PHYTOCHEMICAL AND ANTIMICROBIAL EVALUATION OF LEAF AND SEED OF

MORINGA OLIFERA EXTRACTS.

A. J. Akinyeye (e –mail bayotwo@yahoo.com, Tel- 08038625445), E.O. Solanke (e-mail

olatoyesolanke@yahoo.com, Tel-08032449953) and I.O. Adebiyi (e-mail

itunuadebiyi@yahoo.com, Tel- 07012726041)

1DEPARTMENT OF BIOLOGICAL SCIENCES IGBINEDION UNIVERSITY OKADA,

EDO STATE, NIGERIA.

Abstact

In recent times, the use of plants as a source of vital compounds to combat microbial infections has gained prominence. The necessity to search for plant-based antimicrobials is increasing due to high cost, reduced efficacy and increased resistance to conventional medicines. This study analyzed the phytochemical composition of moringa olifera, and antimicrobial potential of its methanol and hexane extracts on Escherichia coli, Klebsiella pneumonia, Pseudomonas aeuriginosa and Candida albicans, using antimicrobial screening techniques. Phytochemical analysis revealed the presence of alkaloids, glycosides, flavonoids, steroids, saponins and tannins. The methanol extracts of the leaf of this plant at a concentration of 1040mg/ml exhibited antimicrobial activities against all the microorganisms. The hexane leaf extract however inhibited all the microorganisms in all concentration except P aeuriginosa. The methanol extracts generally showed more antimicrobial effects compared to the hexane extracts. This may be due to alkaloid and saponins being largely present in the methanol leaf extract. The variations in the presence of the phytochemicals may also be due to the choice of the solvent used in the extraction, methanol is a polar solvent while hexane is a non polar. The age of the plant was also found to have significant effect on the phytochemicals present and thus on the antimicrobial properties.

KEY Word: Phytochemical, Antimicrobial, Evaluation, Moringa olifera

INTRODUCTION

In Africa and other continents of the world, phytomedicines have been used since time

immemorial to treat various ailments long before the introduction of modern medicine. Herbal

medicines are still widely used in many parts of the world especially in areas where people do

not have access to modern medicines (Hoareau and Da Silva, 1999; Ajibade et al., 2005).

Moreover, in most African countries where herbal medicines are still heavily relied upon because

of the high cost of chemotherapeutic drugs, there is a need for scientific research to determine

the biological activities of medicinal plants. The findings obtained from such research may lead

to the validation of traditionally used and medicinally important plants which will consequently

enable full usage of the properties of these plants (Adde-Mensah, 1992).

Moringa oleifera is a highly valued plant of the Moringaceae family. It is a fast growing

plant widely available in tropics and subtropics with much economic importance for industrial

and medicinal uses. Moringa oleifera, an important medicinal plant is one of the most widely

cultivated species. It is highly valued from time immemorial because of its vast medicinal

properties. In the last few decades, there has been an exponential growth in the field of herbal

medicine. It is getting popularized in developing and developed countries owing to its natural

efficacy and lesser side effects (Brahmachari, 2001).

Also, nutraceutical and pharmaceuticals beneficial properties of different parts of the

Moringaceae plants have different pharmacological actions and toxicity profiles, which have not

yet been completely elucidated (Chinmoy, 2007). For example, leaves of Moringa species have

been traditionally reported to have various biological activities, including antitumoural,

antioxidant, anti-inflammatory/ diuretic, antihepatotoxic properties, hypotensive,

hypocholesterolemic and hypoglycemic actions (Sreelatha and Padma, 2010). The roots, flowers,

gum and seeds are extensively used as antidiabetic and for treating inflammation, cardiovascular

action, liver diseases, hematological, hepatic and renal function (Mazumder et al., 1999).

Caceres et al., (1992) reported anti-inflammatory activity from the hot water infusions of

flowers, leaves, roots, seeds and stalks or bark of M oleifera using carrageenan-induced hind paw

edema in rats. On the other hand, Moringa species' leaves, fruits and seeds have been reported as

rich sources of protein, essential elements (Calcium, Magnesium, Potassium and Iron and

vitamins (vitamins A, C and E) (Ramachandran et al., 1980; Fuglie, 1999).

In recent times, the use of plants as a source of novel compounds to combat microbial

infections has gained prominence. The necessity to search for plant-based antimicrobials is

increasing due to high cost, reduced efficacy and increased resistance to conventional medicine

(Sankar et al., 2012). In developing countries, herbal medicines play an important role in primary

health care, especially where coverage of health care service is limited. This work is aimed at

finding the phytochemical and antimicrobial activity of the leaf and seed extract of Moringa

oleifera.

Materials and Methods

The research was conducted between February and April, 2013 at Igbinedion University

Microbiology Laboratory, Okada, Edo State, Nigeria. Okada is the headquarters of Ovia North-

East Local Government of Edo state.

Collection and Identification of Moringa Oleifera

The plant was identified at Lucado Horticultures, Federal University of Technology,

FUTA road, Akure, Ondo State, where the seeds and leaves were also obtained from. The age of

the plant was estimated at about a year and six months old.

Extraction

Each leaf was destalked and air-dried at average room temperature. Continuous turning

of the leaves was done to avert fungal growth for two weeks. They were kept away from high

temperatures and direct sun light to avoid destroying active compounds. The pods containing the

seeds were also dried at room temperature. After about two weeks, the pods opened up, exposing

the seeds. The leaves and the seeds were reduced to fine powder using mortar and pestle. The

fine powder of the leaves weighed 19.25g while that of the seeds weighed 26.40g. They were

measured using a Scout Pro digital weighing scale.

The soxhlet extraction method (continuous/ successive extraction) was used. The

pulverized plant sample (19.25g) of the leaves of Moringa oleifera was filled into the sample

thimble and placed in the inner of the soxhlet apparatus. The soxhlet was fitted at the bottom to a

round bottom flask of appropriate size containing the solvent N- hexane (BDH, England) and

was fitted on top to a reflux condenser. The solvent (n-hexane) was gently heated and the vapour

passed up through the tube and condensed by the condenser back into the thimble to slowly fill

the body of the soxhlet. When the solvent reached the top of the tube, it is siphoned over into the

flask and removed the portion of the substance which it had extracted in the thimble. The process

was reheated automatically until complete extraction was effected. This process was further

repeated for the seed sample (26.40g) with n- hexane. Both sample (seed and leaves) already

extracted with n- hexane was further re- extracted in soxhlet apparatus with methanol solvent

(JHD, China) till complete extraction was attained. The filtrates extractions were taken in

previously weighed evaporating Petri-dishes and a rotary vacuum evaporator was used to remove

the excess solvents. After the complete evaporation, the weight of the extracts was recorded and

then labelled. The extractions stored separately at 4oC in amber coloured airtight bottles.

Phytochemical Screening

Phytochemical analysis was performed using standard procedure prescribed by Sofowora

(1993), Trease and Evans (1989) and Odebiyi and Sofowora (1978).

Collection and Confirmation of Isolates.

The pure culture of microorganisms used for the evaluation of the antimicrobial potential

of the leaves and seed extracts of Moringa oleifera are Escherichia coli, Staphylococcus aureus,

Klebsiella pneumoniae and Candida albicans. The isolates were all locally isolated pure cultures

obtained from the Medical Microbiology Laboratory of Igbinedion University Teaching

Hospital, Okada. The isolates were identified using various standard biochemical tests described

by Olutiola et al., (1991). All bacterial isolates were maintained on nutrient agar slants and

fungal isolates on Potato dextrose agar at a temperature of 4°C. The isolates were confirmed

using morphological and biochemical examination. The morphological examination include,

culture of microorganism and Gram staining test. Biochemical Tests to include Tube coagulase

test, Catalase test, Oxidase test, Urease test, Indole test, Methyl red test, Citrate test, Vogues

proskauer test, Triple sugar iron slant test, Germ tube (for fungi) and Carbohydrate fermentation

test. Identification of the bacterial isolates was accomplished by comparing the characteristics of

the cultures with that of known data.

Standardization of Microorganisms

The microorganisms were inoculated on petri dishes from the slant bottles and incubated

overnight. For each microorganism, culture on the plates was inoculated into 9mls of nutrient

broth to subculture. The bottles were not tightly shut to allow the aerobic organisms grow. They

were incubated overnight. Normal saline was gradually added to 1ml of the subculture and

compared to the Mc Farland standards to make 0.5 Mc Farland standards.

0.5 Mc Farland standard = 1.5 X 108 cfu/ml

1 Mc Farland standard = 3.0 X 108 cfu/ml

1.5 Mc Farland standard = 6.0 X 108 cfu/ml

Sterility test of Moringa Oleifera Extracts

1ml of the extract were each introduced into the nutrient agar growth media and

incubated for 24 hours at 370C. The absence of growth of microorganisms confirmed its sterility.

Susceptibility test on test Organisms with the Extracts.

Antimicrobial activity of the aqueous, hexane and methanol extracts of the leaves and

seeds and was assayed using the agar well diffusion method. The molten sterile agar (20mls) was

poured into each of the sterile petridishes and allowed to set. The petridishes were streaked with

the 0.5 Mc Farland standard of each of the microorganism. A sterile cork borer was used to bore

five equidistant wells into the agar plates. Two of the wells were for the positive control

(0.4mg/ml gentamicin for bacteria and 150mg/ml fluconazole for the fungi), two were for the test

extracts and one for the negative control (hexane/methanol). 100µL of the hexane extracts of the

Moringa oleifera leaf were introduced into the appropriate well using separate plates for each of

the 7 concentration of the extracts, as well as 100µL each of the positive and negative control.

The plates are incubated for 24 hours at 37oC. The relative susceptibility of the microorganisms

in the various extracts was indicated by clear zones of growth inhibition around the well. This

was repeated for the methanol extract of leaf, hexane extract of seed and the methanol seed

extracts. The zones of inhibition were then measured in millimeter. The above method was

carried out in triplicates and the mean of the triplicate results was taken.

Determination of Minimum Inhibitory Concentration (MIC)

The MIC is the lowest concentration of the extract at which growth of microorganism is

inhibited. 0.2ml of each of the concentration of the extract was added to 1.8ml of nutrient broth.

The microorganisms were inoculated into the mixture. Positive controls were prepared using

0.4mg/ml of gentamicin in place of the extract. Hexane was used as the negative control for the

hexane extracts while methanol was used for the methanol extracts. The tubes were incubated

and observed after 24 hours. The MIC was taken as the lowest concentration that prevented

bacterial growth.

Results

Percentage Yield of Extraction

The percentage yield of the extract is shown in table 1. It indicates that methanol gives the

maximum yield for the seed (25.19%) and hexane gives the maximum yield for leaf at 25.19%.

% Yield =

Table 1: Percentage yield and appearance of the crude extracts of Moringa oleifera

Plant Part Extract Percentage Yield Appearance of Crude Extract

Seed Hexane 17.27% Light green liquid

Methanol 25.19% Brown oily liquid

Leaf Hexane 25.19% Dark green solid

Methanol 23.84% Dark green liquid

Phytochemical Analysis

The Phytochemical screening of the leaf and seed of Moringa oleifera revealed the presence of

the different phytochemical components summarized in table 2. The seed and leaf of Moringa

oleifera contained a number of phytochemicals such as alkaloids, glycerides, flavonoids,

steroids, terpenoids, saponins and tannins. Flavonoids were largely present in both the hexane

and methanol seed extract; tannins were absent in the hexane extracts of the leaves and seeds;

steroids were largely present in all but the methanol leaf extracts; glycosides were also largely

present in the methanol extracts of seed and leaves; terpenoids were absent in all the extracts.

The following were largely present in the methanol extracts of the leaves: alkaloids, saponins,

reducing sugars, carbohydrates, eugenol and glycosides. These data corroborated the findings of

other authors where these compounds exhibited antimicrobial activities (Sato et al., 2004;

Cushine and Lamb, 2009).

Table 2: Phytochemical Analysis of the Hexane and Methanol Extracts of Moringa oleifera Leaf

and Seed.

Phytochemicals Leaf Seed

Hexane Methanol Hexane Methanol

Flavonoid + + ++ ++

Alkaloid + ++ + +

Tannin - + - +

Phenolics + - + -

Steroids ++ + ++ ++

Saponins + ++ + +

Reducing sugars + ++ + +

Carbohydrate + ++ + +

Eugenol + ++ ++ +

Terpenoids - - - -

Glycosides + ++ + ++

Keys: - = absent; + = slightly present; ++ = largely present

Antimicrobial Activity Assay

The antibacterial activity of the hexane and methanol extracts was investigated using agar well

diffusion method, against the selected human pathogens such as Escherichia coli, Pseudomonas

aeroginosa, Klebsiella pneumoniae and Candida albicans. All the examined extracts showed

varying degrees of antibacterial and antifungal activities against the tested organisms. The

maximum mean zone of inhibition was exhibited by the methanol leaf extract (25.5mm at

1040mg/ml in Table 3). Of all the extracts, Moringa oleifera leaf extracts has the highest

antimicrobial value with highest antibacterial activity against the bacteria tested and the highest

antifungal activity against the fungus tested (Table 3-6). This suggests that Moringa oleifera leaf

extract has higher potency antimicrobial activity than the seed (Table 3-6). The hexane extract of

the seed showed no inhibition against Escherichia coli, Klebsiella pneumonia and Pneumoniae

aeruginosa at all concentrations (Table 6).

Table 3: Antimicrobial Activity assay of Methanol Leaf Extracts of Moringa oleifera

Microorganisms

Mean Zones of Inhibition at various Concentration of the Extract(mm)

Positive control

Negative control

16.2

5mg/

ml

32.5

mg/

ml

65m

g/m

l

130m

g/m

l

260m

g/m

l

520m

g/m

l

1040

mg/

ml

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Met

hano

l

E coli 0 0 0 0 0 0 25.5 27.5 - 0P aeruginosa 0 0 0 0 0 10.5 18.5 18 - 0K pnuemoniae 0 0 0 0 0 11.5 15 19 - 0C albicans 0 0 0 0 0 15 22 - 20.5 0Key: 0 = No Inhibition, 0 -10 = moderately sensitive, 10- 20 =sensitive, 20 and above =very

sensitive.

Table 4: Antimicrobial Activity assay of Hexane Leaf Extracts of Moringa oleifera

Microorganisms

Mean Zones of Inhibition at various Concentration of the Extract(mm)

Positive control

Negative control

8.44

mg/

ml

16.8

8mg/

ml

33.7

5mg/

ml

67.5

mg/

ml

135m

g/m

l

270m

g/m

l

540m

g/m

l

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Hex

ane

Eschericia coli 0 0 0 0 0 0 17 29 - 0P aeruginosa 0 0 0 0 0 0 0 25.5 - 0K pnuemoniae 0 0 0 0 0 0 22.5 23.5 - 0C albicans 0 0 0 0 0 0 22.5 - 24.5 0Key: 0 = No Inhibition, 0 -10 = moderately sensitive, 10- 20 =sensitive, 20 and above =very

sensitive.

Table 5: Antimicrobial Activity assay of Methanol Seed Extracts of Moringa oleifera

Microorganis Mean Zones of Inhibition at various Positive Negativ

ms Concentration of the Extract(mm) control control

14.6

7mg/

ml

29.3

4mg/

ml

58.6

8mg/

ml

117.

36m

g/m

l

234.

71m

g/m

l

469.

42m

g/m

l

938.

84m

g/m

l

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Met

hano

l

E coli 0 0 0 0 0 8 19.5 21.5 - 0P aeruginosa 0 0 0 0 0 0 10 27.5 - 0K pnuemoniae 0 0 0 0 0 12 20 24 - 0C albicans 0 0 0 0 0 9 15 - 17.5 0Key: 0 = No Inhibition, 0 -10 = moderately sensitive, 10- 20 =sensitive, 20 and above =very

sensitive.

Table 6: Antimicrobial Activity assay of Hexane Seed Extracts of Moringa oleifera

Microorganisms

Mean Zones of Inhibition at various Concentration of the Extract(mm)

Positive control

Negative Control

11.4

7mg/

ml

22.9

4mg/

ml

45.8

6mg/

ml

91.7

5mg/

ml

183.

5mg/

ml

367m

g/m

l

734m

g/m

l

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Hex

ane

E coli 0 0 0 0 0 0 0 20 - 0P aeruginosa 0 0 0 0 0 0 0 21 - 0K pnuemoniae 0 0 0 0 0 0 0 20 - 0C albicans 0 0 0 0 0 0 20 - 22 0Key: 0 = No Inhibition, 0 -10 = moderately sensitive, 10- 20 = sensitive, 20 and above = very

sensitive.

Percentage Activity

Candida albicans had the highest percentage activity of 107.3% at 1040mg/ml with methanol

leaf extract when compared to the controls followed by Pseudomonas aeruginosa at 104.4%

(table 7). The percentage activity for Pseudomonas aeruginosa with hexane leaf and seed extract

was zero at their highest concentrations (540mg/ml and 734mg/ml respectively) (tables 8 & 10).

%Activity =

Table 7: Percentage Activity of Methanol Leaf Extracts of Moringa oleifera

Microorganisms Percentage Activity at various Concentration of the Extract (%)

16.2

5mg/

ml

32.5

mg/

ml

65m

g/m

l

130m

g/m

l

260m

g/m

l

520m

g/m

l

1040

mg/

ml

E coli 0 0 0 0 0 0 92.73

P aeruginosa 0 0 0 0 0 58.33 104.4

K pnuemoniae 0 0 0 0 0 60.53 78.94

C albicans 0 0 0 0 0 73.17 107.3

Table 8: Percentage Activity of Hexane Leaf Extracts of Moringa oleifera

Microorganisms Percentage Activity at various Concentration of the Extract (%)

8.44

mg/

ml

16.8

8mg/

ml

33.7

mg/

ml

67.5

mg/

ml

135m

g/m

l

270m

g/m

l

540m

g/m

l

Eschericia coli 0 0 0 0 0 0 58.62Pseudomonas aeruginosa 0 0 0 0 0 0 0Klebsiella pnuemoniae 0 0 0 0 0 0 95.74Candida albicans 0 0 0 0 0 0 91.84

Table 9: Percentage Activity of Methanol Seed Extracts of Moringa oleifera

Microorganisms Percentage Activity at various Concentration of the Extract (%)

14.6

7mg/

ml

29.3

4mg/

ml

58.6

8mg/

ml

117.

36m

g/m

l

234.

71m

g/m

l

469.

42m

g/m

l

938.

84m

g/m

l

Eschericia coli 0 0 0 0 0 37.20 90.70Pseudomonas aeruginosa 0 0 0 0 0 0 36.36Klebsiella pnuemoniae 0 0 0 0 0 50 83.33Candida albicans 0 0 0 0 0 51.43 85.7

Table 10: Percentage Activity of Hexane Seed Extracts of Moringa oleifera

Microorganisms Percentage Activity at various Concentration of the Extract (%)

11.4

7mg/

ml

22.9

4mg/

ml

45.8

6mg/

ml

91.7

5mg/

ml

183.

5mg/

ml

367m

g/m

l

734m

g/m

l

Eschericia coli 0 0 0 0 0 0 0Pseudomonas aeruginosa 0 0 0 0 0 0 0Klebsiella pnuemoniae 0 0 0 0 0 0 0Candida albicans 0 0 0 0 0 0 90.9

Minimum Inhibitory Concentration

The MIC value for the Methanolic extracts on E.coli was 1040mg/ml while for K. pneumonia

was 520mg/ml and 1040mg/ml.

Table 11: Minimum Inhibitory Concentration of Methanol Leaf Extracts of Moringa oleifera

Microorganisms

Turbidity at various Concentration of the Extract

Positive control

Negative control

16.2

5mg/

ml

32.5

mg/

ml

65m

g/m

l

130m

g/m

l

260m

g/m

l

520m

g/m

l

1040

mg/

ml

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Met

hano

l

E coli + + + + + + - - +++P aeruginosa +++ ++ ++ ++ ++ + + - +++K pnuemoniae + + + + + - - - +++C albicans ++ ++ + + + + - - +++KEY: - = No growth; + = slight turbidity; ++ = moderate turbidity; +++ = very turbid

Minimum Bactericidal Concentration

Minimum bacteria concentration refers to the lowest concentration of antibiotic required to kill a

particular bacterium. The MBC for the methanol seed extract on E coli was 938.84m/ml, K

pneumonia was 58.68mg/ml and C albicans at 29.34mg/ml (table 12). The MBC for the

methanol and hexane leaf extracts and hexane seed extracts on all the organisms were at zero at

all concentrations.

Table 12: Minimum Bactericidal Concentration of Methanol Seed Extracts of Moringa oleifera

Microorganisms

Minimum Bactericidal Concentration at various Concentration of the Extract(CFU/ml)

Positive control

Negative control

14.6

7mg/

ml

29.3

4mg/

ml

58.6

8mg/

ml

117.

36m

g/m

l

234.

71m

g/m

l

469.

42m

g/m

l

938.

84m

g/m

l

Gen

tam

icin

(0.4

mg/

ml)

Fluc

onaz

ole

(150

mg/

ml)

Met

hano

l E coli 237 75 66 45 36 12 0 0 NP aeruginosa N N N N N N 136 0 NK pnuemoniae 10 20 0 0 0 0 0 0 NC albicans N 0 0 0 0 0 0 0 NKEY: N = Numerous = ˃350 CFU/ml

Discussion

Moringa preparations have been cited in the scientific literature as having antibiotic and

antitrypanosomal activities (Fahey, 2005). The results from the phytochemical screening

revealed the presence of tannins, saponins, alkaloids and phenols. The presence of

pharmacologically useful substances such as tannins, flavonoids, alkaloids, saponins among

other pharmacologically active elements (Table 2) in the seed and leaf of Moringa oleifera as

revealed by phytochemistry confirms the diverse claims and application of parts of the plant in

treatment of ailments (Haristoy et al., 2005). Several plants which are rich in tannins have been

shown to possess antibacterial activities against a number of organisms (Doss et al., 2009).

Saponnins though are haemolytic on red blood cells, are harmless when taken orally and they

have beneficial properties of lowering cholesterol levels in the body (Amos- Tautua et al., 2011).

Alkaloids have been shown to possess both antibacterial (Erdemogli et al., 2009) and

antidiabetic (Constantino et al., 2003) properties and useful for such activities. Phenols and

phenolic compounds have been extensively used in disinfections and remain the standard with

which other bactericides are compared (Uwumarongie et al., 2007).

Thus, the antibacterial activities exhibited by the secondary metabolites: tannins,

saponins, alkaloids and phenols may be responsible for the antimicrobial activity of the extract.

The presence of secondary metabolites in plants have been reported to be responsible for their

antibacterial properties (Rojas et al., 2006; Nikitina et al., 2007; Udobi et al., 2008; Rafael et al.,

2009; Adeshina et al., 2010).

However, the present result reveals that the use of Moringa as an antimicrobial agent is

limited since only the methanol extracts of the seed and leaf exhibited major antimicrobial effect

on the microbes used in this study as compared to the hexane extracts (Tables 3-6). Generally,

the leaf extracts were more effective compared to the seed. This finding is corroborated by

Sankar, (2012). In his research, the methanol extract of leaves, flowers, barks, seeds and fruits of

Moringa oleifera at concentrations of 6mg/ml exhibited antibacterial activities against

Esherichia coli, Pseudomonas aeruginosa, Shigella dysenteriae and Shigella Flexneri. This

may be due to alkaloids and saponins being largely present in the methanol leaf extract.

Alkaloids are basically Nitrogen containing naturally occuring compounds commonly found to

have antimicrobial properties due to their ability to intercalate with the DNA of microrganisms

(Kasolo et al., 2010). Thus, it can be inferred that the Moringa oleifera leaf has more microbial

activity when compared to the seed.

Pseudomonas aeroginosa was found to be totally resistant to all the concentrations of the

hexane leaf extract (table 4). Generally, Gram negative bacteria are known to be resistant to the

action of most antibacterial agents including plant based extracts and these have been reported by

many researchers (Kambezi and Afolayan, 2008; El-Mahmood, 2009). Gram negative bacteria

have an outer phospholipids membrane with the structural lipopolysaccharide components,

which make their cell wall impermeable to anti-microbial agents. The methanol seed extract

displayed notable anti-bacterial activities against Pseudomonas aeruginosa (table 5). This is of

great importance because the infections caused by this bacterium are known to be difficult to

control. It is an opportunistic organism which has been reported to readily receive resistance

carrying plasmid from other bacteria species (Wiley et al., 2008).

The hexane seed extract was found to have no inhibitory effect on the microorganisms

except Candida albicans (Table 6). This may be due to the flavonoid being largely in the extract.

This was coroborated by Galeotti et al., 2008. Flavonoids are widely distributed in plants

fulfilling many functions. They have been shown to have antifungal activity in vitro (Galeotti et

al., 2008). The effect on zone of inhibition was generally low compared to the orthodox

antibiotics used in this study (Tables 6-9). The results of the antimicrobial sensitivity test was

found to be statistically significant (p˂0.05) (Appendix D)

The variations in the presence of the phytochemicals may be due to the choice of solvent used in

extraction. During extraction, solvents may have diffused into the plant material and solubilised

compounds with similar polarity (Ncube et al., 2008). Methanol is a polar solvent while hexane

is non polar. Methanol has been found to extract saponins which have antimicrobial activity

(Ncube et al., 2008). The ability of methanol extract to inhibit the growth of bacterial strains is

an indication of its antibacterial potential that might be employed in the management of bacterial

infections in the future. The age of the plant has been reported not to affect the phytochemicals

present in the plant (Bamishaiye et al., 2011).

The minimum inhibitory concentration showed E.coli to be bactericidal at 1040mg/ml and

bacteriostatic from 520mg -16.25mg/ml of the methanol leaf extract (table 11). The same goes

for Candida albicans.

Findings in this study suggests that methanol extracts of different parts of Moringa oleifera have

potential as antimicrobial compounds against pathogens and their ability to either block or inhibit

resistance mechanisms of bacteria and fungi could improve treatment and eradication of

microbial strains. Thus, these plant extracts could be used in the treatment of infectious diseases

caused by resistant bacteria. Therefore these results lay down a basis for investigation into the

search of compounds in M. oleifera responsible for antibacterial activity.

Since traditional medicine is mostly used as self care, Moringa oleifera, which is an herbal plant

that can be used in treating different ailments and malnutrition, it is therefore recommended that

it be cultivated by growing them in backyard gardens for ready availability.

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