Cynanchum Alkaloids

Cynanchum vincetoxicum (L.) Pers. contains traces of an alkaloid vincetene, which shows an interesting relationship to the phenanthroindolizidines found in Tylophora and other genera of the Asclepiadaceae. Spectroscopic study has shown vincetene to be the benzopyrroloisoquinoline derivative (2), and this structure has been confirmed by synthesis of the racemic dihydro-desoxy-deriva-tive (3).2 

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Lee, D.-U., Shin, U.-S. and Huh, K. 1996. Inhibitory effects of gagaminine, a steroidal alkaloid from Cynanchum wilfordi, on lipid peroxidation and aldehyde oxidase activity. Planta Medica, 62 485-487. 

Few alkaloids have been found in this relatively large family. Those in Cryptolepis, Cynanchum, Pergularia, Tylophora, and Vm-cetoxicum have been characterized, some have been synthesized, others have yet to be isolated in pure form. 

Tylophorine (1) and its analogs, the phenanthroindolizidine alkaloids also referred to as tylophora alkaloids, have been isolated primarily from plants of the family Asclepiadaceae [13-16], Fig. (1), including members of the genus Tylophora, Vincetoxicum, Pergularia, Cynanchum, but also from Hypoestes verticillaris (Acanthaceae) [17], Cryptocarya phyllostemmon (Lauraceae) [18], Ficus hispida and F. septica (Moraceae) [2, 19]. TTie isolations of these alkaloids are summarized in Table 1. The most significant phenanthroindolizidine alkaloids are tylophorine (1), tylocrebrine (2), antofine (3), and tylophorinine (4), Fig. (2). 

The aerial parts of Cynanchum vincetoxicum (L.) Pers. (Asclepiadaceae) contain three phenanthroindolizidine alkaloids, which have been shown to be tylophorine (34), 7-demethoxytylophorine (Alkaloid A, 35), and 7-demethoxy-demethyltylophorine (Alkaloid C, 36). The trimethoxy-base (35) has also been isolated, together with two unidentified alkaloids, from the dried roots of the same plant,and from Vincetoxicum officinale Moench., in which it occurs along with tylophorine. The early work on this trimethoxy-base indicated that it was either (35) or the 3,6,7-trimethoxy isomer, but this latter possibility has now been excluded. The n.m.r. spectrum did not allow a distinction to be made between (35) and the 3,6,7-trimethoxy analogue, hence the alkaloid was oxidised by mercuric acetate, and the immonium salt so obtained was... 

Cynanchum saccatum Asclepi adaceae roots +AUD 3 alkaloids (names NM) 90... 

Zhen CG, Guo YY, Zhang XC, Miao J, Shi WP. Optimisation of conditions for extracting pesticidal alkaloids from Cynanchum komarovii (Maxim.). Nat Prod Res 2013 27(l) 23-7. 

This group of about 20 alkaloids, best known of which is tylophorine (45), are primarily found in the genus Tylo-phora, but also occur in the genera Cynanchum (Vincetoxi-cum), Antitoxicum, and Pergularia of the family Asclepi-adaceae. Some representatives of these alkaloids possess simple indolizidine strucmres. Both these simple types and phenanthroindolizidine alkaloids are also known to occur in the Moraceae (Ficus), Urticaceae (Boehmeria), and the Lauraceae (Cryptocarya) (Bick and Sinchai, 1981 Herbert, 1985 Howard and Michael, 1986). 

Staerk D, Lykkeberg AK, Christensen J, Budnik BA, Abe F, Jaroszewski JW (2002) In Vitro Cytotoxic Activity of Phenanthroindolizidine Alkaloids liom Cynanchum vincetaxicum and Tylophora tanakae Against Drug-Sensitive and Multidrug-Resistant Cancer Cells. J Nat Prod 65 1299... 

An T, Huang RQ, Yang Z et al (2001) Alkaloids from Cynanchum komamvii with inhibitory activity against the tobacco mosaic virus. Phytochemistry 58 1267-1269 Andres A, Donovan SM, Kuhlenschmidt TB et al (2007) Isoflavones at concentrations present in soy infant formula inhibit rotavirus infection in vitro. 1 Nutr 137 2068-2073 Andres A, Donovan SM, Kuhlenschmidt MS (2009) Soy isoflavones and virus infections. J Nutr Biochem 20 563-569... 

Two new secophenanthroindolizidine alkaloids, (13aR)-(—)-secoantofine (1278) and its (R)-(—)-6-0-desmethyl analog 1279, have been isolated from the leaves of Cynanchum vincetoxicum (L.) Pers. (= Vincetoxicum officinale. 

Alkaloids derived from phenylalanine/tyrosine Antofine and related alk. Cynanchum sp. 

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