Terpenoids and steroids from the stem bark of Sesbania grandiflora and biological studies of the plant extracts

Sesbania grandiflora (L.) Pers. commonly known as vegetable hummingbird, agati or hummingbird tree1 is a small tree belonging to the family Leguminoseae. This plant is native to tropical Asia and is widely available in Malaysia, Indonesia, Philippines, and India.2 It has widely been used in the herbal system of medicine to treat various diseases such as for the remedy of a large number of diseases like smallpox, inflammation, dysentery, rheumatism, leprosy, fever, gout, stomatitis and headache.3,4 The flowers and leaf of S. grandiflora were described to contain anxiolytic,5 anticancer6 and antioxidant7 activities. The bark extract demonstrated potent acute inflammation as well as adjuvant-induced arthritis inhibitory activity in rats.8 Qualitative analysis of the plant is carried out using standard chemical methods. The results revealed the presence of alkaloids, carbohydrates, phenolic compounds, tannin, flavonoids and saponins in plant extracts.9 Although S. grandiflora was previously studied extensively for its phytopharmacological potential, no comparative biological studies have been performed before among different extracts of the leaf and stem bark of this plant. We also report herein the isolation of seven compounds including a diterpene, two triterpenes, three steroids and, a fatty acid. The compounds are kaurenoic acid (1), β-amyrin (2) lupeol (3), stigmata-4,22-dien-3-one (4) stigmast-4-en-3-one (5) stigmasterol (6) and linoleic acid (7) respectively among which compounds 1, 2, 3, 4 and 5 are being reported for the first time from Sesbania grandiflora. Previous studies claimed that kaurenoic acid (1) showed significant hemolytic activities,10 whereas compounds lupeol (3)11 and stigmasterol (6)12 showed potential cytotoxic activities on cancer cell lines.