Judul: Comparison of Apigenin, Luteolin, And Eriodictyol Contents of Indonesian and Japanese Plectranthus amboinicus (Lour) Spreng Using HPLC-MWD
Abstrak: Plectranthus amboinicus is a plant cultivated for culinary, medicinal, and decorative purposes in parts of Africa, Latin America, and Asia. Apigenin, luteolin, and eriodictyol are three examples of flavonoids identified in the plant that exhibit potential in combatting degenerative diseases, albeit the presence and concentration of said flavonoids could be impacted by cultivation conditions. With that being said, research on said flavonoids have been limited to merely identification without necessarily taking into consideration the impact of cultivation conditions on the plant. Using High-Performance Liquid Chromatography (HPLC), this research aims to compare the concentration of apigenin, luteolin, and eriodictyol of the leaves of the plant cultivated from two different areas: Indonesia and Japan. The total flavonoid content of the Japanese leaves was found to be greater than its Indonesian counterpart. Moreover, Japanese samples had a higher luteolin concentration but a lower apigenin concentration when compared to the Indonesian samples. Interestingly, eriodictyol was only present in Indonesian samples. Differences in total flavonoid content and the concentrations of apigenin, luteolin, and eriodictyol could be attributed to the differing climates of Indonesia and Japan, in which the tropical climate of Indonesia leads to greater precipitation and lower solar irradiance. With the exception of recovery, the method employed was found to have met all of the other parameters of validation. This shows the need for further optimization.
Keyword: torbangun, Plectranthus amboinicus, apigenin, luteolin, eriodictyol, flavonoid, HPLC-MWD

Judul: Analisis Perbandingan Tiga Klon Torbangun (Plectranthus amboinicus (Lour.) Spreng) Berdasarkan Karakteristik Fenotipe dan Kandungan Senyawa Fenolik
Abstrak: Torbangun (Plectranthus amboinicus (Lour.) Spreng) is a medicinal vegetable consumed in Indonesia. Efficacy of bioactive components within the plant are influenced by environmental factors. In this study, comparison of three clones of torbangun (A, B, and C clones) were analysed through its phenotype and phenolic characteristics, then strengthened by PLS-DA (Partial Least Square - Discriminant Analysis). Initially, the results of the phenotype identification using torbangun descriptor, which was prepared under IPGRI guidelines, showed two types of torbangun: A clone is a thick-leaved torbangun, whereas clones B and C were thin-leaved. These three clones differed significantly in total phenolics content, between 78.68-149.78 mg GAE/100 g DB. Total anthocyanins content was not significantly different in clones A and C, the concentrations are between 0.08-0.18 C3GE/100 mg g DB. Methods of extraction and hydrolysis of flavonoids are flavonol method (2 hours extraction, [HCl] 1.2 M) and flavon method (4 hours extraction, [HCl] 2.0 M). Both methods were successfully quantified the five main flavonoids (myricetin, quercetin, kaempferol, luteolin, and apigenin), where the contents obtained varied from 2.35-86.87 mg/100 g DB. Luteolin was the highest identified flavonoid, while the lowest one was myricetin. PLS-DA of HPLC flavonoids spectral data which obtained from both methods, illustrated the different characteristics of the three clones torbangun. In flavonol method, the marker compounds for A clone were unknown peak-4 and 6; while marker compounds for B clone were myricetin and quercetin, and C clone had only kaempferol. In flavone method, the marker compounds of A clone were apigenin, kaempferol, unknown peak-4, and 6; for B clone, myricetin and quercetin; whereas C clone had only kaempferol.
Keyword: 

Judul: Solusi Geometri Schwarzschild untuk Dimensi 4+1 dengan Invarian Rotasi Isotropik
Abstrak: Metrik Schwarzschild merupakan solusi eksak pertama dari persamaan medan Einstein dengan mangasumsikan metrik statik dan simetris. Metrik Schwarzschild yang ditemukan oleh Karl Schwarzschild masih dalam dimensi 3+1, namun seiring dengan teori-teori terbaru yang menunjukkan bahwa alam semesta tidak hanya di dimensi 3+1. Maka melalui penambahan dimensi, tujuan penelitian ini memperoleh solusi pada geometri Schwarzschild untuk dimensi 4+1 dengan memodifikasi koordinat bola yang invarian rotasi isotropik dan melalui penurunan rumus seperti koordinat bola, simbol Christoffel, dan tensor Ricci. Selain mendapatkan solusi ini, metrik Schwarzschild dimensi 4+1 dapat digunakan sebagai metrik dasar untuk memperoleh solusi blackhole dan wormhole pada dimensi 4+1. Hasil akhirnya, dengan memanfaatkan modifikasi koordinat bola, metrik Schwarzschild dapat dibentuk sehingga diperoleh solusi geometri Schwarzschild untuk dimensi 4+1.
Keyword: metrik Schwarzschild, persamaan medan Einstein, modifikasi koordinat bola, penambahan dimensi, invarian rotasi isotropik