Synsepalum dulcificum

Synsepalum dulcificum is a West African plant that produces a red berry commonly referred to as miracle fruit ⁽¹⁾. The berry has been used as a food sweetener and some cancer patients also use it to improve taste changes caused by chemotherapy. The puff of the berries contains a glycoprotein known as miraculin that may alter taste perception from sour to sweet ⁽¹⁾. Preclinical experiments found antioxidant ^{(2) (3)}, antihyperglycemic ⁽¹⁵⁾ and cholesterol-lowering ⁽¹⁶⁾ effects.
In small studies, cancer patients undergoing chemotherapy reported improvements in taste after consuming miracle fruit ^{(6) (12)}. Confirmatory research is needed.

• Low-calorie sweetener
• Alter taste changes caused by chemotherapy

Miraculin is a glycosylated protein ⁽⁷⁾ that acts on the human sweet taste receptor of the tongue (hT1R2, hT1R3). It binds only in acidic conditions, which allows conversion of sour stimuli to sweet ⁽⁸⁾. The effects last 1 to 2 hours, although the intensity declines with time ⁽⁹⁾. Miraculin alters taste in primates but not in rodents ⁽⁸⁾. Maximum taste-modifying activity is observed at pH 3.0, which allows two key histidine residues to facilitate cooperative binding, dimerization and miraculin-to-receptor binding in an acidic environment ⁽¹⁰⁾. Only the dimeric and tetrameric forms of miraculin are active ⁽¹¹⁾. In a weakly acidic environment, miraculin acts as a positive allosteric modulator; at neutral pH, it acts as an antagonist that can inhibit the activity of other sweeteners including sucrose, saccharine and aspartame ⁽⁸⁾. Results from another study suggest that miraculin binds hT1R2-hT1R3 as an antagonist at neutral pH and changes into an agonist at acidic pH ⁽¹³⁾.

Compounds isolated from the stem of S. dulcificum inhibit proliferation of human melanoma cells via free-radical scavenging activity and by inhibiting tyrosinase ⁽³⁾.

• Allergy or sensitivity to any of the constituents.

• Stomach ache and throat discomfort have been reported ⁽⁶⁾.