Question

A complementary medicine company is interested in determining if herbal extracts can improve the efficiency of antibiotics at low concentrations. Design an experiment to determine if Echinacea diluted 1:100 can increase the effectiveness of ampicillin against E. coli when tested at 10% of the minimum inhibitory concentration of ampicillin.

Answer 1

Echinacea are cone flowers belonging to family Asteraceae. Some common species are: Echinacea angustifolia, Echinacea purpurea, Echinacea pallida, of which, E. purpurae has most therapeutic uses as herbal medicine.

Echinacea extract is found to have be effective against infections like, respiratory ailments, flu, vaginal infections, UTI, ear infections, etc.

Echinacea. Have several side effects, but maybe considered to be used, when antibiotics are not effective against certain species of bacteria.

Antibiotics are most common and major group of antimicrobial agents. To determine the effectiveness, sensitivity of an antibiotic against a microorganism, several tests have bee designed. MIC is minimum inhibitory concentration method, is used to detect the minimum concentration of antibiotic that would inhibit a specific microorganism.

In this case, an experiment is designed to determine the effectiveness of antibiotic ampicillin against bacteria Escherichia coli, and to analyse the complementary effect of Echinacea, on ampicillin. Minimum inhibitory concentration method (MIC) will be used here for the purpose.

Given conditions:

Dilution of the herbal extract (Echinacea): 1: 100

MIC of Ampicillin: 10% (concentration of ampicillin in which 10% bacteria were inhibited or killed)

Test microorganism: Bacteria Escherichia coli.

Experiment:

AIM: To determine the complementary effect of herbal extract of echinacea on bacteria of antibiotic ampicillin on Escherichia coli.

Method:

1. determine the concentration of Ampicillin at which 10% E. coli are inhibited (let it be x ?g/ml).

2. E. coli culture is prepared in broth medium (preferably, Mueller Hinton broth).

3. Separate tubes of bacterial culture were taken.

4. Tube 1: Add 1: 100 or 10^-2 dilutions of Echinacea.

    Tube 2: Add concentration of Ampicillin for 10 % MIC activity, x ?g/ml.

    Tube 3: Mixture of Echinacea + Ampicillin.

5. MIC is observed in each case.

Result:

To determine the effect of an additive on the effectiveness of the antibiotic can be measured by calculating the fractional inhibitory concentration (FIC) value for additive (Echinacea) and antibiotic (Ampicillin), then calculating the FIC index, as:

FIC of Ampicillin = MIC of (Mixture of Echinacea + Ampicillin)/ MIC of Ampicillin (10%)

FIC of Echinacea = MIC of (Mixture of Echinacea + Ampicillin)/ MIC of Echinacea.

FIC index = FIC of Ampicillin + FIC of Echinacea

If FIC index is greater than 0.5, then the effect of Echinacea would be considered as complementary for Ampicillin.