Toxicity test using the BSLT method and antibacterial test against Staphylococcus aureus and Escherichia coli of the extract and fractions of karamunting stem (Rhodomyrtus tomentosa (Aiton) Hassk.) / Uji toksisitas menggunakan metode BSLT dan uji antibakteri Staphylococcus aureus dan Escherichia coli ekstrak dan fraksi batang karamunting (Rhodomyrtus tomentosa (Aiton) Hassk.)

Natural ingredients have been widely used in medicine, commonly referred to as "back to nature," meaning "kembali ke alam." Herbal medicine is recognized as one of the most practical and effective treatment modalities available. One medicinal plant is the stem of Rhodomyrtus tomentosa (Aiton) Hassk., which belongs to the Myrtaceae family and has the potential as an antibacterial remedy. To ensure traditional medicine fulfills its responsibility, scientific research, such as toxicity testing, is necessary. The Brine Shrimp Lethality Test (BSLT) is a preliminary test to assess the toxic effects of plants. This study aims to determine the secondary metabolite compounds, toxicity levels, and antibacterial activity of ethanol extract and n-hexane and ethyl acetate fractions of Rhodomyrtus tomentosa stem. The study includes characterization, phytochemical screening, and toxicity testing by observing the mortality rate of Artemia salina Leach larvae, expressed as LC50. Antibacterial testing against Staphylococcus aureus and Escherichia coli was conducted using the disc diffusion method. The results of phytochemical screening of simplicia powder, ethanol extract, and n-hexane and ethyl acetate fractions of Rhodomyrtus tomentosa stem tested positive for alkaloids and triterpenoids/steroids. Simplicia powder, ethanol extract, and the ethyl acetate fraction also contained secondary metabolites such as flavonoids, tannins, and saponins. The toxicity test results using probit analysis showed that the LC50 value of the extract was 97.6787 µg/mL, the LC50 value of the ethyl acetate fraction was 71.4331 µg/mL, and the LC50 value of the n-hexane fraction was 57.4910 µg/mL. Therefore, it can be concluded that the extract and the n-hexane and ethyl acetate fractions of Rhodomyrtus tomentosa stem are toxic. The antibacterial test results showed that the extract and the n-hexane and ethyl acetate fractions exhibited inhibitory activity against Staphylococcus aureus and Escherichia coli.

Bahan-bahan alami telah banyak digunakan dalam pengobatan, dikenal juga dengan istilah “back to nature” yang artinya “kembali ke alam”. Pengobatan herbal diakui sebagai salah satu modalitas pengobatan paling praktis dan efektif yang tersedia. Salah satu tumbuhan yang berkhasiat obat adalah batang karamunting (Rhodomyrtus tomentosa (Aiton) Hassk.) termasuk family Myrtaceae, berpotensi sebagai ramuan obat antibakteri. Agar pengobatan tradisional dapat memenuhi tanggungjawabnya diperlukan penelitian ilmiah, seperti uji toksisitas. Uji toksisitas metode Brine Shrim Lethality Test (BSLT) adalah uji pendahuluan untuk melihat efek toksik dari tumbuhan. Penelitian ini bertujuan untuk mengetahui golongan senyawa metabolit sekunder, tingkat toksisitas dan aktivitas antibakteri ekstrak etanol dan fraksi n-heksan, etil asetat batang karamunting. Penelitian ini meliputi karakterisasi, skrining fitokimia dan toksisitas dengan melihat jumlah mortalitas larva Artemia Salina Leach yang dinyatakan dalam LC50. Melakukan uji antibakteri Staphylococcus aureus dan Escherichia coli metode difusi cakram. Hasil pengujian skrining fitokimia serbuk simplisia, ekstrak etanol dan fraksi n-heksan, etil asetat batang karamunting positif mengandung alkaloid dan triterpenpoid/steroid. Serbuk simplisia, ekstrak etanol dan fraksi etil asetat juga mengandung metabolit sekunder golongan flavonoid, tanin dan saponin. Hasil uji toksisitas dengan analisis probit menunjukkan nilai LC50 ekstrak 97,6787 µg/mL, nilai LC50 fraksi etil asetat 71,4331 µg/mL, dan nilai LC50 fraksi n-heksan 57,4910 µg/mL. Sehingga dapat disimpulkan ekstrak dan fraksi n-heksan, etil asetat batang karamunting bersifat toksik. Hasil uji antibakteri ekstrak dan fraksi n-heksan, etil asetat memiliki aktivitas menghambat bakteri Staphylococcus aureus dan Escherichia coli.