Loganic acid

Another characteristic of the CID behavior of hthium containing cationized loganic acid is the retro Diels-Alder (RDA) reaction that affords several possible fragmentation products. These so-called cross ring cleavages are very useful iu the stracture determiua-tion of various compounds and are typically present in the CID spectra of alkah cationized ions of several groups of compounds (Schemes 7 and 8) . ... 

The structure of the monoterpenoid alkaloid alangiside (115 R = H) has been confirmed by synthesis of the O-methyl ether (115 R = Me) from secologanin and 3-hydroxy-4-methoxyphenethylamine 202 the isolation of loganic acid from the same plant (Alangium lamarckii) is consistent with biosynthetic theory. 

Acetyl-8-e/>i-loganic acid (iridoid monoterpene glycoside) Monochasma savatierii (Scrophulariaceae) [aerial] AR (rabbit lens) (56)... 

Cyclopentanoid Monoterpenoids.—Further studies confirm that mevalonic acid, but not 3-hydroxy-3-methylglutaric acid, is specifically incorporated into loganic acid (27), and methionine or adenosylmethionine into loganin (28). The latter metabolite is a key intermediate in indole alkaloid biosynthesis. ... 

It is interesting in connection with the above incorporation of deoxyloganic acid into loganin that loganic acid [acid corresponding to (10)] has been isolated... 

S)-isomer. Related studies with [3R,2R- H]mevalonic acid showed that one tritium atom is probably incorporated but none is incorporated from the (2S)-isomer. This implies that if secologanin (36) is a precursor then the aldehyde proton should be labelled. Other precursors which have been proved effective include loganic acid (35 R = H), loganin (35 R = Me), and sweroside ... 

G. linearis is found in Canada and is one of several species endemic to North America. The roots of this species is reported to contain two novel iridoids, 7-O-coumaroyl-loganic acid (84), 7-0-(4"-0-glucosyl)... 

The sesquiterpene lactones- dihydronepetalactone (165), isodihydronepetalactone (166), nepetalactone, epinepetalactone (167). Nepetolglucosyl ester (168) from leaves, 1,5,9-epideoxy loganic acid (169), nepetalic acid (170), nepetariaside, nepetaside (171) have been reported [287-292]. 

Lonicera implexa Inflammation Loganic acid Anti-Inflammatory (p.o.) against carrageenan-induced mouse paw edema and (p.t.) against TPA-induced mouse ear edema Active 130]... 

For all these reasons, we also suggest to investigate the inhibitory activity of TX-synthase of lamiide, ipolamiide, loganin and loganic acid, as well as geniposide and derivatives to confirm the structure-activity relationship. In addition, this test could justify the antithrombotic activity showed by geniposide and derivatives [64]. 

Cyclopentanoid Monoterpenoids.—The incorporation of [2- C,2- H]mevalonic acid into loganin (35), loganic acid (35a). secologanin (36), and secologanic acid... 

Moreno et al. 136) found that feeding loganin, secologanin, or loganic acid to a C. roseus cell culture resulted in a considerable increase of strictosi-dine and ajmalicine levels, and a concomitant decrease of tryptamine. Also, after these iridoids were fed to elicited cells a decrease of tryptamine levels was observed, but strictosidine and ajmalicine levels were much lower than in the normal cells to which the iridoids were fed, suggesting a rapid turnover of strictosidine. 

Production can be increased by addition of precursors to the culture media, in which cases the precursors are not metabolized in the medium and, after uptake, appear in the right compartment of the plant cell. For C. roseus cultures, for example, it was found that increased indole alkaloid production was obtained after feeding with L-tryptophan, tryptamine, secologanin, loganin, loganic acid, or shikimic acid (20). Cell cultures have also been used for biotransformations, for example, the conversion of (-)-codeinone to (-)-codeine in Papaver somniferum cultures (100). For the tropane alkaloids a large number of precursor feeding and biotransformation studies with cultures of various solanaceous plants have been performed (see below). 

SAM loganic acid methyl transferase t Monoterpene hydroxylase, NADPH, O2... 

---