ABSTRACT
Aim: Citrus fruits are well known for its medicinal and food value. Aim of this study is to investigate acetylcholinesterase ((AChE)) inhibitory activity, butyrylcholinesterase (BuChE) inhibitory activity, total phenolics, flavonoids, flavonols content and thrombolytic activities of crude methanol extracts of 6 citrus fruits (Citrus limon, Citrus aurantifollia, Citrus bergamia, Citrus maxima, Citrus sinensis and Citrus macroptera). Methods: The fruits were extracted by using methanol as solvent. Ellman’s colourimetric method was applied to determine both cholinesterase inhibitory activities, while folin-ciocalteau reagent (FCR) and aluminium chloride were used to quantify total phenolics, flavonoids, flavonol content of those fruits. Blood clot lysis method was applied for determining the thrombolytic activity of those fruits. Results: All citrus fruits contain a good amount of phenolics, flavonoids and flavonols. C. maxima found more prominent in containing phenolics and flavonols compare to other citrus fruits, with 414.06 ± 2.87 mg Gallic Acid Equivalent/gm and 12.94 ± 1.31 mg Catechin Equivalent/gm dried extract respectively. Citrus sinensis showed the highest content in flavonoids with 21.16± 1.37 mg Catechin 20 Equivalent /gm dried extract. Citrus fruits are also a quality source of cholinesterase inhibitors. All the examined citrus fruits were found capable of inhibiting both acetylcholinesterases (AChE) as well as butyrylcholinesterase (BuChE). C. bergamia was most effective in inhibiting AChE with IC50 of 27.18 µg/ml where C. macroptera was best in inhibiting BuChE (IC50 32.5 µg/ml). But none of the citrus fruits was found fit for thrombolytic activity. Conclusion: Citrus fruits are found the sound in inhibiting AChE and BuChE as well as containing Phenolics, flavonoids and flavonols. But they lack in their thrombolytic activity.