Chemical constituents from Uncaria laevigata and their anti-inflammatory activities and action mechanism

A new alkaloid 1* (scandine Z) and fourteen known natural products were isolated from 95% ethanol extract of Uncaria laevigata for the first time. Besides compound 1*, these fourteen compounds were firstly isolated from Uncaria laevigata. Excitedly, compound 4 exhibited strong anti-inflammatory activity (IC50 = 8.12 μmol/L), which wasn't described before. Moreover, compound 1* also de--monstrated certain anti-inflammatory activity (IC50 = 10.34 μmol/L). Network pharmacology suggested that compound 4 was involved in the IL-17 signalling pathway and the regulation of inflammation pathway. Molecular docking confirmed that it showed strong binding activity with the target protein (peroxisome proliferator-activated receptor γ, PPAR). Overall, compounds 1* and 4 exhibited strong anti-inflammatory activity and served as lead compounds and anti-inflammatory molecules for further study in vivo.

Environmentally benign cinchonain IIa from Uncaria laevigata for corrosion inhibition of Q235 steel in HCl corrosive medium: Experimental and theoretical investigation

Traditional corrosion inhibitors make great contribution to metal protection, but also cause environmental pollution. To solve the problem, plant extracts as green corrosion inhibitors have attracted much attention in recent years. Plants are good raw materials for corrosion inhibitors and also meet the requirements of industry. However, they have not been successfully applied in industry due to the unknown composition of the effective corrosion inhibitors and large dosage thereof. Therefore, cinchonain IIa was separated from Uncaria laevigata with abundant sources and low cost from nature in this work. Here we hypothesized that cinchonain IIa could show good corrosion inhibition performance for Q235 steel in the acidic medium. Through experiments and theoretical calculation, we studied the corrosion inhibition effect of cinchonain IIa on Q235 in 1 M HCl solution at 298 K for 48 h. Electrochemical experiments revealed that the inhibition efficiency of 200 mg/L cinchonain IIa in 1 M HCl for Q235 steel was 94.08% for 48 h. It even showed over 93% corrosion inhibition efficiency and durable protection performance to 28 d. Surface observations indicated that cinchonain IIa were firmly attached to the steel surface by forming a protective film. Moreover, quantum chemical calculation and molecular dynamics simulation revealed the inhibition mechanism at molecular and atomic level. Compared with some plant extracts, here we demonstrate that the outstanding advantages of cinchonain IIa include sustained protective effect, small dosage, and low toxicity. Accordingly, it may be used as a green industrial corrosion inhibitor with great potential in oilfield acidification and acid pickling.

α-Glucosidase inhibitory triterpenoids from the stem barks of Uncaria laevigata

A phytochemical study on the ethanolic extract of the stem barks of Uncaria laevigata leads to the isolation and characterization of 18 triterpenoid compounds. Ten of these are new, including one novel heptanortriterpenoid (1), four ursane triterpenes (2-4, 10), and five oleanane triterpenes (5-9). Their structures were established by spectroscopic methods, especially by 2D-NMR and MS analyses. All these isolates were evaluated for their inhibitory effects on α-glucosidase: ursolic acid and 3 showed potent activities with IC₅₀ values of 16 ± 2.2 and 49 ± 3.7 μM, respectively.