Work

Kratom (Mitragyna speciosa) alkaloids influence on cardiopulmonary measures and high-fat diet-induced weight gain in mice

Year: 2026

Type: article

Abstract: Kratom (Mitragyna speciosa) has been marketed and used for a variety of health-promoting applications, some related to metabolic health. Kratom contains an expansive bioactive alkaloid profile with mitragynine (MTG) as the most abundant. Individual responses to kratom have been reported, but the role of obesity as a factor influencing the effects of kratom has not been studied. To standardize the kratom preparation, we used a kratom alkaloid-enriched methanolic extract (KE). First, we determined the cardiopulmonary differences with KE (290, 500 mg/kg) and matched MTG (18 mg/kg) in high-fat diet (HFD; 45% Fat) induced obese male C57Bl/6J mice. As measured by whole-body plethysmography, acute oral dosing revealed an approximate 15% reduction in the respiratory rate with all doses of KE and MTG. Unlike a well-known respiratory depressant, alprazolam, KE and MTG did not reduce minute ventilation (MvB; ml/min). As measured by volume-pressure recordings, KE 500 mg/kg produced an approximate 12% reduction in heart rate in normal weight mice. Second, we determined whether daily oral dosing KE (50, 150 mg/kg) prevented HFD-induced weight gain. Daily 150 mg/kg resulted in an increase in body weight gain (~1 g) in the last week after 21 days of dosing. After 4 days following kratom cessation, there was reduced distance traveled in the KE 150 mg/kg compared with the KE 50 mg/kg group in an elevated plus maze test. These findings demonstrate a dose-dependent-increase in weight gain with KE, suggesting further investigation is needed to delineate kratom alkaloid effects on metabolism and body weight control.

Source: Physiology & Behavior

DOI: 10.1016/j.physbeh.2026.115231