Judul: Toksisitas dan Aktivitas Antioksidan Ekstrak Daun Pohon Penghasil Gaharu Hasil Inokulasi
Abstrak: Gaharu leaves are expected to contain many secondary metabolic compounds as a response against fungal infection on gaharu-producing trees. This study aimed to determine the phytochemical components, cytotoxic and antioxidant activities of Aquilaria microcarpa and A. malaccensis leaves with and without fungal inoculation. Gaharu leaves were extracted by using methanol. The phytochemical assay of the crude extract revealed the presence of tannins, steroids, phenols, and flavonoids. The toxicity evaluation with brine shrimp showed that all samples were potencial as active ingredient, but only the juvenile leaves of A. microcarpa inoculated by fungi from Papua and Gorontalo had the potency as anticancer due to their LC50 value < 30 μg/mL. Free radical scavenging activity of the extracts against 2,2-diphenyl-1-picrylhydrazyl showed strong antioxidant activities with IC50 value of < 200 μg/mL. The highest antioxidant activity was exhibited by juvenile leaves of A.microcarpa inoculated by fungi from Timor and uninoculated mature leaves of A. malaccensis.
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Judul: Aktivitas Antioksidan Ekstrak Kemedangan Pohon Penghasil Gaharu Hasil Inokulasi Jenis Aquilaria microcarpa dan Gyrinops verstegii
Abstrak: Agarwood is a non-timber forest product commodity which is traded because of its distinctive fragrance. Kemedangan from gaharu was assumed to have secondary metabolites that are potential as antioxidant. This study aimed to investigate the phytochemicals, toxicity and antioxidant activites of kemedangan from Aquilaria microcarpa and Gyrinops verstegii trees with and without inoculation by Fusarium fungi. Phytochemical assay of ethyl acetate and methanol extract revealed the presence of phenolics, flavonoids, triterpenoids, and alkaloids. The toxicity evaluation using brine shrimp lethality test showed that all extracts were potential as bioactive compounds with 50% lethal concentration value ≤1000 ppm. Antioxidant activities which were measured by using 2,2- diphenyl-1-picrylhidrazyl free-radical scavenging method showed that all extracts had antioxidant activities with 50% inhibition concentration value ≤200 ppm except A. microcarpa ethyl acetate extract from inoculated samples with IC50 of 411 ppm.
Keyword: agarwood, antioxidant, Aquilaria, Gyrinops, kemedangan

Judul: Pembuatan Film Tipis Lithium Niobat (LiNbO3) Menggunakan Metode Chemical Solution Deposition (CSD) dengan Variasi Kecepatan Putar (Rpm).
Abstrak: Film tipis merupakan salah satu aspek yang mendapat perhatian sangat besar dalam bidang material, karena film tipis merupakan material menarik yang memiliki sifat optik yang sangat tergantung pada konstanta dielektrik, indeks bias, dan energi gap. Lithium Niobat (LiNbO3 ) dapat digunakan sebagai pelapis pada film tipis karena memiliki sifat piezoelektrik, electrooptical, pyroelectrical dan photorefractive yang sangat baik. Film tipis Lithium Niobat (LiNbO3 ) ditumbuhkan menggunakan metode Chemical Solution Deposition (CSD) dengan variasi kecepatan 3500 rpm, 5000 rpm, 6500 rpm, dan 8000 rpm. Metode ini memiliki keunggulan dapat mengontrol stokiometri film tipis dengan kualitas yang baik, prosedur yang mudah dan membutukan biaya yang relatif murah. Energi band gap yang dihasilkan dari film tipis Lithium Niobat (LiNbO3) berkisar antara rentang 2.1 eV – 2.8 eV dengan indeks bias berada pada rentang 2.18-3.2. Film tipis LiNbO3 memiliki parameter kisi a=b=5.54Ǻ dan c = 16.35 Ǻ. Struktur morfologi film tipis adalah permukaan yang homogen dan ukuran kristal berada pada rentang 0.417 μm – 0.680 μm.
Keyword: film tipis, sifat optik, litium niobat, chemical solution deposition, kecepatan putar