The Experts below are selected from a list of 8028 Experts worldwide ranked by ideXlab platform

Geoffrey D. Brown - One of the best experts on this subject based on the ideXlab platform.

Benye Liu - One of the best experts on this subject based on the ideXlab platform.

  • Advances in sesquiterpene synthases cyclases of Artemisia annua
    Sheng wu gong cheng xue bao = Chinese journal of biotechnology, 2007
    Co-Authors: Hai-yan Shen, Benye Liu, Hong Wang, Fang Yan
    Abstract:

    Artemisinin,a new and a very potent antimalarial drug, is produced by the plant Artemisia annua L. with a very low yield ranging from 0.01% to 0.8% on a dry-weight basis. This makes artemisinin an expensive drug. Several studies reported chemical synthesis of the artemisinin, but none of them seems a viable economical alternative compared with the isolation of artemisinin from the plant. Hence, a higher artemisinin concentration in the plant is necessary for cheap antimalarial drug production. Many types of cyclic sesquiterpenes in Artemisia annua have been characterized to date, each derived from the common cyclic precursor FDP in a reaction catalyzed by a sesquiterpene synthase. Sesquiterpene synthases are widely regarded as the rate-determining regulatory enzymes in the pathways they participate, and a number of sesquiterpene synthases have been cloned from Artemisia annua up to now. This report is a brief review on the following sesquiterpene synthases: epi-cedrol synthase, amorpha-4,11-diene synthase, beta-caryophyllene synthase, (E)-beta-farnesene synthase, germacrene A synthase, as well as a new sesquiterpene synthase whose function remains largely unknown. The report is of help for a better understanding of metabolic engineering of Artemisia annua.

  • Analysis of Artemisia annua L. volatile oil by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry.
    Journal of chromatography. A, 2006
    Co-Authors: Huahong Wang, Benye Liu
    Abstract:

    Artemisia annua L. is an annual herb native of Asia, it has been used for many centuries for the treatment of fever and malaria. In this paper, analysis of the volatile oil of Artemisia annua L. was performed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF MS). Three hundred and three components were tentatively identified and terpene compounds are the main components of Artemisia annua L. volatile oil. Artemisinic acid is tentatively qualified.

Guang-yi Liang - One of the best experts on this subject based on the ideXlab platform.

  • Terpenoids from the seeds of Artemisia annua.
    Phytochemistry, 2003
    Co-Authors: Geoffrey D. Brown, Guang-yi Liang
    Abstract:

    Fourteen sesquiterpenes, three monoterpenes and one diterpene natural product have been isolated from the seeds of Artemisia annua. The possible biogenesis of some of these natural products are discussed by reference to recently reported experimental results for the autoxidation of dihydroartemisinic acid and other terpenoids from Artemisia annua.

Pascale Guiraud - One of the best experts on this subject based on the ideXlab platform.

  • Artemisia annua, a Traditional Plant Brought to Light
    International journal of molecular sciences, 2020
    Co-Authors: Axelle Septembre-malaterre, Mahary Lalarizo Rakoto, Claude Marodon, Yosra Bedoui, Jessica Nakab, Elisabeth Simon, Ludovic Hoarau, Stephane Savriama, Dominique Strasberg, Pascale Guiraud
    Abstract:

    Traditional remedies have been used for thousand years for the prevention and treatment of infectious diseases, particularly in developing countries. Of growing interest, the plant Artemisia annua, known for its malarial properties, has been studied for its numerous biological activities including metabolic, anti-tumor, anti-microbial and immunomodulatory properties. Artemisia annua is very rich in secondary metabolites such as monoterpenes, sesquiterpenes and phenolic compounds, of which the biological properties have been extensively studied. The purpose of this review is to gather and describe the data concerning the main chemical components produced by Artemisia annua and to describe the state of the art about the biological activities reported for this plant and its compounds beyond malaria.

Frank Van Der Kooy - One of the best experts on this subject based on the ideXlab platform.

  • The complexity of medicinal plants: the traditional Artemisia annua formulation, current status and future perspectives.
    Journal of ethnopharmacology, 2013
    Co-Authors: Frank Van Der Kooy, Shaun Edward Sullivan
    Abstract:

    Abstract Ethnopharmacological relevance Artemisia annua has a long tradition of use for the treatment of intermittent fevers which we now relate to malarial infections. The active principle artemisinin has been isolated from Artemisia annua and today forms the backbone of the global fight against malaria. The traditionally prepared Artemisia annua formulation is however still being used on a global scale for the treatment of malaria, and it is claimed that its action is superior to the single purified drug. Artemisia annua is therefore on the forefront of the heated debate between the single drug–single target approach of western based medicine and the holistic approach of traditional medicinal systems. This review aims to highlight the complexities we face in the general study of medicinal plants at the hand of three levels of complexity. These levels consist of (a) the chemistry of the medicinal plant, (b) the influence of the preparation method on the chemistry of the final formulation and (c) the influence of metabolism on the chemistry of the formulation. We also aim to provide an up-to-date report on all scientific work that has been conducted and published in English on the traditional formulation of Artemisia annua. Materials and methods All English scientific literatures published until the first quarter of 2013 were retrieved from well-known scientific databases (Scifinder scholar, Web of Science, PubMed, Google scholar) and Non-governmental organisations active in this field were consulted. A draft version of this manuscript was sent to the African office of the World Health Organisation (WHO), and to the Non-governmental organisations “Action Medicine Naturelle” (ANAMED) and “Iwerliewen fir bedreete Volleker – Reseau belgo-luxembourgeois pour la valorisation des herbes medicinales” (IFBV-BELHERB) for comments. Results Very little scientific work has been conducted on the Artemisia annua formulation. The available literature contains many discrepancies which are unfortunately selectively being used by the two different sides in this debate to further their arguments. On one side of the argument we have the low content of artemisinin in Artemisia annua , the low bioavailability of artemisinin when the traditional formulation is administered and the high levels of recrudescence, which are being emphasised, while on the other side the possible role of synergism and prodrugs are being highlighted. This review reports that there are still too many gaps in our existing knowledge to provide conclusive evidence for either of the two sides of the argument. Conclusions Much more research is needed into Artemisia annua formulations. We stand to gain invaluable knowledge into how traditional medicinal plant works, discover the identities of new active compounds (which can be used against other diseases such as HIV, diarrhoea, and cancer) and possibly bring both sides of this debate closer together.

  • Ethnopharmacology in overdrive: the remarkable anti-HIV activity of Artemisia annua.
    Journal of ethnopharmacology, 2012
    Co-Authors: Andrea Lubbe, Isabell Seibert, Thomas Klimkait, Frank Van Der Kooy
    Abstract:

    Ethnopharmacological relevance: Artemisia annua contains the well-known antimalarial compound artemisinin, which forms the backbone of the global malaria treatment regime. In African countries a tea infusion prepared from Artemisia annua has been used for the treatment of malaria only for the past 10-20 years. Several informal claims in Africa exist that the Artemisia annua tea infusions are also able to inhibit HIV. Since HIV is a relatively newly emerged disease, the claims, if substantiated, could provide a very good example of "ethnopharmacology in overdrive". The objective of this study was to provide quantitative scientific evidence that the Artemisia annua tea infusion exhibits anti-HIV activity through in vitro studies. A second objective was to determine if artemisinin plays a direct or indirect (synergistic) role in any observed activity. This was done by the inclusion of a chemically closely related species, Artemisia afra, known not to contain any artemisinin in our studies. Materials and methods: Validated cellular systems were used to test Artemisia annua tea samples for anti-HIV activity. Two independent tests with different formats (an infection format and a co-cultivation format) were used. Samples were also tested for cellular toxicity against the human cells used in the assays. Results: The Artemisia annua tea infusion was found to be highly active with IC50 values as low as 2.0 mu g/mL. Moreover we found that artemisinin was inactive at 25 mu g/mL and that a chemically related species Artemisia afra (not containing artemisinin) showed a similar level of activity. This indicates that the role of artemisinin, directly or indirectly (synergism), in the observed activity is rather limited. Additionally, no cellular toxicity was seen for the tea infusion at the highest concentrations tested. Conclusion: This study provides the first in vitro evidence of anti-HIV activity of the Artemisia annua tea infusion. We also report for the first time on the anti-HIV activity of Artemisia afra although this was not an objective of this study. These results open the way to identify new active pharmaceutical ingredients in Artemisia annua and thereby potentially reduce the cost for the production of the important antimalarial compound artemisinin.