The Chinese medicinal plant Artemisia annua L. (Qinghao) is the only known source of the sesquiterpene artemisinin (Qinghaosu), which is used in the treatment of malaria. Artemisinin is a highly oxygenated sesquiterpene, containing a unique 1,2,4-trioxane ring structure, which is responsible for the antimalarial activity of this natural product. The phytochemistry of A. annua is dominated by both sesquiterpenoids and flavonoids, as is the case for many other plants in the Asteraceae family. However, A. annua is distinguished from the other members of the family both by the very large number of natural products which have been characterised to date (almost six hundred in total, including around fifty amorphane and cadinane sesquiterpenes), and by the highly oxygenated nature of many of the terpenoidal secondary metabolites. In addition, this species also contains an unusually large number of terpene allylic hydroperoxides and endoperoxides. This observation forms the basis of a proposal that the biogenesis of many of the highly oxygenated terpene metabolites from A. annua – including artemisinin itself – may proceed by spontaneous oxidation reactions of terpene precursors, which involve these highly reactive allyllic hydroperoxides as intermediates. Although several studies of the biosynthesis of artemisinin have been reported in the literature from the 1980s and early 1990s, the collective results from these studies were rather confusing because they implied that an unfeasibly large number of different sesquiterpenes could all function as direct precursors to artemisinin (and some of the experiments also appeared to contradict one another). As a result, the complete biosynthetic pathway to artemisinin could not be stated conclusively at the time. Fortunately, studies which have been published in the last decade are now providing a clearer picture of the biosynthetic pathways in A. annua. By synthesising some of the sesquiterpene natural products which have been proposed as biogenetic precursors to artemisinin in such a way that they incorporate a stable isotopic label, and then feeding these precursors to intact A. annua plants, it has now been possible to demonstrate that dihydroartemisinic acid is a late-stage precursor to artemisinin and that the closely related secondary metabolite, artemisinic acid, is not (this approach differs from all the previous studies, which used radio-isotopically labelled precursors that were fed to a plant homogenate or a cell-free preparation). Quite remarkably, feeding experiments with labeled dihydroartemisinic acid and artemisinic acid have resulted in incorporation of label into roughly half of all the amorphane and cadinane sesquiterpenes which were already known from phytochemical studies of A. annua. These findings strongly support the hypothesis that many of the highly oxygenated sesquiterpenoids from this species arise by oxidation reactions involving allylic hydroperoxides, which seem to be such a defining feature of the chemistry of A. annua. In the particular case of artemisinin, these in vivo results are also supported by in vitro studies, demonstrating explicitly that the biosynthesis of artemisinin proceeds via the tertiary allylic hydroperoxide, which is derived from oxidation of dihydroartemisinic acid. There is some evidence that the autoxidation of dihydroartemisinic acid to this tertiary allylic hydroperoxide is a non-enzymatic process within the plant, requiring only the presence of light; and, furthermore, that the series of spontaneous rearrangement reactions which then convert this allylic hydroperoxide to the 1,2,4-trioxane ring of artemisinin are also non-enzymatic in nature.

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The Biosynthesis of Artemisinin (Qinghaosu) and the Phytochemistry of Artemisia annua L. (Qinghao)

Sea buckthorn berries: A potential source of valuable nutrients for nutraceuticals and cosmoceuticals

Antimicrobial activity and composition profile of grape (Vitis vinifera) pomace extracts obtained by supercritical fluids.

The use of medicinal plants is an option for livestock farmers who are not allowed to use allopathic drugs under certified organic programs or cannot afford to use allopathic drugs for minor health problems of livestock. In 2003 we conducted semi-structured interviews with 60 participants obtained using a purposive sample. Medicinal plants are used to treat a range of conditions. A draft manual prepared from the data was then evaluated by participants at a participatory workshop. There are 128 plants used for ruminant health and diets, representing several plant families. The following plants are used for abscesses: Berberis aquifolium/Mahonia aquifolium Echinacea purpurea, Symphytum officinale, Bovista pila, Bovista plumbea, Achillea millefolium and Usnea longissima. Curcuma longa L., Salix scouleriana and Salix lucida are used for caprine arthritis and caprine arthritis encephalitis.Euphrasia officinalis and Matricaria chamomilla are used for eye problems. Wounds and injuries are treated with Bovista spp., Usnea longissima, Calendula officinalis, Arnica sp., Malva sp., Prunella vulgaris, Echinacea purpurea, Berberis aquifolium/Mahonia aquifolium, Achillea millefolium, Capsella bursa-pastoris, Hypericum perforatum, Lavandula officinalis, Symphytum officinale and Curcuma longa. Syzygium aromaticum and Pseudotsuga menziesii are used for coccidiosis. The following plants are used for diarrhea and scours: Plantago major, Calendula officinalis, Urtica dioica, Symphytum officinale, Pinus ponderosa, Potentilla pacifica, Althaea officinalis, Anethum graveolens, Salix alba and Ulmus fulva. Mastitis is treated with Achillea millefolium, Arctium lappa, Salix alba, Teucrium scorodonia and Galium aparine. Anethum graveolens and Rubus sp., are given for increased milk production.Taraxacum officinale, Zea mays, and Symphytum officinale are used for udder edema. Ketosis is treated with Gaultheria shallon, Vaccinium sp., and Symphytum officinale. Hedera helix and Alchemilla vulgaris are fed for retained placenta. Some of the plants showing high levels of validity were Hedera helix for retained placenta and Euphrasia officinalis for eye problems. Plants with high validity for wounds and injuries included Hypericum perforatum, Malva parviflora and Prunella vulgaris. Treatments with high validity against endoparasites included those with Juniperus communis and Pinus ponderosa. Anxiety and pain are well treated with Melissa officinalis and Nepeta caesarea.

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Ethnoveterinary medicines used for ruminants in British Columbia, Canada

Phospholipids in rice: significance in grain quality and health benefits: a review.

Data from the last 50 years for various classes of compounds from certain plant species of the oleaster (Elaeagnaceae) family are reviewed

Components of Certain Species of the Elaeagnaceae Family

Descurainia sophia L. (Cruciferae) is widely used in folk medicine. The decoction of the aerial part is used in Middle Asia for throat diseases and as an antipyretic for measles and smallpox. In Tibetan medicine, the roots are used for St. Anthony's fire and anthrax. The tincture is used as a diuretic, antihelmintic, and hemostatic for internal hemorrhages. In veterinary medicine, the decoction of roots is used for helmintoses and diarrhea in horses and cattle [1, 2]. We studied seeds of D. sophia collected in Tashkent district in May 2002. Seeds were ground in an electric grinder and extracted exhaustively with benzine (70-80°C) for extraction to afford a yellowish-brown oil in 22% yield. Total lipids were separated by preparative TLC on silica-gel plates using benzine:diethylether (4:1). The contents of individual fractions were estimated gravimetrically. Table 1 lists the results for benzine separation of the extract of D. sophia seeds. Lipids from seeds contained epoxyacylglycerides according to reaction with picric acid. Their content was 6.4% of the lipid mass. Oxygenated compounds are typically found in seed oil from Cruciferae plants. Total lipids and acyl-containing compounds in them were hydrolyzed by KOH. Fatty acids (FA) were methylated by diazomethane [3] and identified as methyl esters by GC (Table 2). The lipids contained up to 16 FA. The main acids in total lipids and triglycerides (TAG) were linolenic (18:3), linoleic (18:2), arachic (20:0), and eruchic (22:1). The content of these acids and oleic (18:1) in free fatty acids (FFA) were almost identical from 14.2 to 15.9%; of palmitic (16:0), 12.0%. This is two times greater than in the total acids. The FA composition of seeds from plants studied by us differed little with respect to the content of unsaturated C18 acids from that reported in a review on screening of seed oils from Cruciferae plants [4]. The difference in flora from Uzbekistan consists of a content of 16:0 and 22:1 acids that is elevated several times.

Lipids from Descurainia Sophia Seeds

The class and fatty-acid compositions of the total lipids and phospholipids and the types of triacylglycerols of rice bran oil have been studied. It has been shown that the main lipid class consists of the triacylglycerols; in them the 16∶0, 18∶1, and 18∶2 acids predominate. The main phospholipids are the PCs, PIs, and PEs. The predominating TAGs are the trisaturated and the monosaturated-diunsaturated types, which are present in equal amounts.

Lipids of rice bran

Chemical, chromatographic, and spectral methods were used to show that the main components of the lipid extract of flowers and leaves are free and bound aliphatic and cyclic alcohols (sterols and triterpenols) and essential oil. It was shown that the lipid extract of Artemisia annua has a positive influence on skin metabolism and possesses anti-inflammatory activity.

Lipids from Flowers and Leaves of Artemisia annua and Their Biological Activity

Lipids and lipophilic components from seeds of grape seeds and apricot, almond, and peach pits were studied. The compositions of fatty acids and unsaponified oil compounds were established.

N. P. Bekker

Papers

Components of Certain Species of the Elaeagnaceae Family

Lipids from Descurainia Sophia Seeds

Lipids of rice bran

Lipids from Flowers and Leaves of Artemisia annua and Their Biological Activity

Lipids and lipophilic components from seeds of some fruit plants