New lignan glycosides from Justicia secunda Vahl (Acanthaceae) with antimicrobial and antiparasitic properties

Three new lignan glucosides, namely, justisecundosides A (1), B (2a), and C (2b), were isolated from the whole plant of Justicia secunda together with seven known compounds (3-9). Their structures were established based on a comprehensive analysis of HR-ESI-MS, IR, UV, and CD, in conjunction with their 1D and 2D-NMR data. A putative biogenetic pathway of compounds 1-2a,b from coniferyl alcohol was proposed. In addition, the antimicrobialactivities of the extract, fractions, and some isolated compounds were assessed against multiresistant bacterial and fungal strains. Furthermore, the antiplasmodial, antileishmanial, and antitrypanosomal activities were assessed against the sensitive (3D7) and multidrug-resistant (Dd2) strains of P. falciparum, promastigote and bloodstream forms of L. donovani, and Trypanosoma brucei, respectively. Compound 4 exhibited moderate antibacterial activity against Staphylococcus aureus SA RN 46003 with a MIC value of 62.5 μg/mL. Besides, compound 6 demonstrated a very good activity against sensitive (IC50Pf3D7: 0.81 μg/mL) and multidrug-resistant (IC50PfDd2: 14.61 μg/mL) strains of P. falciparum while compound 4 displayed good antitrypanosomal activity (IC50: 1.19 μg/mL). Also, compound 1 was the most active on the promastigote form of L. donovani with an IC50 of 13.02 μg/mL.

Chemoenzymatic Synthesis of Complex Phenylpropanoid Derivatives by the Botrytis cinerea Secretome and Evaluation of Their Wnt Inhibition Activity

In this study, a series of complex phenylpropanoid derivatives were obtained by chemoenzymatic biotransformation of ferulic acid, caffeic acid, and a mixture of both acids using the enzymatic secretome of Botrytis cinerea. These substrates were incubated with fungal enzymes, and the reactions were monitored using state-of-the-art analytical methods. Under such conditions, a series of dimers, trimers, and tetramers were generated. The reactions were optimized and scaled up. The resulting mixtures were purified by high-resolution semi-preparative HPLC combined with dry load introduction. This approach generated a series of 23 phenylpropanoid derivatives, 11 of which are described here for the first time. These compounds are divided into 12 dimers, 9 trimers (including a completely new structural scaffold), and 2 tetramers. Elucidation of their structures was performed with classical spectroscopic methods such as NMR and HRESIMS analyses. The resulting compound series were analyzed for anti-Wnt activity in TNBC cells, with several derivatives demonstrating specific inhibition.

Inhibitory Effects of Phenylpropanoid Derivatives from Oenanthe javanica on Antigen-Stimulated Degranulation in RBL-2H3 Cells

Two diacyldaucic acids (1 and 2), an α,β-unsaturated γ-lactone-type lignan (3) and its derivatives (4-6), and 12 known compounds were isolated from a traditional East Asian vegetable, Oenanthe javanica. The absolute configuration of 1 was validated by obtaining (+)-osbeckic acid through acid hydrolysis. The absolute configurations of 3-5 were determined by comparing their experimental and computed ECD data. The conclusion was supported by applying the phenylglycine methyl ester method to 3. Compound 6 was obtained as an interconverting mixture of isomers in a 3:1 trans- cis ratio. Several water-soluble components (1, 3, and 6) showed concentration-dependent inhibitory effects on antigen-stimulated degranulation in RBL-2H3 cells without producing any direct cytotoxicity against RBL-2H3 or HeLa cells.

Identification of antitumor lignans from the seeds of morning glory (Pharbitis nil)

In the search for antitumor compounds from Korean natural resources, activity-guided fractionation and purification processes were used on seeds of morning glory (Pharbitis nil). Air-dried P. nil seeds were extracted with ethanol and separated into n-hexane, chloroform, ethyl acetate, and n-butanol. Four new lignans, pharbilignans A-D (1-4) were isolated from the most active ethyl acetate fraction of the ethanol extract. Their structures were characterized on the basis of spectroscopic methods, including one- and two-dimensional nuclear magnetic resonance (NMR) techniques, high resolution mass spectrometry (HRMS), and circular dichroism (CD) spectroscopy. The cytotoxic activities of the isolates (1-4) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) using a sulforhodamine B (SRB) bioassay. Pharbilignan C (3) showed potent cytotoxicity against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 1.42, 0.16, 0.20, and 0.14 μM, respectively. On the basis of the expanded understanding that inflammation is a crucial cause in tumor progress, we also evaluated anti-inflammatory activity of the isolates (1-4). Pharbilignan C (3) strongly inhibited nitric oxide (NO) production in the lipopolysaccharide (LPS)-activated BV-2 microglia cell line with an IC50 value of 12.8 μM.

Protein tyrosine phosphatase 1B (PTP1B) inhibitors from Morinda citrifolia (Noni) and their insulin mimetic activity

As part of our ongoing search for new antidiabetic agents from medicinal plants, we found that a methanol extract of Morinda citrifolia showed potential stimulatory effects on glucose uptake in 3T3-L1 adipocyte cells. Bioassay-guided fractionation of this active extract yielded two new lignans (1 and 2) and three new neolignans (9, 10, and 14), as well as 10 known compounds (3-8, 11-13, and 15). The absolute configurations of compounds 9, 10, and 14 were determined by ECD spectra analysis. Compounds 3, 6, 7, and 15 showed inhibitory effects on PTP1B enzyme with IC50 values of 21.86 ± 0.48, 15.01 ± 0.20, 16.82 ± 0.42, and 4.12 ± 0.09 μM, respectively. Furthermore, compounds 3, 6, 7, and 15 showed strong stimulatory effects on 2-NBDG uptake in 3T3-L1 adipocyte cells. This study indicated the potential of compounds 3, 6, 7, and 15 as lead molecules for antidiabetic agents.