Essential oil constituents and their biological activities from the leaves of Cassia fistula growing in Nepal

The genus Cassia is comprised of ten species of yellow, flowering ornamental trees of the Fabaceae (Press et al., 2000). Cassia fistula L., locally known as “rajbriksha” in Nepal, is a deciduous tree native to East India, Nepal, Burma, and Malaysia (Press et al., 2000). Traditionally in Nepal, the plant’s fruit pulp is used as an antipyretic (Gewali, 2008), it is also used to treat habitual constipation (Mabberly, 1997). The leaf is used to treat jaundice, piles, rheumatism, ulcers, insect bites, facial paralysis and skin eruptions (Wealth of India, 2007), the leaf is also one of the most important ingredients in preparing Ayurvedic medicine (Agrawal et al., 2005). C. fistula can attain 6-10 m in height and it has compound leaves of 5-12 cm length (Gupta, 2010). Various pharmacological activities (antitussive, CNS, clastogenic, antipyretic, antioxidant, laxative, anti-inflammatory, hepatoprotective, larvicidal, antitumor, antiparasitic, antifertility, and anti-leishmanial) have been reported for this plant (Danish et al., 2011). Phytochemically, the leaf of the C. fistula contains mainly oxalic acid, flavonoids, tannins, and anthraquinones, while the fruits contain anthraquinones, flavonoids, and waxes (Bahorun et al., 2005). Materials and methods