Kris Herawan Timotius
Krida Wacana Christian University, Jalan Arjuna Utara 6, Jakarta 11510, Indonesia

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Antioxidant Activity of Methanol Extract from Several Indonesian Green Teas simamora, adelina; Steven, Michael; Santoso, Adit Widodo; Rumiati, Flora; Timotius, Kris Herawan
Jurnal Kedokteran YARSI Vol 26, No 1 (2018): JANUARI - APRIL 2018
Publisher : Lembaga Penelitian Universitas YARSI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (515.654 KB) | DOI: 10.33476/jky.v26i1.460

Abstract

As a common beverage, green tea is supposed to have beneficial health effect, such as antioxidant. At present, there are many green teas available in the market in Jakarta. Their quality, in their antioxidant activity, should be proved. This study aimed to investigate the antioxidant activity of extracts of green tea products commercially available in Jakarta. Four green tea samples from different factories (coded as A, B, C, and D) were selected and macerated using methanol. DPPH radical scavenging activity, reducing power ability and total antioxidant capacity were used to measure the antioxidant activity. The total phenolic content (TPC) was also determined. The studied green teas had varied TPC from 23.80  to  84.03 mG GAE/g extract, ranked as B > D > A > C. All samples exhibited various but strong antioxidant activity by DPPH assay, even better than standards ascorbic acid and butylated hydroxytoluene (BHT). However, all extracts showed similar activities in their reducing power ability and total antioxidant capacity, with activities less than standards. These findings confirm that the quality of the Indonesian commercial green teas were heterogeneous both in TPC or DPPH scavenging capacity. But, there is an indication that they are good as an antioxidant containing beverage. 
Low level of plasma VEGF-A and C allele of -2578*C/A polymorphism in the VEGF-A gene are risk factors of diabetic foot ulcer in Javanese ethnic Rahayu, Ika; Sinorita, Hemi; Timotius, Kris Herawan; Sadewa, Ahmad Hamim
Journal of the Medical Sciences (Berkala Ilmu Kedokteran) Vol 53, No 2 (2021)
Publisher : Journal of the Medical Sciences (Berkala Ilmu Kedokteran)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (337.404 KB) | DOI: 10.19106/JMedSci005302202106

Abstract

Diabetes mellitus (DM) is caused by abnormal insulin secretion, impairedinsulin action, or both. Approximately 12-25% of type 2 diabetes mellitus(T2DM) patients will develop diabetic foot ulcers (DFU). Vascular endothelialgrowth factor (VEGF) is a group of platelet-derived growth factors (PDGF)which have a potential role in angiogenesis. Low levels of VEGF-A can causeinsufficient angiogenesis leading to wound healing inhibition. The 2578*C/Apolymorphism of VEGF-A gene has been reported as a candidate markerfor the DFU development. However, the variant role in the development ofDFU in Javanese ethnic needs to be clarified. This study was conducted tocompare VEGF-A levels and the -2578*C/A polymorphism of the VEGF geneamong diabetic patients with and without DFU in Javanese ethnic. In thiscase-control study, the T2DM individuals with DFU as case group (n=19) andwithout DFU as control group (n=41) were recruited. The VEGF-A levelsweredetermined by ELISA. The ARMS-PCR technique was applied to investigate thepresence of -2578*C/A polymorphism of the VEGF gene. Data were analyzedwith independent t, Mann-Whitney, Chi-square, and Kruskal-Wallis tests withsignificance level of p<0.05. The median of plasma VEGF-A level was significantlydifferent between case and control groups (p=0.001). The genotype frequencyof -2578*C/A polymorphism of VEGF gene was no difference between case andcontrol groups. However, individuals with C allele have a higher risk factor todevelop DFU than A allele (CC+CA vs AA;p=0.042; OR=2.5). The plasma VEGF-Alevels were lower in T2DM subjects with DFU than those without DFU. Inconclusion,individuals with C allele of -2578*C/A polymorphism of VEGF geneare more susceptible to have DFU than individuals with A allele in Javaneseethnic with T2DM.