Star Fruit

Star fruit (also spelled starfruit) is the star shaped fruit of Averrhoa carambola. Averrhoa carambola is a tree that is native to the Philippines, Indonesia, Malaysia, India, Bangladesh and Sri Lanka. Star fruit is also known as starfruit and carambola.

Antioxidants Found in Juice

Star fruit juice is a very good source of natural antioxidants. Star fruit was found to contain a good quantity of L-ascorbic acid, (+)-catechin, (-)-epicatechin and gallic acid (in the form of gallotannins).[2][5]

(-)-Epicatechin and (+)-catechin are moderate inhibitors of MAO-B enzymes.

(-)-Epicatechin is a potent inhibitor of SULT1A1.

(+)-Catechin is a potent inhibitor of SULT1A3 and an inhibitor of P-Glycoprotein.

Gallic acid induces Estradiol 17beta-dehydrogenase oxidation by 30%.[7] It induces SULT1A1 and SULT1A3.[8] It also inhibits xanthine oxidase and aldehyde dehydrogenase.

Volatile Compounds in Juice

The major volatile components of star fruit were butyl acetate, ethyl decanoate, hexadecanoic acid, l-Phenyl dodecane, l-Phenyl undecane, and cyclohexyl octadecanal.[5]

Amino Acids in Star Fruit

Star fruit was found to contain several amino acids including
glycine, L-alanine, L-serine, L-aspartic acid, L-glutamic acid, L-valine, and proline.[5]

Vitamins in Star Fruit

Star fruit was found to contain L-ascorbic acid (vitamin C) at 28 mg/100 g, and and beta-carotene (a precursor to vitamin A) at 623 μg/100 g. Other vitamins found were thiamine (vitamin B1), niacin (vitamin B3), and riboflavin (vitamin B2).[5]

Vitamin E (α-tocopherol) and vitamin D could not be detected in star fruit.[5]

Acids in Star Fruit

Star fruit contains citric acid, tartaric acid, succinic acid, fumaric acid, oxalic acid, α-ketoglutaric and, and malic acid.[5]

Minerals in Star Fruit

The major minerals in start fruit were found to be potassium 222 mg/100 g) and calcium (41 mg/100 g).[5]

Effects on the Cytochrome P450 Enzyme System

Effects In Humans In Vivo

No human tests have been found. If a test exists please leave us a note about it by using the DISCUSS link at the bottom of this page.

Effects In Rats In Vivo

The metabolism of carbamazepine, a known substrate of CYP3A4, was inhibited by star fruit in rats, indicating that starfruit is a CYP3A4 inhibitor. The inhibition by star fruit juice was recovered within approximately 24 hours. Inhibition appeared to be enteric and not in the liver.[1]

Effects on Alanine Aminotransferase (ALT) in Rats

Star fruit juice prepared and stored for 3 hours and given to rats caused a 38% increase in alanine aminotransferase (ALT, also known as EC However fresh juice or juice stored for 1 hour had no detectable effect on ALT. Despite higher levels of ALT, no other effects on the liver were identified, and the juice showed no evidence of toxicity in the rats tested. The rats behaved normally and did not show any sign of intoxication.[6]

Elevated levels of ALT are sometimes interpreted as possible signs of liver toxicity. However, elevated levels of ALT do not automatically mean there is liver toxicity. In humans fluctuation of ALT levels is normal over the course of the day, and ALT levels can also increase in response to strenuous physical exercise.

Potentially Fatal Reactions In Individuals With Renal failure

Star fruit juice should be avoided by individuals suffering from renal failure. Star fruit juice ingestion has been fatal in individuals suffering from renal failure.[3][4]

1. Drug Metab Dispos. 2006 Mar;34(3):343-5. Epub 2005 Dec 2.
Transient inhibition of cyp3a in rats by star fruit juice. Hidaka M, Okumura M, Ogikubo T, Kai H, Fujita K, Iwakiri T, Yamasaki K, Setoguchi N, Matsunaga N, Arimori K; Department of Pharmacy, Miyazaki Medical College Hospital, 5200 Kihara, Kiyotake-cho, Miyazaki-gun, 889-1692, Japan; PubMed PMID 16326816
2. Analysis of polyphenolic antioxidants in star fruit using liquid chromatography and mass spectrometry.
Shui G, Leong LP. PubMed PMID 14753772
3. Star fruit poisoning is potentially life-threatening in patients with moderate chronic renal failure.
Herbland A, El Zein I, Valentino R, Cassinotto C, Meunier C, Rieux D, Mehdaoui H. PubMed PMID 19360394
4. Fatal outcome after ingestion of star fruit (Averrhoa carambola) in uremic patients.
Chang JM, Hwang SJ, Kuo HT, Tsai JC, Guh JY, Chen HC, Tsai JH, Lai YH. PubMed PMID 10676715
The multiple nutrition properties of some exotic fruits: Biological activity and active metabolites Valery M. Dembitskya, Sumitra Poovarodomb, Hanna Leontowiczc, Maria Leontowiczc, Suchada Vearasilpd, Simon Trakhtenberge, Shela Gorinsteina; Food Research International; Volume 44, Issue 7, August 2011; ISSN: 0963-9969 E-ISSN: 1873-7145
6. Evaluation of the toxic effect of star fruit on serum biochemical parameters in rats
Z. Y. Khoo, C. C. Teh, N. K. Rao, and J. H. Chin PubMed PMCID: PMC2900059 [[bibliography]]
7. Olive oil phenols inhibit human hepatic microsomal activity.
Stupans I, Stretch G, Hayball P. PubChem PMID 10958837
8. Effects of phenolic acids on human phenolsulfotransferases in relation to their antioxidant activity.
Yeh CT, Yen GC. PubMed PMID: 12590501
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