Tumor inhibitors. XXXIX. Active principles of Acnistur arborescens. Isolation and structural and spectral studies of withaferin A and withacnistin

Withangulatin I, a New Cytotoxic Withanolide from Physalis angulata

“…23) These data revealed that compound 2 is a typical withanolide bearing an acetoxyl group and a D 2 -1,4-dione moiety. The deshielding proton C-NMR spectral data of 2 were similar to those of withangulatin A (1), except for the signals due to ring A.…”

Apoptosis is induced in leishmanial cells by a novel protein kinase inhibitor withaferin A and is facilitated by apoptotic topoisomerase I–DNA complex

“…The homogeneity of the compound was determined by TLC and HPLC (reverse phase) and the structure of the compound was established by detailed spectral studies (IR, 1 H NMR, 2D NMR and MS). Finally, the compound was identified as withaferin A 16 by direct comparison with an authentic sample.…”

“…15,16 Earlier studies have shown that withaferin A at a concentration of 3 mM and above potently inhibits LPS-induced proliferation of B lymphocytes. 17 At 2 mM and above, withaferin A causes HUVECs (cell lines) to go into apoptosis as evidenced by the striking increase in intracellular pools of polyubiquinated proteins, which results in perturbation of many intracellular signaling pathways including activation of NF-kb.…”

Antiproliferative withanolides from the solanaceae: A structure-activity study

“…The unmodified type I withanolides showed more potent cytotoxicity than the other structural types analyzed to date. Based on these observations, it is suggested that the -OH or -OR groups at C-4, 7,11,12,14,15,16,17,18,19,20,23,24, and 27 are non-contributors to the antiproliferative activity. In most cases, withanolides possessing -OH or -OR groups at such positions are slightly less potent than those lacking the -OH or -OR groups.…”

“…From the biogenetic origin, it is likely that type I compounds are precursors to the more advanced structural types II−XXII. Type I withanolides that display the most promising antiproliferative characteristics also contain Δ 2 -1-oxo-functionality in ring A, a 5β,6β-epoxy-group in ring B, and a nine-carbon side chain incorporating the δ-lactone functionality found in withaferin A 1 [17], withacnistin 59 [18,19], withanolide D 48 [20][21][22][23], withanolide E 36 [8,[24][25][26][27], and 4β-hydroxywithanolide E 37 (Fig. 4) [8,[24][25][26][27].…”