Judul: Bioaktivitas Buah Kawista (Limonia acidissima)dan Penentuan Sidik Jarinya Menggunakan Kromatografi Lapis Tipis
Abstrak: Kawistais a tropical fruitwichhas antioxidant activity. The antioxidant activity ofthefruitis affected by the maturity ofthe fruit.The objectives of atudy we are toanalyze theantioxidantactivity ofthefruit andfingerprintanalysiswiththin layer chromatography (TLC)methodthatwas developedtoa densitogram. Determination offingerprintis requiredin determining the qualityof raw materials. The fingerprint was developedin TLCpatterns. The TLC patterns we are analysed by ImageJ software and produce densitogram. Three different maturity levels of kawista fruit were extracted with methanol solvent. These extracts were positively contained flvanoid, saponin and tanins that had been qualitatively tested. The best value of IC50was from ripe fruit and old fruit hydrolyzed in methanol. The IC50we are97.78 μg/mL and 320.70 μg/mL. The best value of LC50is from ripe fruit extract in both solvents, ethyl acetat and methanol. The value of LC50we are 58.71 and 64.15 μg/mL. The fingerprint witha lot spotand thebestdensitogramseparationobtainedon the composition ofthe solvent combination of chloroform:ethyl acetate:formicat acid:acetate acid, with comparison 6:3:1:0.5. This was based on densitogram with good resolution and high number of spots. Therefore it can be usedin quality control of kawista extract as an antioxidant.
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Judul: Analisis Sidik Jari Kromatografi Lapis Tipis Kulit Buah Manggis (Garcinia mangostana L.)
Abstrak: Analisis sidik jari kromatografi lapis tipis (KLT) dapat digunakan untuk mengevaliasi mutu dan keaslian secara multikomponen dari bahan baku ataupun produk tanaman obat. Metode ini dapat mendeteksi pola pemisahan multikomponen yang khas bagi setiap tumbuhan. Penelitian ini bertujuan mengoptimalkan metode analisis sidik jari kromatografi lapis tipis dengan pemilihan fase gerak terbaik pada fase diam silika gel dan tervalidasi sebagai kendali mutu pencegahan pemalsuan bahan baku obat herbal kulit buah manggis (Garcinia mangostana L.). Fase gerak terpilih yang dapat memisahkan 11 pita senyawa dengan keterpisahan yang baik adalah kloroform:etil asetat (85:15). Standar α-mangostin digunakan sebagai senyawa penciri dan dideteksi sebagai pita berwarna hijau kebiruan (Rf = 0,53) di bawah sinar UV 366 nm setelah derivatisasi dengan larutan asam sulfat 10% (v/v). Secara umum, hasil validasi metode sidik jari KLT kulit buah manggis dapat diterima, kecuali untuk parameter ketegaran terhadap jenis bejana. Oleh sebab itu, metode ini dapat digunakan untuk kendali mutu kulit buah manggis., Thin layer chromatographic fingerprint analysis can be used to evaluate the quality and authenticity of multicomponents present in medicinal plant raw materials or products. This method can detect multi-component profiles that are specific to every plant. This study aimed to optimize and validate a method by TLC fingerprint analysis on mangosteen pericarp (Garcinia mangostana L.) as validated quality control for preventing counterfeiting of herbal medicine raw materials by selecting the best mobile phase on silica gel as stationary phase. The best mobile phase in separating 11 bands of mangosteen pericarp was choloform:ethyl acetate (85:15). α-mangostin standard was used as a marker compound and detected as a bluish-green band (Rf = 0,53) under 366 nm ultraviolet light after derivatization with sulfuric acid reagent 10% (v/v). In general, the results of validation revealed that the method is accepted, except for the robustness of different chamber types. Therefore, this method could be used for quality control of mangosteen pericarp.
Keyword: analisis sidik jari, KLT, kulit manggis, fingerprint analysis, Garcinia mangostana, α-mangosteen

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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