NutriDex

The Supplement Research Compendium
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Wax Apple

Syzygium samarangense

Crisp, watery tropical fruit rich in polyphenols

Preliminary evidence 🍎Fruits

✚ Updated · How we grade evidence

Evidence tier
Preliminary
Research weight
Citations
8 verified / 8
Classification
Fruits
❝
What the evidence says. Early or small human trials; promising but not yet conclusive.

Nutrition per serving 1 medium (85 g)

85gSERVING
  • Water 79 g93%
  • Sugars 4 g5%
  • Other carbs 0.8 g1%
  • Protein 0.5 g1%
  • Fat 0.3 g0%
What's in one serving, by weight — average composition (USDA).
Vitamin C21%Potassium3%Calcium2%Carbs2%Protein1%Iron0%
One serving as % of the adult daily requirement (FDA Daily Values). The bold outer ring = 100% of a day's needs.
21 kcal0.5 g protein0 g fiber0.3 g fat
NutrientPer serving% daily value
Vitamin C19 mg21%
Potassium105 mg3%
Calcium25 mg2%
Carbs4.8 g2%
Protein0.5 g1%
Iron0.06 mg0%
Fat0.3 g0%
Calories21 kcal1%

Composition data: USDA FoodData Central ↗

What is Wax Apple?

Wax Apple (Syzygium samarangense) is a fruit used for hydration with a very low calorie load (high water content, ~25 kcal/100 g). NutriDex grades the human evidence as Preliminary. Wax apple (Syzygium samarangense), also called java/rose apple or jambu air, is a very watery, low-calorie tropical fruit (~25 kcal/100 g) valued more as a refreshing, hydrating snack than as a dense nutrient source. Laboratory and rodent studies show its leaf and fruit polyphenols (flavonols such as myricetin/myricitrin, C-methylated chalcones, and condensed/ellagitannins) have antioxidant, antihyperglycemic, anti-inflammatory and cytotoxic activities, including protection of pancreatic beta-cells in streptozotocin-diabetic rats and chalcones cytotoxic to colon cancer cells in vitro. Crucially, however, the great majority of evidence is preclinical (in vitro, in silico and animal), and most bioactivity studies use concentrated leaf or seed extracts rather than the edible flesh. There are essentially no controlled human trials confirming clinical benefit from eating the fruit, so health claims remain unproven in people. Nutritionally the fruit provides modest vitamin C (about 22 mg/100 g) and potassium with little protein, fat or sugar. It is a sensible hydrating, lower-sugar fruit choice, but its medicinal reputation rests on early-stage research. Overall weight of human evidence is preliminary.

Purported Benefits

✓Hydration with a very low calorie load (high water content, ~25 kcal/100 g)
✓Antioxidant / free-radical scavenging activity from polyphenols (preclinical)
✓Antihyperglycemic effects and pancreatic beta-cell protection (preclinical, leaf/fruit extracts)
✓Anti-inflammatory activity (preclinical)
✓Source of vitamin C, which supports normal immune function
✓Cytotoxic chalcones with anticancer activity in cell models (preclinical, isolated seed compounds)

Dosing & Compounds

Typical Dose
1-2 fresh fruits (~85-170 g); eaten raw, skin-on
Active Compounds
Flavonols (myricetin, myricitrin, quercetin glycosides such as guaijaverin, kaempferol)C-methylated chalcones (e.g. 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone, cardamonin)Phenolic acids and ellagitannins (incl. ellagic acid derivatives)Flavan-3-ols / proanthocyanidins ((epi)catechin, (epi)gallocatechin gallate)Vitamin C (ascorbic acid)Potassium, with some calciumTriterpenoids and sterols (betulinic/oleanolic-type)Volatile terpenes contributing aroma

Safety & Cautions

Generally recognized as safe as a food and well tolerated when eaten fresh. No established drug interactions from culinary amounts, but the concentrated leaf and seed extracts used in research are not validated for human use and should not be assumed safe at those doses. There is a theoretical additive risk with antidiabetic medication (hypoglycemia) given preclinical glucose-lowering activity, so monitor if consuming large amounts of extract. As with any fruit, wash before eating; people with known Myrtaceae (clove, guava, eucalyptus) sensitivities should be cautious. It is not a treatment for diabetes or cancer despite folk claims. Educational only — always check with your doctor or pharmacist before combining Wax Apple with any medicine.

Key Studies

Narrative review Uddin 2022 ✓ PubMed
Review of the genus Syzygium documents S. samarangense flavonoids, chalcones and tannins with antioxidant, antidiabetic, anti-inflammatory, antimicrobial and cytotoxic activities, noting the predominance of preclinical data.
Analytical / in vitro study Raju 2023 ✓ Source
In the 'Giant Green' cultivar, total phenolic and flavonoid contents were ~37% and ~54% higher in unripe than ripe fruit, correlating with greater antioxidant and alpha-glucosidase inhibitory activity.
In silico + in vivo study Rashied 2022 ✓ Full text
S. samarangense leaf extract reduced serum glucose and lipid peroxides and raised insulin in STZ-diabetic rats; constituents (e.g. anthocyanins) docked strongly to PPARgamma and GLP-1 receptors in silico.
Ex vivo animal study Hassan 2022 ✓ Full text
S. samarangense leaf extract induced endothelium-dependent vasorelaxation in isolated rat thoracic aorta via the NO/cGMP pathway, supporting a potential cardiovascular/antihypertensive mechanism.
Animal study (STZ-diabetic rats) Khamchan 2018 ✓ PubMed
Wax apple fruit extract (100 mg/kg, 30 days) lowered fasting glucose, raised insulin and HOMA-B, and reduced pancreatic beta-cell apoptosis (lower cleaved caspase-3/Bax, higher Bcl-2/Bcl-xl) in STZ-diabetic rats.
In vitro mechanistic study Sobeh 2019 ✓ Full text
Myricitrin and 3,5-di-O-methyl gossypetin isolated from S. samarangense leaves protected human keratinocytes from arsenite-induced oxidative stress; gossypetin activated Nrf-2, inducing HO-1 and Mn-SOD.
Phytochemical / animal study Sobeh 2018 ✓ PubMed
UPLC-MS/MS of the methanol leaf extract identified 92 polyphenols ((epi)catechin-(epi)gallocatechin, EGCG, myricetin glycosides, guaijaverin); the extract showed antioxidant and silymarin-comparable hepatoprotective activity in CCl4-treated rats.
Phytochemical / in vitro cytotoxicity Simirgiotis 2008 ✓ Full text
Three C-methylated chalcones isolated from wax jambu seeds; 2',4'-dihydroxy-6'-methoxy-3',5'-dimethylchalcone was cytotoxic to SW-480 colon cancer cells (IC50 ~10 uM), with the 5'-methyl group key to activity.
8 sources cited · 8 verified Search all studies on PubMed ↗

Common questions about Wax Apple

What is Wax Apple used for?

Wax Apple is most often taken for Hydration with a very low calorie load (high water content, ~25 kcal/100 g), Antioxidant / free-radical scavenging activity from polyphenols (preclinical), Antihyperglycemic effects and pancreatic beta-cell protection (preclinical, leaf/fruit extracts), Anti-inflammatory activity (preclinical). Crisp, watery tropical fruit rich in polyphenols

Does Wax Apple work — what does the evidence say?

Preliminary evidence. Early or small human trials; promising but not yet conclusive. Wax apple (Syzygium samarangense), also called java/rose apple or jambu air, is a very watery, low-calorie tropical fruit (~25 kcal/100 g) valued more as a refreshing, hydrating snack than as a dense nutrient source. Laboratory and rodent studies show its leaf and fruit polyphenols (flavonols such as myricetin/myricitrin, C-methylated chalcones, and condensed/ellagitannins) have antioxidant, antihyperglycemic, anti-inflammatory and cytotoxic activities, including protection of pancreatic beta-cells in streptozotocin-diabetic rats and chalcones cytotoxic to colon cancer cells in vitro. Crucially, however, the great majority of evidence is preclinical (in vitro, in silico and animal), and most bioactivity studies use concentrated leaf or seed extracts rather than the edible flesh. There are essentially no controlled human trials confirming clinical benefit from eating the fruit, so health claims remain unproven in people. Nutritionally the fruit provides modest vitamin C (about 22 mg/100 g) and potassium with little protein, fat or sugar. It is a sensible hydrating, lower-sugar fruit choice, but its medicinal reputation rests on early-stage research. Overall weight of human evidence is preliminary.

What is the typical dose of Wax Apple?

1-2 fresh fruits (~85-170 g); eaten raw, skin-on

Is Wax Apple safe? Any cautions or side effects?

Generally recognized as safe as a food and well tolerated when eaten fresh. No established drug interactions from culinary amounts, but the concentrated leaf and seed extracts used in research are not validated for human use and should not be assumed safe at those doses. There is a theoretical additive risk with antidiabetic medication (hypoglycemia) given preclinical glucose-lowering activity, so monitor if consuming large amounts of extract. As with any fruit, wash before eating; people with known Myrtaceae (clove, guava, eucalyptus) sensitivities should be cautious. It is not a treatment for diabetes or cancer despite folk claims.

How many studies support Wax Apple?

NutriDex cites 8 sources for Wax Apple, graded "Preliminary".

Cite this page
APA

Peh, D. (2026). Wax Apple (Syzygium samarangense): Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/wax-apple

BibTeX
@misc{nutridex_wax_apple,
  author       = {Peh, Daryl},
  title        = {Wax Apple (Syzygium samarangense): Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/wax-apple},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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