Alkaloids 1–10 were isolated from the aerial parts of Tetrastigma hemsleyanum (APTH) and obtained from species of the genus Tetrastigma for the first time. The chemical structures of the isolated compounds were identified by NMR, UV, and MS analyses. Their anti-inflammatory activities were investigated by measuring nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Among all the isolates, compounds 6, 7 and 10 showed potent inhibitory activity against LPS-stimulated NO production in RAW264.7 cells (IC50: 31.9, 25.2 and 6.3 μM, respectively). Furthermore, APTH and S-(−)-trolline (10) inhibited induction of inflammatory cytokines or mediators such as interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) via suppression of nuclear factor κB (NF-κB) translocation into the nucleus. In addition, 10 suppressed extracellular signal-regulated protein kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) phosphorylation in a dose-dependent manner. These results conclusively demonstrated that compound 10 displays anti-inflammatory activity via suppression of NF-κB activation and the ERK-MAPK signaling pathway in LPS-stimulated RAW264.7 cells.

Actinidia arguta, commonly called hardy kiwifruit or kiwiberry, has cold-resistant properties and can be cultivated in Asia, including Korea. Seven new triterpenoids (2−4 and 8−11) along with eight known triterpenoids were isolated from the leaves of A. arguta through various chromatographic techniques. The new triterpenoids were defined as actiniargupenes A−C (2−4), actinidic acid derivatives with phenylpropanoid constituent units, dehydroisoactinidic acid (8), and actiniargupenes D−F (9−11), asiatic acid derivatives with phenylpropanoid substituents, on the basis of 1D and 2D NMR and MS data. Among the triterpenoids, those with a phenylpropanoid constituent unit showed inhibitory activity on α-glucosidase, which suggested the importance of the phenylpropanoid moiety. Molecular docking analysis demonstrated the interaction between the 4′-OH group of the phenylpropanoid moiety and α-glucosidase.T he genus Actinidia is a deciduous vine belonging to the Actinidiaceae. The species and cultivars of this genus have different physical shapes and tastes. Actinidia arguta, commonly called hardy kiwifruit or kiwiberry, is cold-resistant, in contrast to A. deliciosa (green kiwi) and A. chinensis (gold kiwi). Therefore, they are cultivated in Asia, including Korea. 1 The fruit of A. arguta is widely consumed as fresh fruit. Different parts of this plant including its fruit, leaves, stems, and roots have also been used traditionally for the treatment of various diseases. Previous investigations of hardy kiwifruit reported various activities such as antioxidant, antibacterial, antidiabetic, antiallergic, and anti-inflammatory effects. 2−7 α-Glucosidase is an intestinal enzyme catalyzing the final step of carbohydrate digestion by converting carbohydrates to single monosaccharides. 8,9 Therefore, inhibition of α-glucosidase would delay the digestion and absorption of carbohydrates, resulting in a hypoglycemic effect by controlling postprandial hyperglycemia. Several α-glucosidase inhibitors such as acarbose and voglibose are used for the treatment of carbohydrate-mediated diseases such as diabetes. 10,11 Accordingly, natural products with α-glucosidase inhibitory activity will be beneficial for the treatment and prevention of diabetes and obesity by controlling blood glucose levels. 12−14 Recently, investigation of the leaves of A. arguta reported beneficial effects on diabetes, and phenolic compounds were suggested as active constituents. 15,16 However, its active constituents have not been well characterized. In this study, the isolation and structural elucidation of new triterpenoids are described. In addition, their inhibitory activity on α-glucosidase was also evaluated and analyzed by molecular docking data analysis.

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An effective and previously demonstrated screening method for active constituents in natural products using LC-MS coupled with a bioassay was reported in our earlier studies. With this, the current investigation attempted to identify bioactive constituents of Scutellaria baicalensis through LC-MS coupled with a bioassay. Peaks at broadly 17–20 and 24–25 min on the MS chromatogram displayed an inhibitory effect on NO production in lipopolysaccharide-induced BV2 microglia cells. Similarly, peaks at roughly 17–19 and 22 min showed antioxidant activity with an 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS)/2,2-diphenyl-1- picrylhydrazyl (DPPH) assay. For confirmation of LC-MS coupled with a bioassay, nine compounds (1–9) were isolated from an MeOH extract of S. baicalensis. As we predicted, compounds 1, 8, and 9 significantly reduced lipopolysaccharide (LPS)-induced NO production in BV2 cells. Likewise, compounds 5, 6, and 8 exhibited free radical-scavenging activities with the ABTS/DPPH assay. In addition, the structural similarity of the main components was confirmed by analyzing the total extract and EtOAc fractions through molecular networking. Overall, the results suggest that the method comprised of LC-MS coupled with a bioassay can effectively predict active compounds without an isolation process, and the results of molecular networking predicted that other components around the active compound node may also be active.