Secondary metabolites of <i>Hypericum richeri</i> Vill. collected in Central Italy: chemotaxonomy and ethnomedicinal relevance

Abstract

The results of the phytochemical analysis of a <em>Hypericum richeri </em>Vill. accession collected from a population living in Appennines, Central Italy, are reported in this paper. The secondary metabolites pattern resulted mainly composed of flavonoids as both aglycones and in glycosidic form, such as quercetin (<strong>2</strong>), quercetin-3-<em>O</em>-methyl ether (<strong>3</strong>), 5,7,3′,5′-tetrahydroxyflavanone (<strong>8</strong>), isorhamnetin glucoside (<strong>7</strong>), isoquercitrin (<strong>9</strong>), hyperoside (<strong>10</strong>), quercitrin (<strong>11</strong>) and myricetin-3-<em>O</em>-rutinoside (<strong>12</strong>). It was also observed the presence of the naphtodianthrones hypericin (<strong>5</strong>) and pseudohypericin (<strong>6</strong>) together with organic acids (benzoic acid (<strong>4</strong>)), a glycolipid (2<em>S</em>)-1,2-di-<em>O</em>-[(9<em>Z</em>,12<em>Z</em>,15<em>Z</em>)-octadeca-9,12,15-trienoyl]-3-<em>O</em>-<em>β</em>-D-galactopyranosyl glycerol (<strong>1</strong>) and the saccharides glucose (<strong>13</strong>), galactose (<strong>14</strong>) and sucrose (<strong>15</strong>). Among these constituents, compounds (<strong>1</strong>) and (<strong>3</strong>) have been identified in <em>H. richeri </em>Vill. for the first time during this study. The other difference in composition observed in the present study in respect to population from different regions is the absence of hyperforin and caffeoylquinic derivatives. The observed chemovariability, already reported in <em>H. perforatum </em>L., might be derived from the environmental characteristic of the collection site. The chemotaxonomic aspects, together with the pharmacologic relevance in traditional medicine of the isolated compounds were also discussed.