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Corn silk beats BP, obesity

By Chukwuma Muanya (Assistant Editor) and Oluwatosin Areo
21 September 2017   |   4:19 am
Botanically called Zea mays, corn or maize belongs to the plant family Poaceae. In Nigeria, it is called ka or oka in Edo; ibopot in Efik; oka in Esan; agwado or daawar Masar in Hausa; akpa-akpa in Ibibio; oka in Ibo; oka in Urhobo; and igbado in Yoruba.

Corn silk

Botanically called Zea mays, corn or maize belongs to the plant family Poaceae. In Nigeria, it is called ka or oka in Edo; ibopot in Efik; oka in Esan; agwado or daawar Masar in Hausa; akpa-akpa in Ibibio; oka in Ibo; oka in Urhobo; and igbado in Yoruba.

Corn silk is a yellowish thread like strand of female flower of maize.Phytochemical screening of corn silk showed the constituents include alkaloids, tannins, phytosterols, vitamin E and K, succinic acid, lactic acid, palmitic acid, proteins, vitamins, flavonoids, terpenoids, carbohydrates, calcium, magnesium and potassium salts.

Potential use of corn silk is related to its properties and mechanism of action of its bioactive constituents such as flavonoids and terpenoids. Studies indicate that it possess antihypertensive, antioxidant, anticancer, antidepressant, kaliuretic, neuroprotective properties.

Until now, extracts of corn/maize (Zea mays) silk have been successfully used in the treatment of prostate cancer, kidney damage, kidney stones, urinary incontinence, diabetes among other diseases. Now researchers have validated the plant material to lower blood pressure, body weight, fat deposits and cholesterol as well as improve sight.

Scientists have demonstrated how corn silk aqueous extracts could be used to address intraocular pressure of systemic and non-systemic hypertensive subjects.

The study published in the journal Clinical and Experimental Optometry by George G. O. and Idu F. K. concluded: “Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract.”

According to the researchers, “hypotensive (blood pressure-lowering) properties have been attributed to the stigma/style of Zea mays (corn silk). Although the effect of corn silk extract on blood pressure has been documented in animal studies, we are not aware of any study on its effect on human blood pressure and intraocular pressure.”

A randomised study was carried out on the effect of water only, masked doses of corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) on intraocular pressure and blood pressure of 20 systemic and 20 non-systemic hypertensive subjects. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. Each dose was administered at two-week intervals to each subject in the two study groups.

The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction in mean intraocular pressure and blood pressure within eight hours of administration. The peak effect on intraocular pressure was observed after four hours and this was preceded by the peak effect on blood pressure, which occurred after three hours of administration. The hypotensive effect was dose-dependent in the two groups.

Another study published in Nutrition Research and Practice journal found that high maysin corn silk extract reduces body weight and fat deposition in mice fed high-fat diets.The researchers concluded: “It can be concluded that high maysin corn silk extract inhibits expression of genes involved in adipocyte differentiation, fat accumulation, and fat synthesis as well as promotes expression of genes involved in lipolysis and fat oxidation, further inhibiting body fat accumulation and body weight elevation in experimental animals.”

Yet another study published September 2017 in Biomedicine Pharmacotherapy journal found that corn silk maysin ameliorates obesity in vitro and in vivo via suppression of lipogenesis, differentiation, and function of adipocytes.

The investigated the potential anti-obesity effects of maysin, a major flavonoid of corn silk, in vitro and in vivo using 3T3-L1 preadipocyte cells and C57BL/6 mice. Maysin decreased the levels of intracellular lipid droplets and triglycerides (TG), and down-regulated the protein expression levels of C/EBP-β, C/EBP-α, PPAR-γ, and aP2 in 3T3-L1 preadipocyte cells, suggesting that maysin inhibits lipid accumulation and adipocyte differentiation.

In addition, maysin was shown to induce the apoptotic cell death in 3T3-L1 preadipocyte cells via activation of caspase cascades and mitochondrial dysfunction, which may ultimately lead to reduction of adipose tissue mass. Furthermore, oral administration of maysin (25mg/kg body weight) decreased weight gain and epididymal fat weight in high-fat diet (HFD)-fed C57BL/6 mice. Administration of maysin also reduced serum levels of TG, total-cholesterol, Low Density Lipo-protein (LDL)/ bad cholesterol, and glucose.

According to the researchers, “taken collectively, these results suggest for the first time that the purified maysin exerts an anti-obesity effect in vitro and in vivo. These observations may support the applicability of maysin as a potent functional ingredient in health-beneficial foods or as a therapeutic agent to prevent or treat obesity.”

Previous studies found that extract of corn or rather maize silk (Zea mays) can stop the growth of prostate cancer in humans as well as be used as panacea for diabetes, kidney failure, and liver cancer.

Results of a study titled “Corn silk maysin induces apoptotic cell death in PC-3 prostate cancer cells via mitochondria-dependent pathway” and published in Life Sciences suggested for the first time that maysin inhibits the androgen-independent human prostate cancer cells (PC-3) cancer cell growth via stimulation of mitochondria-dependent apoptotic cell death and may have a strong therapeutic potential for the treatment of either chemo-resistant or androgen-independent human prostate cancer.

According to the researchers, despite recent advances in prostate cancer diagnostics and therapeutics, the overall survival rate still remains low. The study was aimed to assess potential anti-cancer activity of maysin, a major flavonoid of corn silk, in PC-3.According to a study published in Nutrition and Metabolism, corn silk contains proteins, vitamins, carbohydrates, calcium (Ca), potassium (K), magnesium (Mg) and sodium (Na) salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids.

The study is titled “The effects of corn silk on glycaemic metabolism.”The researchers wrote: “Corn silk (Zea mays) refers to the stigmas from the female flowers of maize. Fresh corn silk resembles soft silk threads 10 to 20 cm long that are either light green or yellow-brown in color. Corn silk contains proteins, vitamins, carbohydrates, calcium (Ca), potassium (K), magnesium (Mg) and sodium (Na) salts, fixed and volatile oils, steroids such as sitosterol and stigmasterol, alkaloids, saponins, tannins, and flavonoids.”

Corn silk has been used in many parts of the world for the treatment of edema as well as for cystitis, gout, kidney stones nephritis and prostatitis.
An earlier study of the effect of Zea mays saponin (ZMLS) on ultra-structure of kidney and pancreas in the diabetes rats induced by streptozocin (STZ) showed good effect on decreasing blood glucose and protection action on the kidney and pancreas injury.

The pancreas is a glandular organ that secretes digestive enzymes such as insulin, while STZ is a naturally occurring chemical that is particularly toxic to the insulin-producing beta cells of the pancreas in mammals. STZ is used in medical research to produce an animal model for diabetes.

Diabetes mellitus is a serious metabolic disorder characterised by defects in the body’s use of carbohydrates. It is a serious chronic metabolic disease characterised by an increase in blood sugar levels associated with long term damage and failure of organ functions, especially the eyes, kidneys, nerves, heart and blood vessels. It occurs when the pancreas does not adequately produce insulin, a hormone necessary for the proper utilisation of sugar by the body or when the body cannot properly utilise insulin.

The study by Chinese researchers at Henan College of Traditional Chinese Medicine, Zhengzhou, China, is titled “Influence of Zea mays L. saponin (ZMLS) on ultra-structure of kidney and pancreas in diabetes rats induced by STZ.”

According to the study published in PubMed, the diabetic rat model was established by injections of STZ, and blood glucose, the ultra-structure of the kidney and pancreas were observed.

The results showed that compared with the model group, the large, and middle-dose ZMLS groups could remarkably decrease the blood glucose; and that the large, middle, small-dose ZMLS groups could remarkably prevent the pancreatic islet beta-cell from the injury induced by STZ.The researchers concluded that ZMLS showed good effect on decreasing blood glucose and protection action on the kidney and pancreas injury induced by STZ.

Also, Japanese researchers at the Department of Natural Medicine and Phytochemistry, Meiji Pharmaceutical University, Japan, have found that the water extract of corn suppressed the progression of diabetic glomerular sclerosis (progressive kidney disease) in STZ-induced diabetic rat.

According to another study published in Biological & Pharmacological Bulletin, the effectivity of water extract from the style of Zea mays on diabetic nephropathy was investigated in the development of new natural medicinal resources.

STZ induced diabetic rats were used to evaluate the therapeutic effect of the style. Urinary albumin excretion and creatinine clearance (markers for kidney function) were examined for diagnosis of diabetic nephropathy (caused by longstanding diabetes mellitus characterised by protein in the urine, and is a prime indication for dialysis). From these results it was learned that the style of Z. mays prevented glomerular hyperfiltration (linked to early kidney damage in diabetic patients).

Researchers have found that a decoction of the leaves and roots of corn could be used in the treatment of strangury (slow and painful discharge of the urine, due to spasm of the urethra and bladder), dysuria (painful or difficult urination) and gravel.

The corn silks are used in traditional medicine as cholagogue (a medicinal agent which promotes the discharge of bile from the system, purging it downward), demulcent (serving to soothe or soften), diuretic (induces urination), lithontripic (removes stones from the kidney, bladder), mildly stimulant and vasodilator (drugs that act as blood vessel dilator and open vessels by relaxing their muscular walls). They also act to reduce blood sugar levels and so are used in the treatment of diabetes mellitus as well as cystitis (inflammation of the urinary bladder), gonorrhoea, and gout.

An earlier study indicated renal function improving action of corn silk and binahong in gentamicin-piroxicam induced kidney failure. The study titled “Study of Kidney Repair Mechanisms of Corn Silk (Zea mays L. Hair)-Binahong (Anredera cordifolia (Ten.) Steenis) Leaves Combination in Rat Model of Kidney Failure” was published in International Journal of Pharmacology.

Anredera cordifolia, commonly known as the Madeira vine or mignonette vine, is a South American species of ornamental succulent vine of the family Basellaceae. The combination of fleshy leaves and thick aerial tubers makes this a very heavy vine.Taken together, results of this study suggest that corn silk in combination with binahong possesses renal function improving activity which is slightly better compared to the activity of each extract alone. The results further indicate that reduction of oxidative stress by each extract as well as their combination might be beneficial to the repair of renal damage.

Another study published in the International Journal of Pharmaceutical Sciences Review and Research by Indian researchers from the S. N. Institute of Pharmacy, Pusad, Dist –Yavatmal, corn silk could be used to burst kidney stones.

The researchers found that corn silk was playing an important physical role in treatment by increasing the contraction of smooth muscles a led to increase the urinary output and increased the percentage the passage of urinary stones through the urinary tracts.The study is titled “In-vitro Anti-Urolithiatic Activity of Corn Silk of Zea Mays.”

The researchers noted: “Kidney stone is one of the most important problems in different countries over the world. They are affected by different factors like nutrition, age, drug history and other environmental and family factors. Locally, corn silk used as decompose of stones. This study proved aqueous extracts of corn silk of Zea mays executed on generated calcium oxalate crystals by homogenous precipitation method for in-vitro anti-urolithiatic activity.

“The aqueous extracts of corn silk of Zea mays as shown significant activity on comparison to the synthetic drug Spironolactone, furosemide and poly-herbal formulation Cystone.“The plant drugs survey of corn silk of Zeal mays narrates that; the drug has been utilized for preclinical and clinical activities. “Corn silk is a rich source of potassium, soothing, relaxing diuretic and a wonderful remedy for acute inflammation of the urinary system, such as cystitis, urethritis and prostatitis.

“Also helping the passage of urinary stones. Corn silk encourages urination, while the potassium in the herb offset potassium loss caused by increased urination. It contains flavonoids (may sin), Allantois, Alkaloids, Sapiens, Volatile oil, Mucilage, Vitamins B, C and K, Silicon.”

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