Novel anti-adherence activity of mulberry leaves: inhibition of Streptococcus mutans biofilm by 1-deoxynojirimycin isolated from Morus alba.
OBJECTIVE
The present study focused on isolation, characterization and evaluation of purified compounds from Morus alba against Streptococcus mutans biofilm formation.


METHODS
The effect of crude extract from M. alba leaves was evaluated against oral pathogens, chiefly S. mutans. MICs were determined by the microdilution method. The compound was purified by employing silica gel chromatography and critically analysed with GC-MS, NMR and IR spectroscopy. The S. mutans traits of adherence and biofilm formation were assessed at sub-MIC concentrations of the crude extract and purified compound. Both water-soluble and alkali-soluble polysaccharide were estimated to determine the effect of the purified compound on the extracellular polysaccharide secretion of S. mutans. Its effect on biofilm architecture was also investigated with the help of confocal microscopy.


RESULTS
The purified compound of M. alba showed an 8-fold greater reduction of MIC against S. mutans than the crude extract (MICs, 15.6 and 125 mg/L, respectively). The extract strongly inhibited biofilm formation of S. mutans at its active accumulation and plateau phases. The purified compound led to a 22% greater reduction in alkali-soluble polysaccharide than in water-soluble polysaccharide. The purified compound was found to be 1-deoxynojirimycin (DNJ). Confocal microscopy revealed that DNJ distorts the biofilm architecture of S. mutans. CONCLUSIONS The whole study reflects a prospective role of DNJ as a therapeutic agent by controlling the overgrowth and biofilm formation of S. mutans.
Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh 202002, India.
Barira
B
Islam
Shahper N
SN
Khan
Irfanul
I
Haque
M
M
Alam
M
M
Mushfiq
Asad U
AU
Khan
D017485:1-Deoxynojirimycin / Q000302:isolation & purification / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects; D002850:Chromatography, Gel; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal; D031625:Morus / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D013291:Streptococcus / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D017485:1-Deoxynojirimycin