Antioxidant and hypoglycaemic activities and their relationship to phytochemicals in Capsicum annuum cultivars during fruit development

Four Capsicum annuum L. cultivars (Fiesta, Acuminatum, Orange Thai, and Cayenne Golden) werestudied at two stages of fruits ripening (immature and mature) for total phenols, flavonoids,carotenoids, capsaicin and dihydrocapsaicin content and for their antioxidant and hypoglycaemicactivities. Phenols content reached their maximum concentration in immature fruits and thendeclined, while carotenoids and capsaicinoids concentration increased as the peppers reachedmaturity. The antioxidant activity was elucidated by DPPH andbeta-carotene bleaching tests. Exceptfor Cayenne Golden cultivar, the immature fruits showed the highest radical scavenging activity.On the contrary, the antioxidant activity evaluated by the beta-carotene bleaching test showed asignificant activity for mature peppers. The Cayenne Golden cultivar showed an IC50 value of 2.5microg/ml after 30 min of incubation. Hypoglycaemic effects were examined in vitro via the inhibitionof alpha-amylase and alpha-glucosidase enzymes. Fiesta, Orange Thai, and Cayenne Golden cultivarsshowed the highest inhibitory activity on alpha-amylase in the immature stage. The lipophilic fractionexhibited a selective inhibitory activity against alpha-amylase with IC50 values ranging from 9.1 microg/mlto 28.6 microg/ml in the immature stage. The study proposes the nutritional significance of consumingC. annuum raw peppers at both maturity stages because of interesting properties.