Pharmacological Activities and Phytochemicals of <em>Etlingera pavieana</em> (Pierre ex Gagnep) R.M.Sm

Etlingera pavieana (Pierre ex Gagnep) R.M.Sm. (Zingiberaceae family) is commonly found in Southeast Asia. The rhizome of the plant is used as a spice and folk medicine in southeastern Thailand and Cambodia. The extracts, essential oil, and compounds from E. pavieana were found to possess a variety of pharmacological activities like anti-inflammatory, antioxidant, antiatherogenic, and antimicrobial effects. Furthermore, phytochemical studies have reported the presence of various chemical constituents, the main being phenylpropanoids such as trans-4-methoxycinnamaldehyde (MCD) and 4-methoxycinnamyl p-coumarate (MCC). Therefore, E. pavieana seems to be a potential source of natural products for treatment of various diseases and promotion of good health

Inhibition of human cytochromes P450 2A6 and 2A13 by flavonoids, acetylenic thiophenes and sesquiterpene lactones from Pluchea indica and Vernonia cinerea

The human liver cytochrome P450 (CYP) 2A6 and the respiratory CYP2A13 enzymes play role in nicotine metabolism and activation of tobacco-specific nitrosamine carcinogens. Inhibition of both enzymes could offer a strategy for smoking abstinence and decreased risks of respiratory diseases and lung cancer. In this study, activity-guided isolation identified four flavonoids <b>1-4</b> (apigenin, luteolin, chrysoeriol, quercetin) from <i>Vernonia cinerea</i> and <i>Pluchea indica, </i>four hirsutinolide-type sesquiterpene lactones <b>5-8</b> from <i>V. cinerea</i>, and acetylenic thiophenes <b>9-11</b> from <i>P. indica</i> that inhibited CYP2A6- and CYP2A13-mediated coumarin 7-hydroxylation. Flavonoids were most effective in inhibition against CYP2A6 and CYP2A13, followed by thiophenes, and hirsutinolides. Hirsutinolides and thiophenes exhibited mechanism-based inhibition and in irreversible mode against both enzymes.The inactivation kinetic <i>K</i>_I values of hirsutinolides against CYP2A6 and CYP2A13 were 5.32-15.4 and 0.92-8.67 µM, respectively, while those of thiophenes were 0.11-1.01 and 0.67-0.97 µM, respectively

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<i>supporting information for Boonruang et al</i

Inhibition of human cytochromes P450 2A6 and 2A13 by flavonoids, acetylenic thiophenes and sesquiterpene lactones from <i>Pluchea indica</i> and <i>Vernonia cinerea</i>

<p>The human liver cytochrome P450 (CYP) 2A6 and the respiratory CYP2A13 enzymes play role in nicotine metabolism and activation of tobacco-specific nitrosamine carcinogens. Inhibition of both enzymes could offer a strategy for smoking abstinence and decreased risks of respiratory diseases and lung cancer. In this study, activity-guided isolation identified four flavonoids <b>1</b>–<b>4</b> (apigenin, luteolin, chrysoeriol, quercetin) from <i>Vernonia cinerea</i> and <i>Pluchea indica,</i> four hirsutinolide-type sesquiterpene lactones <b>5</b>–<b>8</b> from <i>V. cinerea</i>, and acetylenic thiophenes <b>9</b>–<b>11</b> from <i>P. indica</i> that inhibited CYP2A6- and CYP2A13-mediated coumarin 7-hydroxylation. Flavonoids were most effective in inhibition against CYP2A6 and CYP2A13, followed by thiophenes, and hirsutinolides. Hirsutinolides and thiophenes exhibited mechanism-based inhibition and in irreversible mode against both enzymes. The inactivation kinetic <i>K</i>_I values of hirsutinolides against CYP2A6 and CYP2A13 were 5.32–15.4 and 0.92–8.67 µM, respectively, while those of thiophenes were 0.11–1.01 and 0.67–0.97 µM, respectively.</p