2.1 | Chemicals Arbutin (AR), gallic acid (GA), hydroquinone (HQ), (1)-catechin hydrate (CH), vanillic acid (VA), caffeic acid (CA), Syringic acid (SA), (2)-epicatechin (EC), vanillin (VL), p-coumaric acid (PCA), trans-ferulic acid (FA), rutin hydrate (RH), ellagic acid (EA) benzoic acid (BA), rosmarinic acid (RA), myricetin (MC), quercetin (QU), trans-cinnamic acid (TCA), and kaempferol (KF) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Acetonitrile (HPLC grade), methanol (HPLC), acetic acid (HPLC), and ethanol were obtained from Merck (Darmstadt, Germany). 2.2 | Plant material Fazli is an imported mango cultivar in Bangladesh. Fazli (Mangifera indica) fruits were collected from the local market of Dhaka, Bangladesh, and the peels removed and dried for further processing. Dried peels were ground into fine powder. The twenty-gram fine powder was packed into filter paper and extracted the crude extract with 80% ethanol in a Soxhlet apparatus (408C). Ethanol was evaporated and the sticky greenish extract was used for further polyphenolic compound analysis. 2.3 | HPLC detection and quantification of polyphenolic compounds Detection and quantification of selected phenolic compounds in the ethanol extract were determined by HPLC-DAD analysis as described by Jahan et al. (2014) with some modifications. It was carried out on a Dionex UltiMate 3000 system equipped with a quaternary rapid separation pump (LPG-3400RS) and photodiode array detector (DAD3000RS). Separation was performed using Acclaim® C18 (5 mm) Dionex column (4.6 3 250 mm) at 308C with a flow rate of 1 mL/min and an injection volume of 20 mL. The mobile phase consisted of acetonitrile (solvent A), acetic acid solution pH 3.0 (solvent B), and methanol (solvent C) with a gradient elution program of 5%A/95%B (0–5 min), 10%A/90%B (6–9), 15%A/75%B/10%C (11–15), 20%A/65%B/15%C (16–19 min), 30%A/50%B/20%C (20–29 min), 40%A/30%B/30%C (30–35), and 100%A (36–40 min). The UV detector was set to 280 nm for 22.0 min, changed to 320 nm for 28.0 min, again changed to 280 nm for 35 min, and finally to 380 nm for 36 min and held for the rest of the analysis period while the diode array detector was set at an acquisition range from 200 to 700 nm. For the calibration curve, a standard stock solution was prepared in methanol containing arbutin (AR), (2)-epicatechin (ECA) (5 mg/mL each), gallic acid (GA), hydroquinone (HQ), vanillic acid (VA), rosmarinic acid (RA), myricetin (MC) (4mg/ ml each), caffeic acid (CA), Syringic acid (SA), vanillin (VL), trans-ferulic acid (FA) (3 mg/mL each), p-coumaric acid (PCA), quercetin (QU), kaempferol (KF) (2 mg/mL each), (1)-catechin hydrate (CH), ellagic acid (EA) (10 mg/mL each), trans-cinnamic acid (TCA) (1 mg/mL), rutin hydrate (RH) (6 mg/mL), and benzoic acid (BA) (8 mg/mL). A solution of the extract was prepared in ethanol at a concentration of 10 mg/mL. Prior to HPLC analysis, all solutions (mixed standards, sample, and spiked solutions) were filtered through 0.20 mm syringe filter (Sartorius, Germany) and then degassed in an ultrasonic bath (Hwashin, Korea) for 15 min. Data acquisition, peak integration, and calibrations were calculated with Dionex Chromeleon software (Version 6.80 RS 10). 2.4 | Animals and treatment Ten to twelve weeks old, 24 Long Evans female rats (150–170 g) were obtained from Animal production unit of Animal House at Department of Pharmaceutical Sciences, North South University and kept in individual cages at room temperature of 25 6 38C with a 12 hr dark/light cycles. They had free access to standard laboratory feed and water, according to the study protocol approved by Ethical Committee of North South University for animal care and experimentation. To study the hepatoprotective effects of mango, all rats were equally divided into four groups (six rats) such as control (Group I), control1 Mango peel (Group II), CCl4 (Group III), and CCl4 1 Mango peel (Group IV). Animals of Group I were treated with 1 mL/kg of saline (0.85%) and olive oil (1 mL/kg) intragastrically twice a week for 2 weeks. Group II received similar treatment of Group I and Group-II was also supplemented with mango peel powder every day for 2 weeks. Rats of Groups III and IV were treated with CCl4 (1:3 in olive oil) at a dose of 0.5 mL/kg intragastrically twice a week for 2 weeks. Animals of Group III received only CCl4 treatment; however, animals of Group IV received both CCl4 treatment twice a week for 2 weeks and mango fruit peel powder mixed in food as supplementation every days (5% of powder food, w/w). Animals were checked for the body weight, food, and water intake on a daily basis. After 14 days, all animals were weighed, sacrificed, collected the blood and all internal organs such as heart, kidney, spleen, and liver. Immediately after collection of the organs, they were weighed and stored in neutral buffered formalin (pH 7.4) for histological analysis and in the refrigerator at 2208C for further studies. Collected blood was centrifuged at 8,000 rpm and the plasma separated and stored in the refrigerator at 2208C for further analysis.