Abstract

Abstract
Background
In Vietnam and in other Asian countries, the above-ground parts of Pogostemon auricularius (L.) Hassk. (Lamiaeae), 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 examining the anti-inflammatory effects of certain fractions and isolated compounds from P. auricularius by measuring various pro-inflammatory factors production.
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 significant activity contrary to the production of nitric oxide (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 lipopolysaccharide (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 nitric oxide and TNF-α, whereas activate anti-inflammatory IL-10 production, thereby explaining the ethnopharmacological traditions of this herb.

Key words: Inflammation; IL-6; IL-10; nitric oxide, Pogestemon auricularius; pogostemin C; TNF-α;