Electronic Theses and Dissertation

Penelitian ini bertujuan untuk mensintesis nanopartikel tembaga (Cu) menggunakan ekstrak metanol daun glodokan tiang (Polyalthia longifolia) melaui metode green synthesis termodifikasi sonikasi, serta menguji aktivitas antibakterinya terhadap Escherichia coli dan Staphylococcus aureus. Ekstrak daun P. longifolia memiliki kandungan Total Phenolic Content (TPC) 69,17 mg GAE/g dan Total Flavonoid Content (TFC) 20,5 mg QE/g. Keberhasilan sintesis nanopartikel Cu-PLLM ditandai dengan perubahan warna larutan dan dikonfirmasi melalui karakterisasi spektrofotometer UV-Vis, FTIR, XRD, SEM-EDS, dan TEM. Analisis XRD menunjukkan pembentukanfasa Cu⁰, Cu₂O, CuO, sedangkan hasil TEM menunjukkan morfologi partikel sferis dengan ukuran dominan 3-4 nm. Uji difusi cakram (Kirby-Bauer) menunjukkan aktivitas antibakteri Cu-PLLM meningkat seiring dengan bertambahnya konsentrasi, dengan daya hambat lebih tinggi terhadap E.coli NP Cu-PLLM sebesar 28,43 nm dan pada S.aureus NP- Cu PLLM sebesar 17,54 nm. Hasil tersebut menunjukkan bahwa ekstrak daun P. longifolia berpontesi sebagai bahan pereduksi alami dalam sintesis hijau nanopartikel temabaga, yang menghasilkan nanopartikel tembaga dengan aktivitas antibakteri yang baik.

Kata kunci: sintesis hijau, nanopartikel tembaga, Polyalthia longifolia, sonikasi, antibakteri

This study aims to synthesize copper (Cu) nanoparticles using methanol extract of Polyalthia longifolia (glodokan tiang) leaves through a sonication-modified green synthesis method, as well as to evaluate their antibacterial activity against Escherichia coli and Staphylococcus aureus. The methanol extract of P. longifolia leaves showed a Total Phenolic Content (TPC) of 69.17 mg GAE/g and a Total Flavonoid Content (TFC) of 20.5 mg QE/g. The successful synthesis of Cu-PLLM nanoparticles was indicated by a color change in the solution and confirmed through characterization using UV-Vis spectrophotometry, FTIR, XRD, SEM-EDS, and TEM. XRD analysis revealed the formation of Cu⁰, Cu₂O, and CuO phases, while TEM results showed spherical particle morphology with a dominant size range of 3–4 nm. The disc diffusion (Kirby-Bauer) assay showed that the antibacterial activity of Cu-PLLM increased with increasing concentration, with a higher inhibition zone against E. coli (28,43 mm) compared to S. aureus (17,54 mm) for the Cu-PLLM nanoparticles. These results indicate that P. longifolia leaf extract has potential as a natural reducing agent in the green synthesis of copper nanoparticles, producing copper nanoparticles with good antibacterial activity. Keywords: green synthesis, copper nanoparticles, Polyalthia longifolia, sonication, antibacterial