Antinociceptive Activity of Petroleum Ether Fraction of Clinacanthus nutans Leaves Methanolic Extract: Roles of Nonopioid Pain Modulatory Systems and Potassium Channels

Figure 8

Comparison between chromatograms of the several standard compounds, namely, cinnamic acid, caffeic acid, coumaric acid, vanillic acid, ferulic acid, gallic acid, epicatechin gallate, catechin, rutin, myricetin, epicatechin, 3,4–hydrobenzoic acid, ellagic acid, protocatechuic acid, and epigallocatechin gallate, against that of PECN at 254 nm. Only peaks with a retention time (RT) of 20.14 min in PECN exhibited similar retention time with cinnamic acid.