Cashew (Anacardium occidentale) leaves have received serious attention due to its numerous health benefits. The cashew nut shell is also of economic importance in pharmaceutical industries. Cashew fruits possess a liquid rich in phenolic compounds, and known as cashew nut shell liquid (CNSL).
The components of cashew nut shell liquid, according to Kumar and colleagues, depend on the method of production, and are classified into two general categories: natural CNSL (LCCI) and technical CNSL (CTCL) liquids. LCCI contains 60-65% of anacardic acid, 15-20% cardol, 10% cardanol and trace amount of methy-lcardol, while CTCL contains 60-65% of cardanol, 15-20% cardol, and trace amount of polymeric methyl-cardol material. Both of the liquids also contain trace amount of phytosterols, triacontane and others.
Cashew is a green perennial. It belongs to the family Anacardiaceae. This family consists of numerous species, numbering over 400. Cashew is a tropical tree, and is widely grown in the tropical African regions. It can grow from 5 to 14 meters high with stunted and irregular branches that may start at the region close to the ground. The young leaves takes about 20-25 days to mature, and are green in color.
Phytochemical properties of cashew leaves
Anacardium occidentale leaves possess β-ocimene, α-copaene and δ-cadienol; they are rich in cardanol, anacardic acid and cardol, which are alkyl phenolic compounds. Some of the major phytochemicals present in cashew leaves include:
- Alkaloids
- Terpenoids
- Phenols
- Phlobatanins
- Saponins
- Tannins
- Flavonoids
- Resins
Health benefits of cashew leaves
Cashew leaves make up the components of several herbal mixture in southwest Nigeria. These herbal mixtures, popularly and commonly referred to as Agbo, are used in treating several health diseases. This may have necessitated the extensive research on the various pharmacological roles the plant leaves, fruits, nuts and stem bark play in solving human health complications.
Cashew leaves in cancer cells
Cashew leaves possess rich amount of anticarcinogenic bioactive compounds such as Pentagalloylglucose, Zoapatanolide A, Agathisflavone, Anacardicin, and methyl gallate. These bioactive compounds possess cytotoxic potential against cancer cell lines.
Of the anticancer compounds, agathisflavone has effects on several cancer cell lines such as colon, lung, renal, breast, and ovarian cancer cell lines, but the activities were marginal. However, the methylated derivatives showed promising anticancer effects. Agathisflavone also induces lymphopenia in vivo and also triggered selective apoptosis on leukemia cells.
Cashew leaves may be mixed with Soursop leaves or pigeon pea roots for effective chemopreventive and therapeutic benefits. This is because both soursop leaves and pigeon pea roots are loaded with various anticancer bioactive compounds, and can affect all cancer cell lines.
Pentagalloylglucose also has significant selective cytotoxicity effect on cancer cells. The mechanism of this activity could be through the induction of reactive oxygen species (ROS) production in the body. This ROS elicits cell apoptosis and death of tumor cells.
Pentagalloylglucose could, according to a study conducted by Taiwo and colleagues, be involved in eliciting anti-cancer effects through mechanisms including pro-apoptosis, anti-proliferation, anti-angiogenesis, anti-metastasis and inhibition of glycoprotein. These studies prove the traditional use of cashew leaves in the treatment of cancers.
Cashew leaves can lower blood cholesterol level
Hyperlipidemia is one of the risk factors of myocardia infarction, and coronary heart diseases. When cholesterol and triglycerides are high in your body, they are usually deposited on the blood vessels. This action causes a blockage of the blood vessels, restricting blood flow, and leads to increased blood pressure. The deposited cholesterols may also form plaques and cause atherosclerosis.
The ability to effectively reduce the blood lipid levels is the right way to improve our heart health and maintain normal blood pressure. The good news is that cashew leaves possess significant hypolipidemic activity against elevated blood lipid levels.
Benefits of cashew leaves in diabetes
Aside possessing hypolipidemic activity, cashew leaves also possess hypoglycemic activity against diabetes mellitus. You may recall that diabetes causes the elevation of blood glucose and lipid profile levels due to the destruction of pancreas beta cells or through insulin resistance of the cells.
Cashew leaves improves insulin secretion and glucose clearance by also improving insulin sensitivity. Cashew leaves greatly reduce glucose and blood lipid levels, thereby affirming its use in traditional medicine for diabetes treatment.
Cashew prevents hypertension
Just like King oyster mushroom and blue oyster mushroom, Cashew leaves is fortified with numerous bioactive compounds that reduces your blood pressure to normal. One of the methods the leaves may do this is by lowering your blood lipid profile level, such as LDL- cholesterol, total cholesterol and triglyceride levels. These bad lipids cause atherosclerosis when they are deposited on the walls of blood vessels.
Another means by which cashew leaves reduces high blood pressure is through the inhibition of angiotensin-1-converting enzyme. This activity has been supported by studies on methanolic extract of cashew leaves.
Read also (9 amazing health benefits of corn silk tea)
Cashew leaves protect the liver
When you drink an alcoholic decoction made with cashew leaves, one of the benefits you would get is the protection of your live from the damaging effects of toxic substances, like carbon tetrachloride (CCl4). This is because cashew leaves possess antioxidant compounds that protect your live from oxidative stress and the harmful effect of free radicals. The compounds which exert hepatoprotective effect on liver are flavonoids and saponins. The chemoprotective activities of flavonoids are related to their ability to inhibit peroxidative damage caused by toxic substances.
Cashew leaves improve your oral health
One of the major dental challenges facing the African populace is dental plaque. Dental plaque is the gummy film of that usually form on the teeth basement above the gum, and sometimes under the gum at the tooth roots. When you eat foods or drink water, the bacteria in this plaque would produce acids that attack the enamel and cause cavities and gingivitis. When the plaques are formed at the tooth root, under the gum, they can break down the bones that support teeth. This has caused severe pains to most dental patients.
An ethanolic decoction of cashew leaves is used as a mouth wash against dental plaque and oral bacterial. This effect of cashew leaves is due to the presence of tannins, which has strong antimicrobial activity.
Used against fungal diseases
The methanolic extract of Anacardium occidentale leaves can be used as antifungals agent against several plant fungal diseases. This is because cashew leaves exhibit high inhibitory activity against some plant fungal pathogens such as the fusarium species. The inhibitory activity, according to a study Udoh Iniekong and colleagues, showed that cashew leaves are more potent against fusarium species than standard drugs.
Cashew leaves can be dissolved in methanol and used as antiseptic, disinfectant, and as a preservative against fruits and vegetables’ fungal diseases. Another study was done on candida albican and enterococcus faecalis. The result showed that cashew leaves could be used as antifungal treatment against urinary tract caused by candida.
Cashew leaves on bacterial infection
In some parts of the world, cashew leaves, bark, and roots are being used in traditional medicine to treat urinary tract infections such as staphylococcus aureus, enterococcus faecalis, Escherichia coli and several others.
This claim to the antibacterial activity of cashew leaves have been scientifically proven. However, the inhibitory activity of aqueous ethanolic leaf extracts were not as effective as gentamycin and chloramphenicol.
Improve wound healing
Cashew leaf and fruits possess wound healing properties when applied topically. To use cashew leaves as wound healing agents, dissolve the dry leaf powder in a hydroethanolic solution; mix the dry extract in a gel and apply topically on wound surface. You may also make a powder of cashew leaves and bitter kola and mix them in a watermelon seed oil
Cashew leaves boost immunity
Cashew leaf powder is usually added to poultry feeds to boost their immunity. This may be due to the antioxidants and anti-inflammatory activities of cashew leaves. It may also be that leaves may boost immunity in human cells.
Benefits of cashew leaves in intestinal health
Cashew leaf extracts have been used in traditional medicines for treating gastrointestinal disorders, such as ulcer and diarrhea. The antiulcerogenic activity of cashew leaves may be through several mechanisms such as through the proton pump, stimulation of prostaglandin, mucus, and bicarbonate production. This is supported by the study conducted by Onoja and colleagues.
Side effects of cashew leaves
Prolong consumption may affect male fertility
Studies has shown that prolong consumption of cashew leaves may affect sperm motility, which may the individual’s fertility. To avoid this do not use the leaves of cashew for a longer period. For a couple that are expecting conception, the man should avoid using the leaf for any medicinal reason.
May result in low birth weight
For the pregnant woman, it is advisable not to use the leaves in any form for any health reason. This is because the use of cashew leaf products may result to low birth weight, stunted growth and poor cognition in the unborn child. To stay safe, avoid the leaves.
May affect blood volume
Frequent use of cashew leaf products may affect you red blood cells production, blood volume and may lead to anemia. To avoid this, eat foods or herbs that boost blood production, or minimize the consumption of cashew leaves.
References
Kumar P, Paramashivappa R, Vithayathil P, Rao PS, Rao AS (2002). Process for isolation of cardanol from technical cashew (Anacardium occidentale L.) nut shell liquid. J. Agric. Food Chem. 50:4705-4708.
Andrade TDJADS, Araújo BQ, Citó AMDGL, Da Silva J, Saffi J, Richter MF, Ferraz ADBF (2011) Antioxidant properties and chemical composition of technical cashew nut shelll liquid (tCNSL). Food Chem. 126:1044-1048.
Maldonado EM, Svensson D, Oredsson SM, Sterner O. Cytotoxic sesquiterpene lactones from Kauna lasiophthalma Griseb. Sci Pharm. (2014) 82:147–60. doi: 10.3797/scipharm.1310-18 PubMed Abstract | CrossRef Full Text | Google Scholar.
Taiwo, B.J., Popoola, T.D., van Heerden, F.R. et al. Pentagalloylglucose, isolated from the leaf extract of Anacardium occidentale L., could elicit rapid and selective cytotoxicity in cancer cells. BMC Complement Med Ther 20, 287 (2020). https://doi.org/10.1186/s12906-020-03075-3.
Udoh, Iniekong & Aladenika, Seto & Eleazar, Clara & Adaeze, Onyebueke & Azubuike, Nkiruka & Okwuosa, Chukwugozie & Ibezim, Nnenna & Okechukwu, Esimone. (2019). ANTIFUNGAL PROPERTIES OF METHANOLIC LEAF EXTRACT OF ANACARDIUM OCCIDENTALE L (CASHEW) AGAINST FUSARIAL ISOLATES FROM HUMAN AND PLANT ORIGIN. Pharmacologyonline. 15. 117-135.
Salehi, B., Gültekin-Özgüven, M., Kirkin, C., Özçelik, B., Morais-Braga, M., Carneiro, J., Bezerra, C. F., da Silva, T. G., Coutinho, H., Amina, B., Armstrong, L., Selamoglu, Z., Sevindik, M., Yousaf, Z., Sharifi-Rad, J., Muddathir, A. M., Devkota, H. P., Martorell, M., Jugran, A. K., Cho, W. C., … Martins, N. (2020). Antioxidant, Antimicrobial, and Anticancer Effects of Anacardium Plants: An Ethnopharmacological Perspective. Frontiers in endocrinology, 11, 295. https://doi.org/10.3389/fendo.2020.00295.
Onoja, Samuel & Ifenkwe, & Daniel-Igwe, Gloria & Ezeh, Gladys & Ezeja, & Anaga, Aruh. (2019). Gastroprotective effects of polyphenol rich extract of Anacardium occidentale L. leaf. 40. 110-117. 10.4314/nvj.v40i2.3.
