Isolation and Characterization of Flavonoids from the Flowers of Butea monosperma Lam (Pauk)

Transcription

1 MM The Jour. Myan. Acad. Arts & Sc Vol. II(Part One) No. 2 (Science) Isolation and Characterization of Flavonoids from the Flowers of Butea monosperma Lam (Pauk) Aye Aye Tun 1, Aye Mya Hlaing 2, Hnin Pwint Aung 3 and Maung Maung Htay 4 Abstract Four flavonoids, namely, butein (1), monospermoside (2), isobutrin (3) and butrin (4) were isolated from the dried flowers of Butea monosperma (Lam.) Kuntze. The structures of compounds have been elucidated by UV, IR, NMR and mass spectroscopy. Key Words: Butea m onosperma, butein; monospermoside; isobutrin; butrin; flavonoids. Introduction Butea monosperma (Lam:) Kuntze (Syn. Butea frondosa Koen ex. Robx) (Fam. Papilinaceae or Fabaceae) is a moderate size deciduous tree which is widely distributed in tropical Asia. Various parts of this plant exhibit significant pharmacological properties. (Anonymous, 1988 and Lai et al, 1978). Flowers of Butea monosperma have been reported to contain many flavonoids (Pun and Seshadri, 1953, 1955; Chopra et. al., 1956 and Gupta et. al. 1970) and have wide medicinal values as a folk medicine. The flower is used to cure for liver disorders, bladder diseases, gout and skin diseases (Wagner et. ah, 1986). The flowers of B. monosperma are used in the traditional medicinal for the treatment of liver disorder and viral hepatitis. Wagner et. al. investigated the antihepatotoxic principles of this flower by using the assay model of CCLj- and D-glactosamine (GalN-) 1. Associate professor, Dept. of Chemistry, Yangon University, Member, MAAS. 2. M.Res. candidate, Dept. of Chemistry, Yangon University. 3. Associate professor, Dept. of Chemistry, University of Distance Education, Member, MAAS 4. Professor and Head, Dept. of Chemistry; Dean, Fac. of Science, Yangon University, Member, MAAS

2 86 The Jour. Myatu Acad. Arts & Sc 2004 Vol. II(Part One) No. 2 (Science) inducing 1 iver 1 esion i n vitro a nd t hey claimed t hat b utrin a nd i sobutrin were responsible for antihepatotoxic property. In Myanmar, a mixture of B. monosperma flowers and Tacca aspera plant in equal amount is especially used by traditional medical practitioners for the treatment of hepatitis B-virus. O-R Glu- O-GIu Butein (1): R = R' = H Monospermoside (2): R = Glu; R'= H Isobutrin (3): R = R 1 = Glu Materials and Methods General Procedures. Mps: uncorr; *H (500 and 400 MHz) and 13 C (125 and 100 MHz) NMR: BRUKER DPX-400 and varian unity INOVA 500, DMSO with TMS as int. standard and in CD 3 OD, CD 2 HOD peak at 3.34 ppm; ESI-MS: TSQ 700 MAT mass spectometer; UV: Shimadzu UV-240, MeOH, shift reagents were prepared by standard procedure; FT-IR: Perkin Elmer GX system, KBr: CC: Merck silica gel 60 ( mesh); TLC: 0.25 mm precoated silica gel (60 F254, Merck), spots were detected by inspection under UV light (254 ran or 365 nm), by spraying with 5% FeCl3 solution, or exposed to NH3 vapour (with or without UV) Plant materials. The flowers used in this study were collected from University Campus, Yangon Division in January 2001 and the plant was identified as Butea monosperma at the Department of Botany, Yangon University. Extraction and isolation. The air-dried powdered flowers (50 g) were extracted with ethanol (300 cm 3 ) in a Soxhlet extractor for 20 hours. After

3 The Jour. Myan. Acad. Arts & Sc Vol.II(Part One) No. 2 (Science) 87 removal of the solvent, the residue (9,80 g) was extracted with petroleum ether (60-80 C) (3 x 50 cm 3 ) to remove waxy material. The dewaxed residue was then dissolved in water (50 cm 3 ) and successively extracted with diethyl ether (3 x 50 cm 3 ), ethyl acetate (3 x 50 cm 3 ) and /z-butanol (3 x 50 cm 3 ). The individual fractions of diethyl ether, ethyl acetate, and n- butanol were distilled under reduced pressure to provide dried extract ( g, g and g, respectively). The ether crude extract was dissolved in ethanol (2 cm 3 ) and thoroughly adsorbed on silica gel (5g). After being dried, the silica gel was carefully placed on the top of silica gel column to obtain a uniform layer. The column was firstly eluted with dichloromethane (100 cm 3 ) and solvent was gradiently changed from dichloroethane-diethyl ether (4:1) to (1:1). The chromatography was monitored by silica gel TLC using dichloroethane - diethyl ether (2:1) as solvent system. The fraction that gave similar TLC pattern were combined together and concentrated. In this way, four major fractions Fi to F 4 were combined. From fraction F 3, butein (1) (R f = 0.42) was isolated by recrystallization in ethanol. The e thyl a cetate c rude e xtract w as d issolved i n e thanol (2cm 3 ) and thoroughly adsorbed on silica gel column (5 g). Then it was placed on the top of silica gel column which had been packed with 35 g of silica gel in diethyl ether. The column was eluted consecutively with diethyl ether, increasing amount of ethyl acetate in diethyl ether, ethyl acetate and then increasing amount of ethanol in ethyl acetate. The chromatography was monitored by silica gel TLC using ethyl acetate-ethanol (9:1) as solvent. The fractions that gave same spot on chromatogarm (R f = G.58) were combined and crystallized by using ethanol to provide monospermoside (2). The «-butanol crude extract was dissolved in hot methanol. After cooling to room temperature a small amount of diethyl ether was added into solution and kept in refrigerator for 3 days. The white solids so obtained was then recrystallized from methanol to provide butrin (4),

4 gg The Jour. Myan. Acad. Arts & Sc Vol. II (Part One) No. 2 (Science) colourless needles. The mother liqueur was then chromatographed on silica gel column using increasing amount of ethanol in ethyl acetate. Fraction that have R f = 0.2 in were combined together and crystallized by using ethanol to provide isobutrin (3). Results and Discussion Butein (1): Orange-yellow needles (17.3 mg, % yield); m.p. 214 C dec. (ethanol); X nax 262 and 381, (+NaOH) 278, 444, (+A1C1 3 ) 302, 483, (+AICI3/HCI) 2 70, 4 28, (+NaOAc) 2 63, 3 86 n m; v mjl 3299 (OH), (CO), 1591, 1599, 1513 cm" 1 (C = C); 5 H 6.30 (1H, d, 3'-H), 6.45 (1H, dd, 5'-H), 6.8 (1H, d, 5-H), 7.15 (1H, dd, 6-H), 7.2 (1H, d, 2-H), 7.58 (lh,d, a-h), 7.78 (1H, d, p-h) and 8.04 (1H, d, 6'H); 6 C 105.1, 110.4, 116.0, 117.1, 117.9, 120.0, 124.9, 130.7, 134.6, 147.9, 148.2, 151.2, 167.7, and 194.8; ESI-MS m/z (%) 273 [M+ H] (100), 163 (63), 130 (85). Monospermoside (2): Yellow needles (21 mg, 0.042% yield); m.p C (ethanol); X^ 260 and 372, (+NaOH) 279, 437, (+AICI3) 264, 430, (+AICI3/HCI) 2 64, 428, (+NaOAc) 2 55, 3 77, (NaOAc/H 3 BO 3 ) 2 55, 3 77 nm; v^ 3351 (OH), 1634, 1631 (CO), 1509 cm" 1 (C = C); 8 H 6.30 (1H, d, 3'-H), 6.45 (1H, dd, 5'-H), 6.8 (1H, d, 5-H), 7.15 (1H, dd, 6-H), 7.2 (1H, d, 2-H), 7.58 ( lh,d, a-h), 7.78 (1H, d, p-h) and 8.04 (1H, d, 6'H); 8 C 64.0, 72.8, 76.2, 78.9, 79.9, 105.1, 105.6, 110.6, 115.9, 118.8, 119.3, 120.4, 128.5, 129.7, 134.9, 146.7, 148.6, 152.8, 167.9, and 194.7; ESI-MS m/z (%) 435 [M+ H] + (100), 457 [M + Na] + (95), 273 (85),293 (85) and 891 (20). Isobutrin (3): Yellow n eedles (21 mg, 0.042% yield); m.p C dec. (ethanol); X mx 254 and 375, (+NaOH) 452, (+AICI3) 429, (+AICI3/HCI) 430, (+NaOAc) 382, (NaOAc/H 3 BO 3 ) 380 nm; v max 3418 (OH), 1629 (CO), 1520 cm- 1 (C = C); 6 H 6.57 (1H, d, 3'-H), 6.62 (1H, dd, 5'-H), 6.87 (1H, d, 5-H), 7.44 (1H, m, 6-H), (3H, m, a-, P- and 2-H), 8.23 (lh,d, 6'-H), and (1H, s br, phenolic OH); 5 C 64.0, 72.8, 76.2, 78.9,

5 The Jour. Myan. Acad. Arts & Sc 2004 Vol.D (Part One) No. 2 (Science) y 79.9, 105.1, 105.6, 110.6, 115.9, 118.8, 119.3, 120.4, 128.5, 129.7, 134.9, 146.7, 148.6, 152.8, 167.9, and Butrin (4): Colourless needles (70 mg, 0.14% yield); m.p C (MeOH) (m.p C, Wagner et al. 1986); X^ 273 and 312, (+NaOH) 439, (+A1C1 3 ) no shift, (+AICI3/HCI) no shift, (+NaOAc) no shift, (NaOAc/H 3 BO 3 ) no shift ; v max 3421 (OH), 1650 (CO), 1611cm" 1 (C = C). Conclusion Four flavonoid, butein, i.e., 2\3,4,4'-tetrahydroxy chalcone (1), monospermoside, i.e., 2',3,4,4'-tetrahydroxy chalcone-3-monoglucoside (2), isobutrin, i.e., 2',3,4,4'-tetrahydroxy chalcone-3,4'-diglucoside (3) and butrin, 4 ',5',7-trihydroxy f lavanone-5',7-diglucoside ( 4) w ere i solated and identified. Acknowledgement The authors wish to thank Department of Higher Education, Ministry of Education, Yangon, Myanmar for provision of opportunity to do this research. The authors gratefully acknowledge Dr. Ute Pyell, Fac. of Chemistry, University of Kassel, Germany and Dr. Miyahara Yuji, Dept. of Chemistry, Fac. of Science, Kyushu University, Japan for recording ^-NMR, 13 C-NMR and ESI-MS spectra.

6 90 The Jour. Myan. Acad. Arts A Sc 2004 Vol. II (Part One) No. 2 (Science) References Gupta, S.R; Ravindranath, B. and Seshadri, T.R The Glucosides of Butea monosperma Phytochemistry, 9, Lai, J; Chandra, S. and Sabir, M Modified Method for Isolation of Palasonin the anthelmintic principles of B. fronosa. Indian J. Pharm. Sci. 40, Pun, P. and Seshadri, T. R Survey of Anthoxanthins: Part Ill-Paper Chromatography of Some Flavonones & Chalkones & Their Glycosides-Isolation & Constitution of Isobutrin, a new Glycoside of the Flowers of Butea frondosa, J. Sci. Industr. Res., 12B, Puri, P. and Seshadri, T.R Survey of Anthoxanthins: Part IV- Chromatographic Study of Yellow Garden Flowers & Constitution of Coreopsin. J.Sci. Industr. Res., 13B, Puri, P. and Seshadri, T.R Survey of Anthoxanthins: Part IX- Isolation and Constitution of Palasitrin. J.Sci. Industr. Res., 14B, Wagner, H.; Geyer, B.; Fiebig, M.; Kiso, M. and Hikino, H Liver protective drugs. Part 30. Drugs for liver therapy. Part 12. Isobutrin and butrin, the antihepatotoxic principles of Butea monosperma Flowers, Planta Med., 52, The Wealth of India-Raw Materials, 1988, PID, CSIR, New Delhi,