MATERIALS AND METHODS
Investigation of phytochemical and physi- cochemical study
The present study was laboratory-based analytical study. The fresh mature fruits of Terminalia chebula Retz. were collected from Magway Division in May and the authenticity was confirmed by competent botanist. The preliminary phytochemical screenings were qualitatively determined according to Harbone (1984) 6 and the physi- cochemical properties of T. chebula Retz. were assessed according to the quality control methods for medicinal plant materials.7, 8 The analysis was conducted at University of Traditional Medicine, Mandalay.
Extraction of fruits of Terminalia chebula Retz.
to the previous study, the 75% ethanol was found to be the suitable solvent for
extraction of T. chebula fruit to
obtain high amount of total polyphenol.9 Dried powder was extracted
with 75% ethanol by cold maceration process for 7 days. Then, 75% ethanolic
extract was filtered and con- centrated at 40ºC under reduced pressure
by rotary evaporator. The obtained liquid extract was then dried on water bath at 50°C for 48 hours until the concentrated viscous extract was obtained.
Acute oral toxicity test
The ethanolic extract of T. chebula Retz. was tested for acute toxicity according to Organization of Economic Cooperation and Development guideline 42510 which was performed at Pharmacology Research Division, Department of Medical Research, Yangon. According to the literature, the ethanolic extract of Terminalia chebula Retz. is likely to be non-toxic.11 Therefore, limit test at 5000 mg/kg was performed.
Determination of total phenol contents in the ethanolic fruit extract of T. chebula Retz
The major constituent that gives antioxidant activity of Terminalia chebula fruit is total polyphenol. This experiment was carried out according to Celep, Aydin & Yesilada (2017) with some modification.12 Determination of total phenolic compounds was done by Folin Ciocalteu colorimetric method and the absorbance was measured at 765 nm with UV-Vis spectrophotometer. Then, the results were expressed as gallic acid equivalent (GAE) (n=3).
Determination of in vitro antioxidant activity of ethanolic extract by DPPH radical scavenging assay
Antioxidant activitiy of ethanolic extract was determined by in vitro DPPH method according to Vieira et al. (2013) with some modification.13 The ascorbic acid was used as standard. The sample solutions were prepared by dissolving the extract in 75% ethanol to obtain the concentrations of 10, 40, 80, 120, 160, 200 µg/mL, respectively. To 2.9 mL of DPPH (60µM) solution, 0.1 mL of extracts with different concent- rations were added and mixed vigorously by a vortex mixer. All solutions were allowed to stand at room temperature for 30 minutes in the dark and measurement of absorbance was done at 517 nm using a UV-Vis spectro- photometer. The percent inhibition was calculated by using the following formula.