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Ethnobotanical Leaflets 12: 758-62. 2008. Medicinal Properties and Antimicrobial Activity of Crotalaria madurensis Var. kurnoolica
L. Md. Bhakshu1, K. Venkata Ratnam2 and R. R.
Venkataraju3* 1Department
of Plant Sciences, 2Department
of Botany, 3Department
of Botany, *Corresponding author: Prof. R.R. Venkata Raju, Department of Botany E- mail: rrvenkataraju@yahoo.com Phone: 918554
255726 (O); 09440289488 (Mobile) Issued ABSTRACT This paper deals with
the antimicrobial and phytochemical studies of Crotalaria madurensis
Wt. var. kurnoolica
Ellis et Swaminathan. (Fabaceae),
an endemic medicinal plant found in the forests of Nallamallias
of Eastern Ghats of India. The ether and ethyl
acetate extracts of the plant material exhibited a broad spectrum of
antimicrobial activity on human pathogenic microorganisms of six bacterial and
two fungal strains. The minimum inhibitory concentrations were provided. The
results were supported by phytochemical analysis. INTRODUCTION Plant
Material �������� Crotalaria
madurensis Wt. var. kurnoolica Ellis et Swaminathan (Fabaceae, Vernacualar name � Adavijanumu)
is an endemic species to METHODS �������� The plant material was collected
based on the information recorded from the local tribal practitioners by
conducting repeated interviews. The leaves were collected from the Nallamalais hill ranges, dried in shade and were used for
the present investigation. The voucher specimen (26967) was deposited at SKU
( Qualitative Phytochemical studies Hundred grams of shade dried leaves were pounded and extracted Successively
using petroleum ether (60-80�C) Ethyl acetate (EtOAc)
and Ethyl alcohol (EtOH) using a Soxhlet apparatus. The extracts yielded 300, 350 and 550
mg, respectively after evaporation in a roto-evaporator
under the reduced pressure. Preliminary phytochemical
studies were conducted on all extracts following the described procedures (Harborne, 1991; Chhabra 1984; Gibbs,
1974) and results were reported in table 1. Table
1. Preliminary phytochemical studies of C. madurensis
var. kurnoolica
(leaves).
-, no reaction; tr, reaction in trace; +, indicates presence of compounds ANTIMICROBIAL ASSAY The agar disc diffusion method was used to determine the antimicrobial
activity of the essential oil and crude extracts (Cruikshank,
1968). The discs (6 mm diameter) impregnated
with known concentrations of the oil and extracts were placed on the surface
of the Petri plates containing 20 ml of the respective media seeded with 0.1
ml of microbial suspensions (5 x 105 CFU/ml). Standard antibiotics
viz., ampicillin, kanamycin,
tetracycline and vancomycin (30 �g/ disc) obtained
from Hi-media, Mumbai, were used as positive controls. The plates were
incubated for 24 hours at 35�2� C for bacteria and for 48 hours for yeasts at
30�C. The inhibition zones formed around the discs were measured and expressed
in millimeters. Three independent trials were conducted for each
concentration and the average values calculated and given in Table (2). The microbicidal activity was confirmed by transferring a
sub-culture from the clear zone of inhibition to a fresh broth media and
observed for the growth of microbes. Determination of minimum inhibitory
concentration (MIC) The minimum inhibitory concentration (MIC) was determined, using a
common broth micro dilution method in 96-well micro titer plates (Camporese et al., 2003; NCCLS, 1999). Two fold dilutions
of each extract were carried out, starting from 5 to 0.15 mg/mL. 10 mL of the previously prepared different microbial
suspensions (105 CFU/ mL) were added to
each well. Plates were incubated for 18 h at 370 C and then were
examined with Elisa reader (TECAN, Table 2. Antimicrobial activity of C. madurensis
var. kurnoolica
leaf extracts.
EtAc: Ethyl Aceate;
Standards: A: Ampicillin; b: Kanamycin;
c: Tetracycline; RESULTS The preliminary investigation of phytochemical
studies (Table1) and antimicrobial activity (Table 2) were reported from the
leaves of Crotalaria madurensis var kurnoolica for
the first time. The petroleum ether and ethyl acetate extracts were proved
as active against the tested microorganisms which exhibited a broad spectrum
of antimicrobial activity. The ethyl alcohol and water extracts were failed
to exhibit inhibitory property. Proteus vulgaris
is resistant to the tested extracts at all concentrations. Based on the Minimum
inhibitory concentrations (MIC) for active extracts represented (Table 2) the
ether extract was effective against M. luteus,
S. aureus, P. aeruginosa,
E. coli, K. pneumoniae and C. albicans, While the ethyl acetate extract was active
against B. subtilis, M. luteus,
S. aureus, E. coli, P. aeruginosa
and C. albicans. The MIC of petroleum
ether extract of leaves was 500 �g against M. luteus,
S. aureus, P. aeruginosa while
750 �g against E. coli, 750 �g on K. pneumoniae,
C. albicans and C. tropicalis. The MIC of ethyl acetate
extract was 500 �g against S. aureus, B. subtilis, M. luteus, and
750 �g against C. albicans, 1000 �g against E.
coli, P. aeruginosa and K. pneumoniae. CONCLUSIONS Petroleum ether and
ethyl acetate extracts of C. madurensis var. kurnoolica
leaves were found to be active on the tested microorganisms
whereas, the alcoholic extract did not show any inhibitory activity. Three
Gram-positive (B. subtilis, M. luteus
and Staphylococcus aureus), two
Gram-negative bacteria (E. coli and P. aeruginosa)
and two fungal species (C. albicans and C. tropicalis) were observed to be sensitive to the tested extracts
where as, P. vulgaris was found to be resistant.
These results lend support the usage of C. madurensis
var. kurnoolica
leaves by the local tribal population in using for wounds and skin
diseases against bacterial and fungal infections. Further studies are under
way to isolate and characterize the major active principles of the oils and
test the compounds on different microorganisms and against various
infections, serve as a strong evidence for the plant as potent antimicrobial
agent. REFERENCES Bhakshu, L. Md., 2002.Ethnobotanical,
Phytochemical and Antimicrobial properties of
certain rare and endemic medicinal plants from Eastern Ghats,
Andhra Pradesh. Ph.D. Thesis, Cruickshank, R.
1968. Medical Microbiology: a guide
to diagnosis and control of infection 11th ed. Gibbs, R.D.
1974. Chemotaxonomy of flowering plants, I-IV. Harborne, J.B.1991. Phytochemical
methods. Chapman and Hall, National
Committee for Clinical Laboratory Standards,1999.
Performance Standards for Antimicrobial Susceptibility Testing: 9th
International Supplement. Pullaiah, T., Chennaiah, E., Moulali, A. 1997. Flora
of Andhra Pradesh ( Venkata Raju, R.R. and T. Pullaiah 1995. Flora of |
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