Overview

The incorporation of many fruits and vegetables into one's daily diet has long been associated with improved overall health and disease prevention. However, some fruits are less well known for their disease-fighting properties than others. This includes the Salacca Zalacca fruit, commonly known as “Salak”, which is a tropical fruit native to Indonesia and grown commonly throughout Asia.

The fruit grows in clusters at the base of the salak tree and the outermost layer appears reddish-brown and scaly, resembling the skin of a snake and giving this fruit its other nickname, “snake fruit”. These fig-sized fruits have a very healthy nutrient profile with high levels of fibre, essential vitamins and minerals. The snake fruit also contains many natural bioactive compounds which may hold potential disease-fighting abilities. 

Research on natural compounds

Natural or bioactive compounds, such as those found in the snake fruit, have diverse chemical structures that have the potential to be converted into novel drugs for disease treatment.¹ The drug discovery potential of natural products has led to a rising interest in plant-based therapeutics in recent years.² Natural products are not only more structurally diverse than synthetic products, but they have often been selected by evolution to be advantageous to human defence systems and can provide novel insights into disease-fighting mechanisms in this way.³ These natural compounds therefore have the potential to aid the development of effective disease treatments. 

Bioactive compounds and nutrition profile of snake fruit

According to organic facts, snake fruit has a rich nutrition profile and 100 grams of it contains:

• Calories: 82
• Carbohydrates: 21.7 grams
• Dietary fibre: 2.6 grams
• Protein: 0.6 grams
• Fats: 0.1 grams
• Vitamin C: 8.4 milligrams
• Iron: 0.6 milligrams
• Potassium: 400 milligrams.

Phytochemical analysis of the pulp from ripe snake fruit has also shown the presence of many bioactive compounds including phenolic compounds such as polyphenols, flavonoids and tannins as well as various vitamins and minerals such as vitamins C, A and E and high levels of potassium.⁴ Pharmacological studies have revealed that these bioactive compounds in both the skin and the pulp of the fruit have great potential to fight many diseases such as cancer and diabetes while also decreasing inflammation in the body by acting as antioxidants.⁵ These bioactive compounds have been linked to combatting several diseases, indicating that the fruit contains:

• Antioxidant properties
• Anti-inflammatory properties (and consequently anti-arthritic capabilities)
• Anti-diabetic properties
• Anti-cancer effects
• Neuroprotective effects 
• General immune boosting capabilities

Antioxidant properties

Antioxidants protect the body from damage by neutralising free radicals. Free radicals cause damage to DNA and other cell parts by attempting to steal electrons in order to complement their own. Antioxidants prevent this from occurring by donating their own electrons instead and sufficient antioxidants are recommended to be consumed daily in a diet to combat oxidative stress.⁶ Through this protection, antioxidants play a vital role in preventing damage-induced diseases such as cardiovascular disease, cancer and anaemia.⁷

Snake fruit antioxidants 

The high phenolic compound content in snake fruits is made of many polyphenols such as flavonoids and tannins. These compounds as well as the high levels of vitamin C in the fruit act as electron scavengers to provide high antioxidant activity.⁴ Both in vitro and in vivo studies have confirmed snake fruit’s high antioxidant activity. Using mass spectrometry, the fruit was found to contain 257.17 μL/mL phenolic content and 10.56 μM TE/g antioxidant activity which are both significantly high.8 An experiment comparing snake fruit to another nutritionally rich tropical fruit called mangosteen by supplementing rat’s diets with both fruits. This study found that over 4 weeks snake fruit increased antioxidant activity to a much higher degree than the mangosteen fruit.⁹

In addition to mangosteen, snake fruit has a higher antioxidant content than many other antioxidant-rich tropical fruits such as avocado, orange, apple, kiwi, melon, banana and watermelon.¹⁰ Overall, snake fruit provides a rich source of antioxidants that are crucial within a diet to counteract the onset of many chronic diseases.

Anti-inflammatory effects

Moreover, an additional benefit of the phenolic compounds found in snake fruit is that they possess anti-inflammatory effects on the body which could serve to reduce symptoms of diseases such as arthritis.¹¹ Snake fruit was also shown to play a crucial role in regulating uric acid levels in the blood. High uric acid buildup can cause hyperuricemia which causes a painful form of arthritis called gout.⁴ A phytochemical found in snake fruit, 2-methyl ester-1-H-pyrrole-4-carboxylic acid, was found to inhibit xanthine oxidase which causes the buildup of uric acid. Through this inhibiting activity, snake fruit is able to help keep uric acid levels within their normal range and prevent hyperuricemic activity.⁵

Anti-diabetic effects

Dyslipidaemia, where glucose is unable to provide energy to the body, is a common feature of diabetes mellitus (type 2 diabetes). The body attempts to provide energy through lipolysis (break down of fats) but this leads to an increase in fatty acids and cholesterol which greatly increase the rates of disease development such as cardiovascular diseases.¹² The aforementioned study where rat’s diets with supplemented with snake fruit also demonstrated that this fruit combatted the rise of plasma lipid content which supports the fruit’s ability to lessen the effects of dyslipidemia.

Vinegar was also prepared using snake fruit extracts and was found to lower glucose and cholesterol levels in rats through its high polyphenol content.¹² Lastly, the snake fruit-infused vinegar was also found to be able to rescue damaged pancreatic cells in diabetic rats.¹³ Collectively, the studies signify the overall positive potential of snake fruit in counteracting the damage induced by type 2 diabetes as well as function to generally promote glucose regulation. 

Anti-cancer effects 

Cancer is one of the leading global causes of mortality worldwide and chemotherapy is a standard treatment that has many associated negative side effects such as hair loss, appetite dysregulation and fertility issues. However, many plants have been shown to possess powerful anti-cancer effects without harbouring the negative side effects.⁵

A study comparing the pulp, seeds and peels of 61 different fruits on four cancer cell lines was investigated and snake fruit was found to have a powerful anti-prolific effect.¹⁴ Snake fruit therefore showed great potential to counter the onset of lung, breast, colon and liver cancer which are some of the most common forms of cancer worldwide. 

Neuroprotective effects

Snake fruit has also coined yet another nickname as the “memory” fruit. It has high levels of beta-carotene, potassium and pectin which all act to increase blood flow to the brain and prevent the onset of neurodegenerative disorders such as Alzheimers.⁴ In general, the onset of Alzheimer's is quickened by increases in oxidative stress which is when levels of antioxidants are too low to combat free radicals in the body.¹⁵ Snake fruit’s aforementioned high antioxidant content can help to combat this high oxidative stress and further fortify against neurodegeneration. 

Immune system boost

In general, increasing daily intake of fruits and vegetables is recommended to boost the immune system and help combat common everyday diseases. Vitamin C, which snake fruit is particularly high in comparison to other fruits, is a key vitamin to build a strong immune system.¹⁶ A study on snake fruit also showed that it has the power to stimulate macrophages in the body.¹⁷ Macrophages function to eliminate foreign, disease-causing substances, and are a crucial part of the immune response. Therefore, snake fruit has the potential to boost the immune system in general and combat the onset of everyday diseases. 

FAQs

Where can I find snake fruit?

Snake fruit is common and inexpensive in most parts of Asia including Indonesia, Malaysia, Thailand and the Philippines. However, the fruit is gaining popularity in Europe and North America and is sometimes available through import in exotic food markets.¹⁸

How to eat snake fruit?

The fruit contains an inedible seed and the recommended way to consume it is to peel the edible but tough outer peel and consume the pulp inside. The fruit has a sweet and citrusy flavour and can be enjoyed in many forms such as on its own, in fruit salads, as a dried snack or as a jam. It can also be eaten as a part of the traditional Indonesian dish, Rujak salak. 

Are there any side effects to consuming Snake fruit?

Snake fruit is beneficial and healthy when eaten in moderate amounts. However, due to its high fibre content, eating excessive amounts of snake fruit may result in indigestion and general stomach issues and is cautioned against. Additionally, if pregnant, it is recommended to consult with a doctor prior to adding snake fruit to your diet. 

Summary 

Snake fruit is an incredibly beneficial fruit that is encouraged to be consumed, in moderation, as a part of an everyday diet. It has an impressive nutritional profile with a low overall caloric impact and high levels of fibre. Moreover, the fruit has much disease-fighting potential and strengthens the body through its high antioxidant and vitamin C levels and general immune-boosting activity. It also has the potential to regulate diabetes, combat cancer formation and protect against memory loss associated with neurodegenerative disorders. Overall, snake fruit strengthens both innate immunity against diseases and has the potential to protect the body against chronic diseases.