Antibacterial Activity and Chemical Constitutions of Olea Europaea L. Leaf Extracts

Abstract

The in vitro antimicrobial activity of aqueous, acetone, diethyl ether and ethyl alcohol extracts of olive leaves (Olea europaea L.) was studied. The aqueous extract of olive leaves had no antibacterial effect against the test microorganisms, whereas acetone extract showed inhibitory effect on Salmonella enteritidis, Bacillus cereus, Klebsiella pneumoniae, Escherichia coli, Enterococcus faecalis, Streptococcus thermophilus and Lactobacillus bulgaricus. Furthermore, the antimicrobial activities of some phenolic compounds against microorganisms were tested. The most effective compound was found to be oleuropein while syringic acid was found ineffective. The characterization of phenolic compounds in different extracts determined by high performance liquid chromatography‐air pressure chemical ionization‐mass spectrometry detector (HPLC‐APCI‐MSD GC‐MS) gas chromatography‐mass spectrometry (GC‐MS). The acetone and the ethyl alcohol extracts had the most and the least oleuropein content, respectively. PRACTICAL APPLICATIONS In recent years the extracts of many plant species have become popular, and attempts to characterize their bioactive principles have gained speed for many pharmaceutical and food‐processing applications. Especially, antimicrobial properties of plants have revived as a consequence of current problems associated with the use of chemical preservatives. Because of consumers' negative perspectives of synthetic preservatives, attention is shifting toward natural alternatives. The findings suggest that olive leaf extracts and their phenolic compounds have good potential as antibacterial substances in food preservation as they may be more acceptable to consumers and the regulatory agencies in comparison with synthetic chemical compounds.

Glucose‐mediated protein glycation: Contribution of methanolic extract of Ceratonia siliqua L. in protection and in vitro potential inhibition of acetylcholinesterase

“…The use of several methodologies of extraction and different solvents (Korukluoglu, Sahan, Yigit, Tumay Ozer, & Gucer, 2010), the sample origin (Hayes, Allen, Brunton, O'Grady, & Kerry, 2011), and its genetic (Custódio et al, 2011b) contribute to the differences observed in phenolic profile by HPLC test from study to another (Roseiro et al, 2013;Rtibi et al, 2017).…”

Antimicrobial efficacy of plant phenolic compounds against Salmonella and Escherichia Coli

“…In addition, they have received great attention in recent decades due to their presumed role in the prevention of foodborne diseases, cancer, chronic and cardiovascular diseases, and in the slowdown of the aging process (Lee, Cesario, Wang, Shanbrom, & Thrupp, 2003;Liu, 2003;Nazzaro et al, 2009;Lou, Wang, Zhu, Ma, & Wang, 2011) indicating that, they have diverse beneficial biological functions including antimicrobial and antioxidant activities (Korukluoglu, Sahan, Yigit, Ozer, & Gucer, 2010;Perumalla & Hettiarachchy, 2011). Phenolic compounds (PC) are one of the most diverse groups of secondary metabolites found in a wide variety of fruits, vegetables, nuts, seeds, stems and flowers as well as tea, wine, propolis and honey (Moreno, Scheyer, Romano, & Vojnov, 2006).…”

Determination of the protective effects of olive leaf extracts on microbiological and physicochemical properties of pepper paste using the image processing methods

“…In other studies of the literature, antimicrobial effects of OLEs in solvents such as water, acetone, ethyl acetate and ethyl alcohol have been tested on gram (+) bacteria and the inhibition effects were almost same even though acetone was slightly better (Korukluoğlu, Şahan, Yiğit, Özer, & Güçer, ). In this study, ethyl alcohol and water were used as solvent for the OLE then antimicrobial effect was obtained.…”