Patulignans A-C, three structurally unique lignans from the leaves of Melicope patulinervia

Natural products with potential hypoglycemic activity in T2DM: 2019-2023

As currently the most common metabolic disease, type 2 diabetes mellitus (T2DM) has shown a continuous increase in the number of patients in recent decades. Most anti-T2DM drugs tend to cause some side effects. Given the pathogenesis of T2DM, natural products have emerged as an important source of anti-T2DM drugs. This article reviews natural products with potential hypoglycemic activity from 2019 to 2023. A total of 200 previously natural products were discovered on SciFinder, PubMed and Web of Science. These products were categorized based on their structural frameworks and their biological activities were summarized. Although the mechanisms of action of most compounds are unclear, these compounds could still serve as candidates for the development of lead compounds. Therefore, further structure and activity research of natural products will significantly contribute to the development of potential anti-T2DM drugs.

Patulinervones A and B, two novel α-glucosidase inhibitory spiro-lignans from Melicope patulinervia (Merr. & Chun) C.C. Huang

(±)-Patulinervones A (1) and B (2), two diastereomers of spiro-lignans sharing an unprecedented dimethyl-spiro[furan-2,2'-furo[2,3-b]furan] 5/5/5 tricyclic moiety were isolated from the leaves of Melicope patulinervia (Merr. & Chun) C.C. Huang. Their structures were established by extensive spectroscopic data and electronic circular dichroism (ECD) analyses. The racemates (±)-1 and 2 and their enantiomers exhibited α-glucosidase inhibitory effect with IC50 values range of 10.08 ± 1.24 - 25.58 ± 1.97 µM.

SARS-CoV-2 main protease inhibition by compounds isolated from Luffa cylindrica using molecular docking

In this study, chemical investigation of methanol extract of the air-dried fruits of Luffa cylindrica led to the identification of a new δ‐valerolactone (1), along with sixteen known compounds (2–17). Their chemical structures including the absolute configuration were elucidated by extensive spectroscopic analysis and electronic circular dichroism analysis, as well as by comparison with those reported in the literature. For the first time in literature, we have examined the binding potential of the isolated compounds to highly conserved protein, M^pro of SARS-CoV-2 using the molecular docking technique. We found that the isolated saponins (14–17) bind to the substrate‐binding pocket of SARS-CoV-2 M^pro with docking energy scores of –7.13, –7.29, –7.47, and –7.54 kcal.mol⁻¹, respectively, along with binding abilities equivalent to an already claimed N3 protease inhibitor (–7.51 kcal.mol⁻¹).

Lithium-7 qNMR as a method to quantify lithium content in brines using benchtop NMR

A novel ⁷Li quantitative NMR (qNMR) method to analyze lithium was developed to determine the lithium content in real brine samples using benchtop NMR instruments. The method was validated, and limits of detection and quantification of 40 and 100 ppm, respectively, were determined. Linearity, precision, and bias were also experimentally determined, and the results are presented herein. The results were compared to those obtained using atomic absorption (AA) spectroscopy, currently one of the few validated methods for the quantification of lithium. The method provides both accurate and precise results, as well as excellent correlation with AA. The absence of matrix effects, combined with no need for sample preparation or deuterated solvents, shows potential applicability in the mining industry.

New lignans and acetophenone derivatives with α-glucosidase inhibitory activity from the leaves of Melicope patulinervia

Four new lignans, patulinones A-D (1-4) and three new acetophenone derivatives, patulinones E-G (5-7) were isolated from the leaves of Melicope patulinervia. Their structures were elucidated on the basis of the interpretation of HR-ESIMS, NMR, CD data. All the isolated compounds were evaluated for α-glucosidase inhibitory activity. Of the isolates, compound 4 was found to exhibit the strongest inhibition against α-glucosidase with IC₅₀ value of 6.02 ± 0.46 μM.

Hot off the Press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as patulignan A from Melicope patulinervia.