Terpene lactones

Ginkgo extracts show rapid absorption after oral administration of capsules, tablets, and drops (Li and Wong 1997 Wojcicki et al. 1995). The pharmacokinetics for the ginkgo terpene lactones have been determined... 

The recommended dosages of an oral standardized dry extract of ginkgo (24% ginkgo flavonol glycosides and 6% terpene lactones) are 120 to 240 mg daily for dementia and memory impairment, and 120 to 160 mg daily for intermittent claudication and tinnitus. Adverse effects include gastrointestinal disturbances, diarrhea, vomiting, allergic reactions, pruritus, headache, dizziness, and nose bleeds. 

Mauri PL, Simonetti P, Gardana C, et al. Liquid chromatography/ atmospheric pressure chemical ionization mass spectrometry of terpene lactones in plasma of volunteers dosed with Ginkgo biloba L. extracts. Rapid Commun Mass Spectrom 2001 15 929-934. 

Ginkgo biloba dried leaf extract is usually standardized to contain 24% flavone glycosides and 6% terpene lactones. The daily dose ranges from 120 to 240 mg of the dried extract in two or three divided doses. 

Extracts of Ginkgo biloba contain dozens of chemical compounds including flavonoids and terpene lactones, which are considered to be the active compounds. Although the pharmacological actions of these compounds are not yet known, a number of studies suggest that Ginkgo biloba has the following pharmacodynamic effects ... 

An improved synthesis of the Cn-terpenic lactone Dihydroactinidiolide was described by A.K. Bose et al. [35]. The synthesis started from a commercially available aldehyde that was subjected to treatment with m-CPBA and a catalytic amount of PTSA (Scheme 10). The intermediate epoxy acid underwent cyclization resulting in the formation of Aeginetolide. Dehydration has been reported earlier by heating of this compound with aqueous NaOH, at 60 °C for 24 h, or with SOCI2 and pyridine at room temperature for 5 h. The authors observed expeditious and convenient dehydration of this compound supported on silica gel, under microwave irradiation for 5 -10 min (domestic oven), yielding Dihydroactinidiolide in 80% yield. 

The remaining wood components make up the fraction that can be extracted with different solvents, mainly comprising volatile and non-volatile acids, sugars, steroids, hydrolysable tannins (ellagitannins), volatile phenols, terpenes, lactones, etc. This review will deal with the volatile components that can leach out into the wine during barrel aging and as a result may affect the sensory attributes of wine. 

The effects of GB are attributed to several chemical constituents of the whole plant rather than to any one individual component. These chemicals include many flavonoids (also called flavonol, flavone, or flavonoid glycosides, ginkgo flavone glycosides, dimeric bioflavones), and the terpene lactones (also called terpenoids, diterpenes, terpenes), including the ginkgolides and bilobalide (2,5-7). 

No mutagenic, carcinogenic, or teratogenic effects have been noted in studies performed using commercially available GB products containing 22-27% flavone glycosides and 5-7% terpene lactones (36). 

Synthesis of mintlactone and isomintlactone, terpene lactones from mint oil 02S2155. 

The further development of 48 is interesting. Conjugate addition of McjOuhi creates a quaternary centre 49 and acid hydrolysis of the furan releases the triketone 50 used to make sesqui terpene lactones. The yields in these three steps are amazingly good. 

McQuillin and Yeats3 found that the terpene lactone (1) could be reduced by the reagent to the lactoi (2). Use of sodium borohydride gave the diol. 

From a specimen of F. cavernosa collected in the Aegean Sea, together with cacospongionolides B (96) and F (98), was isolated a new C21 terpene -lactone (122), closely related to the cacospongionolide B, by the loss of four C atoms, through an oxidative rupture of the y-hydroxy-butenolide ring [145]. 

A number of terpene lactones have been isolated from M tomentosa and M. frutescens and include the germacrolides, montafinsin A and B, and the guaianolides, zoapatanolide C and D [40,41]. 

Soon after harvest, tree nuts, because of their high concentrations of unsaturated fatty acids, may undergo development of oxidative rancidity. This leads to the formation of undesirable rancid flavors and a decline in both unsaturated fatty acids (e.g., oleic, linoleic, and linolenic acids) and natural antioxidants (e.g., tocopherols) [63]. The postharvest stability and sensory quality of tree nuts are influenced by several factors such as chemical composition (e.g., fatty acid composition and presence of antioxidants such as tocopherols), moisture content, oxygen concentration, and temperature, among others. There is some evidence that lipid oxidation is at least in part due to the action of oxidative enzymes, such as lipoxygenases. This is supported by the fact that mild to moderate heat treatment of some nuts, such as pecan, retards the development of rancid flavors during storage [64,65]. Nevertheless, mild oxidation is probably necessary for the development of the characteristic volatile flavor components of natural tree nuts [63], In addition to the Upid oxidation volatiles, some other compounds, such as terpenes, lactones, and short-chain volatile acids, may impact the aroma profiles of some types of natural flee nuts. 

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