Microbial transformation of dehydrocostuslactone by Mucor polymorphosporus

Lappanolides A-N, fourteen undescribed sesquiterpenoids from Saussurea costus (Syn. Saussurea lappa) and their anti HBV activity

Lappanolides A-N (1-14), 14 undescribed sesquiterpenoids, along with 23 known ones (15-37), were isolated from the roots of Saussurea costus, which were primarily categorized into eudesmane, guaiane, and germacrane types. Lappanolide A (1) possessed an unprecedented pseudo-disesquiterpenoids. Their structures and absolute configurations were established using physical data analyses (HRESIMS, IR, 1D and 2D NMR) and ECD calculations. All isolated compounds were tested for anti-hepatitis B virus (anti-HBV) activity. Ten compounds (1, 9, 11, 12, 19, 22, 28, 29, 31, and 36) exhibited activities against HBsAg secretions as determined by ELISA assay, with IC50 values ranging from 5.2 to 45.7 μM. In particular, compounds 28 and 29 showed inhibition of HBsAg secretion with IC50 values of 5.28 and 5.30 μM, and CC50 values of 9.85 and 6.37 μM, respectively, though they all exhibited low selectivity. Several compounds displayed cytotoxicity in the MTT assay. Among them, compound 28 was the most notable and was chosen for further study using flow cytometry. The result showed that it significantly induced HepG2 cell arrest in the S phase and induced apoptosis.

Antifungal and Cytotoxic Assessment of Lapachol Derivatives Produced by Fungal Biotransformation

In the screening for biological active compounds, the biotransformation processes catalyzed by filamentous fungi are useful because they can provide information about the possible appearance of toxic metabolites after oral administration and also generate new leads. In this paper, biotransformation of lapachol (1) by three fungal strains, Mucor circinelloides NRRL3631, Botrytis cinerea UCA992 and Botrytis cinerea 2100, has been investigated for the first time. Lapachol (1) was biotransformed into avicequinone-A (2) by M. circinelloides, 3′-hydroxylapachol (3) by B. cinerea, and into dehydro-α-lapachone (4) by both fungi. All these compounds were evaluated for their cytotoxic activities. The metabolite 2 displayed non-selective cytotoxicity against tumor and normal cell lines, 3 did not show cytotoxicity against the same cells, while 4 showed higher cytotoxicity against cancer cell lines than lapachol (1). The transformation of 1 into harmless and reactive metabolites evidences the importance of the evaluation of drug metabolism in the drug discovery process. Antifungal potential of lapachol (1) and its metabolites 2 and 4 against B. cinerea has also been evaluated. Dehydro-α-lapachone (4) has been shown to be less toxic to fungal growth than lapachol (1), which indicates a detoxification mechanism of the phytopathogen.

Biotransformation of Curcumenol by Mucor polymorphosporus

Biocatalysis of curcumenol (1) was performed by Mucor polymorphosporus AS 3.3443. Six metabolites including five new compounds were obtained, and their structures were elucidated as 10β-hydroxy-9,10-dihydrocurcumenol (2), 2β-hydroxycurcumenol (3), 15-hydroxycurcumenol (4), 12-hydroxycurcumenol (5), 1-hydroxy-4αH-guai-1,6,9-triene-2,8-dione (6), and 5-hydroxycarbonyl-1-oxo-3,7-dimethylindane (7) by spectroscopic analysis. M. polymorphosporus catalyzed unusual degradation and rearrangement reactions to generate a ring-contracted metabolite (7) of curcumenol (1). Curcumenol (1) and metabolites 4-7 exhibited inhibitory activities against lipopolysaccharide-induced nitric oxide production in RAW 264.7 macrophages, with 7 exhibiting more potent activity than curcumenol.

Bioactivity-guided Isolation of Antiproliferative Compounds from the Roots of Onopordum acanthium

Onopordum acanthium has been considered in traditional medicine to be effective against different cancers. The chloroform extracts of the root, which displayed antiproliferative effect against human tumor cell lines, was subjected to bioactivity-guided multistep chromatographic separation. This experiment resulted in the isolation of the sesquiterpene lactones 4β,14-dihydro-3-dehydrozaluzanin C (1), zaluzanin C (2) and 4β,15,11β,13-tetrahydrozaluzanin C (3), the neolignan nitidanin-diisovalerianate (4), besides 13-oxo-9 Z,11 E-octadecadienoic acid (5), 24-methylenecholesterol (6), α-linolenic acid, linoleic acid, stigmasterol and β-sitosterol. The structures of the isolated compounds were established through analytical data (NMR, MS), and by comparison of these with those reported in the literature. All the aforementioned compounds were detected for the first time from this plant. The antiproliferative activities of compounds 1–6 were assessed on cervix adenocarcinoma HeLa, breast adenocarcinoma MCF7 and skin epidermoid carcinoma A431 cells by using the MTT assay. It was found that, 4β,14-dihydro-3-dehydrozaluzanin C (1), the most active antiproliferative compound of the extract, exerted remarkable tumor cell growth inhibitory activity (IC50 2.7–15.1 μM).

Microbial transformation of bufotalin by Alternaria alternata AS 3.4578

The microbial transformation of a cytotoxic bufadienolide, bufotalin (1), was carried out. Three transformed products from 1 by Alternaria alternata were isolated. Their structures were characterized as 3-keto-bufotalin (2), 12 beta-hydroxyl-bufotalin (3), and 3-keto-12 beta-hydroxyl-bufotalin (4) based on the extensive NMR studies. Among them, 3 and 4 were new compounds with strong in vitro cytotoxic activities against HeLa cells.

Structural determination of three new eudesmanolides from Inula helenium

Ten sesquiterpenens were isolated from Inula helenium. Among them, three eudesmanolides: 15-hydroxy-11betaH-eudesm-4-en-8beta,12-olide (1), 3alpha-hydroxy-11betaH-eudesm-5-en-8beta,12-olide (2) and 2beta, 11alpha-dihydroxy-eudesm-5-en-8beta,12-olide (3) are new compounds. Their chemical structures were determined by spectral methods including 2D NMR.

Microbial transformation of alantolactone by Mucor polymorphosporus

Two new transformed sesquiterpenes of alantolactone by Mucor polymorphosporus were obtained. They were characterized as 3beta-hydroxy-11betaH-eudesm-5-en-8beta,12-olide (2) and 3beta,11alpha-dihydroxy-eudesm-5-en-8beta,12-olide (3), on the basis of spectral methods including 2D NMR. And product 3 was an unusual hydroxylation derivative of alantolactone at C-11.

Structural determination of two new sesquiterpenes biotransformed from germacrone by Mucor alternata

Eight transformed sesquiterpenes of germacrone by Mucor alternata were obtained. Their structures were characterized on the basis of spectral methods including 2D NMR. Among them, (1S, 4S, 5S, 10R)-isozedoarondiol (2) and (1R, 4S, 5S, 10R)-diepoxy-12-hydroxygermacrone (3) are new compounds.