Phytomedical studies on the Amazonian traditional medicine "Chuchuguasa" (Maytenus laevis Reissek)

  • Hazar Mouad

Student thesis: Doctoral Thesis

Abstract

The importance of natural products and medicinal plants has continued to grow due to their significant role in the search for new drugs or precursors of potent drugs with minimal side effects for the treatment of numerous illnesses. The Amazonian Rainforest represents the most extensive resource of natural diversity remaining on the planet. The unsurpassed knowledge, culture and medicinal practices, created by its indigenous people over thousands of years, have formed rich foundations for ethnobotanical studies about traditional medicinal plants which might be potential sources of biologically active phytochemicals. Regretfully, this may not be so for very much longer, due to the rate of deforestation and the effects of westernisation on these native societies.From the Amazonian basin, Resguardo Monochoa area of Caquetá-Medio in Colombia, a plant locally named "Chuchuguasa" was collected (root and stem bark) by well known Amazonian sabedores from the indigenous Uitoto and Muinane communities who identified the tree as a Maytenus laevis Reissek (Celastraceae). Following a strict collecting methodology, the plant material (the roots in particular) was chosen from the side of the tree that receives the first rays of sun at 5 am. This plant is used in traditional medicine for several purposes mainly in the form of an alcoholic extract (aguardiente). A considerable amount of phytochemical investigation had already been performed on the Maytenus species associated with Chuchuguasa (mainly the stem bark), however, there is little information so far about the chemistry of M. laevis, particularly that involving the root bark. This project aimed to carry out further phytochemical work on the root and stem barks of M. laevis in an attempt to isolate constituents, which may possess biological activities that could be exploited.Twenty compounds were isolated from solvent extracts of the two plant materials of M. laevis, in addition to a polymer which was characterised as trans-1, 4-polyisoprene (Gutta-percha). Six compounds were identified as novel and were given the names 22(β)-hydroxycelastrol, 22(α)-hydroxynetzahualcoyene, 2,22-dihydroxy-3-methoxy-15, 12-dioxo-5, 8-oxa-24, 30-dinor-5, 6-seco-friedelan-1,3,5(10)-trien-6-al (trivial name jujuborreal*), methyl 2, 3, 22α-trihydroxy-24, 25-dinorfriedelan-1,3,5(10),6,8,14-hexaen-29-oate, 15(β)-acetoxyfriedelane-1,3-dione, and (4R, 4aR, 6aR, 7aS, 8aR, 12aR, 12bS, 14aR, 14bS)- 4, 4a, 8a, 11, 11, 12b, 14a-heptamethyl-7-methyleneoctadecahydrobenzo[a]naphtho[2,1-f]azulene-1, 3(2H,14bH)-dione (trivial name 1,3-dioxocorredor-14,26-ene). The remaining fourteen compounds were not novel and composed of nine triterpenoids of friedelane, norfriedelane and aromatic-types including canophyllol, friedelane-1,3-dione, 28-hydroxyfriedelane-1,3-dione, netzahualcoyondiol, netzahualcoyone, pristimerin, celastrol, salaquinone A, regeol A, two steroids (stigmast-4-en-3-one and β-sitosterol), two simple phenolics (p-hydroxybenzaldehyde and 3,4-dihydroxybenzoic acid) and one isocoumarin (± mellein). Nevertheless, 8 of them are reported for the first time from M. laevis and from those other related species that are often referred to as Chuchuguasa.The structures of the new and known compounds were all elucidated by spectroscopic methods. The novel compound, 1,3-dioxocorredor-14,26-ene, was identified with the aid of X-ray crystallography and was shown to be the first of a new skeletal class of triterpenes for which the name corredorane is suggested. A preliminary in vitro cytotoxicity assessment of the crude extracts and most of the isolated compounds was carried out against the cancer cell line A375 (human, malignant melanoma cell line) and the normal cell line Hs27 (human, skin fibroblast cell line) using a resazurin assay. The n-hexane and ethyl acetate extracts of both parts of the plant showed selective activity o
Date of Award1 Mar 2015
LanguageEnglish
Awarding Institution
  • University Of Strathclyde
SponsorsDAMASCUS UNIVERSITY & EMBASSY OF SYRIAN ARAB REPUBLIC
SupervisorValerie Ferro (Supervisor)

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