Low molecular weight compounds from Zoanthus sociatus impair insulin secretion via Ca+2 influx blockade and cause glucose intolerance in vivo

► Zoanthus sociatus extract inhibits insulin release. ► Active fraction exhibited molecular weights similar to cnidarians neurotoxins. ► Active fraction diminished high glucose and K+ induced rise of [Ca+2 ]in. ► Active fraction produced glucose intolerance in adult rats.