Carica papaya, commonly known as papaya, is a tropical fruit tree belonging to the Caricaceae family, originally from Mexico and Central America. It is cultivated in tropical and subtropical regions worldwide for its juicy fruit, which is celebrated for its sweet flavor and soft texture. Papaya is also valued for its nutritional and medicinal properties.

Botanical Classification

Kingdom: Plantae
Clade: Angiosperms
Class: Eudicots
Order: Brassicales
Family: Caricaceae
Genus: Carica
Species: C. papaya

Plant Characteristics

Papaya is a small tree that can grow up to 10 meters tall but is typically seen between 3 to 6 meters. It has a single unbranched trunk with a broad crown of large, lobed leaves at the top. Leaves are attached directly to the trunk on long petioles. Papaya is a dioecious plant, meaning male and female flowers are on separate plants, but hermaphroditic varieties exist. Flowers are small and yellow, while the fruit is large, with green skin that ripens to yellow or orange and contains orange flesh packed with black seeds.

Chemical Composition and Structure

Papaya is rich in vitamin C, vitamin A, potassium, and dietary fiber. It also contains an enzyme called papain, a proteolytic enzyme that aids in the digestion of proteins. The fruit is a source of antioxidants, such as carotenoids and flavonoids, which provide health benefits including reducing inflammation and protecting against various diseases.

How to Cultivate It

1. Soil: Prefers well-drained, rich, and slightly acidic soils.
2. Light: Requires full sun for optimal growth and fruit production.
3. Water: Needs regular watering to keep the soil consistently moist but not waterlogged.
4. Temperature: Best grown in warm environments, with temperatures between 21°C and 33°C. It is not frost-tolerant.

Uses and Benefits

Papaya is commonly eaten fresh but is also used in salads, smoothies, desserts, and exotic dishes. The fruit is renowned for improving digestion and for its anti-inflammatory properties. It is also used in cosmetic skin treatments, thanks to papain's exfoliating and softening effects on the skin.

Applications

• Culinary: Used fresh or in cooking for its versatility in both sweet and savory dishes.
• Medicinal: Employed for its digestive and anti-inflammatory properties.
• Cosmetic: Included in skincare products for its exfoliating and nourishing properties.

Environmental and Safety Considerations

Papaya cultivation should be managed responsibly to avoid unsustainable practices that could deplete soil resources. It's important to ensure that fruits are grown without excessive use of chemical pesticides. Generally, papaya is safe for consumption, but some people may be allergic to papain.

Studies

Papaya fruit composition contains polyphenols and flavonoids that have antibacterial and antioxidant action (1). There is a good content of Vitamin A, C, E, pantothenic acid, magnesium and potassium in the pulp and peel.

Moreover, papaya and strawberry contains a good content of carotenoids in the pulp (2) :

• ß-cryptoxanthin 34.2%
• lycopene 8,31%
• β-carotene 6,26%.

Fermented papaya powder has an antioxidant effect against age-related diseases and neurological diseases and may be useful in combating excessive production of free radicals in patients with Alzheimer's disease (3).

The components of oil extracted from papaya seeds, oleic acid, linoleic acid, saponins, anthocyanins, tocopherol, have demonstrated beneficial effects on the cardiovascular system (4).

It can therefore be concluded that this fruit is a nutraceutical.

Papaya studies

Carica papaya

Bibliografia________________________________________________________________________

(1) Asghar N, Naqvi SA, Hussain Z, Rasool N, Khan ZA, Shahzad SA, Sherazi TA, Janjua MR, Nagra SA, Zia-Ul-Haq M, Jaafar HZ. Compositional difference in antioxidant and antibacterial activity of all parts of the Carica papaya using different solvents. Chem Cent J. 2016 Feb 3;10:5. doi: 10.1186/s13065-016-0149-0. 

Abstract. Background: Carica papaya is a well known medicinal plant used in the West and Asian countries to cope several diseases. Patients were advised to eat papaya fruit frequently during dengue fever epidemic in Pakistan by physicians. This study was conducted to establish Polyphenols, flavonoids and antioxidant potential profile of extracts of all major parts of the C. papaya with seven major solvents i.e. water, ethanol, methanol, n-butanol, dichloromethane, ethyl acetate, and n-hexane. Results: TPC, TFC, antioxidant and antibacterial potential were determined using different aqueous and organic solvents in addition to the determination of trace element in leaves, pulp and peel of C. papaya. Total soluble phenolics and flavonoids were found in promising quantity (≈66 mg GAE/g) especially in case of methanol and ethanol extracts. Antioxidant activity using DPPH free radical scavenging assay indicated leaves, bark, roots and pulp extracts showed >75.0 % scavenging potential while leaves and pulp showed 84.9 and 80.9 % inhibition of peroxidation, respectively. Reducing power assay showed leaves, pulp and roots extracts active to reduce Fe(3+) to Fe(2+) ions. The antibacterial study showed pulp extract is the best to cope infectious action of bacteria. Conclusion: This study was conducted to test the medicinal profile of all parts of C. papaya by extracting secondary metabolites with organic and aqueous solvents. Ethanol and methanol both were found to be the best solvents of choice to extract natural products to get maximum medicinal benefits and could be used to medicinal formulation against different infectious diseases.Graphical abstractMedicinal evaluation of different parts of C. papaya.

(2)  Swada JG, Keeley CJ, Ghane MA, Engeseth NJ. Relationship between pulp structure breakdown and nutritional value of papaya (Carica papaya) and strawberry (Fragaria x ananassa) nectars using alternative thermal and non-thermal processing techniques. J Sci Food Agric. 2016 May;96(7):2514-23. doi: 10.1002/jsfa.7372. 

(3) Barbagallo M, Marotta F, Dominguez LJ. Oxidative stress in patients with Alzheimer's disease: effect of extracts of fermented papaya powder. Mediators Inflamm. 2015;2015:624801. doi: 10.1155/2015/624801. Epub 2015 Apr 7. PMID: 25944987; 

Abstract. Brain tissue is particularly susceptible to oxidative stress (OS). Increased production of reactive oxygen species (ROS), reduced antioxidant systems, and decreased efficiency in repairing mechanisms have been linked to Alzheimer's disease (AD). Postmortem studies in AD patients' brains have shown oxidative damage markers (i.e., lipid peroxidation, protein oxidative damage, and glycoxidation). Fermented papaya (FPP, a product of Carica papaya Linn fermentation with yeast) is a nutraceutical supplement with favorable effects on immunological, hematological, inflammatory, and OS parameters in chronic/degenerative diseases. We studied 40 patients (age 78.2 ± 1.1 years), 28 AD patients, and 12 controls. Urinary 8-OHdG was measured to assess OS. Twenty AD patients were supplemented with FPP (Immunage, 4.5 grams/day) for 6 months, while controls did not receive any treatment. At baseline, 8-OHdG was significantly higher in patients with AD versus controls (13.7 ± 1.61 ng/mL versus 1.6 ± 0.12 ng/mL, P < 0.01). In AD patients FPP significantly decreased 8-OHdG (14.1 ± 1.7 ng/mL to 8.45 ± 1.1 ng/mL, P < 0.01), with no significant changes in controls. AD is associated with increased OS, and FPP may be helpful to counteract excessive ROS in AD patients.

(4) Santana LF, Inada AC, Espirito Santo BLSD, Filiú WFO, Pott A, Alves FM, Guimarães RCA, Freitas KC, Hiane PA. Nutraceutical Potential of Carica papaya in Metabolic Syndrome. Nutrients. 2019 Jul 16;11(7):1608. doi: 10.3390/nu11071608. 

Abstract. Carica papaya L. is a well-known fruit worldwide, and its highest production occurs in tropical and subtropical regions. The pulp contains vitamins A, C, and E, B complex vitamins, such as pantothenic acid and folate, and minerals, such as magnesium and potassium, as well as food fibers. Phenolic compounds, such as benzyl isothiocyanate, glucosinolates, tocopherols (α and δ), β-cryptoxanthin, β-carotene and carotenoids, are found in the seeds. The oil extracted from the seed principally presents oleic fatty acid followed by palmitic, linoleic and stearic acids, whereas the leaves have high contents of food fibers and polyphenolic compounds, flavonoids, saponins, pro-anthocyanins, tocopherol, and benzyl isothiocyanate. Studies demonstrated that the nutrients present in its composition have beneficial effects on the cardiovascular system, protecting it against cardiovascular illnesses and preventing harm caused by free radicals. It has also been reported that it aids in the treatment of diabetes mellitus and in the reduction of cholesterol levels. Thus, both the pulp and the other parts of the plant (leaves and seeds) present antioxidant, anti-hypertensive, hypoglycemic, and hypolipidemic actions, which, in turn, can contribute to the prevention and treatment of obesity and associated metabolic disorders.