(c) Copyright 2011 EManuscript Publishing Services, India 67 Research Letter Pharmacognosy Communications www.phcogcommn.org Volume 2 | Issue 3 | Jul-Sep 2012 *Correspondence: Md. Nur Alam, Lecturer, Department of Pharmacy, Jahangirnagar University, Savar, Dhaka-1342, Bangladesh. Cell Phone: +8801717852389 Fax: 880-2-7791052 Email: nalamju@gmail.com DOI: 10.5530/pc.2012.3.14 Antioxidant activity of the ethanolic extracts of leaves, stems and fruits of Solanum nigrum Mohammad Nur Alam*, Suvashish Roy, Sharif Mohammad Anisuzzaman and Mohammed. Rafiquzzaman Department of Pharmacy, Jahangirnagar University. INTRODUCTION Free radicals contribute to more than one hundred disorders in humans including atherosclerosis, arthritis, ischemia and reperfusion injury of many tissues, central nervous system injury, gastritis, cancer and AIDS. [1-2] Free radicals due to environmental pollutants, radiation, chemicals, toxins, deep fried and spicy foods as well as physical stress cause depletion of immune system antioxidants, change in gene expression and induce abnormality in proteins. Oxidation process is one of the most important routes for producing free radicals in food, drugs and even living systems. Catalase and hydroperoxidase enzymes convert hydrogen peroxide and hydroperoxides to non-radical forms and functions as natural antioxidants in human body. Due to depletion of immune system natural antioxidants in different maladies, consuming antioxidants as free radical scavengers may be necessary. [3-5] Synthetic antioxidants used commercially such as butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT) and gallic acid esters are supposed to create or aggravate negative health consequences. Besides, these synthetic antioxidants also demonstrate low solubility problem. [6] Traditionally used medicinal plants are already exploited commercially either as antioxidant additives or as a nutritional supplement. But there is still a demand to find more information concerning the antioxidant potential of medicinal plants. Solanum nigrum Linn. (Solanaceae) is commonly known as ‘Black nightshade.’ The plant has been extensively used in traditional medicine in Bangladesh and other parts of the world to cure liver disorders, chronic skin ailments (psoriasis and ringworm), inflammatory conditions, painful periods, fevers, diarrhea, eye diseases etc. [7] The phytochemical studies revealed the plant contains glycoalkaloids (solanine, solamargine, solanigrine and solasodine), steroidal glycosides (β-solamargine, solasonine and α,β- solansodamine), steroidal saponins (diosgenin), steroidal genin (gitogenin), tannin and polyphenolic compounds. Mature fruits are low in alkaloid (solanine) content. [8-10] The fruit of S. nigrum is reported to have antiulcer, antioxidant and antitumor promoting agent in rats. [10-12] The fruit of S. nigrum has been reported in the ancient Indian medicinal literature with beneficial effects in inflammation, tuberculosis, diuretics etc. [13] In this study attempt has been taken to investigate in vitro antioxidant property of the ethanolic extracts of the different parts of S. nigrum. ABSTRACT: Background: Solanum nigrum Linn. (Solanaceae) has been extensively used in traditional medicine in Bangladesh and other parts of the world to cure liver disorders, chronic skin ailments (psoriasis and ringworm), inflammatory conditions, painful periods, fevers, diarrhea, eye diseases etc. Materials and Methods: Crude ethanolic extracts of leaves, stems and fruits of Solanum nigrum were prepared and evaluated for antioxidant activity by two different in vitro methods. Results: All the prepared extracts have antioxidant potential. However, leaf extracts showed highest antioxidant activity irrespective of the method used. Gallic acid equivalent phenolic compounds content as well as quercetin equivalent flavonoids content were highest in the leaf extract of the S. nigrum and that could be the reason behind the highest antioxidant activity of leaf extract. Discussion: As leaf extract showed the highest antioxidant activity among all extracts, it might be investigated further for isolation of antioxidant principles. KEY WORDS: Solanum nigrum, DPPH, antioxidant activity, flavonoid content and phenolic compound content.