Natural products based crown ethers: synthesis and their anticancer potential.

Natural products based novel crown ethers have been prepared by employing biologically active natural structures including tetrahydroisoquinoline, chrysin and biochanin-A as the side arms. The resulting crown scaffolds were evaluated for their anticancer potential against two cancer cell lines i.e. NCI-H460 (non-small lung carcinoma), MCF-7 (breast adenocarcinoma). The comparative study showed that the addition of crown scaffold put marked effects on antiproliferative profile of parent natural precursors and is significant for lung carcinoma in particular. Biochanin-A derived crown ether showed three (03) folds higher antiproliferative activity (IC50 = 6.08 ± 0.07 µM) against lung carcinoma as compared to standard drug cisplatin (IC50 = 19.00 ± 1.24 µM). Cytotoxic trends for NIH-3T3 cell lines were also examined and found reduced as compared to parent natural structures. Hence, these findings could open a new pathway towards developing effective carcinostatic drugs.HIGHLIGHTSFour natural products based novel crown ethers have been developed.Comparative antiproliferative screening of crown ethers and natural precursors.Addition of crown showed marked effects on anticancer profile of natural products.Crown formation is significant for lung carcinoma potential in particular.Biochanin-A derived crown ether found three folds more active than standard drug.

Isoflavanquinones from Abrus precatorius roots with their antiproliferative and anti-inflammatory effects.

Phytochemical studies on the root of Abrus precatorius Linn. (Fabaceae), leads towards the identification of four undescribed (abruquinones M, N, O, and P), and seven known abruquinones, (abruquinones A, E, B, F, I, D, and G). Spectroscopic analyses (1D, and 2D NMR, HRESI-MS) were used in elucidating structures of the all compounds. Evaluation of anticancer activities of the isolated isoflavanquinones revealed that abruquinones M, and N showed cytotoxicity against oral CAL-27 (IC50 values 6.48 and 5.26 µM, respectively), and colon (Caco-2) cell lines (IC50 values 15.79 and 10.33 µM, respectively). Abruquinone M also inhibited the growth of lung cancer cells (NCI-H460) with IC50 of 31.33 µM. The isolated isoflavanquiones also showed potent anti-inflammatory potential through phagocyte oxidative burst and pro-inflammatory cytokine TNF-α inhibition in vitro. These findings suggest isoflavanquinones from A. precatorius roots as candidates for further research in cancer treatment.

Biotransformation of progestonic hormone dydrogesterone with Macrophomina phaseolina, and study of the effect of biotransformed products on phagocytes oxidative burst.

Biotransformation of a synthetic progestonic hormone dydrogesterone (1), C21H28O2, with a plant pathogenic fungus Macrophomina phaseolina yielded two new 2 and 3, and a known 4 metabolites. These analogues were identified as, 3ß,11α-dihydroxy-5ß,9ß,10α-pregna-7-ene-6,20-dione (2), 15ß-hydroxy-9ß,10α-pregna-4,6-diene-3,20-dione (3), and 8α-hydroxy-9ß,10α-pregna-4,6-diene-3,20-dione (4). Major structural changes were observed in metabolite 2. New metabolite 3 showed anti-inflammatory potential, and was found to be the potent inhibitor of intracellular reactive oxygen species (ROS) from whole blood phagocytes (IC50 = 4.2 ±â€¯0.3 µg/mL), as compared to standard drug Ibuprofen (IC50 = 11.2 ±â€¯1.9 µg/mL). The metabolites 2, 3, and 4 were found to be non-toxic to NIH-3T3 (CRL-1658) normal cell line. This indicated anti-inflammatory potential of resulting metabolites.

Microbial transformation of mestanolone by Macrophomina phaseolina and Cunninghamella blakesleeana and anticancer activities of the transformed products.

The microbial transformation of anabolic androgenic steroid mestanolone (1) with Macrophomina phaseolina and Cunninghamella blakesleeana has afforded seven metabolites. The structures of these metabolites were characterized as 17ß-hydroxy-17α-methyl-5α-androsta-1-ene-3,11-dione (2), 14α,17ß-dihydroxy-17α-methyl-5α-androstan-3,11-dione (3), 17ß-hydroxy-17α-methyl-5α-androstan-1,14-diene-3,11-dione (4), 17ß-hydroxy-17α-methyl-5α-androstan-3,11-dione (5), 11ß,17ß-dihydroxy-17α-methyl-5α-androstan-1-ene-3-one (6), 9α,11ß,17ß-trihydroxy-17α-methyl-5α-androstan-3-one (7), and 1ß,11α,17ß-trihydroxy-17α-methyl-5α-androstan-3-one (8). All the metabolites, except 5 and 6, were identified as new compounds. Substrate 1 (IC50 = 27.6 ± 1.1 µM), and its metabolites 2 (IC50 = 19.2 ± 2.9 µM) and 6 (IC50 = 12.8 ± 0.6 µM) exhibited moderate cytotoxicity against the HeLa cancer cell line (human cervical carcinoma). All metabolites were noncytotoxic to 3T3 (mouse fibroblast) and H460 (human lung carcinoma) cell lines. The metabolites were also evaluated for immunomodulatory activity, and all were found to be inactive.

Biotransformation of anabolic compound methasterone with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini, and TNF-α inhibitory effect of transformed products.

Microbial transformation of methasterone (1) was investigated with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini. Biotransformation of 1 with M. phaseolina yielded metabolite 2, while metabolites 3-7 were obtained from the incubation of 1 with C. blakesleeana. Metabolites 8-13 were obtained through biotransformation with F. lini. All metabolites, except 13, were found to be new. Methasterone (1) and its metabolites 2-6, 9, 10, and 13 were then evaluated for their immunomodulatory effects against TNF-α, NO, and ROS production. Among all tested compounds, metabolite 6 showed a potent inhibition of proinflammatory cytokine TNF-α (IC50=8.1±0.9µg/mL), as compared to pentoxifylline used as a standard (IC50=94.8±2.1µg/mL). All metabolites were also evaluated for the inhibition of NO production at concentration of 25µg/mL. Metabolites 6 (86.7±2.3%) and 13 (62.5±1.5%) were found to be the most potent inhibitors of NO as compared to the standard NG-monomethyl-l-arginine acetate (65.6±1.1%). All metabolites were found to be non-toxic against PC3, HeLa, and 3T3 cell lines. Observed inhibitory potential of metabolites 6 and 13 against pro-inflammatory cytokine TNF-α, as well as NO production makes them interesting leads for further studies.

Biotransformation of a potent anabolic steroid, mibolerone, with Cunninghamella blakesleeana, C. echinulata, and Macrophomina phaseolina, and biological activity evaluation of its metabolites.

Seven metabolites were obtained from the microbial transformation of anabolic-androgenic steroid mibolerone (1) with Cunninghamella blakesleeana, C. echinulata, and Macrophomina phaseolina. Their structures were determined as 10ß,17ß-dihydroxy-7α,17α-dimethylestr-4-en-3-one (2), 6ß,17ß-dihydroxy-7α,17α-dimethylestr-4-en-3-one (3), 6ß,10ß,17ß-trihydroxy-7α,17α-dimethylestr-4-en-3-one (4), 11ß,17ß-dihydroxy-(20-hydroxymethyl)-7α,17α-dimethylestr-4-en-3-one (5), 1α,17ß-dihydroxy-7α,17α-dimethylestr-4-en-3-one (6), 1α,11ß,17ß-trihydroxy-7α,17α-dimethylestr-4-en-3-one (7), and 11ß,17ß-dihydroxy-7α,17α-dimethylestr-4-en-3-one (8), on the basis of spectroscopic studies. All metabolites, except 8, were identified as new compounds. This study indicates that C. blakesleeana, and C. echinulata are able to catalyze hydroxylation at allylic positions, while M. phaseolina can catalyze hydroxylation of CH2 and CH3 groups of substrate 1. Mibolerone (1) was found to be a moderate inhibitor of ß-glucuronidase enzyme (IC50 = 42.98 ± 1.24 µM) during random biological screening, while its metabolites 2-4, and 8 were found to be inactive. Mibolerone (1) was also found to be significantly active against Leishmania major promastigotes (IC50 = 29.64 ± 0.88 µM). Its transformed products 3 (IC50 = 79.09 ± 0.06 µM), and 8 (IC50 = 70.09 ± 0.05 µM) showed a weak leishmanicidal activity, while 2 and 4 were found to be inactive. In addition, substrate 1 (IC50 = 35.7 ± 4.46 µM), and its metabolite 8 (IC50 = 34.16 ± 5.3 µM) exhibited potent cytotoxicity against HeLa cancer cell line (human cervical carcinoma). Metabolite 2 (IC50 = 46.5 ± 5.4 µM) also showed a significant cytotoxicity, while 3 (IC50 = 107.8 ± 4.0 µM) and 4 (IC50 = 152.5 ± 2.15 µM) showed weak cytotoxicity against HeLa cancer cell line. Compound 1 (IC50 = 46.3 ± 11.7 µM), and its transformed products 2 (IC50 = 43.3 ± 7.7 µM), 3 (IC50 = 65.6 ± 2.5 µM), and 4 (IC50 = 89.4 ± 2.7 µM) were also found to be moderately toxic to 3T3 cell line (mouse fibroblast). Interestingly, metabolite 8 showed no cytotoxicity against 3T3 cell line. Compounds 1-4, and 8 were also evaluated for inhibition of tyrosinase, carbonic anhydrase, and α-glucosidase enzymes, and all were found to be inactive.

Microbial transformation of contraceptive drug etonogestrel into new metabolites with Cunninghamella blakesleeana and Cunninghamella echinulata.

Biotransformation of a steroidal contraceptive drug, etonogestrel (1), (13-ethyl-17ß-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one) was investigated with Cunninghamella blakesleeana and C. echinulata. Five metabolites 2-6 were obtained on incubation of 1 with Cunninghamella blakesleeana, and three metabolites, 2, 4, and 6 were isolated from the transformation of 1 with C. echinulata. Among them, metabolites 2-4 were identified as new compounds. Their structures were deduced as 6ß-hydroxy-11,22-epoxy-etonogestrel (2), 11,22-epoxy-etonogestrel (3), 10ß-hydroxy-etonogestrel (4), 6ß-hydroxy-etonogestrel (5), and 14α-hydroxy-etonogestrel (6). Compounds 1-6 were evaluated for various biological activities. Interestingly, compound 5 was found to be active against ß-glucuronidase enzyme with IC50 value of 13.97±0.12µM, in comparison to standard compound, d-saccharic acid 1,4-lactone (IC50=45.75±2.16µM). Intestinal bacteria produce ß-glucuronidase. Increased activity of ß-glucuronidase is responsible for the hydrolyses of glucuronic acid conjugates of estrogen and other toxic substances in the colon, which plays a key role in the etiology of colon cancer. Inhibition of ß-glucoronidase enzyme therefore has a therapeutic significance. Compounds 1-6 were also found to be non cytotoxic against 3T3 mouse fibroblast cell lines.

Biotransformation of 6-dehydroprogesterone with Aspergillus niger and Gibberella fujikuroi.

Microbial transformation of 6-dehydroprogesterone (1) with Aspergillus niger yielded three new metabolites, including 6ß-chloro-7α,11α-dihydroxypregna-4-ene-3,20-dione (2), 7α-chloro-6ß,11α-dihydroxypregna-4-ene-3,20-dione (3), and 6α,7α-epoxy-11α-hydroxypregna-4-ene-3,20-dione (4), and two known metabolites; 6α,7α-epoxypregna-4-ene-3,20-dione (5), and 11α-hydroxypregna-4,6-diene-3,20-dione (6). Compounds 2, and 3 contain chlorohydrin moiety at C-6, and C-7, respectively. The biotransformation of 1 with Gibberella fujikuroi yielded a known compound, 11α,17ß-dihydroxyandrosta-4,6-dien-3-one (7).

Microbial transformation of danazol with Cunninghamella blakesleeana and anti-cancer activity of danazol and its transformed products.

Biotransformation of danazol (1) (17ß-hydroxy-17α-pregna-2,4-dien-20-yno-[2,3-d]-isoxazole) with Cunninghamella blakesleeana yielded three new metabolites 2-4 and a known metabolite 5. These metabolites were identified as 14ß,17ß-dihydroxy-2-(hydroxymethyl)-17α-pregn-4-en-20-yn-3-one (2), 1α,17ß-dihydroxy-17α-pregna-2,4-dien-20-yno-[2,3-d]-isoxazole (3), 6ß,17ß-dihydroxy-17α-pregna-2,4-dien-20-yno-[2,3-d]-isoxazole (4), and 17ß-hydroxy-2-(hydroxymethyl)-17α-pregn-1,4-dien-20-yn-3-one (5). Danazol (1) and its derivatives were evaluated against cervical cancer cell line (HeLa). Compound 1 showed a potent cytotoxicity with IC50=0.283±0.013 µM, as compared to doxorubicin (IC50=0.506±0.015 µM), where compound 3 was also found to be significantly active with IC50=13.427±0.819 µM.

Biotransformation of androgenic steroid mesterolone with Cunninghamella blakesleeana and Macrophomina phaseolina.

Fermentation of mesterolone (1) with Cunninghamella blakesleeana yielded four new metabolites, 1α-methyl-1ß,11ß,17ß-trihydroxy-5α-androstan-3-one (2), 1α-methyl-7α,11ß,17ß-trihydroxy-5α-androstan-3-one (3), 1α-methyl-1ß,6α,17ß-trihydroxy-5α-androstan-3-one (4) and 1α-methyl-1ß,11α,17ß-trihydroxy-5α-androstan-3-one (5), along with three known metabolites, 1α-methyl-11α,17ß-dihydroxy-5α-androstan-3-one (6), 1α-methyl-6α,17ß-dihydroxy-5α-androstan-3-one (7) and 1α-methyl-7α,17ß-dihydroxy-5α-androstan-3-one (8). Biotransformation of 1 with Macrophomina phaseolina also yielded a new metabolite, 1α-methyl, 17ß-hydroxy-5α-androstan-3,6-dione (9). The isolated metabolites were subjected to various in vitro biological assays, such as anti-cancer, inhibition of α-glucosidase, and phosphodiesterase-5 enzymes and oxidative brust. However, no significant results were observed. This is the first report of biotransformation of 1 with C. blakesleeana and M. phaseolina.