plant polyphenols that widely distr

plant polyphenols that widely distributed in plant kingdom and its presence was detected in R. tomentosa fruit with mass charge of 169.0142. Gallic acid (Rice-Evans et al. 1996), quinic acid and caffeic acid (Santos et al. 2010) have been shown to possess antioxidant properties.
DPPH ANTIOXIDANT ASSAY
The DPPH assay is commonly used to screen antioxidant activity of plant crude extract and be able to be detected at low concentration (Sanchez-Moreno 2002). The DPPH radical scavenging activity of the fruit crude extracts of R. tomentosa were investigated. As shown in Figure 1, the highest activity was observed in the methanol followed by water, chloroform and petroleum ether extracts. At the concentration of 200 ug/mL, the DPPH radical inhibition of fruit crude extract of R. tomentosa decreased in the following order: methanol (62.13%) > water (59.17%) > chloroform (34.19%) and petroleum-ether (20.29%). Ascobic acid (Vitamin C), a well-known antioxidant which is used as appositive controls shows 95% inhibition on DPPH radical at a concentration of 200 ug/mL. As shown in Table 2, the IC50 values of ascorbic acid, water, methanol, chloroform and petroleum-ether extracts were 0.51, 154, 107, 230 and 250 ug/mL, respectively. The methanol fruit extract showed the highest antioxidant activity in the DPPH assay. This results indicated that R. tomentosa have better performance against DPPH radicals. The high antioxidant activity of the methanol fruit extract was due to the presence of gallic acid, quinic acid and caffeic acid (Table 1) as these compounds have been known for its high antioxidant properties (Catherine et al. 1996; Sonia et al. 2010).
FERRIC REDUCING POWER ASSAY
The reducing power activity of a compound could be used as a useful indicator for antioxidant (Meir et al. 1995). In this assay, the yellow colour of the reaction solution changes to green depending on the reducing power of the test sample. The presence of antioxidant in the solution causes the reduction of the Fe3+/ferricyanide complex to the ferrous form. Therefore, the formation of Fe3+ can be determined by measuring its absorbance at 700 nm (Zhou

Results (Indonesian) 1:

polifenol tanaman yang beredar luas di kingdom tanaman dan kehadirannya terdeteksi di R. tomentosa buah dengan massa biaya sebesar 169.0142. Asam galat (beras-Evans et al. 1996), asam quinic dan asam caffeic (Santos et al. 2010) telah terbukti memiliki sifat antioksidan.DPPH ANTIOKSIDAN ASSAYDPPH assay umumnya digunakan untuk layar aktivitas antioksidan dari ekstrak tumbuhan kasar dan dapat dideteksi di konsentrasi rendah (Sanchez-Moreno 2002). DPPH radikal scavenging aktivitas ekstrak buah mentah R. tomentosa diselidiki. Seperti yang ditunjukkan dalam gambar 1, aktivitas tertinggi diamati dalam metanol yang diikuti oleh air, ekstrak eter kloroform dan minyak bumi. Pada konsentrasi 200 ug/mL, penghambatan radikal DPPH ekstrak buah mentah R. tomentosa menurun dalam urutan berikut: metanol (62.13%) > air (59.17%) > kloroform (34.19%) dan Eter minyak bumi (20.29%). Ascobic asam (Vitamin C), antioksidan yang terkenal yang digunakan sebagai kontrol appositive menunjukkan 95% penghambatan DPPH radikal di konsentrasi 200 ug/mL. Seperti yang ditunjukkan dalam tabel 2, nilai-nilai IC50 asam askorbat, air, metanol, ekstrak kloroform dan Eter minyak bumi adalah 0,51, 154, 107, 230 dan 250 ug/mL, masing-masing. Ekstrak buah metanol menunjukkan aktivitas antioksidan tertinggi dalam DPPH assay. Hasil ini menunjukkan bahwa tomentosa R. memiliki kinerja yang lebih baik terhadap DPPH radikal. Aktivitas antioksidan tinggi metanol ekstrak buah adalah karena adanya galat asam, asam quinic dan asam caffeic (Tabel 1) sebagai senyawa ini telah dikenal untuk sifat antioksidan tinggi (Catherine et al, 1996; Sonia et al. 2010).FERRI MENGURANGI KEKUATAN ASSAYThe reducing power activity of a compound could be used as a useful indicator for antioxidant (Meir et al. 1995). In this assay, the yellow colour of the reaction solution changes to green depending on the reducing power of the test sample. The presence of antioxidant in the solution causes the reduction of the Fe3+/ferricyanide complex to the ferrous form. Therefore, the formation of Fe3+ can be determined by measuring its absorbance at 700 nm (Zhou