From channel modeling to signal processing for Bit patterned media recording

Abstract

<i>Cardiocrinum cordatum</i> (Thunb.) Makino (Family: Liliaceae), commonly known as 'Ubayuri', is native to Japan and some islands in the Russian Far East. It has high value as food, medicinal, and ornamental species. The aim of this study was to isolate and characterize the main chemical constituents of the leaves of <i>C. cordatum</i>. A total of 19 compounds, namely caffeic acid (<b>1</b>), caffeic acid methyl ester (<b>2</b>), caffeic acid <i>β</i>-glucopyranosyl ester (<b>3</b>), caffeic acid 4-<i>O</i>-<i>β</i>-glucopyranoside (<b>4</b>), ferulic acid (<b>5</b>), isoferulic acid (<b>6</b>), protocatechuic acid (<b>7</b>), syringic acid (<b>8</b>), 2,6-dimethoxy-<i>p</i>-hydroquinone 1-<i>O</i>-<i>β</i>-glucopyranoside (<b>9</b>), esculetin (<b>10</b>), taxifolin (<b>11</b>), quercetin 3-<i>O</i>-(6-<i>O</i>-<i>α</i>-rhamnopyranosyl)<i>β</i>-glucopyranoside-7-<i>O</i>-<i>β</i>-rhamnopyranoside (<b>12</b>), 2,7-dimethyl-2,4-diene-deca-<i>α</i>,<i>ω</i>-diacid <i>β</i>-glucopyranoside (<b>13</b>), 4-[formyl-5-(methoxymethyl)-1<i>H</i>-pyrrol-1-yl]butanoic acid (<b>14</b>), (3<i>Z</i>)-3-hexenyl <i>β</i>-glucopyranoside (<b>15</b>), tryptophan (<b>16</b>), adenine (<b>17</b>), adenosine (<b>18</b>), and 2-deoxyadenosine (<b>19</b>) were isolated using various chromatographic methods. The structures of isolated compounds were elucidated on the basis of their NMR spectroscopic data. All these compounds were isolated for the first time from the genus <i>Cardiocrinum</i>. Phenolic acid derivatives and flavonoids can be considered as chemotaxonomic markers in the leaves of <i>Cardiocrinum</i> species.