Endophytic bacteria are microorganisms that exist in the system of plant tissues such as fruits, leaves, twigs, roots and they can form colonies without causing damage to the plant. One potential medicinal plant has endophytic bacteria are Noni fruits (Morinda citrifolia l). This study aimed at isolating endophytic bacterial from Noni fruits (Morinda citrifolia l), screening endophytic bacteria, determining antibacterial activity of potential endophytic bacteria, identifying 16S rRNA of potential endophytic bacteria, and detection of an antibacterial compound using GCMS. Endophytic bacteria were successfully isolated from Noni fruits and disc-diffusion methods were used to screen for antibacterial activity against pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, and Streptococcus mutans). The result of bacterial activity showed isolate ACP1, ACP2, ACP4, and ACP6 were produced antibacterial compounds. The activity shown with the formation of a clear zone and ACP6 isolate could inhibit four pathogenic bacteria with the highest clear zone. Molecular identification was investigated used PCR amplification 16S rRNA gene. The result showed that the potential isolate ACP6 (Acc. No. MH915674.1) belonging as Enterobacter cloacae with 99 % sequence similarities and according to GCMS analysis, ethyl acetate fraction from secondary metabolite ACP6 contains Pyrazine as a bioactive compound. These findings suggest that the identified strains may contribute to the search for new sources of antibacterial substances.

AbstrakKaries gigi adalah penyakit yang umum dialami oleh masyarakat yang terjadi karena buruknya kebersihan mulut. Kebiasaan masyarakat yang kurang menjaga kebersihan mulut mengakibatkan terbentuknya plak. Plak pada gigi terbentuk karena aktivitas dari berbagai macam mikroorganisme di mulut. Mikroorganisme yang diketahui terlibat dalam pembentukan karies gigi adalah Streptococcus mutans. Salah satu bahan alternatif sebagai antibakteri adalah daun cengkeh. Penelitian ini bertujuan untuk mengidentifikasi senyawa bioaktif daun cengkeh dan mengetahui mekanisme aksinya dalam menghambat pertumbuhan Streptococcus mutans. Daun cengkeh (Syzygium aromaticum) yang digunakan dalam penelitian ini dimaserasi menggunakan metanol 96%. Pengujian aktivitas antibakteri dilakukan dengan metode difusi agar, senyawa bioaktif diidentifikasi menggunakan gas chromatography mass spectrometry dan perubahan membran sel bakteri diamati dengan scanning electron microscopy. Hasil penelitian menunjukkan ekstrak metanol daun cengkeh memiliki aktivitas penghambatan terhadap pertumbuhan bakteri Streptococcus mutans dengan zona hambat sebesar ±32 mm serta nilai konsentrasi hambat minimum (KHM) 20% ekstrak. Mekanisme aksi penghambatan ekstrak daun cengkeh terhadap pertumbuhan bakteri diduga dengan membuat lubang pada membran sel bakteri. Hasil penelitian ini juga menunjukkan bahwa daun cengkeh memiliki kandungan senyawa bioaktif 3-allyl-6-methoxyphenol-eugenol, caryophyllene 1,4,7,-cycloundecatriene, 1,5,9,9-tetramethyl, phenol, 2-methoxy-4-(2-propenyl), dan eugenol acetate yang dapat menjadi kandidat penghasil senyawa aktif untuk mengatasi karies gigi.Abstract Dental caries is a common disease experienced by people who do not maintain oral hygiene. Habits of not maintain oral hygiene result in the formation of plaque. The microorganism known to be involved in the formation of dental caries is Streptococcus mutans. Plants that have antibacterial properties, such as clove (Syzygium aromaticum) leaf, can be an alternative for carrying this problem. This study aims to identify the bioactive compounds of clove leaves and to determine the mechanism of its action in inhibiting the growth of Streptococcus mutans. Clove leaves were macerated using 96% methanol for the extraction. Antibacterial activity was examined by agar diffusion method, bioactive compounds were identified using gas chromatography mass spectrometry, and bacterial cell membrane changes were observed by an image captured using scanning electron microscopy. The results showed that the methanol extract of clove leaf had inhibitory activity on Streptococcus mutans growth, with inhibitory zones of ±32 mm and the minimum inhibitory concentration (MIC) of 20% extract. It was suspected that the mechanism of inhibitory action is by making pores in the bacterial cell membrane. The results also showed that the clove leaves contain bioactive compounds of 3-allyl-6-methoxyphenol-eugenol, caryophyllene, 1,4,7, -cycloundecatriene, 1,5,9,9-tetramethyl, phenol, 2 -methoxy-4- (2-propenyl), and eugenol acetate which can be candidates for producing active compounds to overcome dental caries.

Antibacterial Effect of Clove Leaf Extract (Syzygium aromaticum) against Escherichia coli and Staphylococcus aureus Escherichia coli and Staphylococcus aureus are microorganisms that cause infection. Overcoming infection using antibiotics is known to generate bacteria that are resistant to some antibiotics, hence the need of other antibacterial resources. One of the natural sources that can be utilized is clove leaf (Syzygium aromaticum). This study aims to determine the types of compounds contained in clove leaves and their inhibitory activity against E. coli and S. aureus. The study began with extraction using maceration techniques, then the separation of the compounds through ethanol, n-hexane, and ethyl acetate fractionation. Next step was the identification of secondary metabolites of clove leaf compounds using Gas Chromatography-Mass Spectrometry (GC-MS). The results showed the ethyl acetate fraction was the most active in inhibiting the growth of E. coli and S. aureus with a minimum inhibitory value (MIC) of 10%. The most dominant compound in the ethyl acetate fraction was found to be caffeine with a content of 23.36%.  Keywords: antibacterial, clove leaves, GC-MS, MIC, Syzygium aromaticum ABSTRAK Escherichia coli dan Staphylococcus aureus adalah mikroorganisme penyebab infeksi. Penanggulangan infeksi menggunakan antibiotik telah memunculkan bakteri yang resisten terhadap beberapa antibiotik sehingga perlu mencari sumber antibakteri lain. Salah satu bahan alam yang dapat dimanfaatkan adalah daun cengkeh (Syzygium aromaticum). Penelitian ini bertujuan mengetahui jenis senyawa yang terkandung dalam daun cengkeh dan aktivitas penghambatannya terhadap bakteri E. coli dan S. aureus. Penelitian diawali dengan ekstraksi menggunakan teknik maserasi, kemudian dilakukan pemisahan senyawa berdasarkan tingkat kepolaran melalui fraksinasi etanol, n-heksan, dan etil asetat. Hasil fraksinasi diujikan ke bakteri uji. Identifikasi senyawa metabolit sekunder daun cengkeh menggunakan Gas Chromatography Mass Spectrometry (GC-MS). Hasil penelitian menunjukkan bahwa fraksi etil asetat paling aktif menghambat pertumbuhan bakteri E. coli dan S. aureus dengan nilai kadar hambat minimum (KHM) 10%. Senyawa paling dominan pada fraksi etil asetat adalah kafein dengan kadar 23,36%.

Dental caries is a disease that many people experience, which is formed by the buildup of plaque on the teeth and the presence of bacteria. The bacteria known to be involved in the formation of dental caries is Streptococcus mutans. Dental caries used to be treated using antibiotics. However, it is known that many antibiotics are no longer effective against this bacteria hence it is necessary to look for another alternative. One alternative choice as an antibacterial is Noni fruit. This study aims to identify the bioactive compounds of noni fruit (Morinda citrifolia L) and to know the mechanism of action in inhibiting the growth of Streptococcus mutans. Noni fruit was macerated using 96% ethanol, then fractionated using n-hexane and ethyl acetate. Antibacterial activity test was done using agar difusion method, and identification of bioactive compounds was conducted using GCMS. The results showed that ethyl acetate fraction has the highest inhibitory activity on the growth of Streptococcus mutans with inhibition zone of ±17 mm and MIC (minimum inhibitor concentration) value of 10%. The inhibition mechanism is asumed to be done by making holes in cell membranes, which can be seen from the high concentration of proteins and nucleic acids coming out of cells after treatment that in turn means that cell leakage has occurred. The results of this study indicate that noni fruit (Morinda citrifolia L) contain bioactive quinolone compounds that can be a new source for treating dental caries

Clove (Syzygium aromaticum L.) is one type of spice plant that has high antioxidant content because of the high eugenol compounds. However, isolating these bioactive compounds require a significant amount of biomass. A known alternative solution to overcome the problems is through the utilization of endophytic bacteria in clove leaves. Endophytic cloves leaf bacteria can be a good antioxidant resource. Endophytic bacteria are bacteria that grow in plant tissues that is not pathogenic, which can replace these plants. The aim of this study is isolating endophytic bacterial from clove leaves, screening endophytic bacteria, determining potential endophytic bacteria as producer antioxidant compounds, and identifying potential isolate using 16S rRNA. This study used endophytic bacteria isolated from clove leaves (Syzygium aromaticum L.). Antioxidant activity determined using DPPH method. It was founded 7 isolates of endophytic bacteria namely WDY1, WDY2, WDY3, WDY4, WDY5, WDY6, and WDY7. The isolate WDY6 shows the highest antioxidant activity. WDY6 isolate is identical to Staphylococcus sp. with a 100% similarity. Staphylococcus sp. has the highest antioxidant activity in the stationary phase. The content of chemical compounds from WDY6 isolates is p yrazine that belongs to alkaloids.