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Macroalgae Community Structure on Different Substrate in Sabang Waters Darlina; Saida Rasnovi; Amalia
Jurnal Penelitian Pendidikan IPA Vol 11 No 7 (2025): July
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v11i7.11610

Abstract

Research on analysis of macroalgae community structure on different substrates in Sabang waters to identify, analyzing diversity, abundance, and important value index. The data collection method was carried out by purposive sampling using a plot of 1x1 m2 with 10 plots per transect. Sampling was carried out at three stations, namely Station I on Pasir Putih with a medium fine sand substrate, Station II at Anoi Itam with a gravel sand substrate, and Station III on Rubiah Island with a fine sandy clay substrate. Data were analyzed using the Importance Value Index (IVI) and the Shannon-Wiener Diversity Index. The environmental parameters at each station that were measured were substrate particles, temperature, brightness, depth, and current velocity, while the chemical parameters were salinity, pH, COD, phosphate, and nitrate. The results of the study found 2615 macroalgae individuals consisting of three divisions. Chlorophyta division consists of 9 species, Rhodophyta was 7 species, and Phaeophyta was 1 species (Dyctyota dichotoma). The highest Important Value Index at each research station consisted of the Chlorophyta division with two species, namely Dictyosphaeria cavernosa (IVI = 59.18) and Halimeda opuntia (IVI = 54.15). The value of the diversity index (H') of macroalgae in Sabang waters is moderate, namely in Pasir Putih as much as 2.18, Anoi Itam and Rubiah Island as much as 2.01, and 1.97, respectively. The study concluded that the macroalgae community structure in Sabang waters exhibits moderate species diversity, with the Chlorophyta division, particularly Dictyosphaeria cavernosa and Halimeda opuntia, showing the highest importance value indices across different substrates.
Toxicity, Antioxidant and Antibacterial Test of Ethyl Acetate Extract of Jamblang Leaves (Syzygium cumini L.) Zultira Harina Roza; Lenni Fitri; Amalia
Jurnal Penelitian Pendidikan IPA Vol 12 No 4 (2026)
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v12i4.12634

Abstract

Jamblang (Syzygium cumini L.) is a plant from the Myrtaceae family that is used as a traditional medicine, especially its leaves. This study aims to determine the toxicity, antioxidant, and antibacterial activities of the ethyl acetate extract of jamblang leaves and to identify its secondary metabolite compounds. The toxicity test using the Brine Shrimp Lethality Test (BSLT) method showed that the ethyl acetate extract of jamblang leaves had an LC₅₀ value of 174.602 ppm, which falls into the toxic category. The antioxidant test using the DPPH method showed an IC₅₀ value of 4.268 µg/mL, which is classified as strong, although still weaker than vitamin C (IC₅₀ = 2.437 µg/mL). The antibacterial test against Streptococcus mutans using the disc diffusion method produced inhibition zones of 2.58 mm (20%), 6.61 mm (30%), and 9.08 mm (40%), with a Minimum Inhibitory Concentration (MIC) value of 25%. Identification of secondary metabolites using GC-MS revealed 38 compounds belonging to terpenoid, ester and aromatic Hyhrocarbons groups. These results indicate that the ethyl acetate extract of jamblang leaves possesses toxicity, antioxidant, and antibacterial properties, thus having the potential to be developed as a phytopharmaceutical.