In recent years, the development of antibiotics is extremely costly or there may be lack of
effective methods to inhibit growth of plant pathogens, thus resulting in widespread
agricultural diseases. This has led to researchers finding alternative antimicrobial agents.
While the use of silver nanoparticles as an antimicrobial agent is widely acknowledged,
Chinese herbs are also known to contain secondary metabolites which can inhibit the
growth of plant pathogens. Hence, this study aims to investigate the synergistic
antimicrobial effects of silver nanoparticles with Chinese herbs where the
antimicrobial properties of silver nanoparticles, Chinese herbs and their combined effects
against plant pathogens were compared.
Silver nanoparticles were synthesized through the use of tea leaf extracts and washed
before usage as this method is more environmentally friendly as compared to chemicals
such as sodium borohydride. Herb extracts were obtained from Chinese herbs and
were microfiltered before usage to remove any impurities. Colony count was used to
determine the number of bacterial colonies that survived in agar containing silver
nanoparticles alone, Chinese herbs alone and both antimicrobial substances.
Results showed that the use of Chinese herbs Schisandra chinensis and Astragalus
membranaceus have shown little to no synergistic antimicrobial effects with silver
nanoparticles against plant pathogen such as Pectobacterium carotovorum and Ralstonia
solanacearum. This is because results have shown that silver nanoparticles and Chinese
herbs already exhibit strong antimicrobial properties when used individually on the
bacteria above. Applications of silver nanoparticles and Chinese herbs include
antimicrobial coating on wound dressings and biomedical devices to maintain sterility of