Chemical components and antioxidant activities of methanol extract of Syzygium polycephalum Miq. stem bark (Myrtaceae)

127-136This study aimed to reveal chemical components and screen antioxidant activity of methanolic extract of Syzygium polycephalum stem bark. The chemical components were isolated by using column chromatographic techniques and determined by spectroscopic methods (UV-Vis, FTIR, MS, and NMR) and comparison with literature data, in which the antioxidant activity was performed using 2,2’-diphenyl-1-picrylhydrazyl (DPPH). The present investigation resulted in four compounds involving gallic acid, pinostrobin, 3,4,3’-tri-O-methylellagic acid, and 3,3’-di-O-methylellagic acid. The four compounds were all in the form of phenolic compounds found from the extract whereas 3,4,3’-tri-O-methylellagic acid and 3,3’-di-O-methylellagic acid were ellagic acid derivatives. The methanolic extract, the four compounds, and vitamin C (as positive control) showed antioxidant activity against DPPH with the IC50 value of 99.9; 10.0; 183.2; 72.1; 63.3; and 13.9 µg/mL, respectively. The antioxidant activity of gallic acid was more active than that of vitamin C. The present study confirms that Syzygium polycephalumis rich in phenolic compounds and natural antioxidants

Chemical components and antioxidant activities of methanol extract of Syzygium polycephalum Miq. stem bark (Myrtaceae)

This study aimed to reveal chemical components and screen antioxidant activity of methanolic extract of Syzygium polycephalum stem bark. The chemical components were isolated by using column chromatographic techniques and determined by spectroscopic methods (UV-Vis, FTIR, MS, and NMR) and comparison with literature data, in which the antioxidant activity was performed using 2,2’-diphenyl-1-picrylhydrazyl (DPPH). The present investigation resulted in four compounds involving gallic acid, pinostrobin, 3,4,3’-tri-O-methylellagic acid, and 3,3’-di-O-methylellagic acid. The four compounds were all in the form of phenolic compounds found from the extract whereas 3,4,3’-tri-O-methylellagic acid and 3,3’-di-O-methylellagic acid were ellagic acid derivatives. The methanolic extract, the four compounds, and vitamin C (as positive control) showed antioxidant activity against DPPH with the IC50 value of 99.9; 10.0; 183.2; 72.1; 63.3; and 13.9 µg/mL, respectively. The antioxidant activity of gallic acid was more active than that of vitamin C. The present study confirms that Syzygium polycephalumis rich in phenolic compounds and natural antioxidants

Application of Color Variation to Impatiens balsamina L. As An Environmentally friendly acid-base Indicator

An acid-base titration is one of the quantitative analysis methods involving a high-polluting, harmful, hazardous, and relatively expensive synthetic indicator. The development of the concept of green chemistry encourages research to invent natural indicators that are more environmentally friendly. Impatiens balsamina L. flower has a variety of colors and contains anthocyanin pigments. Rose pink, red, violet, orangish red, and pink Impatiens balsamina L. flower were extracted with acidified ethanol solvent. All five I. balsamina L. flower extracts indicate discoloration on pH range 10-12. Violet flower extract has an error percentage of strong acid-strong base titration which was 50.48 ± 2.18%, while in strong acid-weak base titration was 19.27 ± 1.15%. Meanwhile, it cannot be applied in weak acids-strong base titration. Thus, I. balsamina L. flowers can be used as an alternative to environment-friendly natural acid-base indicators

An Ellagic Acid Derivative and Its Antioxidant Activity of Stem Bark Extracts of <i>Syzygium polycephalum</i> Miq. (Myrtaceae)

The investigation of the Syzygium polycephalum Miq. (Myrtaceae) aimed to assess the phytochemical contents and antioxidant activity of the chloroform fraction. In this study, the fraction was obtained from methanol extract of S. polycephalum stem bark partitionated by chloroform. An ellagic acid derivative was successively isolated from the chloroform fraction. The molecular structure of isolated compound was elucidated and established as 3,4,3’-tri-O-methylellagic acid through extensive spectroscopic studies including UV-Vis, FTIR, NMR and LC-MS analyses and by comparison with literature data. The finding of the isolated compound is the first time from the plant, although the isolated compound previously have been found in the other Syzygium species such as S. cumini together with ellagic acid and 3,3’-di-O-methylellagic acid. The chloroform fraction, isolated compound, and vitamin C showed antioxidant activity against 2,2’-diphenyl-1-picrylhydrazyl (DPPH) with IC50 value of 163.6, 72.1, and 11.5 μg/mL, respectively

Application of flower color variations to Impatiens balsamina L. as an environmentally friendly acid-base indicator

An acid-base titration is one of the quantitative analysis methods involving a high-polluting, harmful, hazardous, and relatively expensive synthetic indicator. The development of the concept of green chemistry encourages research to invent natural indicators that are more environmentally friendly. Impatiens balsamina L. flower has a variety of colors and contains anthocyanin pigments. Rose pink, red, violet, orangish red, and pink Impatiens balsamina L. flower were extracted with acidified ethanol solvent. All five I. balsamina L. flower extracts indicate discoloration on pH range 10-12. Violet flower extract has an error percentage of strong acid-strong base titration which was 50.48 ± 2.18%, while in strong acid-weak base titration was 19.27 ± 1.15%. Meanwhile, it cannot be applied in weak acids-strong base titration. Thus, I. balsamina L. flowers can be used as an alternative to environment-friendly natural acid-base indicators