Selected Traditional medicines used in infectious conditions – with special emphasis on external wounds

By: Gertrude Mothibe, NUL

Background

• Traditional medicines have been used in Lesotho to heal various diseases including infected wounds.

• Since these have been used for centuries for the same conditions, an assumption is made that the traditional medicines may have antimicrobial activity.

Background

• Under the assumption that medicine used on infected wounds is most likely antimicrobial,

• Aloe maculata (Lekhala la bafu), Helichrysum caespititium (Phate-ea-ngaka) and pig bile (Nyooko ea kolobe) were selected for antimicrobial investigation.

Methodology

• The 2 plants were collected from the wild in the Roma valley, and the taxonomic identity of the plants was confirmed by the National University of Lesotho botanist.

• Pig bile was collected from the University farm immediately after the slaughter of a pig.

Methodology – cont.

• To obtain extracts, 2 methods were used on the Helichrysum caepestitium – ethanol and methanol extracts were obtained by cold percolation, whilst the aqueous extracts were obtained by the heating method.

• Aloe maculata was blended and the sap used directly.

• Pig bile was used as is.

Methodology – cont.

• Test microorganisms• The test microorganisms used were obtained

from the microbiology laboratory at NUL.• The Gram-positive Staphylococcus aureus; • Gram-negative Escherichia coli;• and the fungus Candida albicans were used.

Methodology – cont.

• Standard antibiotics used as positive controls.

• Amoxicillin 25µg,

• Erythromycin 15 µg and

• Nystatin 100 units

Methodology – cont.

• Medium of growth for microorganisms:

• The medium used for growth of bacteria was nutrient agar,

• while saboraud- dextrose was used for fungi.

Methodology – cont.

• Antimicrobial susceptibility test• The disc diffusion method was used to screen

the antimicrobial activity

FINDINGS

FINDINGS –

HM HE HW A P0

5

10

15

20

25

30

Candida albicansStaphylococcus aureusEscherichia coli

Test compounds

Inhi

tion

zone

dia

met

er (m

m)

FINDINGS

• Figure 1: Mean inhibition zone diameter

• ‘HM’ represents methanol extract of Helichrysum caepestitium,

• ‘HE’ represents ethanol extract, • ‘HW’ is water extract. • ‘A’ represents Aloe maculata and • ‘P’ represents pig bile.

FINDINGS

• The antimicrobial activity was calculated by applying the expression:

FINDINGS

• Where RIZD is the percentage of relative inhibition zone diameter and

• IZD is the inhibition zone diameter (mm)• • This equation compensates the possible effect

of the solvent other than water on the IZD

FINDINGS

HM HE HW A P0

50

100

150

200

250

Candida albicansStaphylococcus aureusEscherichia coli

Test Compounds

Perc

enta

ge o

f rel

ative

inhi

bitio

n zo

ne d

iam

eter

FINDINGS

• Figure 2: Percentage of relative inhibition zone diameter.

• ‘HM’ represents methanol extract of Helichrysum caepestitum,

• ‘HE’, ethanol extract and • ‘HW’ water extract. • ‘A’ represents Aloe maculata and • ‘P’ represents pig bile.

DISCUSSION - Helichrysum

• The antibacterial activity of the Helichrysum caepestitum extract was observed against Gram-positive and Gram-negative bacteria as well as fungi.

• This indicated a broad antibacterial efficacy of this plant.

DISCUSSION - Helichrysum

• Ethanol extracts in particular, showed highest activity,

• the success of extraction by the solvent is probably due to classes of compounds present in Helichrysum such as phenols which are soluble in polar solvents such as ethanol

DISCUSSION - Aloe

• Aloe seemed to have more activity on fungi.

• Aloe is probably lipophilic hence easily inhibits biosynthesis of fungi lipids

DISCUSSION - Aloe

• The test of phenolic groups was made on the extract:

• The test confirmed that Aloe maculata has phenols; this group of compounds possesses significant antimicrobial activity

DISCUSSION – Pig bile

• Pig bile had more activity on Candida albicans compared to both bacteria;

• The overall activity was generally not significant, possibly due to different content of chemical groups with antibacterial properties in bile acids.

DISCUSSION – Pig bile

• Although bile acids are potent antimicrobial agents that prevent bacterial over-growth in the small bowel, it did not seem as potent in the experiment.

• It may possess other properties that promote wound healing such as promoting thrombosis.

Conclusions

• 1. Traditional medicine investigated in this study (Helichrysum caepestitum, Aloe maculata and pig bile) showed antimicrobial activity.

• 2. Thus use of these traditional medicines on external wounds seems to have the effect of preventing sepsis.

Recommendations

• 1. Against the background of growing drug resistance, use of traditional medicine in conditions of infections, especially by communities in remote areas, should not be discouraged.

• Further studies should be done to investigate any possible toxic compounds in these traditional medicines. Where these exist, traditional healers should be advised on use of limited quantities of the medicines.

Recommendations

• 3. Discussions between orthodox medicine personnel and traditional healers should be used to inform future research into drug discovery.

• 4. Use of plants as sources of traditional medicine needs to be controlled in order to avoid extinction.

• 5. Using principles of drug discovery, future studies should also look at identifying target compound structures, for possibilities of synthesising these molecules and avoiding eroding the plant species.