Compounds comprising a linear .beta.1.fwdarw.6 glucan esterified by caproic acid, the number of D-glucose residues being from 7 to 40 and the number of caproic acid residues being from 2 to 30, may be be obtained by fermentation of a microorganism of the genus Aureobasidium. These compounds are designated HS-142-1. Preferred microorganism is Aureobasidium pullulans var. melanigenum KAC-2383 (FERM-BP 2407).The compounds of the present invention exhibit excellent antagonistic activity to ANP and are capable of inhibiting the bonding of ANP to ANP receptors.