The occurrence of the alkaloidsN-formyl andN-acetyl loline, peramine, lolitrem B, and ergovaline and the response of aphids to plants containing these compounds were determined in species and cultivars ofFestuca,Lolium, and other grass genera infected with fungal endophytes (Acremonium spp., andEpichloe typhina). Twenty-nine of 34 host-fungus associations produced one or more of the alkaloids, most frequently peramine or ergovaline. Three alkaloids (lolines, peramine, and ergovaline) were found in tall fescue and in perennial ryegrass infected withA. coenophialum, while peramine, lolitrem B, and ergovaline were present in perennial ryegrass and in tall fescue infected withA. lolii and inF. longifolia infected withE. typhina. WhileA. coenophialum andA. lolii produced similar patterns of alkaloids regardless of the species or cultivar of grass they infected, isolates ofE. typhina produced either no alkaloids or only one or two different alkaloids in the grasses tested. Aphid bioassays indicated thatRhopalosiphum padi andSchizaphis graminum did not survive on grasses containing loline alkaloids and thatS. graminum did not survive on peramine-containing grasses. Ergovaline-containing grasses did not affect either aphid.

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Nʹ-Nitrosonornicotine (NNN), a carcinogenic tobacco-specific Nʹ-nitrosamine (TSNA), is on the FDA list of harmful and potentially harmful constituents (HPHCs). Nornicotine, a product of the demethylation of nicotine, is the immediate alkaloid precursor for NNN formation. Nicotine, nornicotine and NNN are optically active. The accumulation of the isomers of nicotine, nornicotine, and NNN impacts their biological activity. In this paper, we report the determination of tobacco alkaloid enantiomers (including nicotine, nornicotine, anabasine, and anatabine) in samples of different tobacco lines using a reversed phase ultra-performance liquid chromatography-tandem mass spectrometer (UPLC/MS/MS) method. Current method demonstates excellent detection capability for all alkaloid enantiomers, with correlation coefficients (r 2 ) > 0.996 within their linear dynamic ranges. The limit of detection (LOD) and limit of quantitation (LOQ) of all analytes are less than 10 ng/mL and 30 ng/mL, respectively. In addition, their recovery and coefficient of variation (CV%) are within 100–115% and 0.2–3.7%, respectively. The method validated in this paper is simple, fast, and sensitive for the quantification of alkaloid enantiomers in tobacco leaf and has been applied to investigations of tobacco alkaloid enantiomer ratios in different tobacco lines and tobacco products.