634 www.bsmiab.org/jabet Hussain and Agha, J Adv Biotechnol Exp Ther. 2022 Sep; 5(3): 634-641 ABSTRACT Melia azedarach is a plant of the Meliaceae family, used worldwide in various medical fields. Because of the widespread incidence of thrombosis worldwide, especially during the coronavirus epidemic, this study was conducted to evaluate the in vitro thrombolytic effect of methanolic extracts of Melia azedarach leaves and fruits. Series of dilutions starting from 2 mg/ml to 20mg/ml were prepared from the methanolic extracts. The results showed that thrombolysis rates were between (18.7%-29.3%) for fruit extract in distilled water, (18.3%-30.1%) in phosphate buffer, (19.3%-35%) for leaves extract in distilled water and (20%-32.3%) in phosphate buffer for dilutions from 2 mg/ml to 20mg/ml. The streptokinase (positive control) had a thrombolytic effect of 47.54 % in distilled water and 44.36 % in phosphate buffer, compared to negative controls of 5.94 % and 6.34 %, respectively. Phytochemical screening found flavonoids and coumarins in leaves extract and only flavonoids in fruit extract, suggesting that the increase in thrombolytic effect may be attributed to these flavonoids and coumarins. The total phenolic content was 15.78 (mg GAE\1g) in leaves extract and 3.64 (mg GAE\1g) in fruit extract, while the total flavonoid content was 0.813 (mg QE\1g) in leaves extract and 0.17 (mg QE\1g) in fruit extract. In conclusion, these results showed that Melia azedarach has a thrombolytic effect. Evaluation of the thrombolytic activity of the methanolic extract of Melia azedarach fruits and leaves in vitro Hiba Ghanem Hussain 1,* , Mohammed Isam Hasan Agha 1 1 Department of pharmacognosy and medicinal plant, Faculty of pharmacy, Damascus University, Damascus, Syria. INTRODUCTION Coagulation is a complex physiological process performed to stop bleeding, where the blood clot is formed of fibrin, platelets, red and white blood cells [1[. This happens when a blood vessel is damaged, and the platelets are activated, change their shape, then stick to the injury site and each other to create a plug that covers the damaged part and prevents blood from leaking [ 2 ] . During this process, the dissolved fibrinogen transforms into undissolved fibrin and then intertwines with the platelets in the plug to create a network that traps more platelets and cells [2[. But when dysfunction occurs in this process, it will lead to three possibilities: increasing the risk of bleeding, blood clotting, or increasing both. When a blood clot is formed, in this case, it is called thrombosis [3[. Infectious diseases and respiratory infections were the leading causes of death worldwide until 1990 when cardiovascular diseases overtook them. After the coronavirus infection, respiratory disorders resurfaced as the leading cause of death, and the risk of thrombosis in respiratory patients has risen from 5% to 16% [4[. The widely utilized thrombolytic agents have shown numerous drawbacks in recent years. These include alteplase, anistreplase, streptokinase (SK), urokinase (UK), and plasminogen activator (tPA), whereas the most commonly used agents are UK and SK [5[. However, these drugs are not very safe due to the immunogenicity factors, high * Corresponding author Hiba Ghanem Hussain Department of pharmacognosy and medicinal plant, Faculty of pharmacy, Damascus University, Damascus, Syria e-mail: hiba56304@gmail.com Academic editor Akhi Moni, PhD ABEx Bio-Research Center, Dhaka 1230, Bangladesh Article info Received: 01 June 2022 Accepted: 01 July 2022 Published: 26 July 2022 Keywords Flavonoid; Melia azedarach; methanolic extract; thrombolytic effect; phenol. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non- commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ORIGINAL ARTICLE J Adv Biotechnol Exp Ther. 2022 Sep; 5(3): 634-641 eISSN: 2616-4760, https://doi.org/10.5455/jabet.2022.d142 Published by www.bsmiab.org