Antimicrobial Effect of Natural Plant Extracts
against Periodontopathic Bacteria



Seung Hee Lee

Department of Public Health
Graduate School
Yeungnam University
(Supervised by Professor Han-Gon Kim)


ABSTRACT


In this study, we examined the antimicroboal effect against Actinobacillus actinomycetemcomitans and Prevotella intermedia which were the bacteria causing the Periodontopathic by using 34 types of natural plant extracts.
First, each of the 34 types of natural plant extracts were extracted by using the ethanol, and subsequently, the size of growth inhibition zone(clear zone, ㎜) of respective extracts were measured through the disk diffusion method. As a result, it was found that the growth inhibitory activity was found for A. actinomycetemcomitans, which is the bacteria causing the Periodontitis, in 13 types of natural plant extracts such as Raphanus sativus, Akebia quinata, Paeonia lactiflora, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Forsythia saxatilis, Gentiana macrophylla, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus, etc. In the case of P. intermedia, the growth inhibitory activity was found in 13 types of natural plant extracts such as Raphanus sativus, Angelica acutiloba, Akebia quinata, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Cinnamomum cassia, Aster tataricus, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus etc.
In addition, 13 types of natural plant extracts which exhibited the growth inhibitory activity in aforesaid experiment: such as Raphanus sativus, Angelica acutiloba, Akebia quinata, Belamcanda chinensis, Inula britannics, Houttuynia cordata, Cinnamomum cassia, Aster tataricus, Melia azedarach, Scutellaria baicalensis, Coptis chinensis, Phellodendron amurense, Kalopanax Pictus-- were selected out of 26 types of natural plant extracts and extracted by using the organic solvent. and then the growth inhibitory activity was measured in relation to the bacteria causing the Periodontopathic. For A. actinomycetemcomitans, anti-bacterial effect was exhibited in Belamcanda chinensis, Cinnamomum cassia , Kalopanax Pictus, Phellodendron amurense, Coptis chinensis. The Coptis chinensis showed the most excellent growth inhibitory activity in all organic solvent fragment, while P. intermedia showed the growth inhibitory activity in Belamcanda chinensis, Cinnamomum cassia, Meliaazedarach, Phellodendron amurense, and Coptis chinensis.
Moreover, the Minimum Inhibition Concentration was measured by using the ethanol extracts from aforesaid 13 types of natural plant extracts. The results showed the Minimum Inhibition Concentration of 12.5 ㎍/㎖ for Belamcanda chinensis, 6.25 ㎍/㎖ for Kalopanax Pictus, 6.25 ㎍/㎖ for Coptis chinensis, and 6.25 ㎍/㎖ for Scutellaria baicalensis in the case of A. Actinomycetemcomitans. Meanwhile, the Minimum Inhibition Concentration was 100 ㎍/㎖ for Kalopanax Pictus, 12.5 ㎍/㎖ for Coptis chinensis, 6.25 ㎍/㎖ for Scutellaria baicalensis, and 100 ㎍/㎖ for Aster tataricus in the case of P. intermedia.
To compare the degree of anti-bacterial activity of natural plant extracts which were verified in this study, the size of anti-bacterial action growth inhibition zone of tetracycline, berberine, and benzethonium chloride -- the currently available antibiotics against A. actinomycetemcomitans and P. intermedia in the market -- were measured and put into comparison.
In the case of A. actinomycetemcomitans, tetracycline showed anti-bacterial action of 35 ㎜, and benzethonium chloride showed anti-bacterial action of 12 ㎜. Meanwhile, the berberine did not exhibit any anti-bacterial action. In the case of P. intermedia, tetracycline showed anti-bacterial action of 22 ㎜, and benzethonium chloride showed anti-bacterial action of 19 ㎜. Meanwhile, the berberine exhibited anti-bacterial action of 17 ㎜.
Some natural plant extracts, such as Coptis chinensis, had the anti-bacterial activity similar to that of benzethonium chloride, the control group, and therefore, may be able to used as alternative agent for reducing the side effects. As the Coptis chinensis, which has excellent anti-bacterial activity, did not show anti-bacterial activity in berberine, the root component, for A. actinomycetemcomitans, it would be necessary to conduct research into other active components contained in the roots. In addition, the fragment extracts had different anti-bacterial activity, depending on the type of organic solvent, and therefore, it would be necessary to conduct the study with respect to additional natural plant extracts that use different types of organic solvent.