The use of eucalyptus oils in consumer products

Insect repellents As noted in the introduction, Eucalyptus citriodora oil has been used as a ‘natural’ insect repellent. Depending on the product formulation it is used in, Lemon Eucalyptus (known as Quwenling in China) is up to four or five times more effective and longer-lasting than citronella oil (from Cymbopogon nardus), one of the best known natural insect repellents. p-Menthane-3,8-diol is the main active component of Quwenling and this can be isolated and used as a highly effective insect repellent. Eucalyptus citriodora oil contains up to 80–90 per cent citronellal, along with geraniol, both of which are known to have insect repellent activity but tend to dilute the much higher activity of the p-menthane-3,8-diol. The Mosi-guard Natural insect repellent spray produced by MASTA in the UK contains ‘Extract of Lemon Eucalyptus’ and claims on the label: Approved and recommended by the London School of Hygiene and Tropical Medicine. Field trials have shown effective protection for 6 h after a single application in mosquito infected areas. Also protects against many other biting insects. Mosi-guard Natural is made from a natural and renewable resource. It is kind to your skin and has no adverse effects Read more […]

Pharmacology of Poppy Alkaloids: Minor Opium Alkaloids

The pharmacology and biology of minor opium alkaloids have been surveyed previously in two comprehensive reviews (). Thebaine The pharmacology of thebaine was summarized by Reynolds and Randall in 1957 and studied comprehensively by a WHO Advisory Group in 1980. The pharmacological actions of thebaine in various isolated organs have been studied. Thebaine can induce a temporary decrease in blood pressure in anaesthetized dogs and this depressor effect showed a marked tachyphylaxis. In isolated guinea pig atrium, thebaine decreased the heart rate and contractions depending on the concentration. In isolated rabbit ileum it decreased the peristaltic movement and contractions (). The predominant effect of thebaine is stimulation of the central nervous system. In the mouse, rabbit, cat and dog increases in motor activity and reflex excitability were observed at doses around 2-10mg/kg s.c. or i.m. The Straub-tail response was noted only occasionally. The effects of thebaine on body temperature and respiration have also been studied. Convulsions were observed in almost all species of animals including the frog, pigeon, mouse, guinea pig, cat and dog. Transient tremors, restlessness and convulsions were observed in the Read more […]

Pharmacology of Poppy Alkaloids: Major Opium Alkaloids

 The latex obtained by the incision of unripe seed capsules of Papaver somniferum and which is known as opium is the source of several pharmacologically important alkaloids. Dioskorides, in about AD 77, referred to both the latex (opos) and the total plant extract (mekonion) and to the use of oral and inhaled (pipe smoked) opium to induce a state of euphoria and sedation. Since before the Christian era the therapeutic properties of opium were evident, with the first written reference to poppy juice by Theophrastus in the third century BC. Powdered opium contains more than 40 alkaloids which constitute about 25% by weight of the opium and are responsible for its pharmacological activity. In 1803 the German pharmacist Sertiirner achieved the isolation of morphine as one of the active ingredients of opium. Morphine, codeine, thebaine, papaverine, narcotine and narceine are the most important bases, with many of the remaining (minor) alkaloids occurring only in traces. Morphine Morphine has long occupied an eminent position on the list of useful drugs. As a pure alkaloid, it has been employed for over a century and a half and, as the most important constituent of opium, it has contributed to the comfort of the human Read more […]

Tagetes spp. (Marigolds)

Tagetes species were used by ancient civilizations like the Aztecs for various purposes (). The pigments of the flowers were used as a dye and in chicken feed, oil was extracted from the leaves and used as an ingredient of perfumes, and the roots were also assumed to have interesting properties. Field tests in the USA in the 1930s showed that larvae of a root-knot nematode entered the roots of marigolds, but usually failed to develop and neither reached the adult stage nor produced eggs (). In 1953, a Dutch bulb breeder () reported the biological activity of common garden marigolds (Tagetes patula) against root rot in Narcissus caused by free-living nematodes. The latter finding was an incentive for a scientific analysis of the effect of Tagetes plants by the crop protection industry and the academic world. A few years after the initial report by Van de Berg-Smit (), Uhlenbroek and Bijloo () isolated and described some active principles from Tagetes plants. These chemicals belonged to a group of heterocyclic sulphur-containing compounds, the thiophenes. The thiophene oe-terthienyl, which occurs in Tagetes and related species, was first synthesized in 1941 () and isolated from plants in 1947 (). In the past three Read more […]

Solanum dulcamara L. (Bittersweet)

Biology and Distribution Solanum dulcamara L. (=Dulcamara flexuosa Moench) (), known as dogwood or bittersweet (Solanaceae), is a clambering or prostrate, perennial shrub which may grow to a height of 2 m (Hegi 1927). Its stem is angular and woody with the exception of the herbaceous top and ranges in diameter between 0.25 and 2 cm, rarely up to 5-6 cm. The leaves are alternate, long-stalked, sparsely pubescent on both sides, and quite variable in shape. The oval- to egg-shaped leaf blade is pointed at the tip. Its base, however, may also be cordate, arrow-shaped, or may consist of one or two lobes. Different leaf forms may be found on the same plant. The flowers emerge axillary in panicle-like loose clusters. The calyx bears five narrow teeth; the five joint petals are bright purple and their tips are somewhat reflexed when fully expanded. The five stamens have yellow anthers which form a conspicuous column. The fruit is a round- to egg-shaped berry, green when young and becoming bright red when mature. In Europe, the flowering season is May to September. It is distributed throughout Europe and is also a native to North Africa, West Asia, India, the USSR, China, and Japan. It is not clear whether its occurrence in Read more […]

Citrus in Traditional Medicine

Citrus in traditional Asiatic medicine In a comparative study of the use of herbal drugs in the traditional medicines of India and Europe, Pun () found a marked similarity between the drugs used in the two continents. He attributed this not only to the similarity of the vegetation in the two areas, but also to the influence that traditional Indian medicine, in particular the Atherveda, one of the most ancient repositories of human knowledge, had on Egypt, Greece and Rome. He listed the principal uses of a small number of these drugs, including bitter orange peel, which in India is used as an aromatic, stomachic, tonic, astringent and carminative agent, and lemon, which is used as a flavouring and for its carminative and stomachic effects. In the Valmiki-Ramayana, written after the Vedas and one of the most sacred of all religious books which enumerates the virtues of the medicinal plants that Lord Rama (Vishnu) met during his fourteen-year journey around different parts of India, Karnick and Hocking () identified and listed fifty of these drugs with their use as described in the Ayurvedica (or native Indian) system of medicine. The immature fruit of Citrus aurantifolia (Christm) Swingle was used as an fortifier, Read more […]

Artemisia Species in Traditional Chinese Medicine and the Discovery of Artemisinin

Qing hao-an antimalarial herb A herb, named Qing Hao (usually pronounced ching how) in Chinese, sweet Annie or sweet wormwood in English, and properly known as Artemisia annua L. has become well known in western countries during the last 20 years. Herbal companies, which deal with traditional Chinese medicine (TCM), receive several inquiries concerning this herb every day. A. question commonly asked by those about to travel to Africa or S.E. Asia is “Can I take the herb called Qing Hao to prevent malaria during my trip?” Unfortunately, the answer has disappointed many people because although this herb is used for the treatment of malaria in TCM, usually combined with other herbs, it is not recommended for the prevention of the disease or as a deterrent to mosquitoes. However, the leaves of Qing Hao were burned as a fumigant insecticide to kill mosquitoes in ancient China but this practice no longer continues today since the development and marketing of more efficient mosquito-repellant devices. The discovery of artemisinin Qing Hao is a herb commonly used in China with a long history of use as an antipyretic to treat the alternate chill and fever symptoms of malaria and other “heat syndromes” in the traditional Chinese Read more […]

Syringa vulgaris L. (Common Lilac)

Syringa vulgaris L., or common lilac is a horticulturally important member of the Oleaceae, a family in which other economically significant genera (Olea, Fraxinus, Jasminum, Forsythia) also occur. Thirty species of Syringa are found distributed across the temperate and south temperate zones of Europe and Asia, while the common lilac has been introduced even more widely as an ornamental. A woody shrub (or small tree) in habit, lilac is typical of the Oleaceae in having opposite leaves, a calyx of four fused sepals and a corolla of four united petals. The highly scented flowers occur in thyrses, each branch bearing a terminal flower. The high demand for common lilac and lilac hybrids in the woody ornamental trade has led to several studies of in vitro propagation of this and related species. New shoot formation could be induced from explants of actively growing shoot tips on MS medium supplemented with 0.1 mg/1 6-benzylaminopurine (BA) and 0.1-0.5 mg/1 indoleacetic acid. These were multiplied on MS medium containing high (7.5 mg/1) levels of BA and low (0.1 mg/1) levels of auxin (NAA). Low cytokinin levels led to callus formation, from which regeneration has yet to be reported in lilac. Successful in vitro multiplication Read more […]

Toxicology and Clinical Applications of Black Pepper

Toxicology of Black Pepper There are no data available on the acute or chronic toxicologic aspects of pepper and/ or its constituents. Pepper constituents are not used therapeutically in the allopathic system. Pepper has been in use since very early times as a spice and food additive. No health hazard or untoward action may arise in the concentrations used. The total contents of piperine and associated phenolic amides are of the order of 7–9 per cent w/w and that of the volatile oil are 2–4 per cent. At this level the actual doses of the different constituents available from the quantity of pepper powder, oleoresin or extractive used, will be very little to elicit any toxic reactions. Moreover, the pungent taste of piperine and flavour of the volatile oil constituents will themselves serve as a limiting factor for the intake of high doses. No acceptable daily intake (ADI) has been prescribed by the Joint FAO/WHO Experts Committee on Food Additives for piperine and/or the volatile principles. The major untoward action of pepper is the gastric mucosal injury at a dose of 1.5 g/kg food. There are a few reports about the carcinogenic potential of piperine. It enhances the DNA adduct formation, and extract of pepper Read more […]

Pharmacology of Black Pepper

Many spices used in food seasoning have broad spectrum of antimicrobial activity. Their antioxidant activity against lipid peroxidation enhances the keeping quality of food. Apart from the use as a popular spice and flavouring substance, black pepper as drug in the Indian and Chinese systems of medicine is well documented. In the Ayurvedic descriptions, pepper is described as katu (pungent), tikta (bitter), usbnaveerya (potency, leading to storing up of energy, easy digestion, diaphoresis, thirst and fatigue), to subdue vatta (all the biological phenomena controlled by CNS and autonomic nervous system) and kapha (implies the function of heat regulation, and also formation of various preservative fluids like mucus, synovia etc. The main functions of kapha is to provide co-ordination of the body system and regularization of all biological activities). Pepper is described as a drug which increases digestive power, improves appetite, cures cold, cough, dyspnoea, diseases of the throat, intermittent fever, colic, dysentery, worms and piles; also useful in tooth ache, pain in liver and muscle, inflammation, leucoderma and epileptic fits. Black pepper is called maricha or marica in Sanskrit, indicating its property to dispel Read more […]