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Antibacterial Activity Test of the Combination of Bay Leaf (Syzygium polyanthum) Extract and Nanochitosan Against Escherichia coli and Bacillus subtilis

Life Science · Vol. 14 No. 1 (2025) · pp. 1–10

DOI
10.15294/unnesjlifesci.v14.i1.24777
ISSN
2528-5009, 2252-6277
Published
2025-05-31
Publisher
Universitas Negeri Semarang
Language
eng

Abstract

Indonesia is one of the world’s most biodiverse countries, including in medicinal plants that contain active compounds with potential as sources of modern medicine, particularly for treating bacterial infections. The use of herbal plants as antibacterial agents offers an alternative to overcome antibiotic resistance and the side effects of synthetic drugs. Bay leaf (Syzygium polyanthum) and nanochitosan are known for their antibacterial properties due to their bioactive compounds. However, studies on their combined effects are still limited. This study aimed to evaluate the antibacterial effectiveness of combinations of bay leaf extract (15%, 25%, and 35%) and nanochitosan (0.5% and 1%) against Escherichia coli and Bacillus subtilis. A Completely Randomized Design (CRD) was applied, using sterile distilled water as a negative control and 0.1% chloramphenicol as a positive control. The antibacterial activity test was performed using the Kirby-Bauer disk diffusion method. Results showed the positive control produced inhibition zones of 25.45 ± 1.27 mm for E. coli and 25.05 ± 0.39 mm for B. subtilis. The most effective combination was K3 (35% bay leaf extract and 0.5% nanochitosan), which produced inhibition zones of 12.65 ± 0.52 mm and 12.91 ± 0.55 mm, respectively. Statistical analysis using the Tukey HSD post hoc test confirmed significant differences among treatments. These findings suggest that the combination of bay leaf extract and nanochitosan holds promise as an alternative antibacterial agent

Keywords

Collaboration network of the authors

40 authors · 188 co-authorship links · 2 across different organisations · showing the 40 most connected

Hover or tap a name to highlight its co-authors. Double-click to open the author's page.

  • State University of Semarang
  • Diponegoro University
  • Affiliation unknown
  • Different organisations
  • Same organisation
  • Affiliation unknown
  • Thicker line = more joint articles · bigger circle = more articles
Show as table
Co-authorOrganisationJoint articles
Ibnul MubarokAffiliation unknown12
Talitha WidiatningrumAffiliation unknown9
R. SusantiAffiliation unknown4
Ari YuniastutiState University of Semarang4
Dyah Rini IndriyantiState University of Semarang3
Retno Sri IswariState University of Semarang3
Saiful RidloState University of Semarang3
Priyantini WidiyaningrumAffiliation unknown3
Sri SukaesihState University of Semarang3
Maria Ayu PuspitaAffiliation unknown2
Nunung Eni ElawatiAffiliation unknown2
Andhina Putri HeriyantiDiponegoro University2
Arif WidiyatmokoState University of Semarang2
Fidia FibrianaState University of Semarang2
Siti AlimahState University of Semarang2
Dwi Puji HayatiAffiliation unknown2
Nana Kariada Tri MartutiAffiliation unknown2
Nur Rahayu UtamiAffiliation unknown2
Sigit SaptonoState University of Semarang2
Parmin ParminState University of Semarang2
Ernallah YatiAffiliation unknown1
Aura Tirsa MelindaAffiliation unknown1
Rahimma Artantia AnandaAffiliation unknown1
Orchida Puspa JelitaAffiliation unknown1
Delia Alifia FarrezaAffiliation unknown1
Supriyadi SupriyadiAffiliation unknown1
Kusmuriyanto KusmuriyantoAffiliation unknown1
Mochamad Nur SholikhinAffiliation unknown1
Nishfa MufatihahAffiliation unknown1
Niken SubektiState University of Semarang1
Ning SetiatiAffiliation unknown1
Ely RudyatmiAffiliation unknown1
Sriyadi SriyadiAffiliation unknown1
Rusyida AuliyaAffiliation unknown1
Naeli Tamin QonitaAffiliation unknown1
Previanda ArditamaAffiliation unknown1

Affiliations come from OpenAlex; journal OAI-PMH metadata carries none. Authors without an OpenAlex ID are matched by name, which can merge or split people.

Metadata source: OAI-PMH (metadata jurnal) https://journal.unnes.ac.id/journals/UnnesJLifeSci/oai, first harvested 5 Nov 2026, last seen 5 Nov 2026.
Original metadata (oai_dc) 
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	<dc:title xml:lang="en">Antibacterial Activity Test of the Combination of Bay Leaf (Syzygium polyanthum) Extract and Nanochitosan Against Escherichia coli and Bacillus subtilis</dc:title>
	<dc:creator xml:lang="en">Astrid Farmayati</dc:creator>
	<dc:creator xml:lang="en">Siti Harnina Bintari</dc:creator>
	<dc:creator xml:lang="en">Pramesti Dewi</dc:creator>
	<dc:creator xml:lang="en">Dewi Mustikaningtyas</dc:creator>
	<dc:subject xml:lang="en">Antibacterial</dc:subject>
	<dc:subject xml:lang="en">Bacillus subtilis</dc:subject>
	<dc:subject xml:lang="en">Bay leaf</dc:subject>
	<dc:subject xml:lang="en">Eschericia coli</dc:subject>
	<dc:description xml:lang="en">Indonesia is one of the world’s most biodiverse countries, including in medicinal plants that contain active compounds with potential as sources of modern medicine, particularly for treating bacterial infections. The use of herbal plants as antibacterial agents offers an alternative to overcome antibiotic resistance and the side effects of synthetic drugs. Bay leaf (Syzygium polyanthum) and nanochitosan are known for their antibacterial properties due to their bioactive compounds. However, studies on their combined effects are still limited. This study aimed to evaluate the antibacterial effectiveness of combinations of bay leaf extract (15%, 25%, and 35%) and nanochitosan (0.5% and 1%) against Escherichia coli and Bacillus subtilis. A Completely Randomized Design (CRD) was applied, using sterile distilled water as a negative control and 0.1% chloramphenicol as a positive control. The antibacterial activity test was performed using the Kirby-Bauer disk diffusion method. Results showed the positive control produced inhibition zones of 25.45 ± 1.27 mm for E. coli and 25.05 ± 0.39 mm for B. subtilis. The most effective combination was K3 (35% bay leaf extract and 0.5% nanochitosan), which produced inhibition zones of 12.65 ± 0.52 mm and 12.91 ± 0.55 mm, respectively. Statistical analysis using the Tukey HSD post hoc test confirmed significant differences among treatments. These findings suggest that the combination of bay leaf extract and nanochitosan holds promise as an alternative antibacterial agent</dc:description>
	<dc:publisher xml:lang="en">Universitas Negeri Semarang</dc:publisher>
	<dc:date>2025-05-31</dc:date>
	<dc:type>info:eu-repo/semantics/article</dc:type>
	<dc:type>info:eu-repo/semantics/publishedVersion</dc:type>
	<dc:format>application/pdf</dc:format>
	<dc:identifier>https://journal.unnes.ac.id/journals/UnnesJLifeSci/article/view/24777</dc:identifier>
	<dc:identifier>10.15294/unnesjlifesci.v14.i1.24777</dc:identifier>
	<dc:source xml:lang="en">Life Science; Vol. 14 No. 1 (2025): May 2025; 1-10</dc:source>
	<dc:source>2528-5009</dc:source>
	<dc:source>2252-6277</dc:source>
	<dc:source>10.15294/unnesjlifesci.v14.i1</dc:source>
	<dc:language>eng</dc:language>
	<dc:relation>https://journal.unnes.ac.id/journals/UnnesJLifeSci/article/view/24777/4211</dc:relation>
	<dc:rights xml:lang="en">Copyright (c) 2025 Life Science</dc:rights>
</oai_dc:dc>