Rambutan Seeds, containing oleic acid and arachidic acid

Our habit! Crack rambutan open. Suck in the mouth watering flesh, then threw away the seeds and peels.

Imagine it on industry level, canning. They are simply discarded as waste and treated as of no economic value. What a huge waste of resource! Of course, dumped organic materials eventually decay and become fertilizer. However, we want something more than that. Something we can sell for more profit.

Jirawat Eiamwat et. al. (2014) conducted a study on possible toxicity of rambutan seeds. Why?

Taken from their manuscript:

It is a potential source of edible fat, 4-9% of the whole fruit and 14 to 41% of the seed.

Rambutan seed fat is semi-solid at room temperature (25-27°C) and characterized by high levels of oleic acid between 36.8 and 42.0% and arachidic acid between 34.3 and 36.4% (Harahap et al., 2011; Sirisompong et al., 2011; Solís-Fuentes et al., 2010; Yanty et al., 2013). Due to the physical and chemical characteristics, rambutan seed fat may provide an economic advantage with possible utilization in food and cosmetics.

Take that..

Arachidic acid is for production of detergents, photographic materials and lubricants. Oleic acid is a healthy oil known to lower cholesterol levels. It maybe used as salad dressings, on baking and as replacement of animal fat.

The fear of toxicity fear us from using any unproven commodity, especially if it is not a common food for the man. Rambutan is delicious, perfectly edible and safe but we are unsure about the seeds. The usual practice is outright throw. Another example is the guyabano fruit. The flesh is perfectly safe but the seeds in known to have toxic substances. Thanks to its hard shell. I never affects us on accidental ingestion.

Is rambutan seed toxic?

According to their study results, fat and oils are not lethal to rats at levels of 5,000 mg/kg body weight.

Food technologists and Chemists! Grab the opportunity before somebody else do.

Toxicity studies on rambutan (Nephelium lappaceum) seed fat and oil extracts using acute oral, dermal and irritation assays

Jirawat Eiamwat, Sareeya Reungpatthanaphong, Saranya Laovitthayanggoon, Tuanta Sematong, Paramee Pengprecha, Benjaporn Tiensong, Patthanant Natpinit

Are Mahogany Seeds Toxic?

My late grandfather used to chew mahogany seeds regularly. He said it has some health benefits. He failed to discuss the details though.

His seeds reserved were running out so he asked me if I can find some for him. I knew several mahogany trees but they are too high for me to climb. I admit, I am not a good climber. I tried to find fallen fruit but failed.

a whole mahogany fruit

Brother told me that finding a whole fruit on ground was almost impossible. The mature mahogany fruit breaks apart while still attached to tree branches. The light seeds scatter with the help of blowing wind.

After few weeks, grandpa threw away all the mahogany seeds. He heard from news and peers that it is toxic to human.

I did some digging!

Swietenia mahogani Jacquin (Mahogany) is known for treatment of diseases like hypertension, cancer, amebiasis, chest pains and intestinal parasitism. It was reported to be abortifacient  but not supported by any scientific studies. I cannot find any supportive evidence either.

K Bacsal and company, found that mahogany seeds has potential effect on healing gastric ulcers due to phospolipid and long chain unsaturated fatty acid content.

The website mimf.com listed mahogany in their toxic wood list. Mahogany, American: sensitizer/respiratory, eye & skin/small/dust/rare. Mahogany, African: sensitizer/respiratory/great/dust/rare.

According to wilderness-survival.net, all parts of the tree should be considered dangerous if eaten. Its leaves are a natural insecticide and will repel insects from stored fruits and grains. Take care not to eat leaves mixed with the stored food.

Health Benefits of Duhat – Fruits, Bark , Seeds, Roots and Leaves


The black, small, sweet, sour and astringent fruit. Green when unripe. Become red to red-black when rare ripe and full black when fully ripe. The sweetest duhat / plum are those falling on grounds. Sounds crazy but its true. Try staying under the tree and wait for falling fruits.

Read about the health benefits and uses of duhat before going under the tree:

1) Analyses of the fruit show that it is a good source of calcium and fair source of iron.

2) Burkill states that vinegar is made from the juice of the unripe fruit in Malaya. The procedure for duhat wine making is found here. Can also processed to popular products such as jam and juices.

3) Bark contain 19 percent tannin and 1.67 percent garlic acid. Tannin can be useful in protecting kidneys. It also has antiviral, antibacterial and antiparasitic effects. Though intake in large quantities is toxic.

4) Duhat seed was recently suggested in reducing blood sugars of diabetic individuals. It is indeed used in India. The information needs further confirmation. There is no harm in consuming duhat seeds however. Its taste is bland.


5) A boiled bark is a cure for dysentery, diarrhea, enema and ulcers. Can also be used as gurgle. Dried and powdered roots have the same curative effect.

6) The fruit is known to be a remedy for diabetes mellitus (the same as number 4). Leaf and bark juice is also effective alternative. Carminative, diuretic and for head ringworm removal.

7) Leaf extract is an effective poultice – a medical dressing consisting of a soft heated mass of meal or clay that is spread on a cloth and applied to the skin to treat inflamed areas or improve circulation etc.

The side effect: It will make your teeth, gums and tongue dirty – a mixture of violet and blue stain.

benefits are compiled by bureau of plant and industry. image courtesy of wikipedia.

update as of June 2016

Antimicrobial Activity

Study of Venkata Charepalli et al (2016) entitled “Eugenia jambolana (Java Plum) Fruit Extract Exhibits Anti-Cancer Activity against Early Stage Human HCT-116 Colon Cancer Cells and Colon Cancer Stem Cells.

Bioactive compounds in duhat such as anthocyanins have shown potent anti-cancer effects. It selectively inhibit the growth of cancer cells with relatively little or no effect on the growth of normal cells. It clearly demonstrated anti-cancer properties not only against the early stage human colon cancer cells but also induced apoptosis and inhibited self-renewal ability.

Study published by Roja Vilar (February 2016) on Prezi.com, entitled “Anti-bacterial Activity of Duhat Leaves Extract Against Escherichia Coli”.

Duhat extract is effective on inhibiting  the growth of Escherichia coli.