Long-term Consumption of Capsicum annuum (Chili Pepper) and Capsaicin Diets Elevates Anxiety but Improves Motor Coordination in CD-1 Mice

Abstract

Background: Chilli (Capsicum annuum), an extensively cultivated vegetable, is used to spice many dishes. It contains capsaicinoids, which give it a characteristic pungency. The most active and well known amongst these capsaicinoids is capsaicin (8-methyl-N-vanillyl-6-nonenamide), which is neurogenic and may affect neuronal function. Aim: It was hence, the aim of this present study to investigate the effects of long-term consumption of capsaicin and chilli pepper diets on anxiety and motor coordination.  Materials and Methods: Thirty male mice were randomly assigned into three groups of ten mice each, namely; control, pepper-diet (20% w/w) and capsaicin-diet (10%w/w) groups. Drinking water was allowed to all the animals ad libitum. The elevated plus maze and light-dark transition box were used to assess anxiety-related behaviour while the beam walking test was used to determine motor coordination in the mice. Results: The pepper and capsaicin diet-fed groups of mice had significantly shorter (p<0.001 and p<0.01 respectively) open arm durations compared to their control. While the head dips of the pepper group were not significantly different, that of the capsaicin group was significantly higher (p<0.01) compared to the control. The light chamber durations of both the pepper and capsaicin-diet fed mice were significantly shorter (p<0.01) compared to control.  In the beam walking test to assess motor coordination, the frequency of foot slips for both pepper and capsaicin groups were significantly lower compared to control (p<0.001). Conclusion: Long-term consumption of capsaicin and pepper diets increased anxiety but enhanced motor coordination in mice.