Withaperuvins F and G, two withanolides of Physalis peruviana roots

Withanolides and Related Steroids

“…While Michael-type addition of alcohols to the D 2 -1-keto system of withanolides is well known, intramolecular addition is rare. Nevertheless, the same arrangement has been found previously in withaperuvins D (22) and F (23), although the authors did not directly compare the spectroscopic data of these substances.…”

Minor Withanolides from Physalis philadelphica: Structures, Quinone Reductase Induction Activities, and Liquid Chromatography (LC)-MS-MS Investigation as Artifacts

“…7,13) More than ten methoxylated and ethoxylated withanolides (such as 2,3-dihydro-3b-methoxywithaferin A, 2,3-dihydro3b-ethoxywithaferin A, and 4,5-dihydro-5a-methoxyjaborosalactone B) have been hypothesized to be Michael addition adducts due to treatment with alcohols in the extraction and purification processes of these compounds. 2,[14][15][16][17][18][19][20][21] This hypothesis was confirmed experimentally, for example, by heating withaferin A in MeOH or treating this compound with sodium acetate in MeOH, to afford 2,3-dihydro-3b-methoxywithaferin A in either case. [18][19][20] Thus, it was considered of interest to determine if the methoxylated compounds 1 and 2 are extraction artifacts or naturally occurring substances.…”

“…2,14-21) This hypothesis was confirmed experimentally, for example, by heating withaferin A in MeOH or treating this compound with sodium acetate in MeOH, to afford 2,3-dihydro-3b-methoxywithaferin A in either case. [18][19][20] Thus, it was considered of interest to determine if the methoxylated compounds 1 and 2 are extraction artifacts or naturally occurring substances.A larger number of withanolides have been isolated from the aerial parts of P. philadelphica than from the edible fruits. 3,6,8,9) So far, ixocarpalactone A (5) has not been detected in the fruits of P. philadelphica.…”

“…2,14-21) This hypothesis was confirmed experimentally, for example, by heating withaferin A in MeOH or treating this compound with sodium acetate in MeOH, to afford 2,3-dihydro-3b-methoxywithaferin A in either case. [18][19][20] Thus, it was considered of interest to determine if the methoxylated compounds 1 and 2 are extraction artifacts or naturally occurring substances.…”

Phytochemistry and biosynthesis of δ-lactone withanolides

“…There is an obvious effect on C-2 at 55.0 ppm when C-1 is substituted by ketone (Neogi et al 1987). In the meantime, C-3 moves to lower fields of *?1.0 ppm for ketone [ OAc in the inductive effect.…”