Isolation of I-Quinic Acid in Citrus Fruit

The Carbohydrates in the Peel of Oranges and Grapefruita

“…Swift and Veldhuis also found that the peel juice had higher ash content than the segment juice, but concluded that the difference was not enough to account for the higher non-sugar solids unless the salts involved acids of very high molecular weight. The major organic acid in the peel is L-quinic (Ting and Deszyck, 1959)) which has an equivalent weight nearly three times that of malic or citric acids. Sinclair and Crandall (1949) and Sinclair and Jolliffe (1960) found that total sugar accounted for about 60r0 of the total alcohol-soluble solids in grapefruit peel, and for 55.4 and 72.7% in the peel of Valencia and navel oranges, respectively.…”

History, Global Distribution, and Nutritional Importance of Citrus Fruits

“…The soluble portion largely contains mono‐ and disaccharides, nonvolatile organic acids, amino acids, and other minor components, and the insoluble fraction primarily consists of cell structure polysaccharides, which establish the nature and profiling of citrus carbohydrates (Sinclair and Jolliffe 1960). Sucrose, glucose, and fructose, with a general ratio of 2:1:1, represent the major components of citrus fruit carbohydrates and hold the key to sweetness of the juice (Bartholomew and Sinclair 1943; Curl and Veldhuis 1948; McCready and others 1950; Ting and Attaway 1971). The ratios of sucrose to other reducing sugars tend to fluctuate with various stages of maturity and different varieties, and to decrease in the acidic environment with long‐term storage (Ting and Attaway 1971; Chan and Kwok 1975; Kuraoka and others 1976; Daito and Sato 1985; Table 4).…”

“…Sucrose, glucose, and fructose, with a general ratio of 2:1:1, represent the major components of citrus fruit carbohydrates and hold the key to sweetness of the juice (Bartholomew and Sinclair 1943; Curl and Veldhuis 1948; McCready and others 1950; Ting and Attaway 1971). The ratios of sucrose to other reducing sugars tend to fluctuate with various stages of maturity and different varieties, and to decrease in the acidic environment with long‐term storage (Ting and Attaway 1971; Chan and Kwok 1975; Kuraoka and others 1976; Daito and Sato 1985; Table 4). Depending on the specific fruit, total sugar content in the juice could range from lower than 1% in some limes to as high as 15% in some oranges (Ranganna and others 1983).…”

Discovery of Quinic Acid Derivatives as Oral Anti-inflammatory Agents

“…6 The structure and the stereochemistry of QA were assigned in 1932 by H. O. L. Fisher and G. Dangschat. 7 QA is a natural compound found widely in plants, [8][9][10] such as in cinchona bark, particularly in South American barks; also largely in apple, peach, and rose tissue. 11,12 Derivatives of QA, such as chlorogenic acid (CGA) ( Figure 1-1), p-coumaryl quinate, etc., are also common in plants.…”

“…Quinic acid (QA) is a natural compound found widely in plants. [8][9][10] Recently, QA has been identified as an active ingredient in hot water extracts of the herbal Cat's claw (e.g., C-MED-100  ), and shown to enhance immune cell response and DNA repair in humans. [3][4][5] In particular, such extracts have been found to have various anti-inflammatory effects such as inhibition of the production of the inflammatory cytokine TNF, scavenges free radicals 45 and the activation of the central transcription factor nuclear factor κB (NF-κB).…”