Directory UMM :Data Elmu:jurnal:B:Biochemical Systematics and Ecology:Vol28.Issue10.Dec2000:

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*Corresponding author.

E-mail address:sharmaj@icfre.up.nic.in (D. Prasad)

Biochemical Systematics and Ecology 28 (2000) 1027}1030

Constituents of

Rhamnus

v

_irgatus

_(Rhamnaceae)

D. Prasad

!

,

*

_{, Geeta Pant}

_"

_{, M.S.M. Rawat}

_"

_{, Akito Nagatsu}

_#

!Directorate of Research, Indian Council of Forestry Research and Education, PO New Forest, Dehradun-248 006, India

"Department of Chemistry, HNB Garhwal University, Srinagar, Garhwal-246 174, India

#Faculty of Pharmaceutical Sciences, Kyoto University, Sokyou-ku, Kyoto 606, Japan Received 2 August 1999; accepted 24 January 2000

Keywords: Rhamnusvirgatus; Flavonoid triglycosides; Proanthocyanidin; Chemotaxonomy

1. Subject and source

Rhamnusv_irgatus_{Roxb. (Syn.}_{R. dahuricus}_Pall.),_{Rhamnaceae, is a deciduous shrub,}

1.8}4.5 m in height, found throughout the Himalayas at an altitude of 800}3000 m. Aerial parts (twigs with leaves) ofR.v_irgatus_{were collected in July 1996, from Musoli,}

Pauri District, Garhwal, UP, India and identi"ed by Dr. L.R. Dangwal, Department of Botany, HNB Garhwal University Srinagar (Garhwal), India. A voucher specimen (No. 8907) has been deposited in the herbarium of Botany Department, HNB Garhwal University, Srinagar (Garhwal), India.

2. Previous study

Physcion-8-O-b-gentiobioside was isolated from the stem of this plant (Kalidhar and Sharma, 1984). Other species of Rhamnus are known for the production of quinones and#avonoid glycosides (Ram et al., 1988, 1994; Satake et al., 1993).

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3. Present study

Dried and powdered plant material (1 kg) was defatted with light petroleum (60}803C). The defatted material was extracted with 90% hot EtOH. The EtOH extract was partitioned with CHCl

3: MeOH : H2O (6 : 2 : 8) and n-butanol. The

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elution with C

6H6: EtOAc (98 : 2P9 : 1) a!orded physcion (1; 1.11 g), chrysophanol (2; 1.5 g) and kaempferol-7-O-methylether (3; 1.61 g). The n-butanol extract (15 g) on repeated column chromatography over Si-gel using gradient elution with CHCl

3: MeOH (100 : 2P17 : 3) a!orded various fraction. FractionA(175 mg) was

suspended in MeOH}H

2O and "ltered. The "ltrate was evaporated to dryness

(60 mg), the residue was spotted on the precoated reverse-phase TLC plate (Merck) and developed twice by MeOH : H

2O (6 : 4). The spot atR&0.4 was separated, eluted

with MeOH, and the solvent was removed in vaccuo to give 7-O-methylkaempferol-3-O-b-rhamnoside (4; 34 mg). FractionB(150 mg) was spotted on precoated reverse-phase TLC plate and developed twice by MeOH : H

2O (1 : 1). The compounds were

detected by UV absorption and the spots atR

&0.2 and 0.5 were separated and eluted

with MeOH. After evaporation of solvent the spot at R

& 0.2 a!orded

7-O-methyl-kaempferol-3-O-b-rhamnoside (4; 21 mg) and the spot atR

&0.5 a!orded

kaempferol-3-O-b-rhamnoside (5; 60 mg). Fraction C (70 mg) was spotted on precoated reverse-phase TLC plate and developed twice by MeOH : H

2O (6 : 4). The spot atR&0.2 was

separated, eluted with MeOH and after evaporation of solvent gave an A-type proanthocyanidin; ent-epiafzelechin-(4a_P8, 2a_PO_P7)-kaempferol (6; 40 mg). The structures of the compounds isolated were determined by means of spectroscopic methods (IR, UV, HRFABMS, FABMS,1H,13C, DEPT and 2D NMR experiments, COSY, HMQC, HMBC, NOESY).

4. Chemotaxonomic signi5cance

The occurrence of quinones and#avonoid glycosides is not uncommon in the genus Rhamnus. Physcion, chrsophanol (Ram et al., 1988), kaempferol-7-methylether (Ram et al., 1994), kaempferol-3-O-b-rhamnoside and 7-O-Methylkaempferol-3-O-b-rham-noside (Satake et al., 1993) were previously reported from the genusRhamnus. ent-Epiafzelechin-(4a_P8@, 2a_PO_P7@)-kaempferol was previously reported from the roots ofEphedraandPrunus armeniaca(Hikino et al., 1982; Prasad et al., 1997), but this is the"rst time that A-type proanthocyanidin has been reported in Rhamnus.

Acknowledgements

The authors are thankful to G.B. Pant Institute of Himalayan Environment and Development, Almora, India, for"nancial assistance.

References

Hikino, H., Takahashi, M., Konno, C., 1982. Tetrahedron Lett. 23, 673. Kalidhar, S.B., Sharma, P., 1984. Phytochemistry 23, 1196.

Prasad, D., Joshi, R.K., Pant, G., Rawat, M.S.M., 1997. Fitoterapia 67, 275.

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Ram, S.N., Dwivedi, S.P.D., Pandey, V.B., Shah, A.H., 1988. Fitoterapia 59, 78. Ram, S.N., Pandey, V.B., Dwivedi, S.P.D., Goel, R.K., 1994. Fitoterapia 65, 295.

Satake, T., Hori, K., Kamiya, K., Saiki, Y., Fujimoto, Y., Kimura, Y., Maksut, C., Mekin, T., 1993. Chem. Pharm. Bull. 41, 1743.