<jats:title>ABSTRACT</jats:title><jats:sec><jats:title>Introduction</jats:title><jats:p><jats:italic>Phyllagathis rotundifolia</jats:italic> (Jack) Bl. (Melastomataceae) is a creeping herb found in Peninsular Malaysia and Sumatra. Traditionally, a decoction of the leaves is used in the treatment of malaria, fever and stomach ache.</jats:sec><jats:sec><jats:title>Objective</jats:title><jats:p>To provide ESI‐MS<jats:sup><jats:italic>n</jats:italic></jats:sup> data which are applicable for chemical fingerprinting of <jats:italic>P. rotundifolia</jats:italic> to obviate laborious isolation and purification steps.</jats:sec><jats:sec><jats:title>Methodology</jats:title><jats:p>The mass spectral data for the compounds isolated from the leaves of <jats:italic>P. rotundifolia</jats:italic> were obtained by liquid chromatography–electrospray ionisation tandem mass spectrometry.</jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>The MS fragmentation patterns were obtained for galloylated cyanogenic glucosides based on prunasin (prunasin 6′‐<jats:italic>O</jats:italic>‐gallate <jats:bold>1</jats:bold>, prunasin 2′,6′‐di‐<jats:italic>O</jats:italic>‐gallate <jats:bold>2</jats:bold>, prunasin 3′,6′‐di‐<jats:italic>O</jats:italic>‐gallate <jats:bold>3</jats:bold>, prunasin 4′,6′‐di‐<jats:italic>O</jats:italic>‐gallate <jats:bold>4</jats:bold>, prunasin 2′,3′,6′‐tri‐<jats:italic>O</jats:italic>‐gallate <jats:bold>5</jats:bold>, prunasin 3′,4′,6′‐tri‐<jats:italic>O</jats:italic>‐gallate <jats:bold>6</jats:bold> and prunasin 2′,3′,4′,6′‐tetra‐<jats:italic>O</jats:italic>‐gallate <jats:bold>7</jats:bold>), gallotannins (6‐<jats:italic>O</jats:italic>‐galloyl‐<jats:sc>d</jats:sc>‐glucose <jats:bold>8</jats:bold>, 3,6‐di‐<jats:italic>O</jats:italic>‐galloyl‐<jats:sc>d</jats:sc>‐glucose <jats:bold>9</jats:bold>, 1,2,3‐tri‐<jats:italic>O</jats:italic>‐galloyl‐<jats:italic>β</jats:italic>‐<jats:sc>d</jats:sc>‐glucose <jats:bold>10</jats:bold>, 1,4,6‐tri‐<jats:italic>O</jats:italic>‐galloyl‐<jats:italic>β</jats:italic>‐<jats:sc>d</jats:sc>‐glucose <jats:bold>11</jats:bold>, 3,4,6‐tri‐<jats:italic>O</jats:italic>‐galloyl‐<jats:sc>d</jats:sc>‐glucose <jats:bold>12</jats:bold>, 1,2,3,6‐tetra‐<jats:italic>O</jats:italic>‐galloyl‐<jats:italic>β</jats:italic>‐<jats:sc>d</jats:sc>‐glucose <jats:bold>13</jats:bold> and 1,2,3,4,6‐penta‐<jats:italic>O</jats:italic>‐galloyl‐<jats:italic>β</jats:italic>‐<jats:sc>d</jats:sc>‐glucose <jats:bold>14</jats:bold>), ellagitannins [6‐<jats:italic>O</jats:italic>‐galloyl‐2,3‐<jats:italic>O</jats:italic>‐(<jats:italic>S</jats:italic>)‐hexahydroxy‐diphenoyl‐<jats:sc>d</jats:sc>‐glucose <jats:bold>15</jats:bold>, praecoxin B <jats:bold>16</jats:bold> and pterocarinin C <jats:bold>17</jats:bold>], ellagic acid derivatives (3′‐<jats:italic>O</jats:italic>‐methyl‐3,4‐methylenedioxyellagic acid 4′‐<jats:italic>O‐β</jats:italic>‐<jats:sc>d</jats:sc>‐glucopyranoside <jats:bold>18</jats:bold> and 3,3′,4‐tri‐<jats:italic>O</jats:italic>‐methylellagic acid 4′‐<jats:italic>O‐β</jats:italic>‐<jats:sc>d</jats:sc>‐glucopyranoside <jats:bold>19</jats:bold>) and gallic acid <jats:bold>20</jats:bold> that were isolated from the leaves of <jats:italic>P. rotundifolia</jats:italic>.</jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The ESI‐MS<jats:sup><jats:italic>n</jats:italic></jats:sup> technique facilitates identification of galloylated cyanogenic glucosides, hydrolysable tannins and ellagic acid derivatives that were isolated from the leaves of <jats:italic>P. rotundifolia</jats:italic>. It yields MS<jats:sup><jats:italic>n</jats:italic></jats:sup> spectra that are useful for identification of these compounds in complex samples and permit more complete fingerprinting of plant materials. Copyright © 2011 John Wiley & Sons, Ltd.</jats:sec>