Herbs in History: Ricinus

Ricinus Ricinus communis L. CONTENTS An Egyptian poison? Changing fate Through the centuries From tick to castor References

By Alain Touwaide & Emanuela Appetiti | April 2024

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An Egyptian poison?

Illustration 1: Ricinus communis L. (Emanuela Appetiti)

Ricinus communis L. (castor oil tree) (Euphorbiaceae) (Illustration 1) has a strange history from ticks to castors!
 
The only species in the genus, Ricinus communis L. has been supposed for a long time to have an obscure origin, possibly India. Research has now determined that is most probably native to North-Eastern Africa (Somalia/Ethiopia) (Illustration 2). It is found all across Africa, west to east from the Atlantic coast to the Red Sea, north to south from Tunisia to South Africa, and also on islands in the Indian Ocean. It naturalizes well and grows in many areas as a common ruderal plant, growing fast as a shrub in the wild and reaching up to 40 feet, but not so much when cultivated in temperate zones.
 
The African origin is confirmed by the historical documentation. Ricinus is first mentioned in the literature in the Egyptian medical papyrus dated to 1550 ca. BCE acquired in 1873 for the library of Leipzig University by the German Egyptologist Georg Ebers (1837-1898) and identified since as the Ebers Papyrus. Possibly more significantly, it is mentioned by the Father of History, the Greek Herodotus (5^th cent. BCE), for whom it definitely is an Egyptian plant. In the Persian Wars (II.94), Ricinus is not described, but referred to in an unequivocable passage:
 

Those among the Egyptians who live about the marshes use an oil drawn from the fruit—which they call kiki—of red spiny seed pods; they proceed in this way: on the banks of the rivers and lakes, they sow these red spiny seed pods, which grow spontaneously wild in Greece; these seed pods sown in Egypt yield an abundant ill-smelling fruit; when they have harvested it, they either bruise and press it or roast and boil it, and they collect the liquid that flows from it; it is fatty and by no mean inferior to the oil of lamps, emanating a heavy smell.

 

Illustration 2: Native distribution and diffusion of Ricinus communis L.

Illustration 3: The spiny red pods of Ricinus communis L.

Many elements are significant in this text, starting with the type of environment in which Ricinus grows, identified in botanical literature as “typically found in moist, well-drained soils in disturbed areas, such as along riverbeds”. Interesting is also the name used by Egyptians to identify the fruit (in fact, the bean): kiki, which, indeed, is that of Ricinus in the ancient Egyptian medical literature. The most important element of description in this brief passage—and the most absolutely unequivocable—is the mention of “red spiny see pods”. The word (sillikupria in ancient Greek) is not known in another currently known Greek work and it is usually interpreted and translated as the name of Ricinus, which is clearly not the case. In fact, it is a compound term made of two elements: silli, possibly referring to spines, and kuprios, which certainly refers to Cyprus Island, but also to copper—which was one the major natural resources of Cyprus—and to the red color; hence the meaning of red spiny thing, literally, which perfectly describes the mature seed pods of Ricinus (Illustration 3), with the bean they contain, from which the oil is obtained. And, to complete the picture, the reference to both its easy propagation in a wild form and a bad odor of the oil.
 

Changing fate

An Egyptian plant without name known through its spiny red fruit and its oil, Ricinus appears slightly later again in the Greek World, but only in the form of the oil obtained from it. This is in the most famous cosmological dialogue Timaeus by Plato (427-367 BCE), where this oil is listed among different types of oily liquids.
 
The tree itself is found later in the Inquiry into Plants (Historia Plantarum, I.10.1) by Theophrastus (ca. 371-287 BCE), the Father of Botany. It is mentioned only once in a way that hints at a recent way of identifying it: “the so-called krotôn”. This phytonym is strange as it is the name of the tick (Illustration 4) as it appears from the Research into Animals (Historia Animalium, V.19 = 552a15) by Aristotle (384-322 BCE), Theophrastus’ master, founder and director of the Lycaeum. This designation certainly refers to the beans (Illustration 5) that produce the oil described by Herodotus and listed by Plato. It may give the impression that the Greeks knew only the bean and not the whole plant. Herodotus’ text is unambiguous, however, with its mention to a spontaneous wild propagation in Greece, as is also Theophrastus’ text, which is about the shape of the leaves of Ricinus and other common trees of Greece. From an unnamed plant with a strangely red shaped fruit, Ricinus was assimilated to ticks, which, added to the foul odor of its oil, seemed to change its fate and expose it to the danger of being eliminated from daily life and, much more, from medicine.
 

Illustration 4: Tick	Illustration 5: Ricinus beans

This did not happen. Ricinus appears indeed in the first century, in Greek in De materia medica by Dioscorides (IV.161) and in Latin in Naturalis Historia (Natural History) by Pliny (23/24-79 CE).
 
In Dioscorides, Ricinus is referred to by its bean, which is not identified as tick (krotôn), but designated by the Egyptian term used by Herodotus and Plato (kiki). Nevertheless, Dioscorides adds that “some people call it krotôn because the seed is similar to the tick”. Pliny, who does not seem to have ever seen the tree but probably uses written material, provides the same lexicological information (15.25):
 

… cici, a tree that abundantly grows in Egypt (some call it croton, some sibi and others wild sesame) …

 
Returning to Dioscorides and his list of synonyms of the kiki name of Ricinus, he includes seseli kuprion, that is, Cypriot celery. However surprising it might seem at first glance, this denomination can probably be explained as a misunderstanding of the term sillikupria used by Herodotus, which refers indeed to Cyprus as we have indicated, but not to any species of celery! In spite of this strange designation, Dioscorides provides a pretty good description of the tree, which indicates that he certainly did not think of Ricinus as a species of celery:
 

It is a tree with the size of a small fig tree; its leaves are like those of the plane tree but larger, smoother, and of darker color; its trunk and branches are hollow like reeds, the fruit is in grape-like spiny bunches; peeled, it resembles a tick; the so-called kikinon oil is obtained from it by pressing it.
 

Illustration 6: Ricinus in manuscript New York, Pierpont Morgan Library, M 652 (Constantinople, 10th century), folio 86 verso	Illustration 7: Ricinus in manuscript Padua, Seminary, 194 (Constantinople, 15th century), folio 78 recto

 This description is fairly correct (Illustrations 6-7), including the comparison of the palmate leaves of Ricinus with those of the plane tree, which generated another name of Ricinus during the Middle Ages as we shall see. After the reference to the production of the kikinon oil, this description is followed by an organoleptic note that does not leave any doubt about the identification: the oil is inedible. Nevertheless, as Dioscorides immediately added, it has value as both an oil for lamps and an excipient for plasters. This description is followed by the medicinal uses of Ricinus:
 

A quantity of thirty seeds cleaned, ground and taken as a draught eliminates phlegm, bile and water through the bowels; they cause vomiting. This purgation is very unpleasant and efficient, as it violently disturbs the stomach. Triturated and applied as a plaster, they remove skin eruptions and freckles.
 
The leaves, ground with fine barley flour, reduce swellings and inflammations of the eyes, swollen breasts, and stop erysipelas applied as such and with vinegar.

 
Interestingly, in Dioscorides’ text, Ricinus is dealt with just before spurge (several species of the genus Euphorbia), which were reputed in Antiquity as a drastic laxative plant thanks to its acrid milky latex.
 
Pliny, too, reports this laxative effect of Ricinus, adding, however, other uses, some of which are surprising (25.83):
 

Ricinus is taken with an equal quantity of warm water to open the bowels. It is said to act especially upon the hypochondria.
 
It is good also for diseases of the joints, for all indurations, for the uterus, the ears and burns, and, with the ashes of the murex shell, for inflammation of the anus, and likewise for the itch.
 
It improves the complexion, and through its fertilizing power it promotes the growth of the hair.

 
To this he adds a note that does not appear in Dioscorides or in any other ancient source:
 

No animal will touch the seed from which Ricinus oil is made.

 
This seems to be the first attestation of a toxicity of Ricinus seeds, which is all too exact. The seeds are, indeed, highly poisonous, with a toxin (ricin) considered as one of the deadliest natural poisons, possibly “6,000 times more poisonous than cyanide and 12,000 times more poisonous than rattlesnake venom. As few as four seeds can kill an average-sized adult …
Ricin is water soluble, not lipid (oil) soluble, so it is not released during the pressing process, remaining in the leftover “seed cake.” This residue is used as a high-nitrogen fertilizer, or after detoxicating, the meal can be used as livestock feed.” (Wisconsin Horticulture online).
 
In an apparently natural contradiction, ricin is not present in the pure oil, which can be consumed and used in medicine, internally as a remedy for constipation and such other health disturbances as heartburn, and externally as an emollient for dry skin.
 

Through the centuries

This twofold activity—purgative and emollient—crossed the centuries. As early as the 9^th century, it appears in the Arabic World with Yuhanna ibn Masawaih (ca. 777–857), known in the Latin literature of the Middle Ages as Janus Damascenus (from Damascus), or Mesue. This is what ibn Sina (980-1037), best known as Avicenna, reports indeed in the Qanun about Ricinus oil (24.37):
 

Masawaih said that Ricinus is a dissolvent and laxative, and that its oil is better and gentler than the other simple oils.

 
Avicenna provided a similar information in the chapter on Ricinus (19.14):
 

Ricinus is suitable for scabies and head ulcers.
It is suitable for opening the cervix when contracted and for hot swellings of the anus.
It is a laxative, very good to empty out the belly.

 
Returning to the chapter on Ricinus oil (24.37), Avicenna opened it with exactly reproducing Dioscorides’ chapter. He then followed with the uses of Ricinus oil, which he distinguished by uses, medical conditions, or parts of the body:
 

Cosmetics: pounding the seeds and applying them as a bandage, they remove warts and fleckles.
Swellings and pimples: the leaves pounded with barley flour relieve swellings caused by excessive phlegm.
Wounds and ulcers: the oil is useful for scabies and moist ulcers.
Thorax: a bandage with the leaves alone or with vinegar arrests the swelling of the breasts due to milk excess during lactation.
Digestive system: pounding 30 seeds and drinking them induce vomiting because they relax the stomach and cause nausea.
Excretory system: pounded seeds purge out phlegm and bile with cholera, and expel worms.

In the Latin World of the Middle Ages, Ricinus was widely introduced, up to England. In the so-called Old English Herbal, possibly dating as far back as the 11^th century, it appears with a very different use (chapter 176):
 

Ricinus.
 
To avert hail and storm: if you have in your possession this plant that is called Ricinus and [lacuna in the text] by another name, of if you hand its seeds in your house or in whatever place where you have either the plant or its seeds, the plant will turn away the violence of hail. And if you hang either the plant or its seeds aboard a ship, it is so marvelous that it will calm every storm. You must gather this plant saying these words:
 

Ricinum plant, I pray you to be present at my singing and to avert hail and lightning and all storms in the name of the almighty God who bid you to be born.

 
And you must be free from the defilement when you pick the plant.

 
In the following centuries, the Greco-Arabic tradition introduced Ricinus to the medieval world, thanks to the translation of Greek and Arabic medical treatises. Its name was different, however: Cataputia and Palma Christi, with the latter referring to the palmate shape of the leaf, as Christ’s hand (Illustrations 8-9).
 

Illustration 8: Ricinus as per manuscript London, British Library, Sloane 4016 (Italy, 15th century), folio 25 recto	Illustration 9: Ricinus as per manuscript London, British Library, Sloane 4016 (Italy, 15th century), folio 28 verso

 

From tick to castor

With time passing and probably because of its drastic action and toxicity, Ricinus fell into disuse. It was the merit of the English physician Peter Canvane (1720-1786) to reintroduce it into medical practice.
 
Canvane knew Ricinus oil as a laxative thanks his practice in the West Indies where Ricinus grew abundantly, something that led scientists at his time that it was native to India. Upon his return to England, Canvane promoted the use of the oil in a small treatise published in 1764 and further reedited (Illustration 10) that included a wonderful fold-out table with a representation of the tree, characteristically identified according to the medieval name Palma Christi (Illustration 11). However modest it was, this work reintroduced Ricinus oil in the materia medica of that time. As early as 1788, Castor Oil enteredthe London Pharmacopoeia with all necessary instructions for its production. In traditional medicine, Ricinus has been successfully used as a purgative in cases poisoning, cholera, colic, dysentery, enteritis, and constipation.
 

Illustration 10: Title page of Peter Canvane treatise on Castor Oil in the 1769 edition	Illustration 11: Fold-out plate of Peter Canvane treatise with a botanical table of the Castor Oil Tree

Ricinus oil also moved from medicine to arts and crafts and, further on, to industrial uses and cosmetics. In cosmetics, specifically, it replaced castoreum, the glandular secretion from the beaver’s castor sac near the anus, characterized by a powerful leather-like scent. Because of its rarity and expensiveness, castoreum, which had been abundantly used in ancient and medieval medicine, was abandoned in modern industrial production and advantageously substituted with Ricinus oil.
 
With this substitution, Ricinus became known as the Castor Oil Tree. This was the term of a long odyssea and a strange history, from Egypt to Greece, to the Middle Ages and later, from ticks to castors, from purgation to perfumery, and from poison to cosmetics.

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