ABSTRACT:Aegle marmelos(L.), family rutaceae is highly reputed medicinal tree commonly known as the bael. All parts of the plant have medicinal properties and extensively used by the traditional medicine practitioners of Bangladesh in different health ailments like Diabetes, Diarrhea, Jaundice, typhoid. The present study was dedicated to investigate phytochemical and pharmacological properties of ripe fruit, half-ripe fruit, leaf and seed of the plant extracted with methanol solvent. Initial phytochemical screening confirmed the presence of different phytoconstituents including alkaloid, flavonoids, carbohydrate, glycoside, saponin, tannin, glucoside and steroids in different extracts. Antioxidant potential was evaluated using total phenol and total flavonoid contents determination assays, total antioxidant capacity, DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging assay, NO radical scavenging assay, reducing power assessment, CUPRAC (Cupric Reducing Antioxidant Capacity), total alkaloid determination assay. All the plant parts were found to possess moderate amounts of phenolics and flavonoids, expressed as galic acid equivalent (GAE) and quercetin equivalent (QE) respectively. The methanolic extract of half-ripe fruit demonstrated highest phenolic content (6.05 mg/gm GAE) while methanol extract of seed exhibited highest flavonoid content (4.29 mg/gm QE). In addition, the plant parts displayed total antioxidant capacity expressed as ascorbic acid equivalent (AAE) with methanol extract of leaf being the most potent one (10.31 mg/gm AAE). In DPPH radical and NO radical scavenging methods, a dose dependent scavenging of DPPH and NO radical was observed by all the extractives. Highest DPPH radical scavenging was demonstrated by methanol extract of half-ripe fruit with IC 50 value of 251.2 μg/ml whereas IC 50 value of standard ascorbic acid was noted as 18.4 μg/ml. In case of NO radical scavenging method, highest NO radical scavenging was also demonstrated by methanol extract of half-ripe fruit with IC 50 values of 46.364 μg/ml. However in reducing power and CUPRAC assays, methanol extract of half-ripe fruit and leaf were found to exhibit moderate but concentration dependent reducing power respectively. In total alkaloid content determination methanol extract of seed showed the highest alkaloid content expressed as atropine equivalent (4.86 mg/gm).In Brine Shrimp Lethality Bioassay, all the extracts produced dose dependent cytotoxicity effect to brine shrimp nauplii with methanol extract of seed exhibiting highest toxicity having LC 50 value 86.77 μg/ml where standard vincristine sulphate had the LC 50 value of 2.47 μg/ml.