New Thymoquinol Glycosides and Neuroprotective Dibenzocyclooctane Lignans from the Rattan Stems of Schisandra chinensis.

Three new lignans (1 - 3), together with four new thymoquinol glycosides (4 - 7), were isolated from 70%-EtOH extract of the rattan stems of Schisandra chinensis. The structures of 1 - 7 were elucidated by detailed spectroscopic analyses, and these new compounds were identified as pinobatol-9-O-ß-d-glucopyranoside (1), 1,2,13,14-tetramethoxydibenzocyclooctadiene 3,12-O-ß-d-diglucopyranoside (2), 3,7-dihydroxy-1,2,13,14-tetramethoxydibenzocyclooctadiene 12-O-ß-d-glucopyranoside (3), thymoquinol 2-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside (4), thymoquinol 2-O-α-d-arabinofuranosyl-(1→6)-ß-d-glucopyranoside (5), thymoquinol 5-O-ß-d-apiofuranosyl-(1→6)-ß-d-glucopyranoside (6), and thymoquinol 5-O-α-d-arabinofuranosyl-(1→6)-ß-d-glucopyranoside (7). The neuroprotective activity of 1 - 7 was evaluated on PC12 cells with neurotoxicity induced by amyloid-beta 1 - 42 (Aß1 - 42 ). Compounds 2 and 3 showed protecting activity against Aß-induced toxicity in PC12 cells.

The Spectrum of Tigecycline-Induced Pancreatitis in Clinical Characteristics, Diagnosis, and Management.

Introduction: Tigecycline-induced acute pancreatitis (AP) has been frequently increasingly reported in solid organ transplant patients. This review aimed to summarize the characteristics, possible mechanisms, and management of tigecycline-induced AP. Methods: Case reports of tigecycline-induced AP published in Chinese or English were collected until February 2023 for retrospective analysis. Results: Thirty-four patients from 29 articles were included. Fifteen patients (46.9%) had solid organ transplantation, and 4 patients (12.5%) had malignant tumors. Twenty-five patients (89.3%) received a recommended maintenance dose of tigecycline (50 mg q12 h). The median age was 50 years (range 9-87). Compared to the nontransplant patients, the median age of the transplant patients was significantly younger, 44 years (range 12.5-61) versus 57.5 years (range 9-87) (P=0.03). The median time of symptom onset was 7 days (range 2-29), and 91.2% (31/34) were less than 14 days. Typical initial symptoms included abdominal pain (90.6%), nausea (46.9%), vomiting (43.8%), and abdominal distention (21.9%). Most cases were accompanied by elevated levels of pancreatic enzymes. The main radiological features included edematous infiltrate and acute pancreatitis on computed tomography (CT) scan and abdominal ultrasound. Except for one patient who continued tigecycline treatment, all patients discontinued treatment and received symptomatic support such as fasting, acid suppression, and enzyme suppression. The median time to recover pancreatic enzymes to the normal range was 5 days (range 1-43), and the median time to relieve symptoms was 4 days (range 1-12). Four patients died, of whom two died of severe pancreatitis complications and two of cardiogenic shock and septicemia. Conclusion: Tigecycline-induced AP was a rare and serious complication that occurred mainly within two weeks of the medication. This serious side effect should be kept in mind while treating severe infections especially in transplant recipients.

Enhanced Stability and Function of Probiotic Streptococcus thermophilus with Self-Encapsulation by Increasing the Biosynthesis of Hyaluronan.

The harsh conditions of the gastrointestinal tract limit the potential health benefits of oral probiotics. It is promising that oral bioavailability is improved by strengthening the self-protection of probiotics. Here, we report the encapsulation of a probiotic strain by endogenous production of hyaluronan to enhance the effects of oral administration of the strain. The traditional probiotic Streptococcus thermophilus was engineered to produce hyaluronan shells by using traceless genetic modifications and clustered regularly interspaced short palindromic repeat interference. After oral delivery to mice in the form of fermented milk, hyaluronan-coated S. thermophilus (204.45 mg/L hyaluronan in the milk) exhibited greater survival and longer colonization time in the gut than the wild-type strain. In particular, the engineered probiotic strain could also produce hyaluronan after intestinal colonization. Importantly, S. thermophilus self-encapsulated with hyaluronan increased the number of goblet cells, mucus production, and abundance of the microorganisms related to the biosynthesis of short-chain fatty acids, resulting in the enhancement of the intestinal barrier. The coating formed by endogenous hyaluronan provides an ideal reference for the effective oral administration of probiotics.

Aromatic monoterpenoid glycosides from rattan stems of Schisandra chinensis and their neuroprotective activities.

Six new monoterpenoid glycosides, including thymoquinol 5-O-α-L-arabinopyranosyl-(1 → 6)-ß-D-glucopyranoside (1), cuminic acid 7-O-α-D-arabinofuranosyl-(1 → 6)-ß-d-glucopyranosyl ester (2), p-cymene 7-O-α-D-arabinofuranosyl-(1 → 6)-ß-D-glucopyranoside (3), p-methylhyd- ratropic acid 9-O-α-D-arabinofuranosyl-(1 → 6)-ß-d-glucopyranosyl ester (4), (R)-p-cymene 9-O-α- D-arabinofuranosyl-(1 → 6)-ß-D-glucopyranoside (5), and (R)-p-cymene 9-O-ß-D-apiofuranosyl-(1 → 6)-ß-D-glucopyranoside (6), together with three known compounds, such as (R)-p-cymene 9-O-ß-D-glucopyranoside (7), thymoquinol 5-O-ß-D-glucopyranoside (8), and thymoquinol 2-O-ß-D-glucopyranoside (9) were isolated from the 70%-EtOH extract of Schisandra chinensis rattan stems. The structures of the new compounds were elucidated by detailed spectroscopic analyses. Meanwhile, the neuroprotective activities of compounds 1-9 were evaluated on the two co-culture models of microglia and neurons cells and astrocytoma and neurons cells.

Highly enantioselective synthesis of alpha,alpha-disubstituted malonamic acids through asymmetric hydrolysis of dinitriles with Rhodococcus sp. CGMCC 0497.

Highly enantioselective hydrolysis of alpha,alpha-disubstituted malononitriles by the strain Rhodococcus sp. CGMCC 0497 expressing both nitrile hydratase and amidase activity to give (R)-alpha,alpha-disubstituted malonamic acids which could be converted to valuable (R)- or (S)-alpha-alkylated amino acids are reported and the yields of the products are improved remarkably at a lower reaction temperature.

Sugar Ester Modified Lipase Catalyzed Esterification in Organic Media.

The esterification reaction of a long-chain fatty acid and a fatty alcohol catalyzed by sugar ester-modified lipases in organic media was studied. The reaction activity was improved when the lipases were modified with sugar esters. Among four kinds of sugar esters and six kinds of lipases, lipase CES modified with sugar ester SE-7 showed the highest reaction activity. The pH, solvent and temperature on the reaction activity of SE-7 modified lipase CES were also studied.

Lipase Catalyzed Biosynthesis of Lactones.

Lactones derived from hydroxy fatty acids have many applications. Compared to conventional chemical synthesis, lipases catalyzed synthesis of lactones is simple, mild and highly productive. The effects of hydroxy fatty acid chain length, solvents, lipase type and steric factor on the yield and on the distribution of the produced lactones were investigated.

Practical synthesis of optically active alpha,alpha-disubstituted malonamic acids through asymmetric hydrolysis of malonamide derivatives with Rhodococcus sp. CGMCC 0497.

A variety of alpha,alpha-disubstituted malonamides undergo enantioselective hydrolysis with Rhodococcus sp. CGMCC 0497 to give challenging enantiopure alpha,alpha-disubstituted malonamic acids with up to >99% enantiomeric excesses and 98% chemical yields. The enantioselectivity originated from the effects of a highly enantioselective amidase. The products could be converted to valuable (R)- or (S)-alpha,alpha-dialkylated amino acids after routine conversions.

Enhancement of enzyme activity and enantioselectivity via cultivation in nitrile metabolism by Rhodococcus sp. CGMCC 0497.

Racemic 2-phenylpropionitrile was resolved enantioselectively by nitrile-converting enzymes in cells of Rhodococcus sp. CGMCC 0497 to S-(+)-2-phenylpropionic acid and R-(-)-2-phenylpropionamide. By optimization of the culture conditions, great enhancement of enzyme activity and enantioselectivity was achieved. Furthermore, the relationship between cell-growth periodicity and enzyme accumulation was studied; the addition of inducer was delayed by 1 day and the reaction was further improved. This unusual strategy has almost never been reported with other nitrile-converting strains. The resulting culture broth, containing methacrylamide as the inducer, beef extract as the nitrogen source and glucose as the carbon source, with methacrylamide added 24 h later, seemed to be most suitable. S-(+)-2-Phenylpropionic acid and R-(-)-2-phenylpropionamide were produced with yields of 48% (enantiomeric excess, 96%) and 42% (enantiomeric excess, 97%) respectively with no nitrile left after 3 h, or with yields of 52% and 39% (enantiomeric excess, 93% and 99%) respectively after 6 h.

Enantioselective hydrolysis of o-nitrostyrene oxide by whole cells of Aspergillus niger CGMCC 0496.

The asymmetric biohydrolysis is described of o-nitrostyrene oxide with high selectivity by whole cells of Aspergillus niger CGMCC 0496. Both the epoxide and diol could be obtained in a high state of optical purity (over 98%). Product inhibition was found when using a high ratio of substrate to cells.

Enantioselective hydrolysis of various substituted styrene oxides with Aspergillus Niger CGMCC 0496.

Enantioselective biohydrolysis of various substituted styrene oxides using whole fungus cells of Aspergillus nigerCGMCC 0496 are described. The results show not only para- but also some ortho- substituted styrene oxides can achieve high enantioselectivity during the hydrolysis.