Anti-influenza patchoulol-type sesquiterpenoids from Pogostemon cablin

Abstract

• Four new patchoulol-type sesquiterpenoids were isolated from Pogostemon cablin (Blanco) Benth. • This is the second report of patchoulol glucopyranoside from P. cablin . • Compound 10 represented as the first example of nor-patchoulol glucopyranoside. • Compounds 8 and 12 showed potent anti-influenza activity against tamiflu resistant virus. Four new patchoulol-type sesquiterpenoids, including 6 α ,9 β -dihydroxypatchoulol 6- O - β - d -glucopyranoside ( 1 ), 6 α -hydroxypatchoulol 6- O - β - d -glucopyranoside ( 2 ), 3 α ,9 β -dihydroxypathoulol ( 3 ), and 4 β -hydroxynorpatchoulol 4- O - β - d -glucopyranoside ( 10 ), were isolated from the roots of Pogostemon cablin (Blanco) Benth, together with eleven known sesquiterpenoids. Their structures were elucidated on the basis of extensive NMR spectral and high resolution mass spectrometry analysis. This is the second report of patchoulol glucopyranoside from P. cablin and compound 10 represented as the first example of nor-patchoulol glucopyranoside. The anti-influenza virus activities of 1–10 against A/WSN/33/2009 and A/Puerto Rico/8/1934 strains (tamiflu resistant viruses) were evaluated. Compounds 2 β ,12-dihydroxypathoulol ( 5 ) and (5R)-5-hydroxypatchoulol ( 8 ) exhibited moderate anti-influenza activity against A/WSN/33/2009 strain with EC 50 value of 52.7 μ M and 49.6 μ M (positive control oseltamivir, EC 50 = 6.75 μ M). Compounds 8 and pogostol ( 12 ) showed potent anti-influenza activity against A/Puerto Rico/8/1934 strain with EC 50 values of 3.06 μ M and 0.07 μ M, respectively, versus the postive control (amantadine, EC 50 = 67.9 μ M).