Pogostemon cablin (Blanco) Benth., also known as patchouli (廣藿香) is an important herb which possesses several biological activities such as antioxidant, analgesic, anti-inflammatory, and cytotoxic activities. Till now more than 140 compounds have been isolated and identified from patchouli [1]. However, the mechanisms of some traditional uses of patchouli have not been well verified by standardizing and authenticating the bioactivity of purified compounds. In this meeting, the anti-inflammatory effect of pure compounds from patchouli will be investigated.
In our search of compounds with anti-inflammatory activities, 13 compounds (1‒13), including seven flavonoids, ternatin (1), 5-hydroxy-3,6,7,8,3′,4′-hexamethoxyflavone (2), 3,5-dihydroxy-7,3′,4′-trimethoxyflavone (3), rhamnazin (4), pachypodol (5), 5-hydroxy-3,7,4′-trimethoxyflavone (6), and retusin (7), a pyranone, pogostone (8), four benzenoids, veratric acid (9), isovanillic acid (10), α-curcumene (11), and (E)-2-methyl-6-(p-tolyl)hept-3-en-2-ol (12), and a sesquiterpene, α-guaiene (13) were isolated and identified from the aerial parts of P. cablin. The structures of all isolates were determined through spectral analyses and comparison of their physical and spectral data with literatures.
To mimic the pathology of the inflammation, LPS treatment was performed on the RAW 264.7. Rhamnazin (4), pachypodol (5), and (E)-2-methyl-6-(p-tolyl)hept-3-en-2-ol (12) significantly decreased nitrite accumulation in LPS-stimulated RAW 264.7 cells. Western blot assay showed that pachypodol (5) ameliorated increases in inducible nitric oxide synthase (iNOS) via the inhibition of phosphorylation of JNK and elevation of HO-1 in LPS-treated macrophages. The results suggest that the above compounds effectively inhibit the NO production and may be useful in preventing inflammatory diseases mediated by excessive production of NO.
References:
[1] Swamy MK, Sinniah UR. A comprehensive review on the phytochemical constituents and pharmacological activities of Pogostemon cablin Benth.: an aromatic medicinal plant of industrial importance. Molecules 2015; 20: 8521-47.