The effect of Nigella sativa Linn. seed on memory, attention and cognition in healthy human volunteers Muhammad Shahdaat Bin Sayeed a,b,n , Md. Asaduzzaman b,c , Helal Morshed d , Md. Monir Hossain a , Md. Fahim Kadir b,c , Md. Rezowanur Rahman c Q1 a Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Bangladesh b Department of Pharmacy, University of Asia Pacific, Dhanmondi, Dhaka, Bangladesh c Department of Pharmaceutical Technology, University of Dhaka, Bangladesh d Department of Pharmaceutical Chemistry, University of Dhaka, Bangladesh article info Article history: Received 3 September 2012 Received in revised form 24 April 2013 Accepted 4 May 2013 Keywords: Nigella sativa Linn. seeds Neuropsychological tests Memory test Attention test Cognitive test Toxicity study abstract Background: Experimental evidences have demonstrated that Nigella sativa Linn. seed (NS) has positive modulation effects on aged rats with memory impairments, prevents against hippocampal pyramidal cell loss and enhances consolidation of recall capability of stored information and spatial memory in rats. NS has neuroprotective, nephroprotective, lung protective, cardioprotective, hepatoprotective activities as established by previous studies on animals. Several clinical trials with NS on human have also demonstrated beneficial effect. Aim of the study: The present study was designed to investigate the effects of NS on memory, attention and cognition in healthy elderly volunteers. Furthermore, safety profile of NS was assessed during the nine-week study period. Methods: Forty elderly volunteers were recruited and divided randomly into group A and group B—each consisting of 20 volunteers. The treatment procedure for group A was 500 mg NS capsule twice daily for nine weeks and Group B received placebo instead of NS in the similar manner. All the volunteers were assessed for neuropsychological state and safety profile twice before treatment and after nine weeks. The neuropsychological tests were logical memory test, digit span test, Rey-Osterrieth complex figure test, letter cancellation test, trail making test and stroop test. Safety profile was assessed by measuring biochemical markers of Cardiac (total cholesterol, triglycerides and high density lipoprotein cholesterol, very low density lipoprotein, low density lipoprotein cholesterol, creatine kinase-MB); Liver (aspartate aminotransferase, alanin aminotransferase, alkaline phosphatase, total protein, albumin, bilirubin) and Kidney (creatinine and blood urea nitrogen) through using commercial kits. Results: There was significant difference (p o0.05) in the score of logical memory test-I and II, total score of digit span, 30 min delayed-recall, percent score in Rey-Osterrieth complex figure test, time taken to complete letter cancellation test, time taken in trail making test-A and test-B, score in part C of stroop test due to ingestion of NS for nine weeks. There were not statistically significant changes (p 40.05) in any of the biochemical markers of cardiac, liver, kidney function during this nine-week study period. Conclusions: The current study demonstrates the role of NS in enhancing memory, attention and cognition. Therefore, whether NS could be considered as potential food supplement for preventing or slow progressing of Alzheimer disease needs further investigations. However, study with Alzheimer′s patients with large population size for longer period of time is recommended before using NS daily and extensive phytochemical investigations are recommended for novel drug discovery from NS for treating cognitive disorders. & 2013 Published by Elsevier Ireland Ltd. 1. Introduction The seed of Nigella sativa Linn. (NS) (Family: Ranunculaceae), commonly known as black seed or black cumin, is employed as a spice and food additive in various parts of the world (Ali and Blunden, 2003). The nutritional and health improving properties of NS are very well known (Ramaa et al., 2006) and NS is considered as a very effective herbal food substance having diversified use in traditional treatment (Salem, 2005) as well as for reducing the risk of various maladies (Butt and Sultan, 2010). The chemical composition of NS is well studied (Ashraf et al., 2006) and the compounds found therein, especially thymoquinone (TQ), carvacol, p-cymene, t-anethol and 4-terpinol have potent 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/jep Journal of Ethnopharmacology 0378-8741/$ - see front matter & 2013 Published by Elsevier Ireland Ltd. http://dx.doi.org/10.1016/j.jep.2013.05.004 n Corresponding author at: Department of Clinical Pharmacy and Pharmacology, University of Dhaka, Dhaka-1000, Bangladesh. Tel.: +880 2 9664953; mobile: +880 171 3459747; fax: +880 2 9664950. E-mail address: shahdaat2013@yahoo.com (M.S.B. Sayeed). Please cite this article as: Sayeed, M.S.B., et al., The effect of Nigella sativa Linn. seed on memory, attention and cognition in healthy human volunteers. Journal of Ethnopharmacology (2013), http://dx.doi.org/10.1016/j.jep.2013.05.004i Journal of Ethnopharmacology ∎ (∎∎∎∎) ∎∎∎–∎∎∎