Castor Carrier Oil

ORIGIN

Castor oil is derived from the seeds of a castor plant, also known as Ricinus communis, which forms part of the Euphorbiaceae family [1] (Figure 1). This plant grows in Africa and the Mediterranean region.

Figure 1: (a) Young castor plant (b) matured castor capsules (c) castor seeds (d) castor oil

PRODUCTION AND EXTRACTION

Major castor oil producing countries include India, China, and Brazil. India is known as the world leader in castor oil production and leads the international castor oil trade. Castor oil production in this country usually fluctuates between 250,000 and 350,000 tons per year [3].

Castor beans are used to extract castor oil via mechanical pressing, solvent extraction, or a combination of both. The seeds are left to dry to split open. Seeds are then cleaned for foreign objects, and heated in a steam-jacketed press to get rid of moisture and dried again. Crushing castor oil, known as prepressing, is done with a hydraulic press yielding only 45% oil recovery after pressing mechanically at low temperatures. The extraction efficiency can be increased to 80% by prepressing at higher temperatures [3].

Castor oil that has been cold-pressed is lighter in color and has less iodine and acid than oil that has been solvent-extracted. The color of crude castor seed oil is straw or pale yellow, however it can be bleached and refined to almost colorless state. The crude oil also has a distinct odor but can also be deodorized during the refining process [3].

HISTORY

In 1982, a survey was documented highlighting uses of castor oil plant in as many as 50 different countries [4], with its earliest mention was in the 4,000-year-old Papyrus Ebers (1600 B.C.), an ancient Egyptian scroll of herbal medicine, which highlights the usage of castor in promoting hair growth [5]. Additional uses include treating headaches, skin, hair, and eye problems [5, 6].

In ancient Indian scripture of medicine - Charaka Samhita (4th century B.C.E.), castor oil is mentioned as the best one amongst purgatives (drug to drive out diseases). It is popularly used since centuries in Ayurvedic system of medicine for the management of rheumatic disorders, chronic backache, constipation, abdominal disorders, muscle aches, arthritis, chronic headache, menstrual cramps, eczema and skin disorders. [7]

CHEMISTRY

By now, we have known that castor oil is a very unique substance. Its effectiveness is probably due in part to its peculiar chemical composition [6] as shown in Table 1. The ricinoleic acid forms approximately 90% of the total fatty acid content in castor oil and the rest accounts for 10% [1]. Castor oil is valuable due to its high ricinoleic acid, which is responsible for providing oxidative stability, antioxidant properties, anti-inflammatory, prolonged shelf-life and hydrophobicity to the oil [2, 3]. The oxidative stability of castor oil was found to be higher than argan, olive, and sesame oil. The overall phytosterol content (pose positive influence on human health) in castor oil seed is similar to olive oil and higher than walnuts and hazelnuts [8].

Table 1: Fatty acid composition of some typical vegetable oils against those of castor oil [1]

Scientific researches have even progressed in analyzing different varieties of castor oil and their inner chemistry. A study [9], break down the fatty acid composition (% w/w) of different varieties of castor oil procured from different parts of the world (Table 2).

Table 2: Fatty acid composition of castor oils produced from different  parts of the world [9]:

The Indian castor oil contains the highest percentage of ricinoleic acid with traces to non- presence of palmitic, oleic and linolenic acids.

SCIENTIFIC EVIDENCE

It’s important to remember that while castor oil has a strong past in old medicine, only recently it has been studied in the modern sense. Scientific evidence on the efficacy of castor oil with actual participants were investigated through direct topical application and following parameters were analyzed: Transdermal absorption, Pain reduction, Immune system, Liver function, Constipation and Artificial tears [4]. Kennedy concluded that castor oil may modulate white blood cell count, have a positive effect on liver function, cholesterol levels, and reduce pain and inflammation [4, 10].

BENEFITS OF CASTOR OIL

Castor oil is not just another name on the list of natural oils [11]. Rich in vital nutrients, minerals, and fatty acids, it has emerged as a popular natural cure for a variety of illnesses and cosmetic issues. Its versatility is what really boosts its status, earning it the title of "Natural Elixir” [11]. Broad spectrum of topical application of castor oil are:

1. Skin nourishing and protection: Rich in vitamin, anti-oxidant and fatty acid content, castor oil is effective in smoothening and softening the skin. As compared to other emollients, its thicker consistency helps in keeping the skin hydrated by reducing the trans-epidermal water loss (TEWL).

2. Anti-aging properties: In addition to fatty acids, castor oil contains essential phytochemicals that contribute to skin enhancing abilities [9]. The overall phytosterol content in castor oil (1.5-2.6 g/100g) have been found similar to olive oil (1.8-2.3 g/100g), and higher than walnuts (1.1-1.6 g/100g) and hazelnuts (1.5-1.9 g/100g) [2]. Particularly enriched with tocopherols and phytosterols (proven effective in maintaining skin elasticity and reducing aging), the oil stimulates the production of elastin and collagen which have proven effective towards boosting skin elasticity, reducing fine lines and wrinkles, promoting supple and youthful appearance of the skin.

3. Cracked heel remedy: It's an ideal treatment for cracked heels because of its skin-hydrating properties. Rich in vitamins and vital nutrients, it moisturizes dry, chapped skin. Just apply castor oil on cracked heels, cover them with socks, and leave them over night. You'll observe a significant improvement.

4. Imparts strength and shine to hair: Ricinoleic acid content of castor oil stimulates the scalp, promoting blood circulation and potentially encouraging hair growth. With humectant properties that lock in moisture, Castor Oil can treat dry and damaged hair, making it thicker, shinier, softer, and smoother.

5. Strengthen and Lengthen Eyelashes, eyebrows, beard and moustache: When used regularly, castor oil's vitamin E, proteins, minerals, and antimicrobial qualities will help grow and strengthen eyelashes, eyebrows, beard and moustache. When used topically, it seeps deeply into the skin, revitalizing and hydrating the area to encourage faster growth and prevent breakage. 

6. Fights scalp dryness: Due to its deep hydrating, anti-fungal and anti-inflammatory qualities, castor oil can fight scalp dryness and treat scalp infections by eliminating the bacteria and microorganisms that can cause hair loss, dandruff, and infection. When you apply it to the ends of your hair, the castor oil can help reduce frizz and repair split ends.

7. Controls grey hair and damage: Castor Oil can also be applied to the scalp to slow the appearance of graying hairs and prevent further loss of pigment in hairs [5].

8. Natural hair conditioner: Castor oil helps to achieve a more understated and assured look by smoothing out frizz in your hair. You can use castor oil alone as a deep conditioning treatment, or you can add a few drops to your regular conditioner. Your hair is going to feel tangle-free, lustrous, and silky after using it.

9. Minimize appearance of scars and stretch marks: Regular application of Castor Oil not only restores the skin's moisture but also minimizes the appearance of undesired scars and blemishes due to its high fatty acid content. They accomplish this by plumping the scar tissue by deeply entering it, and encouraging the formation of better surrounding tissue. This promotes the fading of imperfections like dark spots, stretch marks, and uneven skin tone. Simultaneously, the emulsifying qualities of Castor Oil function as a barrier protecting the skin from abrasive environmental elements. Note that while it can lessen the appearance of scars you currently have, it cannot remove them.
10. Cuticle care: Castor oil has a high concentration of vitamin E, which works wonders for brittle, dry nails. Massaging it into your nails and cuticles every evening will result in soft cuticles and healthy-looking nails.
11. Soothes skin conditions: Anti-inflammatory and antibacterial properties make Castor Oil effective for treating acne-prone skin. Many skin remedies on the market today contain benzoyl peroxide and salicylic acid, which tend to dry out the skin. Castor oil, on the other hand, draws out dirt, dead skin cells, excess oils, and bacteria without drying out the skin. Its unique antioxidant composition helps reduce the oxidation of lipids in the skin and slows down sebum production [12].
12. Pain relief: Castor oil's anti-inflammatory properties make it an excellent massage oil for arthritic joints, sore muscles, and inflammation of your nerves. The ricinoleic acid that castor oil contains possesses the ability to boost anti-inflammatory properties while increasing blood circulation in the body. Applying castor oil packs to your lymph nodes allows your body to absorb the oil quickly[11]. Experiments conducted on mouse and guinea-pigs by topical application of ricinoleic acid have been proved as an effective anti-inflammatory agent [10]. It is most commonly used to relieve menstrual cramps since ages.
13. Improving Immune Function: A preliminary controlled study was conducted in 1987 on 36 healthy subjects using topical castor oil pack therapy which reported increase in the number of T-11 cells (T-I I cell lymphocytes supply a fundamental antibody capability to keep the specific defense system strong) [13]. The study stresses on more such experiments on ill persons.

14. Relieve Sunburn: Castor oil has antioxidants that fight free radicals from the sun, pollution, and other environmental sources that can cause cellular damage and premature aging. SPF value of castor oil was found ~6, which is higher than almond oil (SPF ~5) and lower than olive and coconut oil (SPF ~8) [14]. Its ricinoleic acid content lessens the inflammation brought on by sunburns and prevents any newly formed blisters from getting infected [12].

15. Hydrates Chapped Lips: The fatty acids found in castor oil help to hydrate and moisten dry, chapped lips. Moreover, it adds a glossy, shiny appearance.

16. Relieve Insomnia: Instead of habit-forming medication, rubbing castor oil along your eyelids promotes healthy circulation and helps you to become more relaxed and aiding in sleep.

17. Deep Facial Cleanser: Castor oil acts as a natural face cleanser and detoxifier. It keeps your skin smooth, silky by eliminating debris, bacteria, dead skin cells, and extra oil, preserving a better texture and uniform complexion.

18. Other DIYs: Castor oil is a perfect ingredient for DIY beauty products. It works well in cleansing products, facial serums and products that require a natural shine like lip balms and gloss. Additional uses include the removal of skin tags and moles, the treatment of rashes, insect bites and toenail fungus.

CASTOR OIL IN COSMETIC INDUSTRY

While the age-old tales of castor oil's efficacy is valuable, its scientific backing and unique composition is what really sets it apart from other natural oils. Whether for skin, hair, or overall well-being, castor oil is the jack of all trades. Using a random sampling of more than 500 products listed in [15] , an attempt has been made to comprehend the use of castor oil in current market products (Figure 2). Note that not all market products are not included in the data displayed, and numbers may vary.

Figure 2: (a) Castor oil distribution amongst personal care market products, (b) Castor oil distribution amongst make-up cosmetic products [15]

Castor oil is the ingredient in 75% of products that are used for make-up, skincare and hair care (Figure 1a). Further breaking down make-up cosmetics, reveals major usage of castor oil in lipsticks and lip products. A wide range of products in the market today clearly reflect its presence in the personal care market.

RISKS ASSOCIATED WITH USING CASTOR OIL

Castor oil offers numerous benefits; however, it is crucial to use it safely and responsibly. It is generally considered safe for use in skin and hair, however since its derived from the nut of plant, people with nut allergies could be affected. For acne-prone skin and sensitive skin conditions, it is best to consult an expert. A patch test is always recommended.

REFERENCES

1. Chauke, N.P., Mukaya, H. E., Nkazi, D. B., Chemical modifications of castor oil: A review. Science Progress, 2019. 102(3): p. 199-217.
2. Yeboah, A., et al., Castor oil (Ricinus communis): a review on the chemical composition and physicochemical properties. Food Science and Technology, 2021. 41(suppl 2): p. 399-413.
3. Patel, V.R., et al., Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production. Lipid Insights, 2016. 9: p. 1-12.
4. Kennedy, D.A., Keaton, D., Evidence for the topical application of castor oil. International journal of Naturopathic medicine, 2012. 5: p. 1-5.
5. Hartmann, A., Back to the roots- dermatology in ancient Egyptian medicine. Deutsche Dermatologische Gesellschaft (DDG), 2016. 14(4): p. 345-456.
6. healing, G. All You Should Know About Castor Oil: An Age-Old Home Remedy. 2019; Available from: https://explore.globalhealing.com/castor-oil/?gad_source=1&gclid=CjwKCAjwuJ2xBhA3EiwAMVjkVD7uDxtfDxdqn8f1o2gbgQm9ACfQYPF_nHIanMwNKyTEHAKrPVcr6RoCAYoQAvD_BwE#references.
7. Pandey, R.K., REVIEW ON THERAPEUTIC USES OF ERAND TAILA (Ricinus communis Linn.). International Ayurveda publications, 2023. 8(5): p. 2386-2396.
8. Said, G., Daniel P., Badr, K., Mohamed, I., Zoubida, C., Chemical characterization and oxidative stability of castor oil grown in Morocco. Moroccan Journal of Chemistry, 2016. 4(2): p. 279-284.
9. Harhar, H., Gharby, S., Pioch, D., Kartah, B., Ibrahimi, M., Charrouf, Z., Chemical characterization and oxidative stability of castor oil grown in Morocco. Moroccan Journal of Chemistry, 2016. 4(2): p. 279-284.
10. Vieira C., et al., Effect of ricinoleic acid in acute and subchronic experimental models of inflammation. Mediators of inflammation, 2000. 9: p. 223-228.
11. THFE, T.h.f.e. A BEGINNER'S GUIDE TO CASTOR OIL BENEFITS. 2023 [cited 2024; Available from: https://thehealthfoodemporium.co.za/blogs/news/a-beginners-guide-to-castor-oil-benefits.
12. OAIH, O.A.I.H.C. 30 Outstanding Castor Oil Uses and Benefits. 2024 25.4.2024]; Available from: https://www.oneagorahealth.com/30-outstanding-castor-oil-uses-and-benefits.html.
13. Grady H., Immunomodulation through castor oil packs. J Nat Med, 1997. 7(1): p. 84-89.
14. Kaur, C.D. and S. Saraf, In vitro sun protection factor determination of herbal oils used in cosmetics. Pharmacognosy Res, 2010. 2(1): p. 22-5.
15. SpecialChem. The material selection platform: Castor. 2024; Available from: https://cosmetics.specialchem.com/searchsites/searchproducts/a-decorative-cosmetics-make-up?q=CASTOR.

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