In this study, 11 plant extracts from Bangladesh were used to evaluate the total phenolic and flavonoid content, in vitro antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis-(3-ethylbenzthiazolin-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assay. Also, the inhibitory effect of nitric oxide (NO) production in RAW 264.7 macrophage cell line and the neuroprotective effect on H2O2-induced PC12 cells were tested. Our results revealed that Piper betle L. showed the highest total phenolic content (162.2 mg GAE/g extract) among the 11 plants from Bangladesh. Most plants showed strong radical scavenging effects and ferric reducing antioxidant power. Besides, Piper betle L. protected PC12 neuronal cells against H2O2 related oxidative stress in LPS-induced PC12 cells. Regarding the antiinflammatory effect, Piper betle L. significantly inhibited NO accumulation in LPS-induced RAW 264.7 cells. Our results provide evidence that Piper betle L. could be useful for the development of functional health foods.