Estimation of neuroprotective effects of Laurocerasus officinalis Roem. (cherry laurel) by in vitro methods Ilkay Erdogan Orhan ⁎, Esra Küpeli Akkol Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey abstract article info Article history: Received 28 November 2010 Accepted 17 January 2011 Keywords: Laurocerasus officinalis Cherry laurel Rosaceae Cholinesterase inhibition Antioxidant activity Total phenol and flavonoid Dichloromethane, ethyl acetate, acetone, methanol, and water extracts prepared from the fruits and leaves of Laurocerasus officinalis Roem. (LO) (Rosaceae) were screened for their cholinesterase inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the key enzymes in pathogenesis of Alzheimer's disease (AD), using ELISA microplate reader at 50, 100, and 200 μg mL -1 . As AD is associated with oxidative stress, the antioxidant activity of the extracts was also tested by radical-forming methods against 2,2-diphenyl-1- picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and superoxide radicals as well as iron- related methods; iron-chelating capacity and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid quantification was achieved using Folin–Ciocalteau and AlCl 3 reagents, respectively. The highest AChE (44.01±1.75%) and BChE (19.91±0.37%) inhibition was caused by the LO-leaf-methanol extract 200 μg mL -1 , while it showed the best radical-scavenging activity against DPPH at 2000 μg mL -1 . Only, the dichloromethane and water extracts of the fruits and the leaf water extract had an iron-chelating capacity, while the leaf methanol extract displayed the highest FRAP. The leaf methanol extract (113.45 ± 0.71 mg g -1 extract) was found to be the richest in total phenols, while the leaf acetone extract (139.90±4.64 mg g -1 extract) had the most abundant amount of total flavonoids. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Laurocerasus officinalis Roem. (Rosacae), [syn: Padus laurocerasus (L.) Miller, Cerasus laurocerasus (L.) Lois, Laurocerasus vulgaris Carr., Prunus laurocerasus L.], is known as “cherry laurel” in English. The plant has been reported to be originated in central and west Asia, southeastern Europe, and Anatolia (Schquenbeg & Paris, 1975) and named as “taflan, karayemis, laz kirazi” in Turkey. L. officinalis is grown throughout the Black Sea region in Turkey and its fruits are commonly consumed as jam, marmalade, fruit juice, tea, and in canned or pickled styles (Islam, 2002). The tea prepared from the leaves of the plant is used against neurological disorders by the local people in Anatolia (personal data). Therefore, we decided to evaluate the neuroprotective activity of the fruits and leaves of L. officinalis (LO) by in vitro experimental methods. In accordance with our purpose, the cholinesterase inhibitory activity of the dichloromethane, ethyl acetate, acetone, methanol, and water extracts prepared from the dried fruits and leaves of LO was tested against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the main enzymes playing a role in the pathogenesis of Alzheimer's disease (AD) (Orhan, Orhan, & Sener, 2006). AD is a progressive neurological disorder, affecting mainly elderly population in the industrialized countries, particularly. It is characterized by memory loss, abnormal behaviors, disability in daily life activities, as well as some cholinergic deficits in AD patients (Bertram, Lill, & Tanzi, 2010). A deficiency in the levels of the neuromediators called acetylcholine (ACh) and butyrylcholine (BCh) has been observed in the brains of AD patients and inhibition of AChE and BChE has become a foremost treatment choice towards AD (Schneider, 2001). On the other hand, oxidative injury caused by free radical formation and iron accumulation has been revealed to be some other factors in AD pathogenesis (Altamura & Muckenthaler, 2009; Lee et al., 2010). Consequently, in addition to cholinesterase inhibition, we determined the antioxidant activity of the fruit and leaf extracts using anti-radical test methods against 2,2-diphenyl-1- picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and superoxide (SO) radicals as well as iron-related methods; iron- chelating capacity and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid quantification in the extracts was achieved spectrophotometrically using Folin–Ciocalteau and AlCl 3 reagents, respectively. 2. Material and methods 2.1. Plant material The fruits and leaves of LO were collected from Darica village nearby Akcaabat town in Trabzon province, Turkey in July, 2010. The plant was authenticated by Serdar Arslan from the Department of Food Research International 44 (2011) 818–822 ⁎ Corresponding author. Tel.: +90 312 2023186; fax: +90 312 2235018. E-mail address: iorhan@gazi.edu.tr (I.E. Orhan). 0963-9969/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodres.2011.01.037 Contents lists available at ScienceDirect Food Research International journal homepage: www.elsevier.com/locate/foodres