Antibacterial Plant Extracts

Introduction

Antibiotics have been used for a long time as the main agents against disease-causing micro-organisms. But over the years too, micro-organisms have developed resistant genes that make it impossible for them to be killed by the same antibiotics. To ensure control of such resistant organisms, herbal extracts with the same qualities can be used.  Such a herbal remedy could be the Sage (Salvia officinalis) that was documented during the expeditions of Lewis and Clark. Sage plant extract has been known for its medicinal functions such as treating skin diseases, anti-inflammatory functions, antibacterial, and even antisyphilitic uses (Abu-Darwish, et al., 2013). Therefore the plant has a variety of uses.

The extracts from the Sage plant have medicinal abilities. Thus their composition is crucial in ensuring this ability. The components of the Sage are affected by the environmental conditions of the place of growth. Amount of water has also been shown to affect its composition by Bettaieb, Zakhama, Wannes, Kchouk, & Marzouk (2009). Another plant whose composition of essential oils has been altered by water stress is the Satureja hortensis L (Baher, Mirza, Ghorbanli, & Rezaii, 2002). The Sage plant composition of chlorophyll, the leaf size and carotenoid contents have been influenced by the amount of light intensity they receive during their growth (Rezai, Etemadi, Nikbakht, Yousefi, & Majidi, 2018). The medicinal value of the plant is thus immense.

The experiment was done to determine whether Sage extract possessed antibacterial properties. Furthermore, the examination was to determine whether it has a better antibacterial agent and if it was effective against some antibiotic-resistant bacteria.

Hypothesis

The following hypotheses were tested:

1. Sage extract is effective at inhibiting bacteria growth.
2. Sage extract is more effective in inhibiting bacterial growth than other common herbs.
3. Sage extract is effective at inhibiting the growth of antibiotic-resistant bacteria.

Materials

1. Petri dishes containing solid bacterial growth media (Luria-Bertani nutrient agar).
2. Growth media made with water
3. Growth media made with water plus ampicillin antibiotic
4. Growth media made with an assortment of herbs (containing 5 g of fresh leaves per 100 ml of boiling water that had been left to steep for 15 minutes). The herbs include Mint, Lavender, Sage in the light and Sage in the shade.
5. Bacterial inoculants
6. non-antibiotic resistant coli culture
7. Ampicillin resistant coli culture
8. Inoculating loop.

Procedure

1. Two sets of each Petri dish containing the growth media was labelled on the bottom half using a marker pen, having a total of 12 Petri dishes.
2. Set 1 of the Petri dishes was inoculated using a clean inoculating loop dipped in E.coli culture. A was streak made across the medium, and this was repeated to make three lines. A new loop was then used each time to repeat the procedure to make streaks on each of the set 1 Petri dishes.
3. The above procedure was repeated using a clean inoculating loop to make streaks on the Set 2 Petri dishes using the ampicillin-resistant E.coli in each one.
4. The plates were then incubated at 37⁰C overnight to promote the growth of the bacteria and then stored at 4⁰C to prevent any further growth of the bacteria.
5. The bacterial growth on the plates was then scored using a scale of 0-5. 0 indicated no growth while 5 indicates growth on the plane agar inoculated by E.coli( Negative control), that was recorded in table 1.

Results

Table 1: Scores obtained from different plates

Conclusion

In set 1, ampicillin in the agar was able to prevent the growth of the non-resistant E. coli completely, this was followed by mint and Sage extract and lavender was the least effective extract. In set 2, sage extract in the shade was more effective in preventing the growth of ampicillin-resistant E.coli, followed by sage extract in the light, then mint and last was lavender.

From the results obtained, it is right to say that all three hypotheses are accepted. Such that, Sage extract can inhibit the growth of bacteria; thus, the first hypothesis is accepted. Compared with the other extracts of mint and lavender, Sage extract is better at inhibiting the growth of bacteria; thus the second hypothesis is also accepted. The last hypothesis is also accepted as the Sage extract of the three other extracts, mint and lavender had the lowest growth of bacteria that were ampicillin resistant. Of the two extracts of Sage, the one in the shade was the most effective as it had the lowest score.

Historical documents can be used to determine herbal extracts that have medical values. For instance, the diary form Lewis and Clark. A branch, aromatherapy can be used to identify the essential oils having medicinal benefits too.

References

Abu-Darwish, M. S., Cabral, C., Ferreira, I. V., Goncalves, M. J., Cavaleiro, C., Cruz, M. T., . . . Salgueiro, L. (2013). Essential oil of common Sage (Salvia officinalis L.) from Jordan: Assessment of safety in mammalian cells and its antifungal and anti-inflammatory potential. BioMed Research International, 1-9.

Baher, Z. F., Mirza, M., Ghorbanli, M., & Rezaii, M. B. (2002). The influence of water stress on plant height, herbal and essential oil yield and composition in Satureja hortensis L. Flavour and fragrance journal, 275-277.

Bettaieb, I., Zakhama, N., Wannes, W. A., Kchouk, M. E., & Marzouk, B. (2009). Water deficit effects on Salvia officinalis fatty acids and essential oils composition. Scientia Horticulturae, 271-275.

Rezai, S., Etemadi, N., Nikbakht, A., Yousefi, M., & Majidi, M. M. (2018). Effect of light intensity of leaf morphology, Photosynthetic capacity and chlorophyll content in Sage(Salvia officinalis L0. Horticultural sciences and technology, 36(1), 46-57.