Major bioactive components of bitter melon and their related functions .
Nature is full of poisons as well as life-saving entities. Extracts of natural products in medicinal plants have been used for thousands of years in traditional medicine throughout the World. Bitter melon (Momordica charantia) is a member of Cucurbitaceae family, widely distributed in tropical regions of the World, that has been used in folk medicine for the treatment of diabetes mellitus, and its fruit has been used as a vegetable for thousands of years. It contains phytochemicals, flavonoids, triterpenes, saponins, ascorbic acid, steroids, proteins, and polysaccharides. This plant is a traditional herbal medicine, possesses various biological, medicinal activities and pharmacological functions, namely antidiabetic, anthelmintic, contraceptive, antimalarial, laxative, antihyperglycemic, antimutagenic, antiulcer, antilipolytic, antifertility, hepatoprotective, anticancer, antibacterial, antiviral, antitumor, immunomodulation, antioxidant, antidiabetic, and anti-inflammatory activities of M. charantia have been reported. Its fruit has a special bitter taste, parts of M. charantia, such as fruits, vines, leaves and even roots have been used as folk medicine for the remedy of diseases like toothache, diarrhea, and diabetes. It is also used for the treatment of eczema, gout, jaundice, pneumonia, psoriasis, and rheumatism. These beneficial effects are attributed to the various bioactive components of M. charantia, which are important sources of phytoconstituents used to treat various diseases since ancient times. This chapter reviews various aspects of the results of investigations involving M. charantia in the recent years, providing a comprehensive overview of the phytochemical application of M. charantia to attract more attention to their biological activities for better utilization of M. charantia; focusing on the review of benefits that bitter melon offers in terms of its potential as a source of bioactive compounds and its role in the control of different diseases.
- Bitter melon
- bioactive compounds
Bitter melon (
2. Nutritional value and chemical composition of
Bitter melon (
Bitter melon has been associated with anti-cancer, anti-microbial, anti-inflammatory and anti-diabetic properties. The medicinal values of the bitter gourd fruit are linked to its high content of phenolics, which act as antioxidants. Phenolic compounds containing phenolic acids, coumarins, lignins, tannins, lignanes and flavonoids are among the secondary metabolites that are abundant in the plant.
|Major Bioactive Components||Functions||Distribution||References|
|Polysaccharides||Antioxidant, antidiabetic, immune enhancement, neuroprotective, antitumor||Various parts of plants||[11, 12, 13, 14, 16, 17]|
|Peptides and proteins||RNA N-glycosidase, polynucleotide adenosine glycosidase (PAG), DNase-like, phospholipase, superoxide dismutase, anti-tumor, immune suppression, antimicrobial||Seed||[18, 19, 20, 21]|
|Lipids||Antitumor, antioxidant||Seed, flesh||[11, 12, 13, 14, 16, 17]|
|Terpenoids||Anticancer, antioxidant, antidiabetic, hypoglycemic, cancer chemoprevention||Stem, leave, fruit||[11, 12, 13, 14, 16, 17, 19, 20, 21, 22]|
|Saponins||antihyperglycemic, hypolipidmic, antiviral||Fruit, root, seed||[18, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29]|
|Phenolics||Antioxidant, anti-inflammation, immune enhancement||Fruit, pericarp, seed||[11, 12, 13, 14, 16, 17, 19, 20, 21, 22]|
|Sterols||Antimicrobial||Pericarp, fruit||[25, 26, 27, 28, 29, 30, 31]|
3. Antioxidant and anticancer activity of
Secondary metabolites are attracting attention for their effects in preventing diseases due to oxidative stress, which leads to degeneration of cell membranes and leads to many pathological diseases. They play a major role in preventing disease due to oxidative stress, which leads to many pathological diseases [11, 12, 13, 14]. Recent investigations have shown that antioxidants with free radical scavenging properties have great importance as therapeutic agents in preventing aging process and in scavenging free radical mediated diseases [11, 12, 13, 14]; such as diabetes, atherosclerosis and other complications .
Many studies have shown that
Several phytochemicals, including bitter melon extracts, are described to possess potentials in anticancer therapies . The extracts of bitter melon have been investigated for their potential use as anticancer agents; suggesting that dietary consumption of bitter melon could help to lower risk of several cancers .
Anticancer properties of bitter melon extracts are reported to have ability to modulate several deregulated signaling pathways in different type of cancer, like MAPK pathway, through the modulation of cell cycle proteins, thereby inducing cell cycle arrest, inducing apoptosis or other cell death pathways. Cucurbitane-type triterpene glycosides have been showed to have significant antitumor activity in hepatic carcinoma derived cell lines .
It is well known that tumor progression toward malignity is strongly related to chronic inflammation that is responsible for tumor invasion of surrounding normal tissues and angiogenesis. Bitter melon components are suggested to exert their antitumor effects by modulation of the inflammation status.
4. Antiinflammatory activity of
Inflammation is known to be a complicated immune process that can be defined by the sequential release of mediators such as pro-inflammatory cytokines, including interleukin (IL)-1, interferon (IFN)-c, IL-6, IL-12, IL-18, tumor necrosis factor (TNF), and the granulocyte-macrophage stimulating factor. It is settled by anti-inflammatory cytokines such as IL-4, IL-10, IL-13, IFN-a, and the transforming growth factor (TGF)-b . Inflammation is known as an overall a protective response against xenobiotics, but chronic inflammation is also known to be detrimental to tissues; causing in chronic inflammation-derived diseases, such as autoimmune diseases, cardiovascular diseases, systemic lupus erythematosus (SLE), aging-associated diseases, such as Alzheimer’s or Parkinson’s disease; and cancers. It is known that oxidative stress and inflammation activate each other and oxidative stress plays a role in chronic infectious diseases . Chronic inflammation is shown to promote tumor initiation and malignant progression of many cancers, considering the importance of inflammatory changes in different cancer types, preventing or reversing inflammation has become an important approach to control cancer progression [16, 37]. Thus, inhibition of the overproduction of inflammatory mediators, especially pro-inflammatory cytokines IL-1b, IL-6, and TNF-a, may prevent or suppress a variety of inflammatory diseases [16, 37].
Dietary habits contribute to a chronic state of inflammation, which can alter gut microbiota and immune status. Various dietary components have demonstrated to modulate chronic inflammatory conditions and to be helpful in their therapy . Bitter melon dietary supplementation has been widely studied to treat several diseases, such as obesity and cancer, promising to possess hypoglycemic and lipid-lowering properties . Chronic inflammation is involved in the pathogenesis of different diseases, such as metabolic syndrome, obesity, cancer, cardiovascular disease, and a neurodegenerative diseases [16, 17]. In diabetic patients, inflammation contributes to increase blood glucose concentration in developing cardiovascular diseases and obesity. The beneficial properties of
Several investigations suggest that oxidative stress plays a role in chronic inflammatory diseases; which are closely related in pathophysiological processes that can activate each other [39, 40, 41]. Bitter melon has shown to have beneficial properties dependent on its anti-inflammatory and anti-oxidant activities [41, 42, 43]; regulating inflammation mainly through NF-κB signaling pathway inhibition, reducing TNF-α production . It is also reported that bitter melon extracts reduced TNF-α-induced expression of inflammatory markers, including inducible NO synthase, p65 subunit of NF-κB, TNF-α, and IL-1β . The bitter melon containing diet also reported to normalize serum levels of the cytokines suggesting its role in reducing inflammation, obesity and insulin resistance in obese mice ; suggesting that bitter melon supplementation may be useful as a preventive agent in individuals at risk for inflammatory-related diseases . Therefore, bitter melon has anti-inflammatory effects by acting on several important signaling pathways involved in inflammation.
Xanthine oxidase, which is a key enzyme for the induction of hyperuricemia and gout, it is involved in many inflammation related diseases . Cucurbitane-type triterpene glycosides isolated from bitter melons fruits is proved to inhibit xanthine oxidase activity . Antioxidant compounds in bitter melon showed potential natural antioxidant activity to inhibit the lipid peroxidation . demonstrating anti-inflammatory effects of phenolic compounds present in the bitter melons extract .
The wound-healing activity of the olive oil macerate of
5. Antidiabetic (Hypoglycemic) activity
Diabetes mellitus is known as a metabolic disease that is the fastest growing diseases in the world, and is characterized by hyperglycemia resulting from defects in insulin secretion and insulin action . Drugs obtained from the plants used all over the world to treat diabetes. Bitter melon is used to treat many diseases with good medicinal values, but more emphasis is given to its anti-diabetic properties. As an antidiabetic drug, bitter melon has been widely used in different countries for thousands of years is suggested as a remedy for the treatment of diabetes .
It contains active compounds, including charantin that reduce blood sugar levels. In addition, bitter melon contains lectin which also reduce blood glucose level that is a major factor of hypoglycemic effect . Some other compounds present in bitter melon such as steroids, inorganic, triterpene, proteid, lipid and phenolic compounds also offer anti-diabetic properties. The aqueous extract of bitter melon fruits is reported to stimulate insulin secretion of β cells in pancreatic islets isolated from obese-hyperglycemic mice [23, 24, 57]. Antidiabetic mechanism of bitter melon extracts is suggested to enhance insulin secretion by the islets of Langerhans, reducing glycogenesis in liver tissue, enhancing peripheral glucose utilization and increasing serum protein levels [23, 24, 57].
Oral administration of the aqueous extract
6. Antihyperlipidemic activity and weight loss
Hyperlipidemia is a major health problem and associated with diabetes due to increase in morbidity and mortality. High blood lipid concentration is associated with cerebrovascular disease, ischemic heart diseases, and atherosclerosis.
7. Antimicrobial activity
8. Anti-parasitic (anti-anthelmintic) activity
Helminthic infection is a problem, which is caused by nematodes, cestodes, and trematodes. The main target of helminthic infection is gastrointestinal system that affects human and livestock’s in the world. Nowadays, in spite of using medicines, functional foods such as bitter melon is considered as an important therapeutic medicinal food with anthelmintic action. The presence of functional ingredients including saponins, momordin, momordicoside, momordicin, the worms are paralyzed by inhibiting the acetyl cholinesterase . Anthelmintic effect of
9. Anti-HIV activity
Bioactive components which are present in
10. Wound healing activity
Growth factor deficiencies, neovascularization, abnormalities such as impaired immune response and decreased synthesis of collagen are known to be associated with diabetes and to the delayed wound healing [18, 19, 28, 29]. Treatment with
11. Immunomodulatory activity
In vitro experiments have shown that
12. Other biological activities
There are also some reports on other bioactivities. Components in
13. Toxicity and side effects
Although the plant is basically harmless to human body under normal conditions, it may induce adverse reactions according to different uptakes, processing methods, physical differences and other conditions. There have been reports of toxicity since 1960s, mainly including acute toxicity, chronic toxicity and reproductive toxicity.
It is known that the majority of the world population prefer traditional folk medicine products to industrial products. One of the main reason for the increased interest in herbal medicinal products is that natural products will be considered less toxic, but this is often a false perception. In health problems, many components of vegetable origin obtained from natural products have the potential to act as supplements, alone or in mixtures. Due to the synergistic effect, many active compounds may have therapeutic potential much higher than the effects they can give alone when given as a herbal preparation. It is helpful for different diseases such as inflammatory, leukemic, diabetic, mutagenic, mycobacterial, microbial, tumor, ulcer, aphrodisiac, viral, astringent, carminative, cytotoxic, hormonal, depurative, hypotensive, immuno-stimulant, etc. Bitter melon is the most important medicinal plant having good therapeutic values. Therapeutic importance bitter melon is traditionally famous due to its medicinal importance. It has as anticancer, antiviral, antidiabetic, anti-inflammatory, immune-stimulant and cholesterol reduction properties. It contains many phenolic compounds, due to this reason, it has antioxidant and antimutagen properties. Its fruit, leaves, stem and roots all are used for the treatment of many diseases such as hyperlipidaemia, digestive disorders, microbial infection and menstrual problems. It has antiviral and anticarcinogenic properties which can boost the immune system. Other medicinal properties such as wound-healing activity have revealed that the bitter melon extract has high amount of therapeutic compounds for the regeneration of tissues that encouraged the proliferation of dermal fibroblasts of human.
Bitter melon is also shown to express anti-HIV activity with alpha- and beta-momorcharin proteins that are present in seeds, leaves, and fruit. Investigation on the bioactivities of
As conclusion, bitter melon has different medicinal properties due to the presence of high bioactive compounds that is beneficial for the human health This chapter provides information about nutritional profile and food value of bitter melon to highlight the bioactive composition that is linked to its therapeutic effects, aiming to fully utilize bitter melon and add further value to this medicinal plant.