Judul: Total Tannin Content and Tyrosinase Enzyme Inhibitory Activity of Surian (Toona sinensis) Leaf Extract in Varying Solvents and Tree Age
Abstrak: Penelitian mengenai tanaman surian telah banyak dikembangkan baik dalam bidang kesehatan maupun industri. Daun surian (Toona sinensis) diketahui memiliki aktivitas penghambatan tirosinase untuk mencegah hiperpigmentasi. Penelitian ini bertujuan mengetahui kandungan total tanin dan aktivitas inhibisi tirosinase dari ekstrak daun surian variasi pelarut dan umur pohon. Penentuan kadar total tanin menggunakan metode follin ciocalteu dan menggunakan substrat LTyrosin untuk inhibisi tirosinase. Hasil penelitian menunjukkan bahwa ekstrak etanol 96% daun surian menghasilkan kandungan total tanin tertinggi pada umur pohon 34 tahun sebesar 24,299 %, terendah pada ekstrak etanol 30% pada umur 16 tahun sebesar 3,723%. Aktivitas inhibisi terbesar ditunjukkan pada ekstrak etanol 96% pada umur 16 tahun sebesar 86,658% dan terendah pada ekstrak etanol 30% pada umur 34 tahun sebesar 35,949 %.. Nilai IC50 terbaik adalah 53, 712 ppm pada ekstrak etanol 96 persen umur tanaman 16 tahun. Simpulan penelitian ini adalah aktivitas penghambatan tirosinase dan persentase kandungan tanin pada daun surian (Toona sinensis) dipengaruhi oleh umur tanaman dan pelarut yang digunakan dalam ekstraksi dan berpotensi sebagai bahan kosmetika., Research on surian plants has been widely developed both in the health and industrial fields. Surian leaves (Toona sinensis) are known to have tyrosinase inhibitory activity to prevent hyperpigmentation. This research aimed to determine the total tannin content and tyrosinase inhibitory activity of surian leaf extract with various solvents and tree age. Determination of total tannin content using the Follin Ciocalteu method and using L-Tyrosine as a substrate for tyrosinase inhibition. The results of the research showed that the 96% ethanol extract of surian leaves produced the highest total tannin content at 34 years of age at 24.299%, the lowest was 30% ethanol extract at 16 years of age at 3.723%. The greatest inhibitory activity was shown in the 96% ethanol extract at the age of 16 years, amounting to 86.658% and the lowest in the 30% ethanol extract at the age of 34 years, amounting to 35.949%. The best IC50 value was 53.712 ppm in the 96 percent ethanol extract at the age of 16 years. The research concluded that the tyrosinase inhibitory activity and the percentage of tannin content in surian (Toona sinensis) leaves are influenced by the age of the plant and the solvent used in extraction and has the potential as a cosmetic ingredient
Keyword: tanin, L-Tyrosin, surian, tirosinase

Judul: Total Phenolic and Antioxidant Activity of Surian (Toona Sinensis) Leaves on Various Tree Age and Solvent Concentration
Abstrak: Ekstrak daun surian (Toona sinensis) memiliki kandungan senyawa fenolik yang dapat berpotensi sebagai antioksidan alami. Pengoptimalan umur panen tanaman serta konsentrasi pelarut (etanol) diperlukan untuk mendapatkan aktivitas antioksidan daun surian terbaik. Penelitian ini bertujuan menguji pengaruh dari variasi umur pohon dan konsentrasi pelarut etanol terhadap kadar total fenolik dan aktivitas antioksidan yang terkandung dalam sampel daun surian asal Sumedang menggunakan uji analisis in vitro. Kadar total fenolik diukur dengan menggunakan metode Folin-Ciocalteu, sedangkan aktivitas antioksidan diukur menggunakan metode 2,2-difenil-1-pikrilhidrazil (DPPH). Ekstrak daun surian umur 34 tahun menggunakan pelarut etanol 96% memiliki kadar total fenolik tertinggi yaitu sebesar 392.28 mg GAE/g bobot kering dan menghasilkan kapasitas antioksidan tertinggi yaitu sebesar 1130.26 μm TE/g bobot kering dengan nilai IC50 terkecil dibandingkan dengan sampel lainnya yaitu sebesar 4.19 μg/mL sehingga dapat dikatakan bahwa ekstrak daun surian 34 tahun menggunakan pelarut etanol 96% memiliki aktivitas antioksidan terbaik. Umur pohon dan konsentrasi pelarut etanol terbukti dapat mempengaruhi hasil kadar total fenolik dan aktivitas antioksidan daun surian., The extract of surian leaves (Toona sinensis) contains phenolic compounds that have the potential as natural antioxidants. Optimization of the plant harvesting age and solvent concentration (ethanol) is necessary to obtain the best antioxidant activity of surian leaves. This study aimed to examine the effect of variations in tree age and ethanol solvent concentration on the total phenolic content and antioxidant activity of surian leaves from Sumedang using in vitro analysis. The total phenolic content was measured using the Folin-Ciocalteu method, while the antioxidant activity was measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The extract of 34-year-old surian leaves using 96% ethanol solvent had the highest total phenolic content of 392.28 mg GAE/g dry weight and also produced the highest antioxidant capacity of 1130.26 μm TE/g dry weight with the smallest IC50 value compared to other extracts, which was 4.19 μg/mL, indicating that the 34-year-old surian leaf extract using 96% ethanol solvent had the best antioxidant activity. Tree age and ethanol solvent concentration were proven to affect the total phenolic content and antioxidant activity of surian leaves.
Keyword: Antioksidan, kadar fenolik, metode DPPH, Toona Sinensis

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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