จำนวน Repository ( 7 )

ฤทธิ์ต้านอนุมูลอิสระของกุ่มบก
ฤทธิ์ต้านอนุมูลอิสระของกุ่มบก

The aim of this research was determine total phenolic content total flavonoid content and antioxidant activity by DPPH and ABTS assay from leaves flower and stem of Crateva adansonii DC. subsp. trifoliate (Roxb) Jacobs that was extracted by Soxhlet method using ethanol dichloromethane and ethyl acetate as solvent. Leaves extract showed the highest total phenolic content and antioxidant activity. Ethanolic leaf extract showed the highest total phenolic content (157.13±0.32 mg GAE/g extract) and antioxidant activity by DPPH assay (53.64±3.78% (IC50 = 1.49±0.02 mg/ml)) and ABTS assay (76.51±0.97% (IC50 = 0.84±0.01 mg/ml)).When we considering solvent effect found that ethanolic extract showed the highest total phenolic content and antioxidant activity. Total flavonoid content ethyl acetate extract showed the highest total flavonoid content. Total phenolic content significantly correlated with antioxidant activity.

2564
Preparation of DPPH and Its Derivatives
Preparation of DPPH and Its Derivatives

Abstract This article reviews literatures concerning preparation of stable free radical DPPH (22-diphenyl-1-picrylhydrazyl) and its derivatives. The key intermediate playing an important role is diarylhydrazine. The article reports solution methods for problems in each step of the reaction. In addition it also shows the development of DPPH synthesis and other stable free radical DPPH derivatives besides DPPH

2556