Isolation of glucoaloe-emodin fromCassia acutifolia Del.

The Chemistry and Biology of Alkannin, Shikonin, and Related Naphthazarin Natural Products

“…An indirect, three-step procedure with dichloromaleic anhydride is usually employed today to produce larger quantities of naphthazarin for laboratory use (Scheme 2, Table 2). [135] OH The symmetry of naphthazarin (64) has been a matter of some debate. [136] The most important aspect from the synthetic viewpoint is that rapid ªtautomerizationº occurs, which leads to a structure that is essentially centrosymmetric as evidenced from its 1 H NMR spectrum, which exhibits only a single signal at d H 7.13, midway between the signals expected for the aromatic (ca.…”

“…Furthermore, the spectroscopic properties of naphthazarin (64), including its intense color in solution, appear to be more consistent with a 1,5-quinoid structures (64 b, c; Figure 9) than the more commonly depicted 1,4-quinoid structure (64 a). [138] Naphthazarin (64) has been described in the crystalline state as deep brown ± red crystals with a green ± golden luster and as deep green crystals with a metallic reflex. [139] It is readily soluble in organic solvents such as benzene and dichloromethane to form blood-red solutions.…”

“…[24] realize that 2 was optically active, and were probably further confused by the widely accepted, but incorrect, structural assignment for naphthazarin (64) as 5,6-dihydroxy-1,4-naphthoquinone (4). Brockmann reinvestigated 2 after the structure of naphthazarin (64) was correctly revised to 5,8dihydroxy-1,4-naphthoquinone. [1] He was the first to identify alkannin (1) and shikonin (2) as enantiomers, to correctly assign their structures, and to finally unite the stories of these natural products, which had for so long run in parallel.…”

“…[36] 48,49] A. hispidissima, [32] A. guttata, [49,50] A. tibetiana, [51±53] Cynoglossum officinale, [36] Echium lycopsis, [54] E. rubrum, [55,69] E. vulgare, [36] Eritrichium incanum, [36] E. sichotenze, [36] Jatropha glandulifera, [56] Lappula consanguinera, [36] L. echinata, [36] Lithospermum erythrorhizon , [48, 57±61, 77] L. officinale, [58±62] Macrotomia echioides, [63] M. ugamensis, [52,53,64] M. euchroma, [36,65,66] Mertensia maritima, [36] Onosma caucasicum, [52,55] O. conferitum, [78] O. hookeri, [42] O. livanovii, [63] O. polyphyllum, [67] O. tauricum, [68] O. sericium, [63] O. setosum, [63] O. visianii, [69] O. zerizaminium. [52±53, 70] cell cultures: Arnebia euchroma, [107e,f] Echium lycopsis, [26] Lithospermum erythrorhizon, [91, 99a] Onosma paniculatum.…”

Chemie und Biologie von Alkannin, Shikonin und verwandten Naphthazarin-Naturstoffen

“…[58±62] Macrotomia echioides, [63] M. ugamensis, [52,53,64] M. euchroma, [36,65,66] Mertensia maritima, [36] Onosma caucasicum, [52,55] O. conferitum, [78] O. hookeri, [42] O. livanovii, [63] O. polyphyllum, [67] O. tauricum, [68] O. sericium, [63] O. setosum, [63] O. visianii, [69] O. zerizaminium [52±53, 70] Zellkulturen: Arnebia euchroma, [107e,f] Echium lycopsis, [26] Lithospermum erythrorhizon, [91, 99a] Onosma paniculatum [105] Biologische Wirkung: Antitumorwirkung (Abschnitt 5.2), antiamöbisch (Abschnitt 5.3), antipyretisch und analgetisch (Abschnitt 5.1), antimykotisch und antibakteriell (Abschnitt 5.3), wundheilend (Abschnitt 5.1), chemoprophylaktisch (Abschnitt 5.2), entzündungshemmend (Abschnitt 5.1), Inhibierung der Topoisomerase II (Abschnitt 5.2), Inhibierung der mikrosomalen Monooxygenase, [71] Stimulierung der Peroxidase, [72] Schutz vor UV-Strahlung, [73] Inhibierung von Testosteron-a-Reduktase, [19f] Induktion und Sekretion des Nervenwachstumsfaktors [74] 15 O O…”