Protective effect of compatible herbs in Jin-Gu-Lian formula against Alangium chinense-induced neurotoxicity via oxidative stress, neurotransmitter metabolisms, and pharmacokinetics

Background: A. chinense frequently used in Miao medicine to treat rheumatic diseases. However, as a famous toxic herb, Alangium chinense and its representative components exhibit ineluctable neurotoxicity, thus creating significant challenges for clinical application. The combined application with compatible herbs in Jin-Gu-Lian formula attenuates such neurotoxicity according to the compatible principle of traditional Chinese medicines. Purpose: We aimed to investigate the detoxification of the compatible herbs in Jin-Gu-Lian formula on A. chinense-induced neurotoxicity and investigate its mechanism. Methods: Neurobehavioral and pathohistological analysis were used to determine the neurotoxicity in rats administered with A. chinense extract (AC), extract of compatible herbs in Jin-Gu-Lian formula (CH) and combination of AC with CH for 14 days. The mechanism underlying the reduction of toxicity by combination with CH was assessed by enzyme-linked immunosorbent assays, spectrophotometric assays, liquid chromatography tandem-mass spectrometry and real-time reverse transcription-quantitative polymerase chain reaction. Results: Compatible herbs attenuated the AC-induced neurotoxicity as evidenced by increased locomotor activity, enhanced grip strength, the decreased frequency of AC-induced morphological damage in neurons, as well as a reduction of neuron-specific enolase (NSE) and neurofilament light chain (NEFL) levels. The combination of AC and CH ameliorated AC-induced oxidative damage by modulating the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC). AC treatment significantly reduced the levels of monoamine and acetylcholine neurotransmitters in the brains of rats, including acetylcholine (Ach), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine (NE), and serotonin (5-HT). Combined AC and CH treatment regulated the abnormal concentrations and metabolisms of neurotransmitters. Pharmacokinetic studies showed that the co-administration of AC and CH significantly decreased plasma exposure levels of two main components of AC, as evidenced by the reduction of maximum plasma concentration (C_max), area under the plasma concentration-time curve (AUC) compared to AC. In addition, the AC-induced downregulation in mRNA expression of cytochrome P450 enzymes was significantly reduced in response to combined AC and CH treatment. Conclusion: Compatible herbs in Jin-Gu-Lian formula alleviated the neurotoxicity induced by A. chinense by ameliorating oxidative damage, preventing abnormality of neurotransmitters and modulating pharmacokinetics.

New phenylpropanoid-substituted and benzyl-substituted flavonols from Alangium chinense

Two previously undescribed flavonols with phenylpropanoid or benzyl substitution, named alangsine A (1), and alangsine B (2), together with four known compounds (3-6) were isolated from the leaves of Alangium chinense. Alangsine A was a racemic mixture, which was further separated into two enantiomers via high-performance liquid chromatography on a chiral column. The absolute configurations of the enantiomer pairs were deduced from the circular dichroism (CD) spectra. The activity of the isolated compounds towards neuronal excitability was examined.

Two new compounds with anti-inflammatory activity from Alangium chinense

A new phenolic glycoside, chinenside A (1), and a new megastigmane glycoside, chinenionside A (2), together with twelve known compounds (3-14), were isolated from the roots of Alangium chinense. Their structures were deduced on the basis of extensive spectroscopic analyses and comparison with data reported in the literature. The anti-inflammatory activity in vitro of all 13 phenolic glycosides was evaluated against lipopolysaccharide-induced mouse macrophage RAW264.7 cells. The compounds 1, 9, and 10 potentially inhibited the productions of nitric oxide (NO), prostaglandin (PEG₂), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β) and interleukin 6 (IL-6). Compound 1 (50 μM) showed stronger anti-inflammatory activity than Triptolide (TPL, 20 nm).

[A new cytotoxic alkaloid from roots of Alangium chinense]

We have carried out the chemical investigation on the roots of Alangium chinense. The chemical constituents from the roots of A.chinense were isolated and purified by various chromatographic techniques, such as silica gel, MCI-Gel resin, Sephadex LH-20 and high performance liquid chromatography. As a result, three alkaloids (1-3) were isolated from 90% EtOH extracts of the roots of this plant. Their structures were elucidated by physical-chemical properties and spectral data. Among them, compound 1 is a new compound, determined as 8-hydroxy-3-hydroxymethyl-6,9-dimethyl-7H-benzo[de]isoquinolin-7-one. Cytotoxicity of the compounds was evaluated by the MTT method. Compound 1 displayed cytotoxicity against NB4, A-549, SHSY5Y, PC-3 and MCF-7 cell lines with IC₅₀ values of 4.2, 3.5, 5.7, 2.8 and 3.9 μmol•L⁻¹, respectively.

Terpenoids from the roots of Alangium chinense

Two new norditerpenoids (1 and 2), four new sesquiterpenoids (3-6), and 22 known compounds (7-28) were isolated from an ethanolic extract of roots of Alangium chinense. The absolute configurations of 1-6 were assigned by experimental and calculated ECD spectra. The skeleton of the compounds (1 and 2) has been reported only one time so far. Compounds 1, 13, and 23 exhibited antiviral activity against coxsackie virus B3 with IC50 values of 38-67 μM. Compounds 8 and 9 displayed neuritis inhibitory activity against microglial inflammation factor, with IC50 values of 6.4 and 10.1 μM, respectively. None of the compounds were cytotoxic in the MTT assay.