Antibacterial substances from Albizia myriophylla wood against cariogenic Streptococcus mutans

Abstract

Albizia myriophylla has been used for long by Thai traditional healers as an important ingredient herb in Thai herbal formulas for caries. In this study, three flavonoids lupinifolin (6), 8-methoxy-7,3',4'-trihydroxyflavone (7), and 7,8,3',4'-tetrahydroxyflavone (8), a triterpenoid lupeol (3) as well as four sterols β-sitosterone (1), stigmasta-5,22-dien-3-one (2), β-sitosterol (4), and stigmasterol (5) were isolated from A. myriophylla wood. The antibacterial activity of these compounds against Streptococcus mutans ATCC 25175 was performed using broth microdilution method. All compounds exhibited antibacterial activity against S. mutans with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) ranging from 1-256 and 2-256 μg/ml, respectively. Among the isolated compounds, lupinifolin (6) was found to be the most potent with MIC and MBC of 1 and 2 μg/ml, respectively. Lupinifolin (6) also showed a strong activity against ten clinical isolates of S. mutans with MIC and MBC ranging from 0.25-2 and 0.5-8 μg/ml, respectively. These results reported the bioactive ingredients of A. myriophylla which support its ethnomedical claims as well. Lupinifolin (6) may have a potential to be a natural anticariogenic agent.

Chemical constituents and biological activities ofAlbizia myriophyllawood

“…The details relating to the extraction method of A. myriophylla wood collected from southern region of Thailand were previously described (Joycharat et al, 2013). The wood of A. myriophylla originating from central region of Thailand (2.9 kg) was dried, ground, and exhaustively macerated with ethanol (EtOH) at room temperature three times, filtered, and concentrated to give a residue of EtOH extract (213 g, 7.34%).…”

“…A broad range of pharmacological effects of this plant including antioxidant, anticandidal, and antibacterial activities has been previously established (Joycharat et al, 2013;Steinrut et al, 2011). Regarding the biological activity of the isolated secondary metabolites from A. myriophylla, only one report is currently available (Joycharat et al, 2013). In our previous work, the flavanone lupinifolin isolated from the wood extract of that originating from southern Thailand exhibited very strong antibacterial activity against Streptococcus mutans ATCC 25175 and its clinical isolates, with MIC values ranging from 0.5 to 4 mg/mL (Joycharat et al, 2013).…”

“…Bioactive secondary metabolites produced by plants have proven to possess a wide range of therapeutic effects for human diseases (Ferrazzano et al, 2011). Recently, scientific interest in these metabolites has increased with the search for new therapeutic agents from plant sources, due to the fact that currently used drugs are relatively toxic or, to a certain extent, ineffective due to the spreading of resistance (Joycharat et al, 2013;Khaomek et al, 2008). In Thailand, medicinal plants are increasingly used by traditional healers and herbalists for the treatment of various ailments (Joycharat et al, 2012;Neamsuvan et al, 2012).…”

“…Albizia myriophylla is among the most important medicinal plant and is used alone or in combination with other medicinal plants in various Thai herbal formulas, especially those for remedy of oral diseases including dental caries and aphthous ulcer (Neamsuvan et al, 2012). A broad range of pharmacological effects of this plant including antioxidant, anticandidal, and antibacterial activities has been previously established (Joycharat et al, 2013;Steinrut et al, 2011). Regarding the biological activity of the isolated secondary metabolites from A. myriophylla, only one report is currently available (Joycharat et al, 2013).…”

“…Regarding the biological activity of the isolated secondary metabolites from A. myriophylla, only one report is currently available (Joycharat et al, 2013). In our previous work, the flavanone lupinifolin isolated from the wood extract of that originating from southern Thailand exhibited very strong antibacterial activity against Streptococcus mutans ATCC 25175 and its clinical isolates, with MIC values ranging from 0.5 to 4 mg/mL (Joycharat et al, 2013). To the best of our knowledge, there is no report on the antibacterial activity of this plant species against other bacterial strains such as Staphylococcus aureus ATCC 29213 and Bacillus cereus ATCC 11778.…”