Stevia: Pharmacology and toxicology of stevioside, rebaudioside A, and steviol

Of the three compounds to be discussed in this post, stevioside and rebaudioside A are major natural glycosides found in the leaves of S. rebaudiana (henceforth in this chapter expressed as Stevia), while the aglycone, steviol is a biosynthetic precursor in the leaves and a putative mammalian metabolite of stevioside. These compounds are structurally related to ent-kaurenoic acid. Stevia leaves contain naturally high levels of the glycosides, and selective breeding has increased these levels further. Typical concentrations range from 5 to 10% w/w of the dried leaf for stevioside, 2–4% for rebaudioside A, 1–2% for rebaudioside C, and 0.4–0.7% for dulcoside A. Newer, commercially developed strains may contain an excess of 14% diterpene glycosides. Stevioside, in the form of the pure compound or of Stevia leaf extracts, has been widely used as a food additive, particularly in Brazil, Korea and Japan. It has been estimated, e.g. that somewhere between 85 and 170 metric tons of stevioside were consumed in Japan in 1987. This is equivalent to approximately 1,700 tons of leaf. The absence of reports of adverse reactions from these countries is primafacie evidence of lack of gross toxicity. Safety concerns, therefore, Read more […]

Historical review of the use of lavender

The classical physicians Lavender has been used as a healing plant and was first mentioned by Dioscorides (c. 40—90 AD) who found what was probably Lavandula stoechas growing on the islands of Stoechades (now known as Hyeres); this was used in Roman communal baths. Dioscorides attributed to the plant some laxative and invigorating properties and advised its use in a tea-like preparation for chest complaints. The author also recounts that Galen (129—99 ad) added lavender to his list of ancient antidotes for poison and bites and thus Nero’s physician used it in anti-poison pills and for uterine disorders. Lavender in wine was taken for snake bites stings, stomach aches, liver, renal and gall disorders, jaundice and dropsy. Pliny differentiated between Lavandula stoechas and Lavandula vera, the latter was apparently used only for diluting expensive perfumes. Pliny the Elder advocated lavender for bereavement as well as promoting menstruation. Abbess Hildegard The Abbess Hildegard (1098—1179) of Bingen near the Rhine in what is now Germany, was the first person in the Middle Ages to clearly distinguish between Lavandula vera and Lavandula spica (): On Palsy one who is tormented should take galangale, with Read more […]

Artemisia Absinthium L.

Artemisia absinthium L. is a member of the family Compositae (Asteraceae) and is known by the common names wormwood (UK), absinthe (France) and wermut (Germany). The name Artemisia is derived from the Goddess Artemis, the Greek name for Diana, who is said to have discovered the plant’s virtues, while absinthium comes from the Greek word apinthion meaning “undrinkable”, reflecting the very bitter nature of the plant. The plant is also known by a number of synonyms which include: Absinthium, Wermutkraut, Absinthii Herba, Assenzio, Losna, Pelin, Armoise, Ajenjo and Alsem. The herb is native to warm Mediterranean countries, usually found growing in dry waste places such as roadsides, preferring a nitrogen-rich stoney and hence loose soil. It is also native to the British Isles and is fairly widespread. Wormwood has been naturalised in northeastern North America, North and West Asia and Africa. Brief Botanical Description The stem of this shrubby perennial herb is multibranched and firm, almost woody at the base, and grows up to 130 cm in height. The root stock produces many shoots which are covered in fine silky hairs, as are the leaves. The leaves themselves are silvery grey, 8 cm long by 3 cm broad, abundantly pinnate Read more […]

The Therapeutic Potential For Cannabis

«Cannabis Use and Abuse by Man: An Historical Perspective» of this site provides a fascinating, historical account of the use of cannabis across many cultures and centuries. Suffice it to say here that any natural substance with over 5000 years of medical history will have attached to it a heritage of hearsay and legend through which one must sift to identify areas of true therapeutic potential for us in the late twentieth century and beyond. A summary of conditions for which cannabis has been used, ranging through various shades of rationality, appears in Table Medicinal and quasi-medicinal uses for cannabis and its derivatives: Indications for which only anecdote or reports of traditional use exist: aphrodisiac muscular spasm in rabies / tetanus Huntingdon’s chorea jaundice toothache earache tumour growth cough hysteria insanity menstrual cramps rheumatism movement disorders gut spasm pyrexia inflammed tonsils migraine headache increasing uterine  contractions in childbirth urinary retention/ bladder spasm parasite infection fatigue allergy fever herpetic pain hypertension joint inflammation diarrhoea malaria forgetfulness Indications Read more […]

Specific Medicinal Uses of Cannabis

The historical and contemporary, medicinal uses of cannabis have been reviewed on several occasions. Perhaps the earliest published report to contain at least some objectivity on the subject was that of O’Shaughnessy (1842), an Irish surgeon, working in India, who described the analgesic, anticonvulsant and muscle relaxant properties of the drug. This report triggered the appearance of over 100 publications on the medicinal use of cannabis in American and European medical journals over the next 60 years. One such use was to treat nausea and vomiting; but it was not until the advent of potent cancer chemotherapeutic drugs that the antiemetic properties of cannabis became more widely investigated and then employed. One can argue that the available clinical evidence of efficacy is stronger here than for any other application and that proponents of its use are most likely to be successful in arguing that cannabis should be re-scheduled (to permit its use as a medicine) because it has a “currently accepted medical use”. Specific Medicinal Uses of Cannabis: Use as an Antiemetic Specific Medicinal Uses of Cannabis: Glaucoma Specific Medicinal Uses of Cannabis: Multiple Sclerosis Spastic Conditions A discussion Read more […]

Specific Medicinal Uses of Cannabis: Effects on Anxiety and Insomnia

Cannabis smoking produces a relaxant effect which most users value and it has been suggested that the beneficial effects of cannabis and THC observed in neurological disorders such as motor tics, dystonias and Huntingdon’s chorea are due to sedative and anxiolytic actions. In addition, sedation is by far the most common side effect of cannabis, and in particular THC, observed in clinical trials against a range of disorders. This has lead to the suggestion that cannabis and some cannabinoids may be useful in disorders accompanied by anxiety and/or insomnia. Cannabis Sethi et al. () noted a reduction of anxiety in 50 chronic cannabis users compared to controls, in terms of scores on the Taylor Manifest Anxiety Scale. Oral preparations of cannabis have a sedative or tranquillising effect in man, accompanied by diminished anxiety at doses much lower than those producing psychoactivity. However, anxiety and panic, possibly due to depersonalisation, intoxication and loss of control, can also feature as side effects. These symptoms have been observed after smoking or oral ingestion of cannabis, but particularly after intravenous administration of aqueous extracts. This may be due to the rapid onset of altered mental state Read more […]

Specific Medicinal Uses of Cannabis: Multiple Sclerosis

Like so many other applications, there are numerous anecdotal reports from both patients and their carers who say that cannabis has proffered relief from a range of symptoms associated with MS, including tremor, spasticity and muscle pain. Evidence for the efficacy of cannabis in the relief of spasticity other than that found in MS is discussed in Spastic Conditions. Cannabis Meinck et al. () describe a case where the benefits of smoking cannabis reported by the patient — improvement in muscle tone, reflexes, spasticity, tremor and walking ability — were quantifiable in the laboratory and deteriorated on withdrawal. In a double-blind, placebo controlled trial of cannabis in 10 ambulant patients with MS, the drug impaired posture and balance although several patients reported an improvement in subjective feelings of well-being; a formal psychological assessment was not carried out. Anecdotal evidence gathered from the testimonials of MS sufferers indicates that a considerable proportion obtain at least partial relief from night-time spasticity, and reduced muscle pain, tremor and depression. THC Petro and Ellenburger reported a placebo-controlled trial of oral THC in 9, cannabis-naive patients with MS. Each Read more […]

Fritillaria spp. (Fritillary)

Fritillaria belongs to the family Liliaceae and its bulb is a traditional Chinese medicine (“Beimu” in Chinese). The bulb of the fritillary is divided into two groups according to its medical use: the fritillary bulb of zhebei and the fritillary bulb of chuanbei. The former is the underground bulb of Fritillaria thunbergii Miq. and the latter the underground bulb of F. sungbei Hsiao et K.C. Hsia, mss, F. cirrhosa D. Don, F. cirrhosa D. Don var. paohsinensis S.C. Chen, F. delavayi Franch., F. pallidiflora Schrenk., F. sichuanica S.C. Chen, and F. ussuriensis Maxim. Geographic Distribution F. thunbergii Miq. is a glabrous perennial plant. Its semi-globate bulb is white, 2-6 cm in diameter, and contains two or three thick bulb scales which are fused at one end. It is an erect, cylindrical, single stem with no branches, 30-70 cm high and green or light purple. The leaf is monophyllous and sessile. The leaves are opposite in the lower part of the stem, whorled with three to five leaves in the middle part of the stem, and alternate at the top of the stem. The leaves at the top of stem are shorter than those in the middle, and are lanceolate. The leaves above the middle of the stem and the apex of the leaf-like bract appear Read more […]

Catha edulis (Khat)

Distribution, Botany, and Morphology Khat, Catha edulis (Vahl) Forssk. ex Endl. (Celasteraceae), is an evergreen shrub or tall tree that may reach up to 25 m in height if not pruned. Extensive pruning makes it a small shrub, as it is usually described. Its life span may extend for 40 years. The plant is indigenous to East Africa and southern Arabia, but may have originated in the Harar district of Ethiopia, according to earlier reports. Its habitat extends from northern Ethiopia to the mountainous regions of East Africa and Yemen, all the way to south Africa, between latitudes 18 °N and 30 °S. It is cultivated mostly on hillsides and mountain slopes at altitudes of 1500-2000 m above sea level. Besides Ethiopia and Yemen, the khat plant is now grown in Djibouti, Somalia, Kenya, Tanzania, Uganda, and Madagascar. However, the use of the plant is by no means restricted to the natives of these countries, but extends to other Asian countries and immigrant communities in several Western countries. The fact that the khat plant is not allowed to produce seeds and is mainly propagated by cuttings, and that only fresh leaves are used, may have confined its cultivation to the regions of origin and neighboring areas. In these Read more […]

Adverse Reactions Associated with Echinacea and Other Asteraceae

Fifty percent of Australians report using some form of complementary alternative medicines (CAM) apart from vitamins in any 12-month period, with similar patterns of use in British and North American subjects. Despite the common perception that “natural therapy” is safe, toxic and hypersensitivity reactions to complementary and alternative medicine have been described. Given that these products are rarely packaged in childproof containers, accidental exposure also occurs. Allergic reactions are most common in atopic subjects. This is not surprising when one considers that up to 20% of atopic subjects use CAM. Furthermore, these patients are more likely than others to become sensitized to cross-reactive allergens and some use (or are advised to use) products such as Echinacea for treatment of allergic disease. When interpreting reports of immediate hypersensitivity to Asteraceae-derived CAM, it is helpful to bear in mind a number of important concepts: (1) exposure to Asteraceae is common; (2) sensitization is more common in subjects with preexistent allergic disease; (3) there is allergenic cross-reactivity between different Asteraceae, and between Asteraceae and some foods; and (4) patients sensitized by inhalation Read more […]