Judul: Study of biomass characters, content and profile of xanthones derivates, and antioxidant properties of mangosteen fruit’s hulls on the several aspects of agronomy
Abstrak: Research reports about the presence of xanthones compounds in the fruit hull of mangosteen and xanthone bioactivity provides great hope for Indonesia as mangosteen producing countries and is the center of origin of the mangosteen plant to explore utilization. Studies on isolation of types of xanthones and biological activity have been widely reported. However, there is a gap between research of chemical /pharmacological and agronomy fields, so it has not been clearly the known the cultuvation and environmental factors on the mangosteen tree. Xanthones development as industrial materials of phytopharmaca or other natural industry requires cultivation standard to produce the raw material of fruit hull which is determined according to industry standards. To achieve this we need studies on biomass production potential of mangosteen fruit hull, xanthone derivatives and profile, and antioxidant properties in aspects of agronomy. This research aims to study the influence of agroecology of production centers, various stages of fruit development of mangosteen and after the fruit is harvested, a diverse group of fruit quality, and the influence of farming inputs of N, P, K fertilization on biomass production of fruit hull, levels and profiles of xanthone derivates, and antioxidant properties. Research began in 2006 through January 2009. The plant material of the mangosteen fruit from mangosteen population in various centers: Leuwiliang, Bogor; Wanayasa, Purwakarta; Puspahiang, Tasikmalaya; Kaligesing, Purworejo dan Watulimo, Trenggalek. The analysis was conducted in various laboratories at the Department of Agronomy and Horticulture; Laboratory of RGCI, Laboratory of Ecophysiology; Integrated Laboratory, Faculty of Agriculture, IPB; and analytical profile of xanthones with Liquid Chromatography Mass Chromatography (LCMS) at the Institute of Molecular Biology, University of Queensland. The results showed that there are fruit hull varries with production location and different stages of fruit maturity. Production of fruit hull is not affected by cultivation technology. Watulimo mangosteen is the largest fruit size and thick hull, so it have the high hull biomass. During the development of fruit, fruit diameter and fruit weight increased until the fruit was 3 month after anthesis (MAA) and then did not change significantly when entering the final process of maturation, 74.99-75.51 g per fruit. The thickness of fruit hull is different between stage of fruit maturity, the highest is 2 MAA and decrease when the ripening fruit; the weight of the hull increase in accordance with the age of the fruit with the highest weight at 3 MAA that is 51.48 g/ fruit. After the fruit is harvested and stored happen deterioration of physical characteristics of fruit. Grouping of fruit quality based on physical characteristics affect hull thickness, weight of wet hull, dry and weight hull but does not affect the hardness of fruit hull; and also affect chemistry characters namely total soluble solids and vitamin C. Input cultivation of N and K fertilization did not increase the physical characters of the mangosteen fruit. Only posphor fertilization increases fruit weight significantly in both doses 600 and 1200 g P2O5 per tree, with fruit weight range 70.22-73.63 g/fruit. The thickness and weight of the fruit hull biomass increased with fertilization at the doses of
Keyword: Radical scavenger, Garcinia mangostana, Guttiferae, Fruit hull, Xanthones derivate, Xanthones profile, Antioxidant

Judul: Karakter Kulit Manggis, Kadar Polifenol Dan Potensi Antioksidan Kulit Manggis (Garcinia mangostana L.) Pada Berbagai Umur Buah Dan Setelah Buah Dipanen
Abstrak: The objective of this study were to know the character of mangosteen rind during development of the mangosteen fruit, studying the total phenol content and antioxidant potential of mangosteen rind. Research was done at Plant Analysis and Chromatoghrapy Laboratory, Deparment of Agronomy and Horticulture, Bogor Agricultural University. This research used Completely Randomized Desain Group (RKLT) single factor wich is harvesting, with continue test Duncan Multiple Range Test (DMRT) at level 5%. Harvesting one month after anthesis (BSA), 2 BSA, 3 BSA, 4 BSA and the rind storage two and four weeks after harvesting were done separately. Mangosteen fruit was harvested from Leuwiliang, Bogor. The result showed that total phenolic at crude extract mangosteen and antioxidant capacity to reach IC50 of harvesting and storage have negative correlation. Harvesting handling have effect to fruit weight, aril weight, wet weight rind and vitamin C content. Total phenolic of Harvesting and storage handling have a negative correlation with antioxidant capacity to reach IC50 which are value about -0.53 and -0.91. Assumed that total phenolic content will increase antioxidant capacity in mangosteen rind. Antioxidants capacity on harvesting and sorage handling of mangosteen have IC50<50 (capability of antioxidant are very strong).
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Judul: Kriteria Osilasi Untuk Pertidaksamaan Diferensial Taklinear Orde Dua
Abstrak: dimana pertidaksamaan dibatasi pada suatu selang [T,oo) dengan T?:O, aCt) kontinu pada selang [0,00) dan j(u) mempunyai turunan pertarna yang kontinu pada selang (-00,00) dengan uj(u) >0 untuk u;"O. Dengan menggunakan Asumsi A dan Asurnsi B, diperoleh beberapa teorerna ten tang kriteria osilasi untuk pertidaksamaan diferensial taklinear orde dua.
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