Preparation of Hemigraphis reptans water extract with different parameters (temperatures and extraction times): antioxidant and toxicity study
Mohd Kamal N.H., Zaridah M.Z., Azman M., Meor Abdullah Ghazey, NA., Muhammad Danial C.R., Muhammad Azreal Adam AH.

Abstract
Hemigraphis reptans (G. Forst.) belongs to the Acanthaceae family. This plant is traditionally used to treat centipede bites and facilitate the process at birth. However, scientific experiments on H. reptans are still few. This study is to determine the antioxidants activity and toxicity of H. reptans water extract that was prepared with different parameters. Powder of dried H. reptans was placed in tubes containing water and heated to different temperatures of 40oC, 60oC, 80oC, and 100oC. For each temperature, the extract was heated at different extraction times (30 min, 1 h, 2 hours, and 3 hours). All extracts were tested for antioxidant tests (DPPH and FRAP), phenolic content, and brine shrimp lethality test. The DPPH result showed H. reptans water extract that was prepared using the parameter of 80oC/30 min has the highest DPPH inhibition. Besides that, the FRAP test showed that H. reptans water extract prepared using a parameter 60oC/1 hour and 80oC/1 hour has the highest FRAP value. For the TPC test, preparation of H. reptans water extract using a parameter of 80oC/30 min has the highest phenolic content. For MDA test, it showed that 100oC/2 hours has the lowest malondialdehyde level. For the toxicity test, the brine shrimp lethality test showed that H. reptans is mildly toxic and only reduces the population of brine shrimp if the concentration is too high which was 5 mg/ml. This study showed that H. reptans has the potency to be used as a source of antioxidants. However, in vivo study using an animal laboratory must be performed to verify the toxicity of this plant.

Keywords: Hemigraphis reptans, temperature, duration time, antioxidant, toxicity