1 1 diphenyl 2 picrylhydrazyl dpph

Folin-ciocalteau (FC reagent), gallic acid, 2,2-azino-bis (3-ethylbenzo thiazoline-6-sulfonic acid) diammonium salt (ABTS), sodium nitrite, sulfanilic acid, acetic acid, sodium citrate, ascorbic acid and ferrous sulfate heptahydrate (FeSO₄) were obtained from Sigma-Aldrich Co. LLC (St. Louis, MO, USA). 1,1-Diphenyl-2-picrylhydrazyl (DPPH) was obtained from Wako Pure Chemical Industries Ltd. (Osaka, Japan). D-Catechin was purchased from MP Biomedicals, LLC (Illkich, France). Hydrogen peroxide 30% was obtained from Daejung Chemicals and Metals Co. (Gyeonggi-do, Korea). pBR322 DNA and 6× DNA loading dye were purchased from Thermo Fisher Scientific Inc. (NYSE: TMO, Waltham, MA USA; Gyeonggi-do, Korea). RAW 264.7 cells were purchased from the Korean Cell Line Bank (Seoul, Korea). DMEM, penicillin-streptomycin and fetal bovine serum (FBS) were purchased from GIBCO BRL (Life Technologies, Grand Island, NY, USA). All chemicals were used without any further purification.

The stems of D. benthami Prain were obtained from marketplace vendors from Guangxi Province, China, in June 2017. The voucher specimens were identified by Professor Songji Wei at the Department of Zhuang Pharmacy, Guangxi traditional Chinese Medical University, Nanning, China. 1,1-Diphenyl-2-picryl hydrazyl (DPPH) (purity 98%) was purchased from Wako Chemicals, California, CA, USA. 2,2′-Azobis-(3-ethylbenzothia zoline-6-sulfonic acid) (ABTS), camptothecin and Butylated hydroxyl toluene (BHT) were purchased from Sigma Aldrich Co. St. Louis, MO, USA. Other chemicals were purchased from China National Medicine Group Shanghai Corporation, Shanghai, China. All chemicals and solvents that were used were of analytical grade.