Lovastatin Analogues from the Soil-Derived Fungus Aspergillus sclerotiorum PSU-RSPG178

Three new lovastatin analogues (1, 4, and 5) together with four known lovastatin derivatives, namely, lovastatin (2), α,β-dehydrolovastatin (3), α,β-dehydrodihydromonacolin K (6), and α,β-dehydro-4a,5-dihydromonacolin L (7), were isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178. Their structures were established using spectroscopic evidence. Compound 5 exhibited the most potent activity against HMG-CoA reductase, with an IC50 value of 387 μM. In addition, the present study indicated the direct interaction of compound 5 with HMG-CoA reductase. Compound 5 was considered to be noncytotoxic against noncancerous Vero cells, with an IC50 value of 40.0 μM, whereas compound 2 displayed much stronger activity, with an IC50 value of 2.2 μM.

Production and purification of statins from Pleurotus ostreatus (Basidiomycetes) strains

Pleurotus ostreatus strains were cultured in liquid medium and on wheat straw. The yields of lovastatin were compared.

Production of lovastatin examined by an integrated approach based on chemometrics and DOSY-NMR

Microbial secondary metabolites are one of the sources of therapeutic molecules in the pharmaceutical industry. Product quality and high yields of secondary metabolites are the main goals for the commercial success of a fermentation process. Our novel approach was based on the decision-tree algorithm to determine the key variables correlated with the process outcome and on DOSY-NMR to identify both co-metabolites and impurities, and it improves fermentation systems and speeds up bioprocess development. The approach has been validated in the case of lovastatin production from Aspergillus terreus.

[Concentration on Diapak C 16 capsules of lovastatin, mevinolinic acid and other inhibitors of biosynthesis of sterins produced by Penicillium citrinum 89]

The method of lovastatine and mevinolinic acid known as competitive inhibitors of HMG-CoA-reductase and produced by micromycetes was elaborated. The inhibitors from diluted water solutions were fully absorbed on Diapak C16 patrons. The rate of inhibitors elution from the patrones was more than 95 per cent. Patrons may be used for concentration of lovastatine group inhibitors from the culture media. Inhibitors synthesis by the Penicillium citrinum 89 was investigated in dynamics with the use of Diapak C16 patrones. It was shown that UV-spectrum of inhibitor produced by P. citrinum 89 was identical with compactin spectrum and had absorbance maximum at 230, 237 and 247 nm.

Chromatographic purification of some 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

The purification of pravastatin, simvastatin and lovastatin in the sodium salt or lactone form and of mevastatin in the lactone form by reversed-phase displacement chromatography is presented. The mobile phases consisted of water or mixtures of water-methanol and water-acetonitrile. Six different displacers were successfully used. Up to 0.14 g of raw sample per gram of stationary phase was loaded on a column packed with silica-based octadecyl phase. Crude substances from 85 to 88% chromatographic purity were purified and at least 99.5% purity was achieved.

Investigation of primary and secondary modifiers for the subcritical extraction of lovastatin from MEVACOR tablets with carbon dioxide

The subcritical fluid extraction of lovastatin from tablet powder mixtures prepared in this laboratory and MEVACOR tablets is successfully demonstrated. Methanol modifier percentage, additive type (acidic, basic, or neutral), and additive concentration on the extraction efficiency are examined. The extraction recoveries of lovastatin from MEVACOR tablets are shown to be highly dependent on methanol concentration and additive type. Isopropylamine is shown to be the most successful additive investigated. An optimized extraction method is developed, and lovastatin recoveries of 99.5% were achieved with a relative standard deviation of 1.2% from MEVACOR tablets with 15% (v/v) (1.0% [v/v] isopropylamine) methanol-modified CO2.

Microbial conversion of mevinolin

About 3000 microorganisms (bacteria, Actinomyces, Zygomyces, Deuteromyces) were screened for their capacity to convert mevinolin. Absidia coerulea IDR 705 was found to produce two hydroxylated derivatives of mevinolin, 2 and 3. Compound 2 is a new transformation product while compound 3 was described as a chemical modification product of mevinolin. By combination of spectroscopic techniques, the structures of 2 and 3 were identified with beta,delta-dihydroxy-7-(1,2-dihydro-2-hydroxymethyl-6-methyl-naphthal en-1-yl)-heptanoic acid delta-lactone and beta,delta-dihydroxy-7-[1,2,3,5,6,7,8,8a-octahydro-3,5-dihydroxy-2, 6-dimethyl-8-(2-methyl-butyryloxy)-naphthalen-1-yl]-hepta noi c acid delta-lactone, respectively. The inhibitory effects of the two derivatives on the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase were similar to that of mevinolin.

L-669,262, a potent HMG-CoA reductase inhibitor

The microbial transformation of simvastatin (MK-733) by Nocardia autotrophica subspecies amethystina yielded iso-simvastatin-6-one as a minor component. This transformation product is a dienone and is one of the more potent inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase found to date.

Enantioselective synthesis of cyclohexenone derivatives by a chemicoenzymatic approach: stereo- and regioselective route to potential intermediates of compactin (ML 236B) and mevinolin

As a synthetic application of the chiral monoester 2, prepared by pig liver esterase (PLE)-catalyzed hydrolysis of the corresponding meso diester 1, conversion of 2 into various cyclohexenone derivatives was examined. This paper describes the preparation of the isomeric cyclohexenones 6 and 7, potential intermediates for the synthesis of anti-hypercholesmic compactin (ML 236B) and mevinolin, under stereo- and regioselective control.

Biochemical aspect of HMG CoA reductase inhibitors

Subsequent to the discovery of compactin (ML-236B) as a specific inhibitor of HMG CoA reductase, a series of compactin analogs have been either isolated or synthesized. Several of these compounds, which include compactin, mevinolin (monacolin K) and CS-514, have been extensively studied. The inhibition of HMG CoA reductase by these compounds is reversible and competitive (Ki = approximately 1 nM). The 3', 5'-dihydroxypentanoic acid portion of the acid form of compactin analogs, which resembles the HMG portion of HMG CoA, plays a crucial role in inhibitory activity. These inhibitors block sterol synthesis both in cultured mammalian cells and in animals. Strong inhibition of sterol synthesis results in a marked increase in HMG CoA reductase activity both in vitro and in vivo. These compounds strongly lower plasma LDL-cholesterol levels in animals and humans. The lowering of LDL-cholesterol levels occurs by an inhibition of LDL synthesis and/or by an elevation of the receptor-mediated LDL catabolism in the liver.

Biosynthesis of mevinolin, a hypocholesterolemic fungal metabolite, in Aspergillus terreus

Mevinolin and compactin are fungal metabolites which inhibit cholesterol biosynthesis in mammalian systems. Biogenetically, mevinolin is formed from polyketide chains, one 18-carbon and one 4-carbon, derived from acetate in normal head to tail fashion. The remaining two carbons in mevinolin, namely C-2' and C-6 methyl groups, are transferred from S-adenosylmethionine. To distinguish the timing and sequence of these two methylation steps, [Me-14C]- and [Me-3H,14C]-L-methionine were fed to Aspergillus terreus at several selected production intervals. Location and distribution of labels were determined by the specific chemical degradation methods. The results have demonstrated clearly that transfer of methyl groups from two S-adenosylmethionine molecules to the biosynthetic precursors of mevinolin was a sequential process. Methylation at C-6 preceded that at C-2' of mevinolin. Both methylation steps proceeded with complete retention of hydrogens. Methyl groups were probably transferred to the anion-like intermediates.