‘Corn silk stops prostate cancer, diabetes’

Scientists have 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.

The study titled “Corn silk maysin induces apoptotic cell death in PC-3 prostate cancer cells via mitochondria-dependent pathway” was published in Life Sciences.

The results of the study 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 (Zea mays), in PC-3.

Maysin was isolated from CS of Kwangpyeongok, a Korean hybrid corn, via methanol extraction and preparative C18 reverse phase column chromatography. Maysin cytotoxicity was determined by either monitoring cell viability in various cancer cell lines by MTT assay or morphological changes. Apoptotic cell death was assessed by annexin V-FITC/PI double staining, depolarization of mitochondrial membrane potential (MMP), expression levels of Bcl-2 and pro-caspase-3 and by terminal transferase mediated dUTP-fluorescein nick end labeling (TUNEL) staining. Underlying mechanism in maysin-induced apoptosis of PC-3 cells was explored by evaluating its effects on Akt and ERK pathway.

Maysin dose-dependently reduced the PC-3 cell viability, with an 87 per cent reduction at 200 μg/ml. Maysin treatment significantly induced apoptotic cell death, DNA fragmentation, depolarization of MMP, and reduction in Bcl-2 and pro-caspase-3 expression levels. Maysin also significantly attenuated phosphorylation of Akt and ERK. A combined treatment with maysin and other known anti-cancer agents, including 5-FU, etoposide, cisplatin, or camptothecin, synergistically enhanced PC-3 cell death.

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.

The cobs of corn, with white to yellow grains, are the delight of most Nigerians. But the silky tassel inside its husk, which is not often considered as food is highly valued because of its medicinal properties.

According to a study published in Nutrition and Metabolism, corn silk contains proteins, vitamins, carbohydrates, Ca, K, Mg and 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.”

Until now, there have been many reports on the biological activities of corn silk constituents. Methanol extracts of corn silk showed an antioxidative activity on the level of lipid peroxidation. Volatiles from corn silk inhibited the growth of Aspergillus flavus, indicating that it has an antifungal activity. In addition, extract of corn silk inhibited TNF and LPS-induced cell adhesion, but not cytotoxic activity or TNF production.

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.

Gonorrhoea is a common ually transmitted infection caused by the bacterium Neisseria gonorrhoeae. Gout (also known as podagra) is a medical condition characterised by recurrent attacks of acute inflammatory arthritis – a red, tender, hot, swollen joint.

Folklore uses of a decoction of the cob include treatment of nose-bleeds and menorrhagia (an abnormally heavy and prolonged menstrual period at regular intervals). The seed is diuretic and a mild stimulant. It is a good emollient poultice for ulcers, swellings and rheumatic pains, and is widely used in the treatment of cancer, tumours and warts. It contains the cell-proliferant and wound-healing substance allantoin, which is widely used in herbal medicine to speed the healing process. The plant is said to have anticancer properties and is experimentally hypoglycaemic (lowers blood sugar) and hypotensive (lowers blood pressure).