1.1. Genus Atropa belladonna (Table 1)
Although
Atropa belladonna was introduced and grown outside of its original area, its origin can be traced back to eastern, central, and southern Eastern Europe, as well as Turkey, the Caucasus, Iran, and North Africa. It was mentioned in the Skne Flora 1870 as being grown in Malmö apothecary gardens in southern Sweden [
11].
In Britain,
Atropa belladonna only grows naturally on tainted ground, calcareous soils, field borders, open forests, and hedgerows. As an alien species and often a relic from its previous use, it is more commonly found as a medicinal herb. According to the “Online Flora Atlas of Britain and Ireland,” birds are the primary means of seed dispersal [
11].
In some North American regions,
Atropa belladonna has become naturalized and can frequently be found in damp, shaded areas with limestone-rich soils. The Plants Profile for
Atropa belladonna describes it as a weed that thrives in disturbed soils around the world [
12].
Table 2 shows the various names of
Atropa belladonna.
1.2. Atropa belladonna Morphology:
The species
Atropa belladonna belongs to the Solanaceae family and thrives in uncultivated and desolate regions. It is widespread throughout the Himalayas, Western Europe, and the Mediterranean, including Greece. According to Lee (2007) [
13], it has also made its way to Northern America. The name “
Atropa belladonna” is derived from the Greek word “Atropos,” which refers to one of the three mythological Fates, and “belladonna” is an Italian translation meaning “beautiful lady.” The plant acquired this name because Venetian women used
Atropa belladonna for cosmetic purposes, as it causes dilation of the pupils (mydriasis). It is also commonly known as deadly nightshade. In dry quarries and plains,
Atropa belladonna grows as a perennial shrub. It produces greenish-purple flowers, spherical leaves, and sweet purple-black berries. It can reach a height of 1.5 m [
13].
The alkaloids scopolamine, atropine, and hyoscine are present in all parts of the plant, which gives it its toxic and hallucinatory properties. According to Zárate, el Jaber-Vazdekis, Medina, and Ravelo (2006) [
14], the highest concentration of alkaloids is found in fully ripe fruits and green foliage. Atropine, primarily found in ripe fruits, is the most abundant alkaloid, constituting approximately 98% of the alkaloid content. It is estimated that the plant’s fruits contain around 2 mg of atropine, as shown in
Figure 1.
1.3. Medicinal Uses of Atropa belladonna:
Belladonna is known for its extreme toxicity. It contains over 20 distinct anticholinergic alkaloids that inhibit the function of acetylcholine in the body. One of the main active molecules is hyoscyamine, which is transformed into a combination known as atropine [
15,
16]. While cholinergic activity is generally beneficial in the body, inhibiting cholinergic action can be helpful in certain conditions, particularly respiratory problems. Belladonna has been used to alleviate headaches, irritable bowel syndrome, and menopausal symptoms [
17,
18].
The alkaloids in Belladonna, its major active ingredients, serve as deterrents to prevent animals from consuming the plant. The roots contain approximately 0.7% alkaloids, while the leaves have about 0.04% alkaloids. Hyoscyamines, scopolamine, atropine, apoatropine, cuscohygrine, and aposcopolamine are among the alkaloids found in varying concentrations in the leaves and roots [
19,
20]. The seeds of Belladonna contain around 0.06% alkaloids, with atropine and scopolamine being the most abundant [
20,
21]. Each mature berry of Belladonna contains approximately 2 mg of alkaloids, with 98% being atropine [
22].
Ingesting two to five berries or even a single leaf can be lethal. Most cases of poisoning occur due to the mistaken consumption of the berries, often confused with blueberries, or intentional self-harm. Unintentional poisonings have also been linked to extracts of Belladonna [
23]. Due to its high toxicity, even a single leaf or a small number of berries can be fatal, and the resemblance of the berries to other fruits can lead to confusion [
23].
Organophosphates are highly toxic insecticides that inhibit the acetylcholinesterase enzyme responsible for degrading acetylcholine, leading to its accumulation in the body. In cases of poisoning with organophosphates, atropine, derived from Belladonna, is commonly used to alleviate the overstimulation of cholinergic activity. Anisodamine, a less potent alkaloid, has been explored as a potentially successful alternative to atropine with lower toxicity [
24].
The total extract of alkaloids, including hyoscyamine and atropine from Belladonna, has been found to reduce mortality rates in dogs and rats poisoned with the insecticide parathion [
25]. In rats, a commercial extract of belladonna alkaloids, combined with ergotamine, enabled survival from otherwise fatal scorpion toxin injections [
26]. In two separate modern trials involving nearly 150 individuals with irritable bowel syndrome (IBS), a 10 mg belladonna extract drug combined with 50 mg of opium papaverine alkaloid reduced discomfort, cramps, and bowel movements. However, two other commercial drugs were found to be more effective [
27,
28]. A study from 1979 on 12 individuals discovered that scopolamine, a belladonna alkaloid (10 mg of hyoscine butylbromide taken four times daily), provided relief for irritable bowel syndrome, particularly when combined with lorazepam and ispaghula husk laxative [
29]. In conventional medicine, additional medications are often used to treat the symptoms of irritable bowel syndrome, as it is a complex disease that requires a comprehensive approach addressing various underlying imbalances [
30].
In two clinical trials involving over 100 menopausal women, a 0.2 mg alkaloids drug called Bellergal was found to relieve symptoms. However, after 8 weeks, the effects of one of the trials were no longer distinct from those of the placebo [
31]. Bellergal was also used to treat hot flashes among 31 postmenopausal breast cancer survivors in an observational study [
32]. In three clinical studies involving more than 200 individuals undergoing prostate and urinary procedures, opium suppositories and Belladonna were found to alleviate pain, urgency of urine, and reduce the need for painkillers. However, in two clinical trials involving over 100 women, they were unable to reduce pain from bladder injections or vaginal surgery [
33].
Belladonna alkaloids have been found to minimize airway obstruction by inhibiting bronchial constriction. In two investigations involving over 100 children, oral tinctures of belladonna (providing 0.01 mg per kg of atropine 1-2 times per day for 7 days) improved breathing and unblocked airways [
34,
35]. However, in the case of chronic obstructive pulmonary disease (COPD), obstructed airways are typically treated in conjunction with other medications, including beta-agonists and anticholinergics [
36]. In an earlier clinical experiment involving 55 individuals with regular headaches, a combination of 0.2 mg belladonna alkaloids, phenobarbital, and ergotamine taken twice daily for four weeks alleviated discomfort and reduced the need for pain medication. A similar combination, known as Bellergal, achieved “good results” in reducing headaches in 73% of individuals in a case series from the 1950s [
37].
A previous clinical study on 25 women taking Bellergal, which contains belladonna alkaloids at a dose of 0.2 mg three times daily for 10 days before menstruation, demonstrated alleviation of symptoms [
38]. In two therapeutic trials, the alkaloid atropine derived from Belladonna was found to reduce drooling in seven adults and 19 disabled children. In a trial involving 140 children, it also alleviated drooling caused by the sedative ketamine, but this effect was not observed in an observational study of 164 individuals [
39].
Pregnant women often experience increased salivation, which can be associated with nausea. Belladonna, by inhibiting the rest-and-digest function of acetylcholine, reduces salivation. In two pregnant women, the alkaloids of belladonna (administered four times daily for 5 days) in combination with phenothiazine suppositories reduced nausea and excessive drooling [
40].
In an earlier clinical trial involving 75 individuals with digestive ailments, a dose of 0.1 mg of Bellergal taken four times daily for 4 weeks effectively reduced anxiety, surpassing the effects of the sedative Librium (chlordiazepoxide) [
41]. However, in another earlier clinical trial with almost 1,100 participants, both 20 drops of oral tincture or atropine at a dose of 0.4 mg were unable to alleviate anxiety induced by a contrast agent used for evaluating the urinary tract [
42].