The invention relates to the use of 1-(4,6-dipentyl-5,6-dihydro-2H-1,2,3-oxadiazin-2-yl)-3-hydroxypropan-1-one in treating and/or preventing infections caused by a bacterium, fungus or virus or in treating and/or preventing cancer. Additionally, the invention relates to a process for obtaining the compound of formula (I) of the invention, said process comprising the steps of cultivating a strain of Dolichospermum sp in an aqueous nutrient medium with assimilable carbon and nitrogen sources and salts, under controlled aerobic conditions, and then recovering the compound of general formula (I) from the culture broth.