Page 40 - Abstract book - TJSSF-2020

Thailand – Japan Student Science Fair 2020 (TJ-SSF 2020)
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Study of the Oral Bacterial Inhibition of Crude Edo Longan Seed
(Dimocarpus longan) Extract

Apirat Wijarn , Ekkapong Jomwong , Kitisak Sawangphanapan
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Advisor: Anek Chaiboot
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Princess Chulabhorn Science High School Chiang Rai
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Abstract
The study aimed to examine the oral Bacterial inhibition of crude extract from Edo longan seed.
The experimental method had 2 steps. The first step was to prepare crude extract from longan
seed by using water as solvent. Then the solvent was evaporated by Rotary Evaporator. For the
preparation of bacteria, 1 ml of oral secretions was put in Nutrient Broth food in test tubes and
was incubated for 24 hours. The second step was to test the turbidity of the samples that
contained oral secretions from test tubes after 24,48and 72 hours incubation. The bacteria,
prepared in the test tube, were added by crude longan seed extract at the concentration of 0.1
g/ml in the amount of 0.1 ml - 1 ml. After incubation for 24 hours, the experiment was found
that the turbidity of the samples were decreased. Thus, the crude longan seed extract could
inhibit the growth of oral bacteria. The amount of crude longan seed extract at 0.8 ml showed
the highest inhibitory growth ability in oral bacteria with the average turbidity of 55.27 NTU
and the turbidity range of 73.80 – 55.27 NTU. In conclusion, the crude longan extract has
bacterial inhibitory ability in oral bacteria from chemical components such as polyphenol
compounds.

Keywords: Edo Longan, Bacterial inhibition, Polyphenol compounds

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