title: Namibian chewing stick, Diospyros lycioides, contains antibacterial compounds against oral pathogens.
abstract: The twigs of Diospyros lycioides, a plant commonly known as "muthala", are frequently used as chewing sticks for the cleaning of teeth by rural and urban people in Namibia. Preliminary studies showed that a methanol extract of D. lycioides inhibited growth of selected oral pathogens. Subsequent bioassay-guided fractionation led to the isolation of four novel bioactive naphthalene glycosides, diospyrosides A, B, C, and D (1-4), and two known bioactive naphthoquinones, juglone (5) and 7-methyljuglone (6). The structures of the new compounds were elucidated using spectroscopic techniques including 1D and 2D NMR. These compounds inhibited the growth of oral cariogenic bacteria (Streptococcus mutans and Streptococcus sanguis) and periodontal pathogens (Porphyromonas gingivalis and Prevotella intermedia) at minimum inhibitory concentrations ranging from 0.019 to 1.25 mg/mL. Juglone exhibited the strongest inhibitory activity among these compounds.
authors.affiliation: Department of Periodontics, College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, Illinois, 60612-7212, USA.
authors.forename: L
authors.initials: L
authors.lastname: Cai
authors.forename: G X
authors.initials: GX
authors.lastname: Wei
authors.forename: P
authors.initials: P
authors.lastname: van der Bijl
authors.forename: C D
authors.initials: CD
authors.lastname: Wu
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001424:Bacterial Infections / Q000517:prevention & control*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009059:Mouth Diseases / Q000517:prevention & control*; D009910:Oral Hygiene; D010945:Plants, Edible / Q000737:chemistry*; D017861:Porphyromonas / Q000187:drug effects; D018720:Prevotella / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents