Suwan Temsiri, Khongkhunthian Sakornrat, Okonogi Siriporn
Interdisciplinary Program in Nanoscience and Nanotechnology, Chiang Mai University.
Research Center of Pharmaceutical Nanotechnology, Chiang Mai University.
Drug Discov Ther. 2018;12(4):189-196. doi: 10.5582/ddt.2018.01034.
Rice is staple food for people in many countries for centuries. It is therefore considered as safe and environmental friendly material for pharmaceutical formulations. In the present study, aqueous extracts of three different parts of rice grain; rice bran (RB), rice husk (RH), and rice germ (RG) were compared for their use as reducing agents in synthesis of silver nanoparticles (AgNPs). AgNPs from those three different parts of rice, RB-AgNPs, RH-AgNPs, and RG-AgNPs, respectively showed different reducing activity, which the highest capacity was RB. RG-AgNPs and RB-AgNPs showed the maximum absorption of AgNPs at 440 nm whereas that of RH-AgNPs was at 480 nm. FTIR spectra of all AgNPs indicated the presence of different functional groups from rice attached to the nanoparticles and these groups prevented the particle agglomeration. Size analysis using dynamic light scattering revealed that RB-AgNPs was the smallest particles (346.4 ± 36.8 nm) and possessed the highest negative zeta potential. Antimicrobial test showed that the AgNPs obtained from green synthesis mediated by rice extracts have great antimicrobial activity against Streptococcus mutans, the severe oral pathogenic bacteria causing dental caries. These results suggest that aqueous extracts of RB, RH, and RG have potential to be used as reducing agents in synthesis of silver nanoparticles.
几个世纪以来，大米一直是许多国家人们的主食。因此，它被认为是用于药物制剂的安全且环保的材料。在本研究中，比较了水稻籽粒三个不同部分（米糠（RB）、稻壳（RH）和稻胚芽（RG））的水提取物作为合成银纳米颗粒（AgNPs）的还原剂的用途。分别来自水稻这三个不同部分的AgNPs，即RB-AgNPs、RH-AgNPs和RG-AgNPs，表现出不同的还原活性，其中还原能力最强的是RB。RG-AgNPs和RB-AgNPs在440nm处显示出AgNPs的最大吸收，而RH-AgNPs在480nm处。所有AgNPs的傅里叶变换红外光谱（FTIR）表明纳米颗粒上附着有来自水稻的不同官能团，这些官能团防止了颗粒团聚。使用动态光散射进行的尺寸分析表明，RB-AgNPs是最小的颗粒（346.4±36.8nm），并且具有最高的负zeta电位。抗菌测试表明，通过水稻提取物介导的绿色合成获得的AgNPs对变形链球菌具有很强的抗菌活性，变形链球菌是导致龋齿的严重口腔病原菌。这些结果表明，RB、RH和RG的水提取物有潜力用作合成银纳米颗粒的还原剂。
