Drug Research Unit, Faculty ofPharmacy, University ofIfe,Nigeria

PHYTOCHEMICAL EXAMINATION O F DRACAENA MANNIZ STEM BARK -

By E. A. SOFOWORA and A. A. OLANIYI

The stem bark of Dracaena manni BAKERwas extracted with light petroleum (40-60° C), chloroform and ethanol successively. The solids from both the light petroleum and ethanol fraction showed antibacterial activity against Staphylococcus aureus. Palrnitic acid, an unidentified gummy material and heptacosane were found in the petroleum ether fraction whilst the ethanolic fraction consisted mainly o f a~nmonizt?n nitrate.

T h e tree Dracaena mannii BAKERis the largest of the Dracaenas found in Nigeria (KEAY,ONOCHIEand STANFIELD, 1964) and is readily distinguished by its long narrow leaves. It is a copiously branched tree reaching up to 10-25 m in height and up to 2 m in girth with its fragrant flowers in lax panicles. It is situated in wet areas of West Africa, usually in closed forests. T h e leaves are 10-45 cm long and 2-5 cm broad and are strap-like. T h e bark is brown-grey, shallowly fissured, flaking off in small irregular patches. T h e fruits are about 2 cm in diameter, red o r reddish-orange, hanging down in very conspicuous panicles ( H U T C R ~ N ~and ON DALZIEL,1931). Thke chemistry of the red dye contained in the fruits of some species started long ago (FRANKELand DAVID,1927). T h e leaf of related species have been studied for their use as raw material in the paper industry (HOPNER,1957, SHALAMBERIDZE and POLSKHVERASHVILI, 1963) whilst steroidal sapogenin and saponin have been reported in other species (MARKER et al., 1943; WASICKY and HOEHNE, 1951). MALCOLM and SOFOWORA (1969) had reported the bark of this plant as being one of three that warrant further study, out of the forty six components of three antimicrobial native remedies they had studied. T h e water extract of the bark of D. mannii had produced marked antibacterial activity against the Gram negative and Gram positive organisms used in their investigation. Little is known, however, of the chemistry of the constituents of this bark, and a preliminary investigation of it is here reported.

Downloaded by: National University of Singapore. Copyrighted material.

Abstract

66

Sofowora and Olaniyi

Planta medica Vol. 27 1975

Experimental

Extraction and purification T h e dried stem bark of Dracaena manni (700 g ) was first extracted with light petroleum boiling range 40-60' C), then the marc was extracted with chloroform and finally with ethanol. Each extraction was carried out to exhaustion (48 hours) in a Soxhlet extraction apparatus. T h e coloured extracts obtained from each solvent extraction was evaporated to low volume (10 ml) in rracuo. T h e solid deposited by each was filtered, washed' with the parent solvent and the yield was noted. A sample of each of the soIid thus obtained was tested for antimicrobial activity. T h e residue obtained from the light petroleum extract was separated into its components bv preperative T L C o n silica gel plates (2 mm thick) using benzene: chloroform (7: 3) as solvent system. Three clear zones (Rf-X = 0-0.0.01; Y = 0.0-0.6; 1. = 0.8-0.9) which appeared when the chromatogram was examined in iodine vapour were scraped out separately and the adsorbent exhausted with absolute ethanol, in each case, after allowing iodine to volatilise. T h e alcoholic extracts thus obtained were concentrated to about 5 ml, in vacuo, then the solids (compounds X, Y and Z, respectively) deposited were filtered off and recrystallised.

Results and Discussion

T h e exhaustion with light petroleum yielded 0.6 g - (I); that of chloroform 1.01 g - (11) and that of alcohol afforded 8.81 g - (111) of total solids. T h e residues I, 11, and 111 produced 2.1 mm, 0 mm, and 4.1 mm zones of inhibition (measured from the edge of the cup) respectively when tested for antibacterial activity. T h e alcohol deposit was found by chemical analysis to consist mainly of ammonium nitrate. Compound X was recrystallised from chloroformlacetone and it afforded colourless prisms. m.p.: 63-65' C Vmax: 3400-3200 (broad), 1690,1300,1100 and 940 cm-' nmr: i = 9.05,8.70,7.5-7.75 (Total Number of Protons = 32H) MS: M' = 256, precise mass measurement a t m/e 256 gave mol. wt. as 256. 2396. Calculated for ClaHYzOz: M = 256.2402 Compound X was similar in all respect (m.p., m.m.p., i.r., n.m.r.) with an authentic sample of Palmitic acid. Compound Y was obtained as a gum and could not be re~r~stallised. It was, however, the only fraction with antibacterial activity out of the compounds obtained from the light petroleum extract.

Downloaded by: National University of Singapore. Copyrighted material.

M.p's were determined using an electrothermal melting point apparatus. 1.r. spectra were determined as nujol mulls o n a perkin Elmer Model 257 spectrometer. Deuterio-chlorofornl was used assolvent for n.m.r. spectra run o n a Perkin-Elmer R-12A spectrometer. Mass spectrn measurements were carried out by P.C.M.U. Harwell, England. Antibacterial activity was testetl using the ditch-plate method as earlier described with Staphylococcus aureus as test organism (EL-SAID eta., 1971).

Phytochernical examination of Dracaena rnannii

67

Vmax: 3390-3350 (broad) 1715,1240 and 1165 cm-' nmr: i = 9.05,8.70,7.5 MS: Showed 3 different compounds i n a homologous series M+ a t m/e 820, 834 and 848. Compound Z was recrystallised from acetone and obtained as a fine .white powder, m.p. 5 5 ~ 5 C. 7~ Vmax: 1250,1165,1085 and 800 cm-' nmr: i = 9.05,8.70,8.04,7.4-7.8 (Total number of protons = 56H) MS: M+= 380,. Found M' = 380.4376, Calculated for Cp7Hj6:M = 380.4382. Compound Z was identical with an authentic sample of n-heptacosane (m.p., i.r., n.m.r.). Acknowledgements We are grateful to the staff of the Museum and Herbarium, Forest Research Department, Ibadan, Nigeria for identification of the plant species. We are also grateful to the University of Ife for a grant to research into Nigerian medicinal plants. References E. A.: Lloydia, 34,171 (1971) EL-SAID, F., FADULU, S. O., KUYE,J. 0. and SOFOWORA, FRANKEL, S., and DAVID,E.: Biochern. Z. 187,146 (1927) T.: Das Papier 11,229 (1957) HOPNER, HUTCHINSON, J., and DALZIEL,J. M.: Flora of West Tropical Africa. Publ. The Crown Agents for the Colonies. London. Vol. I1 part 1,384 (1931) D. P.: Nigerian Trees. Publ. Dept. of Forest KEAY,R. W. J., ONOCHIE,C. F. A. and STANFIELD, Research, Ibadan. Vol. 11,440 (1964) MALCOLM, S. A. and SOFOWORA, E. A.: Lloydia 32,512 (1969) R. B., ULSHAFER, P. R., WITTBECKER, E. L., GOLDSMITH, D. P. J. and MARKER, R. E., WAGNER, RUOF,C. H.: Jour. Amer. Chern. Soc. 65,1199 (1943) SHALAMBERIDZE, KH. and POLSKHVERASHVILI, B.: Tr. Gruz. Sel'skokhoz. Inst. 60,181 (1963) WASICKY, R. and HOEHNE, W.: Anais Faculdade farm e. Odoutol, Univ. Sao Paulo 9,17 (1951)

Address: Dr. E. A. Sofowora, Drug Research Unit,Faculty of Pharmacy, University of Ife, Ile-Ife, Nigeria

Downloaded by: National University of Singapore. Copyrighted material.

'

Phytochemical examination of Dracaena mannii stem bark.

Drug Research Unit, Faculty ofPharmacy, University ofIfe,Nigeria PHYTOCHEMICAL EXAMINATION O F DRACAENA MANNIZ STEM BARK - By E. A. SOFOWORA and A...
234KB Sizes 0 Downloads 0 Views