Novel oligomeric neolignans with PTP1B inhibitory activity from the bark of Magnolia officinalis var. biloba

The barks of Magnolia officinalis var. biloba, Magnoliae cortex, have been used as traditional Chinese medicines for several centuries. In this study, phytochemical investigation of M. officinalis var. biloba bark extract afforded five pairs of novel enantiomeric oligomeric neolignans, (±)-mooligomers A-E (1-5). (±)-1 and (±)-2 were two diastereomeric pairs of enantiomers with six C6-C3 subunits, and (±)-4 was a pair of previously unreported tetrameric neolignans bearing eight C6-C3 subunits. (±)-5 is the first example of a naturally occurring trilignan featuring an eight-membered ring with a magnolol moiety. The absolute configurations of (±)-1-(±)-5 were elucidated on the basis of HRESIMS, 1D and 2D NMR spectroscopy and electronic circular dichroism (ECD) calculations. Among the compounds tested for their PTP1B inhibitory activities, (±)-2, (±)-4 and (±)-5 displayed significant PTP1B inhibitory activities with IC₅₀ values of 0.14-2.10 μM. Furthermore, a Molecular docking simulation of PTP1B and active compounds [(±)-2, (±)-4 and (±)-5] exhibited that these active compounds possess low binding affinities ranging from - 5.9 to - 7.7 kcal/mol.

Hepatoprotective effects of total phenylethanoid glycosides from Acanthus ilicifolius L. against carbon tetrachloride-induced hepatotoxicity

ETHNOPHARMACOLOGICAL RELEVANCE

Acanthus ilicifolius L. has been used as a folk medicine in the treatment of acute and chronic hepatitis in China for a long time. Phenylethanoid glycosides are one of main components in A. ilicifolius L.

AIM OF THE STUDY

The aim of present study was to assess the hepatoprotective activities of total phenylethanoid glycosides from A. ilicifolius L. (APhGs) against carbon tetrachloride (CCl₄)-induced liver injury in vivo and in vitro.

MATERIALS AND METHOD

The APhGs was separated by resin column chromatography. The purity of total phenylethanoid glycosides was determined by UV-Vis spectrophotometry using acteoside as a standard. The hepatoprotective activities of APhGs against CCl₄-induced liver injury were performed on experimental mice and L-02 hepatocytes. Moreover, the antioxidant activities of APhGs were tested in vitro.

RESULTS

The results showed that pre-administration of APhGs to mice decreased alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in serum, and improved superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) level in serum and liver tissue induced by CCl₄. Specifically, the SOD activities of APhGs-H and APhGs-M treatment groups were stronger than that of silymarin treatment group. The protective activities of APhGs were confirmed by histopathological results. Moreover, immunohistochemical analysis showed that APhGs could remarkably down-regulate the protein expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). In vitro experiment, APhGs was observed to increase L-02 hepatocyte viability against CCl₄-induced hepatotoxicity. In addition, antioxidation assays revealed that APhGs showed 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing ability.

CONCLUSION

Overall, total phenylethanoid glycosides from A. ilicifolius L. displayed promising hepatoprotective effects. These results offer a support for the medicine uses of A. ilicifolius L.

Photoprotection of maqui berry against ultraviolet B-induced photodamage in vitro and in vivo

Maqui berry extracts could ameliorate oxidative stress, cellular DNA damage, and inflammation induced by UVB-irradiation in vitro and in vivo.

Magmenthanes A-H: Eight new meroterpenoids from the bark of Magnolia officinalis var. Biloba

Eight new meroterpenoids with different types of monoterpene units, namely, magmenthanes A-H (1-8), were identified from the bark of Magnolia officinalis var. biloba. Magmenthane A (1) possesses a 1,3-dioxabicyclo [4.3.0^1,5] nonane skeleton, 1-5 possess five pairs of enantiomers and 6 possesses a 1,1'-diallyl-biphenyl fragment. The structures of 1-8 were elucidated on the basis of 1D and 2D NMR, HRESIMS and electronic circular dichroism (ECD) calculations. Compounds 5 and 8 displayed significant PTP1B inhibitory activities with IC₅₀ values of 4.38 and 3.88 μM, respectively.

Identification of minor lignans, alkaloids, and phenylpropanoid glycosides in Magnolia officinalis by HPLC‒DAD‒QTOF-MS/MS

An effective strategy based on high-speed counter-current chromatography (HSCCC) knockout combination with HPLC-DAD-QTOF-MS/MS analysis were developed to identify minor lignans, alkaloids, and phenylpropanoid glycosides in M. officinalis. Petroleum ether/ethyl acetate/methanol/water (8:4:7:5, v/v/v/v) as solvent system was firstly selected to separate the crude extract of M. officinalis. Two major lignans, honokiol and magnolol were knocked out, and minor components were enriched. Then, five standards (honokiol, magnolol, magnocurarine, magnoflorine and acteoside) were used as examples to discuss their fragmentation patterns for structural identification. By comprehensive screening, sixteen lignans, nine alkaloids, six phenylpropanoid glycosides were unambiguously or tentatively identified by comparing their retention time, UV spectra, accurate mass and fragmentation patterns with standards or reported components. Eight of them, as far as was known, were discovered from M. officinalis for the first time. The proposed method might provide a model for the effective identification of minor components from complex herbs. Additionally, this study laid a foundation for the study of quality control, and clinical applications of M. officinalis.