Journal of Ethnopharmacology, 31 (1992) 8 l-83 Elsevier Scientific Publishers Ireland Ltd.

Short Co~unication

81

Activities of Chromolaena odorata (Compositae) leaf extract against pseudomonas aeruginosa and streptococcus faecalis

O.N. Irobi

Department of Biological Sciences, Federal University of Technology, Minna. P.M. B. 6.5, Niger State (Nigeria)

(Received October 20, 1991; revision received May 21, 1992; accepted May 23, 1992)

Introduction

The development of resistance by hospital pathogens to many of the commonly used antibi- otics provides an impetus for further attempts to develop new antimicrobial agents to combat infec- tions. Plant extracts have been used in folk medical practice for the treatment of different ailments since antiquity (Okanla et al., 1990). In 1989, Fadeyi and Akpan reported on the antibacterial activities of leaf extracts of Eugeniu uniflora L. against Staphylococcus aureus, Shigella dysenreriae, Escheri~hia coli and nacelle ~bt~lis.

Chromolaena odorata (L} King & Rob., a member of the Compositae, is a native of tropical America from where it has spread to other parts of the tropical world. It was probably introduced into Nigeria three decades ago (Metawally and Ekejiuba, 1981) and is commonly referred to as ‘Awo weed’ by local people in Southern Nigeria. The plant is listed by Hutchinson and Dalziel in their book Flora of West Africa published in 193 1. At present the populace use the leaves for treat- ment of skin diseases.

Previous chemical analyses of the plant indicate the presence of flavones and flavonoids (Bose et al., 1973; Metawally and Ekejiuba 1981), as well as tannins, saponins and sesquiterpenes (Agu, 1980). Previous studies of the antibacterial activity of the oils distilled from the plant showed that they in- hibited Klebsiella aerogenes and Staphylococcus aureus (Agu, 1980). In 1991, Irobi et al. described

Correspondence to: O.N. Irobi, Department of Biological Sciences, Federal Univeristy ofTechnology, Minna, P.M.B. 65, Niger State, Nigeria.

the antifungal activities of the plant. The present paper reports on activities of ethanolic leaf extract of Chromoluena odorata against hospital strains of Pseudomonas aeruginosa and Streptococcus fuecalis.

Materials and Methods

Source of micro-organisms Hospital isolates of Pseudomonas aeruginosa

and Streptococcus faecalis collected at the Univer- sity of Ilorin Teaching Hospital were used. The organisms were stored on blood agar slants at 4°C prior to testing.

Plant material The plant material used for this work was col-

lected and authenticated by Mr. J.N. Etukudo (Etukudo 231) and a voucher specimen has been deposited at the Herbarium of the Department of Biological Sciences, University of Ilorin, under accession number 684. The leaves were shade- dried at ambient temperature prior to grinding,

Extract preparation Powdered leaves of the plant (100 g) were ex-

haustively extracted with 500 ml of ethanol (95%) (BDH Chemical Limited, Poole, UK) using a Sox- hlet apparatus for a period of 8 h. The greenish- yellow extract obtained was passed through mem- brane filters with 1.2 pm and 0.45 ,um pore sizes, respectively. The extract was then concentrated in vacua at 40°C using a rotary evaporator (Buchii type) to obtain a sticky brown-black semi-soiid substance. This was lyophilised in 15-ml ampoules and stored in the refrigerator (Thermocool, Elinda

0378-8741/92/$05.00 0 1992 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland

82

TABLE 1

ANTIBACTERIAL SCREENING OF C. ODORATA LEAF EXTRACT AGAINST PS~~~O~ONAS AERUGINOSA (PA)

AND STREPTOCOCCUS FAECALIS (SF)

Vehicle control Leaf extract Ciprofloxacin

aNT = not tested.

Amount per well or disc

50 pl 30 mg

10 gg

Mean i S.E.M. of Minimum inhibitory zones of inhibition concentration (rn~rnl)~

PA SF PA SF

0 0 NT NT 7 I 0.49 12 f 0.57 8.0 6.0 9 f 0.0 II f 0.55 NT NT

S-A. Greece). The yield was 5.6 g in terms of the dried leaf materials.

Antibacterial susceptibility testing The extract of the plant was reconstituted in

minimal amount of ethanol and then diluted subsequently with glycerol to give a final concen- tration of 600 mg/ml which was used for the sensi- tivity testing. Susceptibility testing was carried out using the modified agar diffusion of Garrod et al. (1981).

A sterilized calibrated Pasteur pipette was used to introduce 0.05 ml (equivalent to 30 mg of ex- tract) of the stock solution into three wells bored into the surface of a plate of brain-heart infusion agar (BHI Oxoid, UK) previously seeded with lo6 cells per ml of test bacteria. A standard ciproflox- acin disc (IO pg) was placed on the agar surface away from the wells in each plate. The plates were allowed to equilibrate after which they were in- cubated at 37°C for 24 h. Antibacterial activity was expressed as the average diameter of the zones of inhibition calculated as the difference in diameter of the observed zone and the diameter of the well or disc. Zones of inhibition which were either equal to or greater than the control disc were regarded as a measure of antibacterial activity (Emeruwa, 1982).

Determination of minimum inhibitory concentration

(MIC) MIC was determined by the agar dilution tech-

nique. Varying amounts of the reconstituted ex- tract (0.125-64 mg/ml) were incorporated separately onto brain-heart infusion agar plates. A loopful of the test organisms previously adjusted to a concentration of 1 O6 cells per ml was streaked onto the surface of the medium. A vehicle control plate was similarly inoculated. After allowing the

plates to equilibrate, the plates were incubated at 37°C for 24 h, The MIC was regarded as the lowest concentration that did not give any visible growth of the bacteria.

Results

The results in Table 1 show that the extract pro- duced measurable antimicrobial activity against the micro-organisms. The mean zone of inhibition obtained using the agar diffusion assay ranged from 7 mm for P. aeruginosa to 12 mm for S. faecafis. The cipro~oxa~in control yielded a mean zone of 10 mm against the two organisms, while the glycerol vehicle control did not inhibit any of the bacteria tested. The MIC was 8.0 mg/ml for P. ae~ginosa and 6.0 mgiml for S. faecalis. These results suggest that S. faeculis may be slightly more sensitive to the extract than P. aeruginosa.

Discussion and Conclusions

This study shows that the ethanolic extract of ~hromolaena odorata possesses some antibacterial activity against Pseudomonas aeruginosa and Streptococcus faecalis. The minimum inhibitory concentration was large for P. aeruginosa (8.0 mglml), a Gram-negative organism, and somewhat less (6.0 mg/nnl) for S. fuecalis a Gram-positive organism. It was observed that large concentra- tions of the extract (30 mg/ml) were needed to give an inhibitor action comparable to that obtainable with ciprofloxacin.

The fact that the extract produced antibacterial activities against both Gram-positive and Gram- negative bacteria suggests that there may be a scientific basis for their utility in traditional medicine for the treatment of skin infections.

83

The author wishes sincerely to acknowledge the technical advice provided by Dr. 0.0. Agbede of the Department of Pathology, University of Texas Medical Branch, Galveston, Texas {USA), during the course of this research. Thanks are also due to Miss Ruth Ehigboria of Nigemorth Limited, Minna, Nigeria, for typing and reading this manuscript.

References

Agu, S.I. (1980) Phytochemical and Microbiological Investiga- tions of Nigerian Medicinai P/ants Used in the Treatment of Skin Diseases. M.Phil. Thesis, University of Ife, Nigeria.

Bose, P.H., Chakrabarti, P., Chakravarti, S., Bulta, S.P. and Batrus, A.K. (1973) Flavonoid constituents of ~u~forium odoratum. Phyrochemistry 12, 667-671.

Emeruwa, AC (1982) Anti~crobiaI substance from Caricu papaya. Lloydia 45, 123-127.

Fadeyi, M.O. and Akpan, U.E. (1989) Antibacterial activities of leaf extracts of Eugenia unifora Linn. (Synonym: Stenocalyx miehellii Linn.). Phytotherapy Research 3 (4), 154-155.

Garrod, L.P., Lambert, H.P. and O’Grady, I. (1981) Antibiotics and Chemotherapy. Churchill Livingstone, London.

Hutchinson, J. and Dalziel, J.M. (1931) Flora of West A&ica, Vol. 2. Whitefriars Limited, London and Tonbridge, pp. 171472.

Irobi, O.N., Agbede, G.O. and Ogunbanjo, B.O. (1991) An- tifungal activity of an extract of Chromolaena odorafa. In: Proceedings of the 20th West African Society of Phar- macology Conference at Ma~dugur~, in press.

Metawally, A.M. and Ekejiuba, E.C. (1981) Metoxylated flavonoids and flavones from Eupatorium odoratum. Journal of Medicinal Research 42, 403-405.

Okanla, E.O., Oyewale J.A. and Akinyanju, J.A. (1990) Trypanocidal effect of aqueous extract of Acajypha h~pida leaves. Journal of Erhnopharmacology 29, 233-236.