Sesbania grandiflora (L.) Pers. is a common traditional medicinal plant used in bronchitis, anaemia, headache, fever, ophthalmia, nasal catarrh, leprosy, inflammation, gout and rheumatism. The present study aimed to assess plant regeneration and plantlets development in vitro using explants of S. grandiflora together with the estimation of total phenolic content and antioxidative activity of various extracts obtained from the plant. Murashige and Skoog (MS) basal medium added with different concentrations of plant growth regulators (PGRs) was used for plant tissue culture, whereas ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays were used to evaluate the antioxidant potential of different extracts of the plant. In the presence of 6-benzylaminopurine (BAP; 0.1 mg/l), the highest level (85.41%) of seed germination was achieved while the highest callus formation (96.6%) was recorded with 2,4-dichlorophenoxyacetic acid (2,4-D; 0.5 mg/l). In addition, the highest shoot induction, shoot formation and shoot elongation were observed with BAP (0.1 mg/l), indole-3-butyric acid (3 mg/l) and naphthaleacetic acid + BAP (0.4 + 0.2 mg/l) respectively. The extract of dried calluses showed highest contents of proline (110.94 mg/g), phenol (16.42 mg/g) and flavonoid (22.22 mg/g), and also highest antioxidant potential with FRAP and DPPH assays. From the present study, we may conclude that the MS basal medium supplemented with PGRs is effective for the commercial production of S. grandiflora.Keywords: Antioxidant activity, in vitro micropropagation, phenolic content, plant growth regulators, Sesbania grandiflora.SESBANIA GRANDIFLORA (L.) Pers., commonly known as hummingbird tree of the family Leguminosae, is a popular traditional medicinal plant used in bronchitis, anaemia, headache, fever, ophthalmia, nasal catarrh, leprosy, inflammation, gout and rheumatism 1 . The dried leaves are used as tea and also as an antibiotic, antitumour and contraceptive. The juice obtained from fresh leaves was found effective in bruises 2 . The seeds of the plant are rich in protein while seed oil is a potent antioxidant agent. Various studies confirmed the presence of phytosterols in the seed oil which shows anti-inflammatory, analgesic and antipyretic activities. The presence of high phytosterol content makes it an important plant for the commercial production of steroidal hormones and cosmetics 3 . The flowers of S. grandiflora contain tannin and other nutritious contents. Moreover, its astringent nature also contributes in antimicrobial activity 4 . The process of plant tissue culture is considered to be highly valuable in terms of commercial production of a medicinal plant, in which the aseptic culture of cells and organs can be achieved under in vitro conditions 5 . Several compounds with a varied array of structures influence the tissue growth and morphogenesis under exposed atmosphere. Besides, this technique is useful for conserving medicinal plants and enhancing their secondary metabolites of industr...