Two new xanthone glycosides from Tripterospermum lanceolatum

Oleanolic acid, mangiferin, and two new xanthone glucosides, named lanceoside (1,8-dihydroxy-3,7- dimethoxyxanthone- 4-O-β-d-glucoside) and lancerin (C-4-β-d-glucosyl-1,3,7-trihydroxyxanthone), respectively, were isolated from the aerial parts of Tripterospermum lanceolatum.     

Anatomical Structures of the VA Mycorrhiza in the Apocynaceae (Gentianales)

Roots of 19 Apocynaceae species were studied anatomically with respect to their symbiosis with VAM-fungi. In plants collected from the field, VAM-fungi were established in the root cortex. Also, inoculations with different Glomus species on the cultured plants are very successful in the infection and colonization of the root cortex. After penetration of the rhizodermis, the special exodermal short cells become colonized by winding hyphae. Then, in the root cortex of many Apocynaceae species, the VAM-fungi produce intercellular running hyphae which leads to extensive colonization of the root. Arbuscules develop on intracellular running hyphae, whereas vesicles develop mainly on intercellular hyphae. Except for some special details, this is the most common type of colonization of VAM fungi in flowering plants. But in Amsonia tabernaemontana, Nerium oleander, and Thevetia peruviana, another type of colonization could be observed. In these species, the colonization of the hyphae within the root cortex is only possible by intracellular growth. Intercellular running hyphae in the root are lacking. Therefore, after penetration the colonization in the cortex is cluster-like and strictly limited. Only by additional penetrations from hyphae in the soil, will roots show heavy infestations. This type of growth of the VAM fungi in the root is well known from the Gentianaceae and was explained as a structural incompatibility. In Catharanthus roseus, Pachypodium lamerei, and Trachelospermum jasminoides, intermediate stages of both types of colonization could be described. The results are discussed in the search for possible stimulants for structural incompatibility.     

Xanthones as systematic markers

An evolutionary scheme for shikimate-acetate derived xanthones is deduced from their substitution pattern. Increasing distance of a particular xanthone from the primitive precursor is symbolized by increasing numbers. Each xanthone containing plant species is characterized by the average of the numbers attributed to its constituents. Each genus is characterized by the average of the numbers calculated for its species. The method is useful in comparing phyletic order of genera within the Guttiferae.     

Axillary multiplication of <Emphasis Type="Italic">Swertia chirayita</Emphasis> (Roxb. Ex Fleming) H. Karst., a critically endangered medicinal herb of temperate Himalayas

The present study describes the micropropagation of Swertia chirayita, an endangered medicinal herb of the temperate Himalayas, through axillary multiplication from 4-wk-old seedling-derived nodal explants. We obtained 4.5-fold multiplication every 4 wk on Murashige and Skoog (MS) medium supplemented with 4 μM benzyl amino purine (BA) and 1.5 μM 6-(γ,γ-dimethylallylamino)purine (2iP). Rooting was optimized on modified MS medium supplemented with 1 μM naphthalene acetic acid (NAA) and 500 mg l⁻¹ of activated charcoal (AC). A success rate of 94 % was obtained by in vitro hardening in the growth-room and by ex vitro hardening in greenhouse conditions. The present study can serve as a tool for the mass multiplication of elite genotypes of this critically endangered species and can also be utilized for multiplying large numbers of quality planting material for the replantation in their natural habitat. This approach can also help meet the requirements of the growing pharmaceutical industry by ensuring the regular supply of authentic planting material.     

Identification de C-glucosides flavoniques dans le genre Gentiana (section coelanthe)

Isoorientin, isovitexin, isoorientin-4′-O-glucoside and isovitexin-4′-O-glucoside have been identified in the leaves and roots of Gentiana punctata L., and in the leaves of G. purpurea L., G. pannonica Scop., G. villarsii Ronn., and G. burseri Lapeyr. Comparison with other gentians is discussed.     

Xanthones of Swertia bimaculata

The whole plant of Swertia bimaculata Hf. & T. has been shown to contain four tetra-and five penta-oxygenated xanthones, three of which are previously unreported in nature. The xanthones are broadly based on 1,3,5- and 1,3,7-oxygenated systems with added oxygen functions at C₂, C₄ and/or C₈ positions and represent a number of methoxylated patterns. In addition, three xanthones have been found to be present in a bound form, the sugar moiety containing glucose and glucuronic acid. This is the first demonstration of the occurrence of xanthones and xanthone disaccharides in a Swertia species which are common to both Swertia and Frasera species. The results are thus of considerable phylogenetic significance.     

A xanthone glycoside from Tripterospermum taiwanense and rutin from Gentiana flavo-maculata

Oleanolic acid, norathyriol, and a new xanthone glycoside, tripteroside, which was characterized as norathyriol 6-O-β-d-glucoside, were isolated from the fresh herb Tripterospermum taiwanense, and quercetin and rutin were isolated from the fresh herb Gentiana flavo-maculata.