Volatile Constituents of Festuca nigrescens, Phleum alpinum and Poa alpina from N.W. Italian Alpine Pastures

Abstract

The composition of the volatile fractions of three important grasses from sub-alpine N.W. Italian pastures, namely Festuca nigrescens Lam. non Gaudin (chewing fescue), Phleum alpinum L. (alpine timothy) and Poa alpina L. (alpine bluegrass) was investigated. The fresh aerial parts were collected at the flowering stage during the summer season. The volatile oils obtained from green tissues by steam distillation in a Clevenger-type apparatus, were analyzed by GC/FID and GC/MS. The oil yield was 0.04 ± 0.01% weight/fresh weight bases for each of the investigated species. Several classes of compounds were found in the volatile fractions, including aldehydes, alcohols, acids, hydrocarbons, esters, ketones, terpenes, and phenolics. Qualitative and quantitative differences were observed.

Characterization of the volatile fraction ofNigritella nigra(L.) Rchb. F. (Orchidaceae), a rare species from the Central Alps

“…In this respect, saturated alkanes were reported to exert an interesting, although limited, activity in pollinator deception in Orchidaceae (11,12). On the other hand, the function and regulation of these compounds seems to be also related to protection mechanisms of the plant from environmental factors, such as prevention of water loss, of thermal-or UV-related stress, and their occurrence at relevant concentrations in plants growing at high altitude has been reported (13,14).…”

Composition of Volatile Fraction from Inflorescences and Leaves of Dendrobium moschatum (Orchidaceae)

“…The non-polar fraction (N) was eluted with pentane. Successive elution with diethyl ether afforded the polar fraction (P), while elution with diethyl ether -1% acetic acid gave the acidic fraction (A) [25].…”

“…Data from literature demonstrated that hydrocarbons are endowed with an interesting, although limited, activity in pollinator deception in Orchidaceae, D. moschatum included [19,23]. Furthermore complex protection mechanisms of the plant from environmental factors such as water loss, thermal-or UV-related stress, seem to be strictly related to the presence of this class of compounds [24,25]. Methylketones were detected in higher amount in inflorescences, accounting for 11.1% (491.9 g/g fresh weight) of the total volatiles compared to leaves, in which they represent only 0.1% (0.6 g/g fresh weight) of the total oil.…”

Characterization of Two Agrostis–Festuca Alpine Pastures and Their Influence on Cheese Composition

“…Plant material (100 g) and 0.34 mg of 3-methylcyclohexanone, added as an internal standard, were steam-distilled with odor-free water in a Clevenger-type apparatus for 1 h. The distillate was saturated with NaCl, extracted with freshly distilled diethyl ether (3 × 100 mL), dried over anhydrous Na 2 SO 4 , and concentrated in a rotary evaporator to give a pale-yellow oil. The obtained volatile oils were diluted in diethyl ether and analyzed by gas chromatography–mass spectrometry (GC–MS) and gas chromatography with a flame ionization detector (GC–FID), applying the analytical condition described by Tava et al The identification of the oil components was performed by their RIs, authentic reference compounds, peak matching library search, as well as published mass spectra. , RIs were calculated using a n -alkane series (C 6 –C 34 ) under the same GC conditions as for the samples. The individual components were expressed as mg kg –1 of fresh forage.…”