Star fruit ( Averrhoa carambola L . ): Exploring the wonders of Indian folklore and the miracles of traditional healing

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INTRODUCTION
In recent decades, there has been a significant shift in people's attitudes towards the modern medicinal system.Many individuals have become increasingly interested in exploring ancient healing systems such as Ayurveda, Siddha, and Unani.This shift is primarily driven by concerns about the adverse effects associated with synthetic drugs used in modern medicine.As a result, herbal drugs are gaining prominence and are seen as vital components of health care programs, especially in developing countries (Kamboj, 2000).Alternative medicine is not widely accepted in developed nations because of poor documentation and strict quality control.Properly documenting research on traditional medicines is crucial to build trust and integrate these practices into mainstream healthcare (Kirtikar & Basu, 2005).For traditional medicines India is one of the ancient heritages, and for folklore customs and conventional characteristics of medicinally significant secondary metabolites.India provides Materia medica with full of information.Materia medica of India provides approximately 2000 natural origin drugs list which are the derivatives of folklore and traditional systems.For the discovery of new pharmaceuticals historically natural products and plants that originated from higher plants played a pivotal role (Gupta et al., 2001;Mukherjee, 2002).According to WHO (World health organization) eighty percent people of developing countries depend on traditional remedial system for their primary healthcare system (Chopra & Nayar, 1956;Gupta & Gupta, 2020).Around the world, 21000 plants species are used medicinally and in India around 2500 plant species are used indigenously (Yadav et al., 2006).About 400 families of flowering plant, out of which 315 are represented by India (Jain et al., 2006).
The plant Averrhoa carambola L., commonly known as star fruit or "Kamarakh," belongs to the Oxalidaceae family and is native to Malaysia.Its distinct star-shaped appearance is matched by its delightful sweet and sour flavor (Warrier, 1993).The Sanskrit term "Karmaranga" is derived from "carambola," signifying a culinary appetizer.A. carambola is a hardy, drought-resistant tree known for its longevity (Manda et al., 2012).It holds significant commercial value in India due to its versatile applications and the delectable nature of its fruit (Warrier, 1993).While the unripe fruit is employed as a vegetable, ripened fruits find their way into various forms such as jams, jellies, fermented and non-fermented beverages, and desserts (Patil et al., 2010).
Considering the potential of ethnobotany in future medicinal applications, A. carambola is gaining substantial attention.Various parts of the tree have been utilized in traditional folk medicine.Additionally, it serves as a rich source of essential nutrients including copper, potassium, folate, and pantothenic acid.The level of ascorbic acid in a ripe fruit is a determining factor for its taste, whether sweet or tart (Manda et al., 2012).

BOTANICAL STUDY 2.1. Averrhoa carambola (Oxalidaceae): Herbal Plant
The fruit scientifically known as Averrhoa carambola goes by various names in different languages.In English, it is commonly referred to as Star fruit or simply carambola.In Hindi, it is known as Kamrakh or Karmal, in Myanmar known as mak-hpung, zaung-ya while in Malay and Indonesia, it is called Belimbing.In Sanskrit, it is referred to as Karmaranga, in Bengali as Kamranga, and in Gujarati as Kamrakh.In Marathi, it is known as Karambal, and in Tamil, it goes by Thambaratham or Tamarattai (Nandkarni, 1976;Orwa et al., 2009).Star fruit, scientifically known as Averrhoa carambola, belongs to the Plantae kingdom, which encompasses all plants.It falls under the category of vascular plants (Tracheobionta), indicating that it has specialized tissues for conducting water and nutrients.Further classification places it in the Spermatophyta division, denoting plants that produce seeds.Within this division, it is categorized as an Angiospermae, signifying that it produces flowers and encloses its seeds in fruits.In terms of class, star fruit is classified as Magnoliopsida, which refers to a class of flowering plants.This class includes a wide range of familiar plants like roses, peas, and sunflowers.Within the order Oxalidales, star fruit finds its place.This order includes various families of plants, one of which is the Oxalidaceae family to which star fruit belongs.Oxalidales is a diverse order that encompasses several different plant families, each with its own unique characteristics.
Finally, within the genus Averrhoa, star fruit is identified by the species name carambola L., specifically referring to the carambola variety (Avinash et al. in 2012).

Botanical Description with Habitat and Distribution
A. carambola is a tiny, slow-growing, evergreen tree that grows to a height of 3-16 m.The leaves of A. carambola are alternating, spirally organised, and range in length from 15 to 25 cm.The under side of leaves is quite pale in colour, while the upper side is smooth and greenish.Leaves at night incline and curl but most active in daylight, so delicate to sudden jolt.Surface of leaves are glabrous, acute type of apex and base is oblique with characteristic taste and odor (Kirtikar & Basu ,1987;Dasgupta et al., 2013).Clusters of small, six-millimetre-wide flowers, crimson in color with purple-red hues, often reveal a delicate hint of pink or white on their backside.These blooms form tight clusters along the leaf axis, creating a visually stunning display.(Avinash et al., 2012).The versatile A. carambola fruits are both edible and multifunctional.These fruits are fleshy and start off as light green when unripe, transitioning to an orangish-yellow hue upon maturity.Their brown seeds are contained within a 5-6 edged, star-shaped cross-section, spanning 5-15 cm in length.With a crisp, waxy texture, their taste spectrum ranges from sour to sweet, emitting a fragrance reminiscent of oxalic acid shown in Figure 1 (Dasgupta et al., 2013).For centuries, A. carambola has been cultivated in Malaysian and various Southeast Asian nations.Originating from Ceylon and the Moluccas, this fruit has thrived and spread across these regions (Morton, 1987).This annual herbaceous plant is generally full-fledged in the warmer parts of India, Bangladesh, Brazil, Philippines, China, Malaysia, Indonesia, Israel, Florida, Thailand, Taiwan, Australia, and other divisions of world with similar climate (Ghani, 1998).It can tolerate wider range of climate and survive in both the subtropical countries and hot tropical areas together with Israel and Egypt and freezing temperatures as low as −3° C can tolerate.Ideally, they grow in humus rich soil with acidic pH range but also withstand with pH range of 8.5 also (Bircher & Bircher, 2000).

TRADITIONAL AND POTENTIAL BENEFITS 3.1. Conventional Practices of A. carambola
For millennia, A. carambola has been employed in traditional medicine for a diverse range of ailments.This medicinal plant encompasses various components-roots, leaves, stems, fruits, flowers, and seeds-each offering distinct therapeutic properties in different regions such as Malaysia, Brazil, India, and China.
In India, the juice and ripe fruits of A. carambola have been used to address scurvy, boost appetite, act as an astringent, stimulate saliva production, alleviate fever, treat hemorrhoids, relieve thirst, and act as a purgative (Vasant & Narasimhacharya, 2014;Sheth, 2005).
Meanwhile, in Brazil, the ripe fruit is employed for urinary concerns, serving as a diuretic for bladder and kidney-related issues, and proving useful in managing hypertension and diabetes (Soncini et al., 2011).Sri Lanka recognizes A. carambola for its remarkable hypoglycemic effects, employing it in diabetes prevention (Abeysekera et al., 2015;Herbal Medicine Research Centre, 2002).In Malaysian traditional medicine, the fruit serves as a febrifuge, addresses recurrent aphthous ulcers, acts as an emetic, and aids in chest pain relief (Yang et al., 2020).Additionally, its leaves are utilized for treating ringworm, chickenpox, and headaches (Pang et al., 2017).
In Chinese medicine, ripe A. carambola fruits are employed for countering food poisoning from flesh consumption and for addressing an enlarged spleen (Carolino et al., 2005).They are also used to manage conditions like jaundice, diarrhea, throat infections, inflammation, toothaches, rashes, and strokes.Moreover, in women, it is utilized to stimulate milk secretion and, when the dosage is increased, to promote menstrual discharge.It is also known to enhance sexual desire in both males and females (Sung et al., 1998).Simultaneously, star fruit leaves find application in improving diabetes mellitus, alleviating emesis, addressing coughs, countering hangovers, and managing headaches (Ferreira et al., 2008;Thomas et al., 2008).Regarding the use of seeds, crushed seed decoctions are utilized to stimulate milk production, acting as a galactagogue.For colic pain and asthma, powdered seeds are applied.In Southeast Asia, A. carambola flowers are beneficial for skin inflammation and are also used as febrifuges, vermifuges, and for addressing malaria (Sheth, 2005;Sung et al., 1998).

Star Fruit Benefits as Food
There are numerous advantages and uses of A. carambola as a food.In different countries it has different uses from various parts of plant like flowers and leaves having sour and delicate taste unless used as salads.Due to its exotic flavor and unique shape, A. carambola finds application in crafting beverages and enhancing pastry presentations.Ripe, fresh fruit serves as a base for alcoholic drinks, achieved by fermenting it with Saccharomyces cerevisiae yeast.This yeast naturally converts the fruit sugars into alcohol and CO2 during a five-day fermentation process at 25°C, resulting in the creation of fruit wine (Napahde et al., 2010;Valim et al., 2016).Asian peoples used these fruits in different ways in cooking as sausages to cakes and jams to sauces while population of Malaysia generally prepare a sauce by boiling the fruit with sugar, cloves, and apples.Similarly Thai people used unripe fruit boiled with shrimp but the Chinese's people cooked the fish with the fruit.Also, in Taiwan and China star fruit is cut into strips and exported in boxes (Roopa et al., 2014).Even star fruit juice is used as energizing drinks or for its sour taste and also as condiments in dishes of fish.From the juice of star fruit an excellent frozen dessert can also be prepared by mixing the gelatin, sugar in the juice and kept its mixtures at low temperature for few hours (Ferrara, 2018).The unripe fruit serves as a key ingredient in jam-making, undergoing a process of marination with salt and vinegar, followed by maceration in honey overnight.After this, it is briefly cooked, transforming into jam, ready to be preserved in sterilized, sealed jars (Prati et al., 2002).

CHEMICAL COMPOSITION AND PHARMACOLOGICAL ACTIVITIES 4.1. Significant Phytochemical Constituents of A. carambola
When A. carambola analyzed for their phytochemical screening it showed the presence of alkaloid, phenylpropanoids, terpenes, saponins, phenols and flavonoids too.(Thomas et al., 2008).In the fruit major sterols found are, lupeol (a), Isofucosterol (b), β-sitosterol (c), and campesterol (d) apart of these sterols four major plant fatty acids are foundlinolenic acid (e), linoleic, oleic and palmitic acid (f).(Gupta & Gupta, 2020;Nordby & Hall, 1979) The fruit edible portion is found to be rich source of dietary fibers, pectin, cellulose, reducing and nonreducing sugars, minerals, calcium, phosphorous, hemicellulose and carotenoid compositions (Tiwari et al., 1979).The A. carambola fruit also includes gallic acid in gallotannin form, epicatechin (g), proanthocyanidins and L-ascorbic acid.Till now approximately 132 compounds are extracted and identified from A. carambola (Shui & Leong, 2004).Some of the extracted compound structures from A. carambola are shown in Figure 2.

Terpenes
Terpenes are also called isoprenoids as isoprene is the building blocks of terpenes and it is found as the secondary metabolites in plants and specifically used for fragrances and pigmentation for plants, vegetables and fruits but apart from this, having lots of medicinal properties (Bahramsoltani et al., 2020;de Paulo Farias et al., 2020).About 29 terpenes have been identified and separated from A. carambola fruits using various spectroscopic techniques.The major terpenes found were cis and trans-abscisic acid (h), cis and trans-abscisic alcohol β-D-glucopyranoside, cis-abscisic alcohol β-D-glucopyranoside (6S,9R)-roseoside, and vomifoliol (i) (Gunawardena et al., 2015).Apart from this two components C13-and C15norisoprenoids derived from A. carambola of terpenes massively intensify the flavor of fruits (Jia et al., 2019).

Flavonoids
Flavonoids have its place in class of natural products specifically as plant secondary metabolite with polyphenolic structures.Maqsood et al. (2020) identified a flavonoid in A. carambola that exhibits excellent pharmacological action, primarily in the area of radical scavenging and antioxidant activity, making it effective for the treatment or prevention of heart problems.From different organs of A. carambola plants like roots, leaves, fruits and stems around 51 flavonoids were isolated and characterized via various spectroscopic techniques viz Mass spectrometry (MS) and Nuclear magnetic resonance (NMR).Among these 51 compounds some are dihydrochalcone C-glycosides-Carambolaside R1-R3, Carambolaside A-H, Carambolaside I, Ia, Carambolaside J, Ja, Carambolaside M-Q, Carambolaside T1-T3, 3-Hydroxycarambolaside T1, Carambolaside S1-S2, 3-Hydroxycarambolaside P (Abeysekera et al., 2015;Jia et al., 2019;Yang et al., 2015) and other agents which exhibited radical scavenging activity against ABTS  (Cazarolli et al., 2009;Cazarolli et al., 2012).

Potential Medicinal Benefits of A. carambola
The A. carambola plant holds immense medicinal potential, showcasing a wide array of benefits such as anti-inflammatory, hepatoprotective, antimicrobial, antioxidant, neuroprotective, and antitumor activities, among others, as illustrated in Figure 3.In both Ayurvedic and Traditional Chinese Medicine (TCM), A.carambola is valued for its diverse medical advantages, addressing conditions such as coughs, dermal fungal infections, eczema, severe headaches, and diarrhea (Wang et al., 2016;Patel et al., 2015).

Antitumor activity
Various studies have shown that an alcoholic extract from the stems of A. carambola was used against brain tumour cells, while an extract from the leaves was more effective against liver cancer cells (Tadros & Sleem, 2004).Methanol extract of A. carambola leaves (MEACL) at the dose of 25 and 50 mg/kg, i.p. once a day for 5 days substantially decreases the viability of cell and weight of the body, progressive change in hematologic estimations (Hgb, White Blood Cells, Red Blood Cells) and prolongs survival time in Ehrlich ascites carcinoma (EAC) cellbearing mice (Siddika et al., 2020).

Anti-inflammatory activity
One study stated that A. carambola leaf ethanolic extract and butanol, ethyl acetate, and hexane fractions showed beneficial effects to diminishing the induced ear edema by croton oil and cellular migration in animal (Cabrini et al., 2011;Soncini et al., 2011).In another investigation, aqueous extract of A. carambola inhibited carrageenan-induced rat paw inflammation when given intraperitoneally.At the same time stem extract of A. carambola stated the bactericidal activity against Streptococcus aureus (Sripanidkulchai et al., 2002).

Hypoglycemic effect
A. carambola has demonstrated the potential to lower blood sugar levels.This effect was attributed to specific types of dietary fiber found in the fruit, including those that are not soluble in alcohol or water.These fiber-rich fractions were isolated from the leftover pulp of A. carambola (Chau et al., 2004).In a different study, it was found that the ripe fruit pulp of A. carambola had a hypoglycemic effect in healthy male Sprague Dawley rats.This effect was observed after an 8-week treatment period, specifically in comparison to the control group of normal rats (Dasgupta et al., 2013).This suggests that regular consumption of ripe star fruit may help regulate blood sugar levels.

Antimicrobial activity
In a study using the disc diffusion method, researchers investigated the antimicrobial properties of the A. carambola plant.They found that various extracts from the bark of A. carambola including petroleum ether, carbon tetrachloride, chloroform, aqueous soluble fractions, and methanolic extract were effective in inhibiting the growth of both gram-positive and gramnegative bacteria as well as fungi.The potency of these extracts varied depending on their concentration, with the lowest concentration (0.78125 μg/ml) showing the highest effectiveness and the highest concentration (400 μg/ml) exhibiting the lowest.Notably, the carbon tetrachloride soluble fraction of the methanolic extract demonstrated the most promising antimicrobial activity.This suggests that A. carambola extracts, particularly from the methanolic fraction, have potential as natural antimicrobial agents against a range of microorganisms (Mia et al., 2007).

Antioxidant activity
In a study assessing antioxidant capabilities through various tests like ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH), vitamin C content, total phenolic content, and total flavonoid content, A. carambola ranked as the third most potent antioxidant among 20 commonly available fruits in Sri Lanka (Silva & Sirasa, 2018).Furthermore, when the methanol extract of A. carambola leaves (MEACL) was tested at concentrations ranging from 50 to 375 μg/mL, it displayed a dose-dependent moderate antioxidant effect in both DPPH and ABTS+ assays.The IC50 values, which indicate the concentration required to achieve a 50% reduction in activity, were measured at 62.0 μg/mL for DPPH and 6.0 μg/mL for ABTS+.This signifies that the leaf extract of A. carambola holds promising antioxidant properties (Siddika et al., 2020).Azeem et al. (2010), in their study, investigated the impact of A. carambola fruit extract on liver damage induced by carbon tetrachloride.The results showed a significant decrease in serum levels of enzymes ALT, AST, and ALP, indicating improved liver function.Additionally, the levels of liver-reduced glutathione significantly increased 24 hours after administering carbon tetrachloride, indicating enhanced antioxidant activity.In another research conducted by Huang et al. (2019), mice with acute liver injury were treated with A. carambola root extract for seven days.The study found that the treatment led to lower levels of enzymes associated with liver damage (AST and ALT), reduced levels of inflammatory markers (IL-1 and IL-6), and decreased levels of malondialdehyde (MDA) in the liver.Conversely, levels of antioxidants like superoxide dismutase (SOD), Glutathione (GSH), and plasma glutathione peroxidase (GSH-Px) were elevated.At the molecular level, proteins involved in inflammation and cell death were downregulated, suggesting a protective effect.

Hepatoprotective activity
In their study Pang et al. (2017) investigated the impact of A. carambola free phenolic extract (ACF) on hepatic steatosis in mice deficient in the leptin receptor (db/db mice).After eight weeks of ACF administration, the content of liver triglycerides (TG) significantly decreased compared to the control group.The treatment worked in part by reducing the activity of key enzymes involved in lipogenesis (SREBP-1c, SCD1, and FAS) and increasing the activation of AMP-activated protein kinase α.Additionally, certain microRNAs, specifically mircoRNA-34a and mircoRNA-33, played a crucial role in modifying this signaling pathway.This indicates a potential therapeutic effect of ACF on liver steatosis.

Neuroprotective activity
In a study by Lu et al. (2019), they investigated the effects of a compound called DMDD (2dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione) on memory and brain cell loss in mice with Alzheimer's disease (AD), specifically those with a genetic predisposition (APP/PS1 transgenic mice).During the study, the mice were administered at varying doses of DMDD for a period of 21 days.The results showed that DMDD had a neuroprotective effect, meaning it helped protect the brain.It led to a reduction in cell death (apoptosis) in the hippocampal tissues of the APP/PS1 mice.This resulted in improved memory and spatial learning abilities, and also prevented the loss of neurons.This suggests that DMDD may have potential as a treatment for memory problems and brain cell loss in Alzheimer's disease.

Antiulcer activity
In their study Goncalves et al. (2006) investigated the potential gastroprotective effects of an alcoholic aqueous extract derived from the leaves of A. carambola in rats.They tested this extract in various ulcer models.When it came to an acidified-ethanol-induced model, they observed a notable anti-ulcer activity.However, in models involving indomethacin and acutestress ulcer formation in mice, the extract did not demonstrate any protective benefits.This led the researchers to conclude that star fruit possesses a relatively lower level of antiulcer activity.

TOXICITY PROFILE OF STAR FRUIT 5.1. A. carambola Really Toxic or Fable
There's ongoing debate regarding the toxicity of star fruit, with conflicting findings.High intake, especially when the fruit contains elevated levels of oxalic acid, has been linked to nephrotoxicity.In cases of excessive consumption or concentrated fruit juice intake, nephropathic patients have exhibited symptoms like abdominal pain, vomiting, nausea, and kidney blockage (Neto et al., 2003;Chen et al., 2005).Studies suggest that individuals experiencing symptoms due to oxalate deposition can recover within about four weeks with standard treatment.However, in severe cases, obstruction caused by oxalate crystals may lead to renal failure.This isn't the sole reason; programmed cell death of renal epithelial cells, as depicted in Figure 3, might also contribute to this condition.Moreover, separate research has highlighted additional neurotoxic symptoms associated with star fruit toxicity.These symptoms include back pain, mental confusion, intractable hiccups, epileptic seizures, vomiting, and insomnia, which have proven lethal for some patients (Martin et al., 1993;Tsai et al., 2005).Until the 1980s, neurotoxic symptoms were attributed to oxalic acid present in fruit juice, as indicated by Chen et al. in 2001.Research showed that injecting mice with a peritoneal dose of 8 g/kg resulted in tremors (Muir & Lam, 1980).However, recent studies have shed new light on the neurotoxic effects observed in the central nervous system, such as confusion, hiccups, convulsions, and even fatalities.These effects are linked to the inhibition of the GABAergic system and a substance called caramboxin.Patients with fatal renal conditions exhibited severe symptoms in a dose-dependent manner, particularly those who consumed over 2 liters of juice or around eight carambola fruits.Intriguingly, a study challenged the notion of attributing toxicity solely to the carambola fruit.It revealed that avoiding this fruit for individuals with kidney disease eliminates the triggering of detrimental effects, as both oxalic acid and caramboxin are eliminated, as depicted in Figure 4 ( Garcia-Cairasco et al., 2013).

CONCLUSION
The current analysis provided an overview of Averrohoa carambola's traditional usage, therapeutic benefits, phytochemical, pharmacological, and intoxication profile.These days, the culinary and pharmaceutical industries are very interested in star fruit.A. carambola is a top pick for the pharmaceutical and health industries because of its superior nutritional, medicinal, and pharmacological qualities.The A. carambola plant is widely spread worldwide and possesses a variety of pharmacological properties, including anti-inflammatory, hepatoprotective, hypoglycemic, analgesic, antioxidant, and antibacterial properties.Star fruit contains several phytoconstituents with specific pharmacological activity i.e., gallotannin, catechin, epicatechin, flavonoids, saponins, alkaloids.There have been few investigations on the toxicity of consuming large amounts of star fruit juice, and the substances caramboxin and oxalates have been linked to nephrotoxicity and neurotoxicity.Further study is needed to close this knowledge gap and determine the precise mechanism underlying star fruit intoxication.Until there are a number of studies on starfruit that address the phytoconstituent and its bioactive components, additional work and studies need to be concentrated.Certainly, this plant has many opportunities with countless beneficial effects, but we must not forget the challenges.This review offers a balanced assessment, setting it apart from other studies.

Declaration of Conflicting Interests and Ethics
The authors declare no conflict of interest.This research study complies with research and publishing ethics.The scientific and legal responsibility for manuscripts published in IJSM belongs to the authors.

Figure 2 .
Figure 2. Chemical structures of some isolated compounds from A. carambola.

Figure 4 .
Figure 4. Schematic representation of toxicity, benefits, and description about A. carambola.