17β-Hydroxy-18-acetoxywithanolides from Aeroponically Grown Physalis crassifolia and Their Potent and Selective Cytotoxicity for Prostate Cancer Cells

Abstract

When cultivated under aeroponic growth conditions, Physalis crassifolia produced 11 new withanolides (1-11) and seven known withanolides (12-18) including those obtained from the wild-crafted plant. The structures of the new withanolides were elucidated by the application of spectroscopic techniques, and the known withanolides were identified by comparison of their spectroscopic data with those reported. Withanolides 1-11 and 16 were evaluated for their potential anticancer activity using five tumor cell lines. Of these, the 17β-hydroxy-18-acetoxywithanolides 1, 2, 6, 7, and 16 showed potent antiproliferative activity, with some having selectivity for prostate adenocarcinoma (LNCaP and PC-3M) compared to the breast adenocarcinoma (MCF-7), non-small-cell lung cancer (NCI-H460), and CNS glioma (SF-268) cell lines used. The cytotoxicity data obtained for 12-15, 17, and 19 have provided additional structure-activity relationship information for the 17β-hydroxy-18-acetoxywithanolides.

Production and Structural Diversification of Withanolides by Aeroponic Cultivation of Plants of Solanaceae: Cytotoxic and Other Withanolides from Aeroponically Grown Physalis coztomatl

“…The molecular formula of 9 was determined to be C 36 H 48 O 13 by a combination of its HRESIMS and NMR data, suggesting thirteen degrees of unsaturation. The 1 H NMR spectrum of 9 (Table 2 The absence of a signal due to an oxygenatied carbon around 87 ppm in the 13 C NMR spectrum indicated that C-17 is non-oxygenated [18]. Thus, 9 was suspected to contain a 16,17-double bond and this was confirmed by the HMBC correlations (see Supplementary Data, Figures S7 and S60 3) of one of the methyl group suggested that it was attached to an olefinic carbon.…”

“…We have previously demonstrated that unlike the most extensively studied cytotoxic withanolides including withaferin A (1) with a β-oriented side chain, 17β-hydroxywithanolides (17-BHWs) such as physachenolide C (8), with an α-oriented side chain, selectively inhibited prostate cancer (PC) cell lines at nanoMolar concentrations without affecting many other cancer cell lines and normal human fibroblast cells [18][19][20][21]. Our recent studies suggested that the 17-BHW, physachenolide C (8), was also capable of potentiating immunotherapy of renal carcinoma and melanoma, when used in combination with the immune adjuvants, tumor necrosis factor-α related apoptosis-inducing ligand (TRAIL) and the ds-RNA mimetic, poly I:C [29][30][31][32][33], respectively.…”

“…This was confirmed to be C-27 methyl group by the HMBC correlations of H 3 -27 [δ H 1.85 (s)]/C-26 (δ C 165.9), H 3 -27/C-25 (δ C 123.4), and H 3 -27/C-24 (δ C 148.2). The absence of a signal due to C-28 methyl group and the presence of an oxygenated CH 2 group suggested the possible attachment of an O-glucosyl moiety to C-28 [18]. The HMBC correlations of H 3 -19 [δ H 1.22 (s)]/C-1 (δ C 204.4), H 3 -27 [δ H 1.85 (s)]/C-26 (δ C 165.9), H 3 -27/C-25 (δ C 123.4), and H 3 -27/C-24 (δ C 148.2) (see Supplementary Data, Figure S60) precluded oxygenation of C-19 and C-27 methyl groups.…”

“…The HRESIMS, 1 H and 13 C NMR data of physacoztolide K (11) were consistent with the molecular formula, C 30 H 40 O 9 . The 1 H NMR data of 11 (Table 2) exhibited signals typical of a withanolide consisting of three olefinic protons [δ H 5.57 (brs, H-6), 5.84 (dd, J = 10.0, 2.0 Hz, H-2), and 6.78 (ddd, J = 10.0, 4.8, 2.4 Hz, H-3)], suggesting the presence of 2,3-en-1-one and 5,6-double bond moieties similar to physachenolide D (3) [18]. The 1 S15 and S60).…”

“…Thus, aeroponic cultivation of W. somnifera resulted in the production of two unusual withanolides, 3α-(uracil-1-yl)-2,3-dihydrowithaferin A and 3β-(adenin-9-yl)-2,3-dihydrowithaferin, in addition to withaferin A (1), 2,3-dihydrowithaferin A-3β-O-sulfate (2), and ten other known withanolides [17] (see Supplementary Data, Figure S2). Significantly, the aeroponic cultivation of P. crassifolia produced eleven new 17β-hydroxywithanolides (17-BHWs) [18] together with 15α-acetoxyphysachenolide D, 15αacetoxy-28-hydroxyphysachenolide D, 18-acetoxy-17-epi-withanolide K, and physachenolide D encountered in the wild-crafted/soil-grown plant [19] (see Supplementary Data, Figure S3). We have also had notable success with the aeroponic technique in cultivating other plants of the Solanaceae, such as P. peruviana [20], P. philadelphica [21], P. acutifolia [22], and P. coztomatl (this study) and isolating and characterizing over 33 new withanolides, some with promising activities related to their potential use as anticancer agents.…”