In Pursuit of Bioactive Constituents from Sri Lankan Medicinal Plants

R Samarasekera; KP Hemalal; A Ata

doi:10.1055/s-0030-1251803

Planta Medica, Table of Contents

In Pursuit of Bioactive Constituents from Sri Lankan Medicinal Plants

R Samarasekera ¹, KP Hemalal ², A Ata ³

¹Herbal Technology Section, Industrial Technology Institute, 363, Bauddhaloka Mawatha, Colombo 7, Sri Lanka
²Applied Research & Development Centre, Hemas Manufacturing (Pte) Ltd. P.O. Box 1, Dankotuwa, Sri Lanka
³Department of Chemistry, University of Winnipeg, 515, Portage Ave., Winnipeg, Canada

Abstract

In search for bioactive natural products in Sri Lankan medicinal plants, Terminalia arjuna (Roxb.) Wight & Arnot. (Combretaceae), Nelumbo nucifera (Nymphaeaceae), Nymphaea stellata (Nymphaeaceae), Barleria prionitis Linn. (Acanthaceae), Caesalpinia bonduc L. (Fabaceae) and Artocarpus nobilis (Artocarpaceae) were identified to exhibit anti-microbial, free radical scavenging, anti-tyrosinase and acetylcholinesterase (AchE) and glutathione s-transferase (GST) inhibitory activities. Bio-assay guided fractionation of extracts of these plants by chromatography afforded active constituents and spectroscopic techniques including multi-dimensional NMR techniques were utilized to elucidate the structures of compounds. Two antibacterial compounds, olean-1α, 3β, 22β-triol-12-en-28-oic acid and olean-1α, 3β, 22β-triol-12-en-28-oic acid-3β-D-glucopyranoside were isolated from ethyl acetate extract of the stem bark of T. arjuna. Stamen extracts of N. nucifera and N. stellata afforded free radical scavenging compounds, Kaemperferol and Cyanadin 3-O-2((Prime))-O-galloyl-β-galactopyranoside). Extracts of B. prionitis, a plant extensively used in Ayurveda, exhibited GST and AchE inhibitory, antibacterial and free radical scavenging activities and the ethanolic extracts afforded iridoid glycosides as potential GST and AchE inhibitors. Chemical studies of C. bonduc, which is used in indigeneous system of medicine, afforded GST inhibiting 13,14-seco-steroids. Extracts of A. nobilis exhibited AchE and GST inhibitory and antibacterial activities and afforded cycloartane-type triterpenoids, artocarpuate A and B and flavonoids, artoblidxanthone and artoninse exhibiting GST and AchE inhibitory activities. Acknowledgements: Research students, Gunathilaka S, Abeysekera K, Gayani P G and Kosmulalage K S who involved in various aspects of this research are greatly acknowledged. References: [1] Gunathilaka WDS (2005) M.Sc Thesis, University of Peradeniya, Sri Lanka. [2] Gayani PG (2009) M.Sc Thesis, University of Peradeniya, Sri Lanka. [3] Ata A, Kosmulalage KS, et al. (2009) Phytochem Lett 2: 37–40. [4] Ata A, Samarasekera R (2009) Phytochem Lett 2: 106–109. [5] Ata A, Samarasekera R (2007) Z Naturforsch B 62b: 280–284.