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Okra, Aloe employed to filter microplastics out of wastewater

By Chukwuma Muanya
31 March 2022   |   4:15 am
Until now, several studies had shown that regular intake of okra soup could provide novel ‘cure’ for diabetes, breast and prostate cancers, stomach disorders, prolonged labour during childbirth...

Aloe vera

•Combo could provide novel ‘cure’ for diabetes, cancers, stomach disorders, prolonged labour during childbirth, goitre

Until now, several studies had shown that regular intake of okra soup could provide novel ‘cure’ for diabetes, breast and prostate cancers, stomach disorders, prolonged labour during childbirth and goitre (caused by iodine deficiency).

However, okra may not be very good for males who are still producing children especially, those that have previously had infertility problems.

Also, previous studies had shown that Aloe vera could provide the next novel drugs for diabetes and colon cancer.
Despite being a good source of vitamins and fibre, many people are put off eating okra due to the weird ‘slime’ that oozes from the vegetable when people cut into it.

Now, scientists say okra slime could be put to good use, as a way to filter water of microplastics – tiny pieces of plastic less than 0.2 of an inch (5mm) in diameter.

Goo from okra, as well as plants including aloe and cactus, contain chemicals that are called ‘flocculants’ – meaning they clump up, taking microplastics with them.

Scientists say such a method offers an alternative to using potentially dangerous chemicals for filtering water intended for human consumption.

They want to commercialise a new plant-based water filtering method so microplastics can be removed from water on an industrial scale – enabling cleaner and safer water for everyone to drink.

Researchers tested extracts from fenugreek, cactus, Aloe vera, okra, tamarind and psyllium as flocculants to capture microplastics. They tested compounds from the individual plants as well as in different combinations.

Microplastics, small pieces of plastic, less than 5 mm (0.2 inch) in length, occur in the environment as a consequence of plastic pollution. Microplastics are present in a variety of products, from cosmetics to synthetic clothing to plastic bags and bottles. Many of these products readily enter the environment in wastes.

Microplastic pollution has been detected in human blood for the first time, with scientists finding the tiny particles in almost 80 per cent of the people tested.

The discovery shows the particles can travel around the body and may lodge in organs. The impact on health is yet unknown. But researchers are concerned as microplastics cause damage to human cells in the laboratory and air pollution particles are already known to enter the body and cause millions of early deaths a year.

Researchers have hypothesised that human exposure to microplastics could lead to oxidative stress, Deoxy ribo Nucleic Acid (DNA)/genetic material damage and inflammation, among other health problems. Particularly, when inflammation becomes chronic, this can pave the way to very serious health problems.

Why is okra slimy? The sticky ‘goo’ that sticks to the knife when one cuts okra, is called mucilage, which plays a role in water storage and food for the plant.

Okra pods have a high concentration of mucilage. Mucilage is also found in the leaf of the okra plant (Abelmoschus esculentus).

Mucilage is not only produced by okra but nearly all plants including aloe, cactus and psyllium. Commonly called okro, okra or Lady’s fingers in English; the French call it gombo or gumbo and to the Portuguese it is quiabo, quiabeiro or quingombo.

Scientifically known as Abelmoschus esculentus, okra belongs to the plant family malvaceae. In Nigeria it is called ikhiavbo in Edo, etigi in Efik, ikhiabo in Esan, okmi in Gwari, bera or dan dawan betso in Hausa, oro kpoloko in Igala, atike in Ibibio, okwulu or okwuru in Igbo, ihaa in Isoko, dena in Jukun, gebalgo in Kanuri, kpanmi roko in Nupe, ishavbo in Urhobo, ila in Yoruba, among others.

A researcher at Tarleton State University in Stephenville, Texas, United States, Rajani Srinivasan, is the principal investigator for the project.

“We think that microplastics by themselves may not be much of a health hazard, but anything that they get into or any type of toxic substance that gets attached to these plastics could go inside our bodies and cause problems,” she said.

The health effects of ingesting microplastics – tiny pieces of plastic 5 mm (0.19-inch) or smaller – are currently unclear.

Studies suggest that people unintentionally consume tens of thousands of these particles every year. Microplastics also enter a variety of water sources, such as ocean water, estuary water, freshwater and groundwater, or even wastewater, possibly because humans have ingested them before being secreted.

Different water types, including wastewater, can be treated so that the water can be reused for a variety of purposes, such as irrigation, flushing toilets or even replenishing drinkable water supplies.

In the typical wastewater treatment process, microplastics are removed from water in two steps. First, plastic particles that float are simply skimmed off the top of the water; however, this step only removes a fraction of the total microplastics that are present.

The rest must be removed by adding ‘flocculants’ – sticky chemicals that promote the clumping of particles. These flocculants attract microplastics and form large clumps, which then sink to the bottom of the water and can be separated from it.

However, some substances currently used to remove contaminants are potentially harmful. Microplastic pollution has been found in human organs — with scientists fearing the tiny particles could increase the risk of infertility and cancer — a study has reported.

Experts from the Arizona State University are the first to show that the tiny plastic particles — which form when larger plastics break down — can enter our tissues.

Microplastics are typically less than 0.2 inches (5 mm) across, but so-called nanoplastic particles can be as small as a fiftieth of the width of a human hair.

Previous studies had established that humans and animals could ingest the particles — such as via drinking water — and pass through the gastrointestinal tract.

The latest findings, however, are the first to show that they can also accumulate within human organs including the kidneys, liver and lungs.

Although the health impacts of this build-up in humans are unknown, experts have linked microplastic pollution to inflammation, infertility and cancer in animals.

For example, one common flocculant, polyacrylamide, can break down into toxic chemicals under certain conditions. So the team turned their attention towards food-grade plant extracts as non-toxic flocculants – most notably okra.

In many cuisines, okra serves as a master thickener of stews and soups due to its characteristic slime, called mucilage. Mucilage is a thick, gluey substance produced not only by okra but nearly all plants including aloe, cactus and psyllium.

The team specifically focused on polysaccharides in the goo extracts, because these biopolymers can attract and capture pollutants like dyes or even bacteria.

They tested polysaccharide extracts from fenugreek, cactus, Aloe vera, okra, tamarind and psyllium – all of which are food-grade materials – as flocculants to capture microplastics.

They tested compounds from the individual plants, as well as in different combinations. To do this, they added these extracts to various microplastic-containing water sources.

Then, they examined microscope images of the flocculant clumps before and after treatment and counted the microplastics to determine how many particles had been removed.

Polysaccharides from okra paired with those from fenugreek could best remove microplastics from ocean water, they found, whereas polysaccharides from okra paired with those from tamarind worked best for freshwater samples.

Overall, the plant-based polysaccharides worked better than, or as well as, the traditional flocculant polyacrylamide, depending on the combination of extracts and water source.

Importantly, the plant-based flocculants could potentially be implemented in existing water treatment processes, the team claim.

“The whole treatment method with the non-toxic materials uses the same infrastructure,” said Srinivasan. “We don’t have to build something new to incorporate these materials for water treatment purposes.”

Looking forward, she and her team will tweak the ratios and combinations of plant-based flocculants to best remove microplastic from multiple water types.

They also plan to scale up their non-toxic microplastics removal process in field studies outside of the lab.
The researchers presented their results at the spring meeting of the American Chemical Society, which was held virtually and in-person from March 20-24.

What are microplastics? Microplastics come from a number of sources, including synthetic clothing; packaging plastic and bags; make-up; paint; larger pieces of plastic that break down; and fragments of worn car tyres. Microplastics are less than 5mm in diameter. Nanoplastics are less than one ten-thousandth of a millimetre.

Where are they found? Nanoplastics are so small and light that they can be carried on the air around us. They have been detected in a wide range of food and drink products, including bottled and tap water, beer, salt, sugar, and seafood.

What happens to them? Only nine per cent of the nine billion tons of plastic ever produced has been recycled. Most of the rest has ended up in the environment, in the sea, or been buried or burned.

Are they harmful? Microplastics are increasingly being found in vital organs in humans such as the brain, womb and lungs. While the science is in its infancy, scientists suspect microplastics can potentially cause or aggravate respiratory conditions. The particles have also been found in the gut and blood. Some researchers suspect their presence is likely to worsen inflammation.

Do they carry dangerous chemicals? Plastic particles can act as carriers of chemicals and pollutants. These can include endocrine disrupting chemicals, which are associated with disruption in fertility, delayed neurodevelopment in children, immune disorders, and hormone-related cancers.

Meanwhile, researchers have the first time, confirmed that Abelmoschus esculentus peel and seed possess blood glucose normalization and lipid profiles lowering action in diabetic condition.

The study was aimed to study the anti-diabetic and antihyperlipidemic potential of Abelmoschus esculentus peel and seed powder (AEPP and AESP) in streptozotocin (STZ)-induced diabetic rats.”

The study published in Journal Pharmacy Bioallied Sciences is titled “Antidiabetic and antihyperlipidemic potential of Abelmoschus esculentus (L.) Moench in streptozotocin-induced diabetic rats.”

Previous studies reported that okra polysaccharide possesses anti-complementary and hypoglycemic activity in normal mice. Also, okra polysaccharide lowers cholesterol level in blood and may prevent cancer by its ability to bind bile acids.

Also, another study published in Asian Pacific Journal of Tropical Medicine has shown therapeutic effect of okra extract on gestational diabetes mellitus rats induced by streptozotocin.

The Chinese researchers concluded: “Okra extract, rich in antioxidant substances, could avoid the excessive consuming of antioxidant enzymes, then, suppresses the oxidative stress and insulin resistance, thereby improving blood glucose level of Gestational Diabetes Mellitus (GDM) rats.”

Meanwhile, researchers have observed in laboratory studies that okra potently inhibits highly metastatic mouse melanoma cells and kills human breast cancer cells outright, while one fascinating population study has revealed that men eating okra as part of a Southern eating pattern experienced 40 per cent less prostate cancer.

The study titled “Lectin of Abelmoschus esculentus (okra) promotes selective antitumor effects in human breast cancer cells” was published in Biotechnology Letters.

A newly discovered lectin in common okra was shown to kill up to 72 per cent of human breast cancer cells (MCF7) in vitro, mostly by inducing programmed cell death (apoptosis). The okra lectin was also shown to slow the growth of the breast cancer cells by 63 per cent. Note that the lectin is found in okra seeds, and researchers in this study obtained their lectin by water extraction from okra seed meal. This anti-cancer lectin was only discovered in 2012, and interestingly, also possesses anti-inflammatory and anti-nociceptive (pain relieving) properties, which makes it a very interesting compound for future research.

The researchers in this study noted that the lectin compound is a “potential therapeutic to combat human breast cancer.” But don’t scrape out the seeds and throw away the rest of the pod, because another component of okra also has demonstrated anti-cancer properties, namely the pectin.

Okra pectin is found just under the skin of the pods, and scientists have discovered it contains very unique compounds (highly branched rhamnogalacturonans), which have never before been observed in other pectins. Perhaps it is the newly discovered compounds that are responsible for the effectiveness of the pectin against melanoma.

In a recent study conducted by French and Dutch researchers, the pectin inhibited the proliferation of highly metastatic mouse melanoma cells (B16F10) by 75 per cent after 48 hours of treatment and also increased the rate of programmed cell death (apoptosis) by nearly 23-fold. The researchers also discovered that the pectin triggered apoptosis by interacting with Galectin-3. This is a similar mechanism to what is observed with the well-known compound Modified Citrus Pectin, and it is very interesting that okra pectin does not have to be modified in any way to have this effect.

The two studies above show clearly that two different components of okra (pectin and lectin) have potent anticancer properties, therefore, as usual, we are probably better off consuming the entire edible portion of okra if one wants to maximise its anti-cancer benefits.

A recent cohort study carried out in the United States found that men eating a Southern dietary pattern (characterized by eating okra, grits, cornbread, beans, rice and sweet potatoes) experienced 40 per cent less prostate cancer than those not eating such a diet. Although the result bordered on statistical significance, this was a fair-sized study, which followed nearly 3,800 men for ten years. What is truly fascinating about this study is that, apart from okra, beans and sweet potatoes, the Southern eating pattern was actually not a very healthy diet, and contained high portions of red meat and bacon which are both known to increase cancer risk. Moreover, the Southern eating pattern protected men from prostate cancer much more than a vegetable and fruit rich diet did, even though it contained 24 per cent less fruit and vegetables (29 servings weekly on the Southern diet vs. 38 servings weekly on the fruit & vegetable rich diet).

Also, a team of Swiss and German researchers has found that okra juice may in fact help to prevent Helicobacter pylori, a bacterium that can cause stomach ulcers and cancer, from sticking to the stomach wall.

Previous studies have recorded the presence of iodine in the leaves and stems of okro plant, with greatest concentration when the green coloration is most conspicuous. It has also been shown to offer medical benefits in areas of high goitre incidence. A decoction of the leaf is reportedly given to women in labour to ease childbirth.

Meanwhile, a pooled analysis of nine studies that examined the effect of oral Aloe vera in people with diabetes and pre-diabetes suggests the medicinal plant should be further investigated as an anti-diabetic compound.

Aloe vera should be further investigated as a potential anti-diabetic compound, say researchers after analyzing evidence that it lowered blood glucose in patients with diabetes and pre-diabetes.

The analysis is the work of researchers at the David Grant USAF Medical Center at Travis Air Force Base in Fairfield, CA, who report their findings in The Journal of Alternative and Complementary Medicine.

The analysis shows people with diabetes whose fasting blood glucose (FBG) is above 200 mg/dl may benefit the most from treatment with oral Aloe vera.

More recently, Aloe vera has been used as a skin application to treat seborrheic dermatitis, psoriasis vulgaris, and genital herpes, and orally as a laxative.

Seborrheic dermatitis, also called seborrheic eczema is a skin condition that causes scaly patches and red skin, mainly on the scalp.

Aloe vera contains dozens of active compounds. The part of the Aloe vera plant that is used medicinally is the leaves, the major components of which are the green outer rind and the colorless inner gel. Aloe vera products are made from either of these components, or both.

The Aloe vera plant contains at least 75 active compounds, “which notably include vitamins, enzymes, minerals, anthraquinones, monosaccharide, polysaccharides, lignin, saponins, salicylic acids, phytosterols, and amino acids,” note the authors, who also cite studies suggesting some of these compounds play a role in improving blood glucose control.

The plant also contains trace elements such as chromium, magnesium, manganese, and zinc, known to be important for glucose metabolism by improving the effectiveness of insulin.

Studies of oral Aloe vera as a remedy for a range of chronic diseases – such as asthma, glaucoma, high blood pressure, inflammatory bowel disease, and diabetes – have produced limited or inconsistent evidence.

However, oral Aloe vera is becoming more popular, and evidence about its effect on lowering blood glucose has been mounting, so the researchers decided to analyze it.

For their analysis, the team looked for studies of the effect of oral Aloe vera on fasting blood glucose (FBG), hemoglobin A1c (HbA1c), oral glucose tolerance test (OGTT), and a number of other measures in pre-diabetic and diabetic populations.

They found only nine studies had appropriate data for meta-analyses and covered FBG and HbA1c only. Of these, all nine measured FBG (total of 283 participants), and five measured HbA1c (89 participants).

FBG (sometimes called fasting plasma glucose, FPG) measures the blood glucose level during a period when the patient has not had anything to eat or drink, except water, for at least 8 hours. A level in the range of 100-125 mg/dl is defined as pre-diabetic and 126 mg/dl or higher as diabetic.

HbA1c (glycated hemoglobin, sometimes called haemoglobin A1c or simply A1c) is a measure of average blood glucose over the past two to three months. A level greater than or equal to 6.5 percent is considered diabetic.

The meta-analysis showed Aloe vera decreased FBG by 46.6 mg/dl and HbA1c by 1.05 in the populations studied. The researchers also noted “the data suggest that patients with an FBG ≥200 mg/dl may see a greater benefit,” and this population saw an average FBG reduction of 109.9 mg/dl.

In their conclusion, the researchers point to several limitations of the data and findings. For example, there were inconsistencies across studies in the formulation of Aloe vera used, making it difficult to determine which products would be effective.