Potential of Amara extract, a preparation of nine herbal extracts, in alleviating opioid-induced constipation

Opioids such as morphine and codeine are analgesic drugs, but their therapeutic value is limited due to side effects, particularly opioid-induced constipation (OIC) [ 1 ]. Morphine inhibits intestinal motility by targeting μ-opioid receptors [ 2 ]. While some μ-opioid receptor antagonists treat OIC, they often cause adverse effects like diarrhea [ 3 ]. Herbal remedies have shown promise in alleviating OIC symptom. Previous studies have demonstrated that the extract of Amara-Drops (Amara extract), a preparation containing nine herbal extracts traditionally used for gastrointestinal dysmotility, binds and inhibits μ-opioid receptors (IC 50 : 109 and 202 μg/mL, respectively). Further research was needed to explore its therapeutic potential in OIC in vivo . Studies were conducted in ICR mice, with Amara extract (400 mg/kg) or vehicle administered by oral gavage (PO) 30 minutes before morphine (10 mg/kg) or vehicle. At 60 minutes post-morphine, the animals received a PO suspension of 5% charcoal in 10% gum Arabic solution and were sacrificed 15 minutes later. The intestines were removed, and the extent of charcoal movement was measured. Morphine significantly (p