Termipaniculatones A-F, chalcone-flavonone heterodimers from Terminthia paniculata, and their protective effects on hyperuricemia and acute gouty arthritis.

Terminthia paniculata (Sanyeqi) is widely used for treating inflammation and rheumatic arthritis in the folk areas of Yunnan province, China. Its total extract was first revealed with xanthine oxidase (XO) inhibitory activity in vitro and anti-hyperuricemic effect in vivo. Bioassay-guided separation on Fr. A5 yielded six chalcone-flavonone heterodimers, termipaniculatones A-F. Their structures were elucidated based on extensive spectroscopic analyses involving HRESIMS, 1D and 2D NMR, UV, IR and [α]D, and the absolute configuration of termipaniculatone F was verified by ECD calculation. Termipaniculatones A and E showed obvious XO inhibitory activity with IC50 values of 55.6 and 89.5 µM, respectively, which took effects via a mix-type mode. A molecular modeling study revealed that termipaniculatone A was well located into the active site of XO by interacting with Glu802, Arg880, Thr1010 and Val1011 residues. Termipaniculatone A showed anti-hyperuricemic effects by decreasing serum uric acid levels and inhibiting XO activity in both serum and liver on potassium oxonate (PO)-induced hyperuricemia mice, and anti-inflammatory activity through alleviating paw swelling on monosodium urate (MSU)-induced mice, at the concentration of 20 mg/kg. This is the first time to reveal the anti-hyperuricemic and anti-acute gouty arthritis potency of T. paniculata and the characteristic biflavonoids as active constituents, which provides valuable information for searching new XO inhibitors from natural sources.

Synthesis and biological evaluation of magnolol derivatives as melatonergic receptor agonists with potential use in depression.

Depression is associated with high mortality and morbidity rates worldwide. By our random screening, it was first revealed that 23 magnolol derivatives were synthesized followed by in vitro and in vivo evaluation of their antidepressive potential. Compound 7c was found to be the most promising compound, with EC50 values of 396.5 and 383.0 µM agitating on MT1 and MT2 receptors, respectively. Additionally, we carried out in vivo experiments to confirm the efficacy and safety of compound 7c; the compound was found to be orally bioavailable and highly effective, leading to a significant reduction of immobility time in a mouse model of depression (forced swimming test and tail suspension test); the acting mechanism was explored by determining its effect on the levels of monoamine neurotransmitters and their metabolites in different mice brain regions; the acute toxicity study showed that the 50% lethal dose (LD50) of 7c was higher than 2000 mg/kg, p. o. A total of 25 metabolites of 7c were identified, including 5 metabolites in phase I and 20 metabolites in phase II. Altogether, these results indicate that magnolol derivative 7c is a promising lead compound for the development of a new chemical class of antidepressant drugs.

LC-MS guided isolation of diterpenoids from Sapium insigne with α-glucosidase inhibitory activities.

Ten new (1-10) and ten known (11-20) diterpenoids involving ent-atisane, ent-seco-atisane, ent-kaurane and ent-seco-kaurane types were isolated from Sapium insigne under the guidance of LCMS-IT-TOF analyses. Their structures were characterized by extensive spectroscopic analyses (HRESIMS, UV, IR, 1D and 2D NMR). A putative biosynthetic pathway was proposed for ent-seco-atisane diterpenoids. Their inhibitory activities on α-glucosidase in vitro were tested for the first time. Compound 4 showed moderate inhibitory effect on α-glucosidase with an IC50 value of 0.34 mM via a noncompetitive inhibition mechanism (Ki = 0.27 mM). The preliminary structure-activity relationships of the ent-atisane diterpenoids inhibiting α-glucosidase were discussed.