds from olive leaves are safe antioxidants, antibacterials, and preservatives compared to synthetic ones. In this work, olive leaf samples were collected from different geographical regions of Palestine at different maturation stages. The olive leaves samples were dried, grinded, and extracted with water at room temperature for two hours. The crude extracts were then analyzed for their total phenolic content, total flavonoid content, and antioxidant activity. Results revealed that olive leaves are rich with antioxidants (polyphenolic and flavonoid compounds), and the extracts showed antibacterial activities against two gram positive bacteria (staphylococcus aureus, and staphylococcus epiderrmidis) with activity of about 80-90% compared to well known antibiotic (Neomycin). Based on these results, the olive leaf extracts were used in cosmetics, pharmaceutical, and food applications as natural antioxidant and antibacterial agent. In cosmetics, olive leaves extracts were used in moisturizing day cream, anti- aging cream, and shampoo formulations at three concentrations (0.1%, 0.4% and 1.0%, w/w). Results showed that all physical and rheological properties of the formulations with olive leaves extract were the same as commercial product. Furthermore, stability studies showed stable homogenous appearance and effective during one year storage period at room temperature. A questionnaire analysis on 100 volunteers who used these creams and shampoos showed that they are satisfied with these preparations. In pharmaceutical industry, the olive leaf extracts were used as natural antibacterial, and antioxidant in non-sterile pharmaceutical dosage forms instead of conventional chemical preservatives which have toxicity to human beings even at low concentrations especially when used in pediatric/children preparations. Results showed that the extracts work as natural antibacterials and antioxidants for the prepared pediatric syrup and potentially can substitute the chemical preservatives. Regarding food applications of the extracts, they were added into meat fillets as antioxidants and compared to chemical preservatives that are used usually in meats (BHT), and results indicated significant decrease in the amount of secondary oxidation products (represented as malonodialdehyde) of the tested meat samples treated with different concentrations of olive leaves extracts, indicating that this extract can be used as natural antioxidants in meat substituting synthetic ones. Additionally the extracts were tested for the stabilization of edible oils as substituents to synthetic additives (BHT and BHA), and results showed that incorporation of olive leaves extracts in the unsaturated edible oils resulted in significant decrease in primary and secondary oxidation products of the oil, and therefore this extract has protecting effect against induced lipid peroxidation of edible oils.