Penstemon

Penstemon australis Small Polygonum pensylvanlcum L. Sorghum halapense (L.) Pers. Carduus splnoslsslmus Walter Desmodium canescens... 

Meadow vole, Microtus Penstemon digitalis Alkaloids... 

Lindroth, R. L., Batzli, G. 0., and Avildsen, S. I. (1986). Lespedeza phenolics and Penstemon alkaloids effects on digestion efficiencies and growth of voles.Journal ofChemicalEcol-Ogy 12,713-728. 

B. Gering, P. Junior, and M. Wichtl, Iridoid glycosides from Penstemon confertus, Phytochemistry, 26 (1987) 3011-3013. 

P. Junior, Iso-scrophularioside, a new iridioi glucoside from Penstemon eriantherus, Planta. Med., 43 (1981) 34-38. 

Carbomethoxy-pedicularine (30) was proposed as the structure for an alkaloid of mass 235 amu from a NH3 chemical ionization gc/ms analysis of the alkaloid extract of the flowers of Penstemon whippleanus (Scrophula-riacaeae) (30). No molecular ion was observed in the electron impact mass spectrum, only an (M-45)+ ion at m/z 190. The further fragmentation of this ion (m/z 162,146, and 117) compared well with the mass spectrum of pedicularine (31) (1,82,83), so the alkaloid was tentatively suggested to be a carbomethoxypedicularine (30). Isomeric structures for this alkaloid cannot excluded, particularly given biogenetic considerations. The isolate may even be the methyl ester of pedicularine. 

Noractinidine (95) was tentatively identified (UV, MS) as being present in the flowers of Penstemon whippleanus (30), although other isomers could not be excluded. It was also detected in the leaves of Tecoma starts (89) and the aerial parts of Pedicularis macrochila (Scrophulariaceae) (41). 

A current compilation of Mexican medicinal plants indicates that no pharmacological studies have been carried out to test the presumed properties of the decoction [13]. Chemical studies of the aerial parts of Penstemon barbatus have afforded four aucubin iridoid glycosides catalpol (53), scutellarioside (54), globularin (55) and barbatoside (56) "Fig. (15)." The two former compounds were isolated as their acetate derivatives [101]. Several iridoid glycosides have shown anti-inflammatory activity in experimentally induced edema in mice best results were obtained when administered topically. The most active compounds were two catalpol derivatives, besides aucubine, verbalin and loganin these compounds induced a 72 to 80% edema inhibition when applied at a dose of 1 mg/ear [102]. 

Lira-Rocha, A. Estudio Quimico de Penstemon barbatus and Penstemon campanulatus. M. Sc. Thesis (Pharmacy). Universidad Nacional Aut6noma de Mexico Mexico, 1991. 

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