• Thatsanee Saladyanant D.D.S., M.Sc.
• Naulchavee Hongprasong D.D.S., M.D.S., Diplomate, Thai Board of Periodontology
• Sunan Pongsamart B.Sc. (Pharmacy), Ph.D.
• Wandee Apinhasmit D.D.S., Ph.D.
• Pasutha Thunyakitpisal D.D.S., Ph.D.

Objective To study the antibacterial activity of polysaccharide gel extracted from durian fruit-hulls
(PG) against Streptococcus mutans and Aggregatibacter actinomycetemcomitans which are associated
with the development of caries and periodontal disease, respectively.

Materials and methods An inhibitory activity of PG against S. mutans ATCC 25175 and A.
actinomycetemcomitans ATCC 43718 was determined by treated them with 50, 100 and 150 mg/ml
of PG for 1, 5, 10, 20, 30 and 60 min in broth. Treated bacteria were subsequently cultured on agar
for 48 hrs. Their survivals were evaluated in comparison with 0.1% chlorhexidine and the negative
control group using the drop plate method.

Results At 1 min, 150 mg/ml of PG and 0.1% chlorhexidine had bactericidal activity against both
S. mutans and A. actinomycetemcomitans, whereas 100 mg/ml of PG had bactericidal activity
against S. mutans and inhibitory activity against A. actinomycetemcomitans. The bactericidal activity
against both bacteria was shown after the incubation with 50 mg/ml of PG for 60 min.

Conclusion The bactericidal activities of 100 and 150 mg/ml of the PG in 1 min against both S. mutans
and A. actinomycetemcomitans, respectively, suggest that the PG may be developed as an active
ingredient in oral health care products to control caries and periodontal disease.

(CU Dent J. 2007;30:235-44)