## 4 Discussion
The results show that EH-Ch extract and EH-EA exhibited antibacterial inhibitory effect better than other extracts. Among them, EH-EA has the strongest antibacterial activity. However, all extracts almost have no inhibitory activity against _E. coli_, _S. aureus_ and _P. aeruginosa_ at most concentrations. The result of antimicrobial property of _E. hirta_ extracts is almost compatible with previous studies [45; 46; 47; 48; 49; 50]. DPPH free radical scavenging is one of the important mechanisms for the evaluation of the antioxidant activity of a sample. The effect of antioxidants on DPPH were predicted through their hydrogen donating ability of the sample [51]. Literature suggested that total polyphenols content and radical scavenging antioxidant activity are highly correlated. Radical scavenging activities are very important to prevent the deleterious role of free radicals in different diseases, including cancer [52; 53; 54]. To investigate the antioxidant activity of _E. hirta_ extracts, DPPH radical scavenging assay of _E. hirta_ extracts was carried out. The IC\({}_{50}\) values of EH-Me, EH-PE, EH-Ch, EH-EA, EH-Bu were measured to estimate the potential scavenging abilities of the samples. Our results reveal that EH-Me and EH-EA extracts had stronger free radical scavenging activity than other extracts. This result could be explained by EH-Me and EH-EA extracts containing many phenolic compounds and flavonoids. According to IC\({}_{50}\) values, it can be speculated that EH-EA showed the highest scavenging activity. This result shows that there is similarity to previous research results [55]. For lipid peroxidation inhibitory activity, IC\({}_{50}\) values of EH-Me, EH-PE, EH-Ch, EH-EA, EH-Bu were also measured to evaluate antioxidant properties of _E. hirta_ extracts. According to IC\({}_{50}\) values given, EH-Me, EH-PE, EH-EA and EH-Bu extracts possess strong inhibitory properties against lipid oxidation. In particular, EH-EA extract appeared to be 18.74-fold as potent as Trolox, whereas EH-Me, EH-Bu, EH-PE were about 5.93, 5.36, 1.07-fold, respectively (Table 4). These experimental results can be explained by the high concentration of bioactive ingredients extracted from extracts using highly polar solvents. Taken together, these results indicate that _E. hirta_ extracts may have therapeutic effects such as inhibiting lipid peroxidation and preventing radical damage. Moreover, previous studies have also reported that _E. hirta_ extract had efficacy against selective cancer cell lines such as Hep-2, malignant melanoma, and squamous cell carcinoma [56; 57]. In 2014, [PERSON] et al. evaluated anticancer activities of _E. hirta_ ethanolic extract [55]. The ethanolic extract showed selective anticancer activity at a concentration of 100 ug/mL (p \(<\) 0.05). Anticancer activity and cytotoxicity of silver nanoparticles tested against neuroblastoma cell (SH-SY5Y cells) and breast cancer (MCF-7 cell) was reported. That study proved that the ethanolic extract of _E. hirta_ showed significant anticancer activity against neuroblastoma cell (SH-SY5Y cells) and breast cancer (MCF-7 cell) [58]. In the present investigation, in the in vitro screening for cytotoxic activity of _E. hirta_ extracts, at a concentration of 100 ug/mL, EH-EA extract has significant inhibitory activity against the growth of lung cancer cells NCI-H460 and live cancer cells Hep G2, about 55% and 48%, respectively. Similar to the biological activities described above, EH-EA extract was also shown to be much more effective in inhibiting two line of cancer cells than the crude extract EH-Me and three remaining fractions. At the same concentration of 100 ug/mL, EH-Me, EH-PE, EH-Ch and EH-Bu did not show significant high cytotoxicity on NCI H460 and Hep G2. For the mentioned results, EH-EA extract may be rich in bioactive compounds, and these compounds exhibited significant antibacterial, antioxidant and anticancer activities.