The effect of Pogostemon auricularius fractions and its compounds on some pro-inflammatory and anti-inflammatory molecules in LPS-stimulated RAW 264.7 macrophages

Abstract

Linh Thuy Thi Tran, Duc Viet Ho, Dung Viet Le, Hanoi Thi Nguyen, Ain Raal

Background: In Vietnam and in other Asian countries, the above-ground parts of Pogostemon auricularius (L.) Hassk. (Lamiaceae), having a different range of ethnopharmacological traditions, are used as a natural cure with antiseptic, analgesic, and anti-inflammatory properties. This study pointed out the anti-inflammatory effects of some fractions and isolated compounds from P. auricularius. Aim: This study aims to examine the anti-inflammatory effects of certain fractions and isolated compounds from P. auricularius by measuring the production of various pro-inflammatory factors. Methods: The anti-inflammatory effects of methanol extract, n-hexane, dichloromethane, ethyl acetate, and aqueous fractions, as well as Pogostemins A–C and Pogostemon A–C, isolated from above-ground parts of P. auricularius, were ascertained by measuring the quantity of pro-inflammatory factors such as interleukin (IL)-6, tumor necrosis factor (TNF)-α, nitric oxide (NO), and anti-inflammatory IL-10 produced by lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Results: The fractions of ethyl acetate and dichloromethane displayed a significant activity contrary to the production of NO having IC50 values of 25.28 and 28.68 µg/ml, respectively. The new compound, pogostemin C, had the strongest inhibitory effect with an IC50 value of 1.36 µg/ml. Besides, pogostemin C displayed the ability to decrease pro-inflammatory TNF-α and increase anti-inflammatory IL-10 in LPS-stimulated RAW 264.7 cells. Conclusion: This study reveals that the fractions and pogostemin C extracted from the above-ground parts of P. auricularius can inhibit the production of NO and TNF-α but activate anti-inflammatory IL-10 production, thereby explaining the ethnopharmacological traditions of this herb.