The copper nanoparticles (CuNPs) have attracted much attention due to their application in diverse fields. The applications of CuNPs depend on their physical and chemical properties. This study presents the first report for the use of medicinal fruit extract of Piper retrofractum Vahl as an eco-friendly reagent in the synthesis of CuNPs using copper sulfate as a starting material. Piper retrofractum Vahl extract was employed as a bioreductor as well as a capping agent in the formation of CuNPs. The reaction process was assisted by sonication and stirring. The influences of extract concentration, pH, temperature, and reaction time on the size of CuNPs were studied in detail. The morphology and structure of synthesized CuNPs were characterized by UV-Vis, FT-IR, SEM-EDS, TEM, and XRD. The UV-Vis measurement showed the surface plasmon resonance (SPR) peak at 234-255 nm, whereas FTIR characteristic peaks of metal-oxygen (Cu-O) were confirmed in the range 550-570 cm À1 and Cu-O-H bonds led to bending absorptions in the region 870-880 cm À1. The synthesized CuNPs possess the spherical shapes and high content of copper (70.3%) as confirmed by SEM-EDS. From the TEM micrograph, it can be seen that the particle size distribution of CuNPs has a high uniformity with a size of 2-10 nm under the optimum condition. The crystalline nature of CuNPs as confirmed by XRD showed the crystallinity phase of 26.4%. The synthesized CuNPs have relatively good stability and could inhibit Escherichia coli and Staphylococcus aureus. The results proved that Piper retrofractum Vahl fruit extract could be applied for a greener synthesis of CuNPs with high uniformity of particle sizes.

Finding new antibiotic based on local resources is always a challenging effort, since Indonesia almost totally import the antibiotics. Then, antibiotic based jamu is an alternative. Jamu is a traditional herb prepared from local plants and some rhizomes, such as Curcuma longa, Zingiber officinale, and Syzigium aromaticum. These plants have been reported for their antibacterial capability. This paper is focused on the evaluation of antibacterial of these mixtures and their spectral consistency. The method was initiated by extraction of each plants/rhizome using ethanol and water. Each extract was mixed with equal ratio, and further evaluation for growth inhibiting activity in Staphylococcus aureus and Escherichia coli. Meanwhile, the spectral analysis was determined using FTIR and UV-Vis spectrophotometry. The result showed that the mixture of ethanol extract gives a slightly better activity than that using water extract. Furthermore, the UV-Vis spectra of the mixture from ethanol extracts indicates different band absorption in 439 and 417 nm, but no absorption observed in water extract in this range. In addition, the ethanol mixture extract also gives new band (FTIR spectra) in between 1010-1045 cm−1, that these are not observed in water extract. In short, it can be summarized that ethanol extraction process give better extraction procedure and provide better antibacterial activity.