MEDICINAL PLANTS AND DIABETES

INTRODUCTION

Diabetes is the most widespread endocrine disease (or rather syndrome).
It is estimated that there are more than 500 million diabetics (2023) worldwide and this figure, as well as the percentage of the population affected, are constantly increasing .
The number of people with diabetes in France has more than doubled in 20 years according to figures from the Health Insurance, going from 1.6 million in 2000 to more than 4 million in 2023.

Several causes or factors are responsible for it:

certainly a better diagnosis of the diabetic state due to greater ease and wider detection (geographically) of blood glucose disorders,
certainly also an increase in the percentage of the affected population by this metabolic-endocrine « disorder » in rich countries where the relative cost of food has dropped considerably and daily stress has increased, but also in many « developing » countries; it is even in these that the increase is the fastest.
It is necessary to differentiate the two classic types of diabetes:
insulin-dependent diabetes (type 1), which accounts for 20 to 25% of people with diabetes, usually coming early in life and treated with insulin injection plus a strict food monitoring (of carbohydrate intake),
non-insulin-dependent diabetes (type 2, or diabete of the elderly often overweighted) who come out later and are most often balanced by a diet (slimming) hypocaloric-hypoglucidic with or without associated drug treatment (mainly hypoglycemic sulfonamides, biguanides, insulin).
It is the latter type of diabetes that seems to be constantly growing and can be cured by herbal medicine.

Main drug treatments

Insulin is a natural hormone that regulates glucose metabolism (the main « sugar » in blood), secreted by the pancreas;
it decreases the glucose content of the blood (glycemia) by acting on several levels:

by increasing the « capture » of blood glucose in the liver and muscles and its transformation into a reserve substance, glycogen,
by reducing the reverse operation (glycogen degradation),
by increasing the conversion of glucose to fat (stored),
and by increasing protein synthesis from glucose.

Other antidiabetic medicines are artificial:

hypoglycemic sulfonamides temporarily increase the natural secretion of insulin,
biguanides (inactive in non-diabetic subjects) increase glucose utilization in the body, improve insulin efficiency, decrease glycogen breakdown and also decrease intestinal absorption of glucose.

For several years, new drugs have been marketed to specifically treat type 2 diabetes, they are ineffective and may be dangerous for patients with type 1 diabetes.
These new drugs target a natural molecule (GPL1) secreted by certain parts of the digestive tract (intestine) which mainly :

increases pancreatic secretion of insulin,
blocks glucagon secretion,
delays stomach emptying
and acts on the brain to suppress appetite (satiety effect).
All this limits food consumption and induces a decrease in blood glucose (antidiabetic effect).
There are two types of new drugs: some act like the GPL1 hormone, others delay its disappearance in the body, because this small GPL1 hormone has a lifespan of a few minutes.
These new products are very expensive, in 2024, a treatment can reach several thousand dollars or euros per year when you are not covered by insurance. These treatments have many side effects (especially digestive) and can promote the development of thyroid cancer.
These are injectable drugs that require one injection per week, often at an increasing dose.
They are often used to combat excess weight or obesity.
In the family of long-acting GLP-1 analogues: Semaglutide (Ozempic, Wegovy), Dulaglutide (Trulicity), Tirzepatide (Mounjaro, Zepbound), Amycretin or Bydureon.
Those that prevent the disappearance of the GPL1 hormone, gliptins: pharmacovigilance data report numerous side effects, sometimes serious: heart failure (observed with saxagliptin but not with other gliptins), kidney disorders, immune problems, pancreatitis, skin disorders, disabling joint pain, etc.

Diabetes is a complex metabolic disorder (or pathogenesis) that can lead to serious accidents (coma hypo or hyper glycemic), but is also accompanied by various secondary complications (sometimes more difficult to treat than the main disorder). These complications are related to a disruption of the metabolism of fats (cholesterol, lipoproteins) and an increase in the creation of « free radicals » chemically very reactive and which modify the functioning of the cells, or even causes their destruction.
At the same time inflammatory microreactions are observed in many tissues and especially in small blood vessels; blood circulation is decreased which favoured trophic disorders and infections.
While synthetic antidiabetic drugs are most often used to control blood glucose levels, they generally do not act on complications.

PHYTOTHERAPY AND DIABETES

Diabetes is an old disease whose classic symptoms: hunger and thirst with increased volume of urine, thinness or obesity, risk of coma, are well known by the majority of healers or traditional healers;
many plants are traditionally considered as antidiabetics some are at the origin of the development of drugs eg biguanide metformin thanks to Gallega officinalis.

Faced with the considerable increase in the number of diabetics in countries whose « standard of living » is improving (eg India, China, Southeast Asia, the Mediterranean region), many researchers have evaluated the pharmacological action of these traditional plants and therefore their interest in daily medicine in these countries where synthetic drugs are still quite expensive and where the tradition of plant medicine is well established (for example in Morocco, a survey in a group of diabetics (type 2 ) reveals that 25% use only plants to heal).

In « rich » countries where the treatment of diabetes (insulin-drugs) is easy to access, it is interesting to use herbal medicine, alone or in addition, to reduce the dose of synthetic drugs, but also because some phytomedicines seem at the same time able to fight against the complications of diabetes (sclerosis of the blood vessels, arteritis, hypertension, infections.)

Two types of plant substances seem interesting:

those that act in the same way as insulin or other hypoglycemic drugs:

by preventing the absorption of glucose at the intestinal level
by increasing the synthesis and release of pancreatic insulin
by decreasing that of glucagon
by accelerating the consumption of blood glucose (absorption in cells, synthesis of glycogen, fats or proteins).

Others, mainly tannins, act on diabetes itself at the cellular level, promoting the action of insulin (by decreasing insulin resistance) and on the complications of diabetes by their antioxidant and antienzymatic properties, neutralizing the effect of free radicals and limiting the inflammatory reaction in different tissues.

Some plant extracts sometimes contain these two types of substances.

MEDICIAL PLANS TO CURE DIABETES 2
and its complications(some examples) :

Allium cepa (onion)

The sulfur compounds are the active molecules, the fraction extracted with ethyl ether is the most antidiabetic.
Uses :
Daily consumption of raw onions at a rate of 30 to 40 g per day (quite difficult to bear), but the cooked onion and its aqueous extract are also hypoglycemic (soup, infusion), or ethanolic tincture (40 to 50 drops 3 times per day).

The onion has hypoglycemic properties, antihyperglycemic, antioxidant and lowers the level of blood lipids.

Allium sativum (garlic)

Sulfur compounds are moderately active on blood glucose (rather unstable), but these same compounds are interesting for their action on the complications of diabetes: blood dyslipidemia (cholesterol and triglycerides) and cardiovascular complications (atheroma plaques, vascular sclerosis)

Use :

Raw garlic 1 to 2 pods a day (crushed or finely chopped),
Garlic powder 0.5 to 1g per day (in gastroresistant capsules)
Garlic in alcoholic tincture (1/10) (20 to 30 drops a day)

Eucalyptus globulus (eucalyptus)

Eucalyptus essential oil (2 to 3 drops 3 times a day)

It is an antiseptic of the respiratory tract but is also considered by many herbal therapists as slightly hypoglycemic as the ethanolic tincture ( 1/10) (50 drops 3 times a day).

Leaf infusion is slightly hypoglycemic (in artificially diabetic animals) by increased secretion of insulin;

Example of use :
A teaspoonful of broken dry leaves in a cup of very hot water,10 minutes of infusion, 2 or 3 times a day.

This infusion has a tendency to suppress appetite, which can help to support the hypocaloric diet necessary to equilibrate diabetes type 2.

Trigonella foenum graecum (fenugreek)

Fenugreek seeds, known for their ability to facilitate gain weight in case of weight loss or muscle wasting, are also hypoglycemic.

They contain, in particular, an amino acid (4-hydroxyisoleucine) which increases the release of pancreatic insulin in both animals (rats) and humans.
The aqueous extracts of the leaves are also hypoglycemic and antyhyperglycemic.

In a human clinical trial, 50 g seed powder, twice daily for 10 days, in non-insulin-dependent diabetics significantly reduced fasting blood glucose and urinary glucose leakage, as well as blood lipid level.

The hypoglycemic effect is proportional to the ingested dose which could therefore be lowered in a long-term treatment.

The ethanolic extract (tincture) is also hypoglycemic in animals (I am not aware of any trials in humans).

Olea europea (olive tree)

Olive leaves are traditionally considered as hypoglycemic;
They also contain a secoiridoid, oleuropeoside, hypotensive and antioxidant properties (which allows to fight against the sclerosis of blood vessels and inflammation of their walls).

Leaf infusion is less effective than :

Hydroalcoholic extract (ethanolic tincture (1/10) : 60 drops per day).
Glycerine maceration of buds in 1D (50 to 100 drops per day).
Or leaf powder (0.5 to 1g per day).

Some medicinal plants with tannin:

Juglans regia (walnut)
Rubus fructicosus (bramble)
Rubus idoeus (raspberry)
Fragaria vesca (strawberry)
Morus nigra (mulberry)
Vaccinium myrtillus (blueberry)
Camellia sinensis (green tea)
The leaves and buds of these plants contain « medicinal » tannins and often other vascular protective or anti-inflammatory compounds.
Tannins inhibit various enzymes that trigger or participate in the inflammatory response, which may be one of the causes of the inefficiency (resistance) of insulin at the cellular level.

Infusion is the simplest preparation:
30 to 40 g of leaves (a small handle) in 1 liter of very hot water, settle for 15 minutes, 3 to 6 cups a day

For green tea settle for the proportions of traditional infusion.

Ethanolic tincture (1/10) may also be used when they exist:
ex: Vaccinium myrtillus tincture (1/10) or glycerine maceration of buds in 1D , 50 drops three times a day
ex: Juglans regia tincture ( 1/10) , 50 drops three times a day

In the tropical and subtropical countries there are many plants with antidiabetic potential or whose leaves, bark, flowers or fruits contain tannins for use in human medicine.

Here are some examples:

Two species of « COSTUS » are often called « insulin plants » or more often « anti-diabetes plant ».

CHAMAECOSTUS CUSPIDATUS formerly COSTUS IGNEUS native to eastern Brazil with orange flowers, the fairly large and fleshy leaves grow in a spiral on the stem, they are green with purple reflections on their underside, the spiral plant reaches 50 to 60 cm.
COSTUS PICTUS native to MEXICO and neighboring countries of Central America with yellow flowers tinged with red dots and stripes, the leaves are narrower, they grow in a spiral on the green stem sometimes tinged with red which reaches 50 to 60 cm.

The few pharmacological studies on these plants do not reveal the presence of original compounds or with a particular pharmacological activity but several studies mainly in India show that the extracts of these plants have hypoglycemic and blood sugar regulating properties.

These plants are now present in many tropical and equatorial countries, they are acclimatized and cultivated in India, Indonesia and the Philippines where they are part of local pharmacopoeias (in particular in Ayurvedic medicine and Siddha medicine).
The medicinal parts of the two « Costus » commonly called « insulin plants », « anti-diabetes plants » are: mainly the leaves, to a lesser extent the stems and rhizomes, the essential oil of the whole plant.

These two plants are not part of the pharmacopoeias of Western medicine until now but they are widely used in Asia (India, Indonesia, Philippines) and to a lesser extent in Mexico to try to control type 2 diabetes.

The leaves of these plants are used fresh, dried or powdered.

The leaves are sometimes just chewed, we then absorb the leaf juice mixed with saliva.
infusion of fresh or dried leaves like a tea, once or twice a day
addition of leaf powder (one to two teaspoons) to food.

Momordica charantia (bitter gourd)

Widely used in India despite its slight toxic risk; Ayurvedic medicine uses fruit extracts, seeds, leaves or the whole plant.
The probable active substance is a peptide (such as insulin).
Clinical trials in humans (diabetics) have shown that regular administration of Momordica charantia extract results in a significant decrease in blood glucose.
This plant (bitter) is used raw (juice, salad), cooked with water (soup, infusion, spinach), or fried in oil.

Catharanthus roseus ( Madagascar periwinkle)

It is a plant traditionally considered as an antidiabetic in many tropical areas.
It contains many alkaloids.
Experience shows that aqueous and ethanolic extracts (tincture) of leaves given orally in normal rats cause a slight drop in blood glucose and are antihyperglycemic in artificially diabetic rats.
The « tea » of periwinkle of Madagascar (traditional mode of absorption) is perhaps also anorexiant thus favors the follow-up of the diabetes diet).

Syzygium cumini(jambolan, Java plum, black plum or jamun)

Many parts of the tree are hypoglycemic:
Seeds (aqueous and ethanolic extract, powder), fruit, leaves (light decoction or infusion).

It is a plant that contains a lot of tannin, the fruits are astringent ( constipation risk )

Different extracts cause a fairly rapid decrease in blood glucose (probably by release of insulin) with glycogen synthesis in the muscles and liver (which corresponds to the action of insulin released)
There is no toxic effect in animals (diabetic rats)

Ficus bengalensis (sacred fig tree, Indian banyan)

The bark of this majestic tree (or rather of its aerial roots) contains several molecules (glucosides and flavonoids) with hypoglycemic and antihyperglycemic properties.
The glucoside « leucopelargonidine » is the most effective: hypoglycemic effect and lowering of blood lipids with significant increase in insulin release.
The bark also contains tannins.

Terminalia chebula (black myrobolan),Terminalia belerica
Emblemica officinalis ,Terminalia catappa

These trees contain a lot of medicinal tannins.
In traditional Hindu medicine, they are often used in preparations combining several plants.
The combination of their methanolic extracts is marketed (Triphala);
administered orally, 100mg / kg / day, it significantly lowers blood glucose (lower insulin resistance).
Antioxidant action, against free antiradicals, inhibition of certain enzymes (peroxidases) limiting the inflammatory tissue reaction.

Caesalpinia bonducella

It is a powerful, thorny vine, along tropical coastline, often considered as an invasive plant pest.

This plant, native to the Indo-Malayan region was used by the natives of the Andaman and Nicobar Islands to cure the symptoms of diabetes.

Animal tests have shown that the aqueous and ethanolic extract (alcoholic tincture) of the outer part of the seed (not the kernel) seems to be able to control the hyperglycemia of type 2 diabetes while decreasing the level of cholesterol and blood triglycerides.

This plant also has many other medicinal properties.

ZIZIPHUS Species (Chinese date, ber, Chinee apple, jujube, Indian plum, Regi pandu, Indian jujube)

The most useful ZIZIPHUS are:

The Chinese jujube tree or Zizyphus vulgaris (probably equivalent to Z. sativa and Z. jujuba) of very ancient use in food and traditional Arab and Chinese medicine found in temperate or Mediterranean climates.
It is distinguished from Zizyphus mauritiana or tropical jujube tree that can grow in the desert or rather dry areas of sub-tropical regions but also in tropical areas even wet in Africa, in the Indo-Pakistani region, the West Indies, South America .
Z. lotus and Z. spina-christi are mostly present in the Mediterranean and the Middle East.

The interesting parts of ZIZIPHUS species from a dietary or medicinal point of view are the fruit ( jujube), the seed and to a lesser extent the leaves and the roots.
ZIZIPHUS LEAVES are commonly used in plasters on infected or uninfected wounds in deprived areas or when antiseptics or dressings are not available.
Because of its content in flavonoids and tannins, it can be used in case of moderate type 2 diabetes, in the form of daily infusion.
The daily dose will be decreased or spaced in case of constipation.

Phyllanthus niruri Phyllanthus urinaria (stone breaker, seed under leaf)

In Ayurvedic medicine, this small widespread tropical plant is prescribed for its diuretic (and against urinary lithiasis),and hypotensive properties.
It is also hypoglycemic at a rate of 5g per day orally by splitting this dose in the day.

EXAMPLE OF DOSAGE:

Infusion : a small handful of aerial parts in 1/2 liter of very hot water, 10 minutes of infusion
2 to 3 cups a day (it’s very bitter).

Punica granatum (pomegranate)

The red flowers of pomegranate contain medicinal tannin but in less quantity than the other parts of this shrub.
They are considered a cure for diabetes in medicine Unani (India), which has been verified in the diabetic rat (dose: 400mg per kg)

DIET AND DIABETES TYPE 2

In general, type 2 diabetes is a disease associated with prolonged food overload.

It is important to remember the importance of a balanced low-calorie diet to reduce type 2 diabetes.
Very often this will be enough, when the diabetes is moderate and when the resistance of the tissues to the effect of insulin is not constituted.

We must focus on vegetables in the diet, especially « GREEN VEGETABLES »: salad, dandelion, spinach, lettuce, purslane, leaves of amaranth (wild spinach), cabbage, cauliflower, taro leaves (calalou ), cassava leaves, green beans, MORINGA leaves (horseradish tree).

These green vegetables are present in all climates (including the many varieties of cabbages: green cabbage, cabbage, brussels sprouts, Chinese cabbage, broccoli, rapeseed leaves, cauliflower leaves …).

CONCLUSIONS

Medicinal plants or their extracts seem interesting in the case of non-insulin-dependent diabetes (type 2).
However, care should be taken not to abruptly suppress the drugs prescribed or used, but to lower their dosage gradually (this is common sense) until the possible suspension of their intake but always by monitoring the evolution of blood glucose and glycosuria (and glycated hemoglobin is possible).
The association of 2 or 3 plants seems desirable, some act on the release of insulin, f others at the peripheral cellular level, as scavenger of free radicals, on the metabolism of lipids, on hypertension.

Examples in temperate countries:
Onion and blueberry
Onion and walnut
Fenugreek and bramble
Fenugreek and olive tree.
The tannins are not without dangers; at high doses they disrupt the digestion and assimilation of food, cause constipation or even promote digestive carcinogenesis.
Therefore, tannin plants will be used in limited or reduced doses (green tea, bramble tea, tincture of walnut or blueberry).

Antidiabetic plants can cause a sharp drop in blood glucose with hypoglycemic discomfort, or even coma, especially if these plants are associated with a treatment equilibrating the diabetes.

Moreover, the search for a cheap treatment sometimes leads diabetic patients to use any kind of plant, some may be antidiabetic but at doses that make them toxic, others are too dangerous for antidiabetic use (A survey in Morocco reveals that some patients use plants as poisonous as oleander or castor oil to treat their diabetes).

As always, common sense must prevail and information must be controlled or verified.

However, medicinal plants can in some cases (prediabetes, moderate diabetes) be the only treatment (associated with the diet) and in other cases (always type 2 diabetes) can help lower the dosage of antidiabetic drugs while fighting against complications of this « disease ».

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