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Summary: The isolation of a natural product conventionally precedes its chemical synthesis. Often, the isolation and structure determination of a natural product present in minute quantities in its natural source pose formidable challenges, akin to finding “a needle in a haystack.” On the other hand, leveraging plausible biosynthetic insights and biomimetic synthetic expertise would allow for the prior synthesis of presumed natural products, followed by their verification in natural sources. In this study, we unveil two novel securinega alkaloids, securingines H and I, employing the natural product anticipation through synthesis approach. Structural analysis of securingines H and I suggests that they are biosynthetic derivatives of secu’amamine E and securinol A, respectively. We posit that this “synthesis first” strategy represents a valuable approach to the discovery of new natural products.

Salix koreensis Anderss (Salicaceae), commonly referred to as Korean willow, is native to East Asia, particularly Korea and China, and it has been used in traditional Korean folk medicine for its potent anti-inflammatory, analgesic, and antioxidant properties. In our ongoing research efforts to discover biologically new natural products, phytochemical analysis on an ethanolic extract of S. koreensis twigs yielded the isolation and identification of ten phenolic compounds (1–10), including a newly discovered phenolic glycoside (1) named isograndidentatin D, isolated via HPLC purification. The structure of compound 1 was determined through extensive 1D and 2D NMR spectral data analysis and high-resolution electrospray ionization mass spectrometry (HR-ESIMS). Its absolute configuration was established using DP4+ probability analysis combined with gauge-including atomic orbital NMR chemical shift calculations and chemical reaction methods. The other known compounds were identified as isograndidentatin B (2), trichocarposide (3), glanduloidin C (4), tremuloidin (5), 3-O-acetylsalicin (6), 2-O-acetylsalicin (7), salicin (8), salireposide (9), and coumaric acid (10), confirmed by comparing their NMR spectra with previously reported data and further verified through liquid chromatography/mass spectrometry (LC/MS) analysis. The isolated compounds 1–10 were tested for their anti-Helicobacter pylori activities. Among these, compounds 4 and 5 demonstrated moderate anti-H. pylori activity at a concentration of 100 μM. Specifically, compound 5 showed an inhibitory activity of 35.9 ± 5.4%, making it slightly more potent than compound 4, with 34.0 ± 1.0% inhibition. These results were comparable to that of quercetin, a known anti-H. pylori agent used as a positive control in this study, which showed 38.4 ± 2.3% inhibition. The remaining compounds exhibited very weak inhibitory effects. This study highlights the potential of S. koreensis twigs as a valuable natural source of bioactive compounds for therapeutic applications against H. pylori.

Podostroma cornu-damae, one of the lethal toxic mushrooms, is known to contain macrocyclic trichothecene mycotoxins exhibiting potent cytotoxic effects, attracting attention as an important research subject for scientists interested in natural product chemistry and toxicity research. To investigate the mycotoxins from the toxic mushroom P. cornu-damae and evaluate their cytotoxic activities, the fungus was large-cultured on solid plates and successively extracted to acquire a crude methanol (MeOH) extract. After performing successive separation and purification processes, a total of eight macrocyclic trichothecenes were isolated from the MeOH extract of plate cultures of P. cornu-damae using the liquid chromatography/mass spectrometry (LC/MS)-guided isolation technique. Extensive interpretation of nuclear magnetic resonance (NMR) spectroscopic and high-resolution (HR)-electrospray ionization (ESI)-MS data allowed for the structural identification of all isolated macrocyclic trichothecenes, including satratoxin I (1), satratoxin H (2), roridin E (3), miophytocen D (4), roridin L-2 (5), trichoverritone (6), 12′-episatratoxin H (7), and roridin F (8). We conducted a cytotoxicity evaluation of compounds 1–8 against 4T1 breast cancer cells and fibroblast cell lines (L929 cells) using the Counting Kit-8 (CCK-8) cell viability assay to validate their cytotoxic potential. Our results indicated that compounds 1–6 lack anti-cancer effects on 4T1 cells and have minimal impact on the viability of the fibroblast cell line, L929 cells. In contrast, compounds 7 and 8 exhibited no cytotoxicity in normal cells (L929) and demonstrated specific cytotoxicity in breast cancer cell lines. Notably, the cytotoxic effects of compounds 7 and 8 in 4T1 cells were significantly stronger than those observed with free doxorubicin. These findings suggest that compounds 7 and 8 may possess targeted anti-cancer effects, specifically against breast cancer cells, emphasizing their efficient and selective toxicity towards breast cancer cells.

Jatropha podagrica holds a longstanding place in traditional herbal medicine, primarily utilized for addressing skin infections, acting as antipyretics, diuretics, and purgatives. In this study, our primary objective was to investigate the secondary metabolites present in J. podagrica leaves, with the aim of pinpointing natural compounds exhibiting potential antiviral activities. Five secondary metabolites (1–5), including an auronol glycoside (1), two coumarins (2 and 3), a chromane (4) and a gallotannin (5), were isolated from J. podagrica leaves. Compound 1 presented as an amalgamation of unseparated mixtures, yet its intricate composition was adroitly unraveled through the strategic deployment of a chiral HPLC column. This tactic yielded the isolation of epimers (+)-1 and (−)-1, ascertained as unreported auronol glycosides. The structures of these novel compounds, (+)-1 and (−)-1, were elucidated to be (2S)-hovetrichoside C [(+)-1] and (2R)-hovetrichoside C [(−)-1] through NMR data and HR-ESIMS analyses, enzymatic hydrolysis, and comparison of optical rotation values. Cytotoxicity and antiviral effects were assessed for the isolated compounds ((+)-1, (−)-1 and 2–5), along with compound 1a (the aglycone of 1), in the A549 human alveolar basal epithelial cell line. Each compound demonstrated a cell viability of approximately 80% or higher, confirming their non-toxic nature. In the group of compounds, compounds 3–5 demonstrated antiviral effects based on RT-qPCR results, with individual enhancements ranging from approximately 28 to 38%. Remarkably, compound 4 exhibited the most substantial antiviral effect. Utilization of compound 4 to assess immune boosting and anti-inflammatory effects revealed increased levels of STING, RIG-I, NLRP3, and IL-10 along with a decrease in TNF-α and IL-6. Therefore, these findings underscore the potential of these active compounds 3–5 not only as therapeutic agents for SARS-CoV-2 but also as new contenders for upcoming pandemics.

Brown algae comprise up to 2000 species with wide dissemination in temperate zones. A comprehensive untargeted metabolic profiling guided by molecular networking of three uninvestigated Red-Sea-derived brown algae, namely Sirophysalis trinodis, Polycladia myrica, and Turbinaria triquetra, led to the identification of over 115 metabolites categorized as glycerolipids, fatty acids, sterol lipids, sphingolipids, and phospholipids. The three algae exhibited low-to-moderate antioxidant capacity using DPPH and ABTS assays. Preliminary in vitro antiproliferative studies showed that the algal extracts displayed high cytotoxic activity against a panel of cancer cell lines. The most potent activity was recorded against MCF-7 with IC50 values of 51.37 ± 1.19, 63.44 ± 1.13, and 59.70 ± 1.22 µg/mL for S. trinodis, P. myrica, and T. triquetra, respectively. The cytotoxicity of the algae was selective to MCF-7 without showing notable effects on the proliferation of normal human WISH cells. Morphological studies revealed that the algae caused cell shrinkage, increased cellular debris, triggered detachment, cell rounding, and cytoplasmic condensation in MCF-7 cancer cells. Mechanistic investigations using flow cytometry, qPCR, and Western blot showed that the algae induced apoptosis, initiated cell cycle arrest in the sub-G0/G1 phase, and inhibited the proliferation of cancer cells via increasing mRNA and protein expression of p53, while reducing the expression of PI3K, Akt, and mTOR.

Sedum kamtschaticum Fischer, of the Crassulaceae family, is a perennial and medicinal plant used in Asian folk medicine to alleviate inflammatory disease and improve blood circulation. As part of our ongoing exploration into natural products, seeking to identifying bioactive compounds, we characterized, identified, and isolated an unreported bioactive compound, prenylhydroquinone glycoside (1), which we named kirinchoside from S. kamtschaticum leaves. Using high-resolution (HR)-ESIMS, NMR spectroscopic data, and enzymatic hydrolysis, followed by LC–MS analysis, we determined the structure of this isolated compound. Despite a previous report on the planar structure of compound 1 (kirinchoside), the absolute configuration of 1 had not been verified. We investigated the effects of kirinchoside on hyperphosphorylated tau (p-tau) accumulation, a hallmark of Alzheimer’s disease (AD) progression. We observed that treatment with 5 μM kirinchoside suppressed p-tau levels by 16.9% in amyloid β (Aβ)1–42-treated SH-SY5Y cells, compared to the negative control. These findings indicate that kirinchoside, an unreported prenylhydroquinone glycoside found in S. kamtschaticum leaves, could be a candidate preventive agent against AD via inhibition of p-tau accumulation.

Kaempferia parviflora Wall. ex Baker (Zingiberaceae), commonly known as Thai ginseng or black ginger, is a tropical medicinal plant in many regions. It has been traditionally used to treat various ailments, including ulcers, dysentery, gout, allergies, abscesses, and osteoarthritis. As part of our ongoing phytochemical study aimed at discovering bioactive natural products, we investigated potential bioactive methoxyflavones from K. parviflora rhizomes. Phytochemical analysis aided by liquid chromatography–mass spectrometry (LC-MS) led to the isolation of six methoxyflavones (1–6) from the n-hexane fraction of the methanolic extract of K. parviflora rhizomes. The isolated compounds were structurally determined to be 3,7-dimethoxy-5-hydroxyflavone (1), 5-hydroxy-7-methoxyflavone (2), 7,4′-dimethylapigenin (3), 3,5,7-trimethoxyflavone (4), 3,7,4′-trimethylkaempferol (5), and 5-hydroxy-3,7,3′,4′-tetramethoxyflavone (6), based on NMR data and LC-MS analysis. All of the isolated compounds were evaluated for their anti-melanogenic activities. In the activity assay, 7,4′-dimethylapigenin (3) and 3,5,7-trimethoxyflavone (4) significantly inhibited tyrosinase activity and melanin content in IBMX-stimulated B16F10 cells. In addition, structure–activity relationship analysis revealed that the methoxy group at C-5 in methoxyflavones is key to their anti-melanogenic activity. This study experimentally demonstrated that K. parviflora rhizomes are rich in methoxyflavones and can be a valuable natural resource for anti-melanogenic compounds.

Acer tegmentosum, a deciduous tree belonging to Aceraceae, has been used in traditional oriental medicine for treating hepatic disorders, such as hepatitis, cirrhosis, and liver cancer. We evaluated the estrogen-like effects of A. tegmentosum using an estrogen receptor (ER)-positive breast cancer cell line, namely MCF-7, to identify potential phytoestrogens and found that an aqueous extract of A. tegmentosum promoted cell proliferation in MCF-7 cells. Five phenolic compounds (1–5) were separated and identified from the active fraction using bioassay-guided fractionation of crude A. tegmentosum extract and phytochemical analysis. The chemical structures of the compounds were characterized as vanillic acid (1), 4-hydroxy-benzoic acid (2), syringic acid (3), isoscopoletin (4), and (E)-ferulic acid (5) based on the analysis of their nuclear magnetic resonance spectra and liquid chromatography-mass spectrometry data. All five compounds were evaluated using an E-screen assay for their estrogen-like effects on MCF-7 cells. Among the tested compounds, only 4-hydroxy-benzoic acid (2) promoted the proliferation of MCF-7 cells, which was mitigated by the ER antagonist, ICI 182,780. The mechanism underlying the estrogen-like effect of 4-hydroxy-benzoic acid (2) was evaluated via western blotting analysis to determine the expression levels of extracellular signal-regulated kinase (ERK), phosphoinositide 3-kinase (PI3K), serine/threonine kinase (AKT), and ERα. Our results demonstrated that 4-hydroxy-benzoic acid (2) induced the increase in the protein expression levels of p-ERK, p-AKT, p-PI3K, and p-Erα, concentration dependently. Collectively, these experimental results suggest that 4-hydroxy-benzoic acid (2) is responsible for the estrogen-like effects of A. tegmentosum and may potentially aid in the control of estrogenic effects during menopause.

Salix species, including willow trees, are distributed in the temperate regions of Asian countries, including South Korea. Willow trees are used to treat pain and inflammatory diseases. Due to the medicinal properties of willow trees, pharmacological studies of other Salix spp. have gained attention; however, only a few studies have investigated the phytochemicals of these species. As part of our ongoing natural product research to identify bioactive phytochemicals and elucidate their chemical structures from natural resources, we investigated the marker compounds from indigenous Korean Salix species, namely, Salix triandra, S. chaenomeloides, S. gracilistyla, S. koriyanagi, S. koreensis, S. pseudolasiogyne, S. caprea, and S. rorida. The ethanolic extract of each Salix sp. was investigated using high-performance liquid chromatography combined with thin-layer chromatography and liquid chromatography–mass spectrometry-based analysis, and marker compounds of each Salix sp. were isolated. The chemical structures of the marker compounds (1–8), 3-(4-hydroxyphenyl)propyl β-D-glucopyranoside (1), 2-O-acetylsalicin (2), 1-O-p-coumaroyl glucoside (3), picein (4), isograndidentatin B (5), 2′-O-acetylsalicortin (6), dihydromyricetin (7), and salicin (8) were elucidated via nuclear magnetic resonance spectroscopy and high-resolution liquid chromatography–mass spectrometry using ultrahigh-performance liquid chromatography coupled with a G6545B Q-TOF MS system with a dual electrospray ionization source. The identified marker compounds 1–8 were examined for their antimicrobial effects against plant pathogenic fungi and bacteria. Dihydromyricetin (7) exhibited antibacterial activity against Staphylococcus aureus, inducing 32.4% inhibition at a final concentration of 125 μg/mL with an MIC50 value of 250 μg/mL. Overall, this study isolated the marker compounds of S. triandra, S. chaenomeloides, S. gracilistyla, S. koriyanagi, S. koreensis, S. pseudolasiogyne, S. caprea, and S. rorida and identified the anti-Staphylococcus aureus bacterial compound dihydromyricetin.

Atopic dermatitis (AD) is a chronic inflammatory disease characterized by hyperactivated immune reactions in the skin. AD is a prevalent health concern in developing countries, with a particularly high incidence among children. Despite ongoing research on AD, prevention and treatment strategies for patients remain inadequate. In this study, the inhibitory effects of Cornus walteri on AD were investigated. C. walteri (Cornaceae), commonly known as “Walter’s dogwood,” is a deciduous shrub used as a traditional medicine to treat dermatologic inflammation caused by lacquer poisoning. However, the role of C. walteri in AD remains largely unknown. To evaluate its anti-AD potential, we investigated the anti-inflammatory activity of the MeOH extract of C. walteri stems (CWS) using the HaCaT human keratinocyte cell line. CWS reduced the secretion of AD-related chemokines, eotaxin-3/CCL26 and thymus and activation-regulated chemokine (TARC/CCL17). In addition, CWS also inhibited the mRNA expression of macrophage-derived chemokine (MDC/CCL22) and upregulated filaggrin, which plays an essential role in skin barrier functions. To identify the bioactive constituents of CWS, phytochemical investigation of CWS led to the isolation of potential bioactive constituents (1–6), including four triterpenoids, one steroid and one diterpene analog, the structures of which were identified as lupeol (1), betulinic acid (2), 5α-stigmast-3,6-dione (3), 3-O-acetylbetulin (4), betulinic acid methyl ester (5) and norphytan (6) through nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography (LC)–mass spectrometry (MS) analysis. The isolated compounds (1–6) were evaluated for their inhibitory activities against eotaxin-3 expression. Compounds 1, 2 and 3 significantly reduced the levels of eotaxin-3. These findings provided experimental evidence that CWS, particularly active compounds 1, 2 and 3, could be further utilized as potential therapeutic agents to treat AD.

Abstract Among the various methods, Non Thermal Plasma (NTP) has been recently introduced and is being studied to recover the damaged nerve. In the recent years, several studies have suggested that NTP accelerates nerve cell regeneration, but the mechanism remains unknown. This study evaluated the effect of NTP on neuronal proliferation in SH-SY5Y (Human neuroblastoma cells) cells differentiated by retinoic acid (RA) and investigated the mechanism by which NTP promotes cell proliferation. We analyzed the morphology of differentiated SH-SY5Y cells, and performed western blot analysis and reverse transcription polymerase chain reaction (RT-PCR). Immunofluorescence analysis was performed in an in vivo study by categorizing Wistar A rats into three groups: non-nerve damage (Non-ND), nerve damage (ND), and nerve damage + NTP treatment (ND + NTP). The cell morphology analysis revealed that the number of cells increased and axonal elongation progressed after NTP treatment. In addition, western blots indicated that tau expression increased significantly after NTP treatment. The RT-PCR results revealed that the expression of tau, wnt3a, and β-catenin increased after NTP treatment. The in vivo immunofluorescence assay showed that NTP increased the markers for tau and S100B while regulating the over-expression of MAP2 and GAP43. NTP treatment accelerated cell proliferation and regeneration of damaged neurons in differentiated SH-SY5Y cells. These results establish the fact of NTP as a noninvasive and effective treatment for nerve injury.

Abstract Background This study aimed to evaluate the effect of argon-based No-ozone Cold Plasma (NCP) on neuroblastoma cancer cell apoptosis. Methods Experiments were performed with SK-N-SH and HS 68. Cell cultures were treated with NCP for 1, 3, and 5 min. NCP was applied using three different strategies: direct NCP application to cell cultures, to only media, and to only cells. Evaluation of cell viability and the level of the reactive oxygen species (ROS) was performed. N-acetyl-L-cysteine (NAC) was also used to antagonize intracellular ROS. Cleaved caspase 3, PARP, aquaporin (AQP) 3 and 8 were detected. Results NCP induced a gradual decrease in the SK-N-SH cell viability. In contrast, the viability of HS 68 cells did not change. SK-N-SH cells viability was reduced the most when the only media-NCP application strategy was employed. Intracellular ROS levels were significantly increased with time. Cleaved caspase 3 and PARP were increased at 6 h after NCP application. SK-N-SH cells remained viable with NAC after NCP application. AQP 3 and 8 were over-expressed in SK-N-SH cells. Conclusion These findings demonstrate the anti-cancer effect of NCP on neuroblastoma cells. NCP enhanced the selective apoptosis of neuroblastoma cells due to the increased intracellular ROS.