Oxidative stress promotes cytotoxicity in human cancer cell lines exposed to Escallonia spp. extracts.

BACKGROUND: Standard cancer treatments show a lack of selectivity that has led to the search for new strategies against cancer. The selective elimination of cancer cells modulating the redox environment, known as "selective oxycution", has emerged as a viable alternative. This research focuses on characterizing the unexplored Escallonia genus plant extracts and evaluating their potential effects on cancer's redox balance, cytotoxicity, and activation of death pathways. METHODS: 36 plant extracts were obtained from 4 different species of the Escallonia genus (E. illinita C. Presl, E. rubra (Ruiz & Pav.) Pers., E. revoluta (Ruiz & Pav.) Pers., and E. pulverulenta (Ruiz & Pav.) Pers.), which were posteriorly analyzed by their phytoconstituents, antioxidant capacity, and GC-MS. Further, redox balance assays (antioxidant enzymes, oxidative damage, and transcription factors) and cytotoxic effects (SRB, ∆Ψmt, and caspases actives) of those plant extracts were analyzed on four cell lines (HEK-293T, MCF-7, HT-29, and PC-3). RESULTS: 36 plant extracts were obtained, and their phytoconstituents and antioxidant capacity were established. Further, only six extracts had EC50 values < 10 µg*mL- 1, indicating high toxicity against the tested cells. From those, two plant extracts were selective against different cancer cell lines: the hexane extract of E. pulverulenta´s stem was selective for HT-29, and the ethyl acetate extract of E. rubra´s stem was selective for PC-3. Both extracts showed unbalanced redox effects and promoted selective cell death. CONCLUSIONS: This is the first study proving "selective oxycution" induced by Chilean native plant extracts.

Effect of Industrial Pollution in Puchuncaví Valley on the Medicinal Properties of Senecio fistulosus Poepp. ex Les (Asteraceae): Content of Phytoconstituents and Their Antioxidant and Cytotoxic Activities.

Senecio fistulosus, an endemic plant in Chile, is highly regarded for its medicinal properties and is popular in alternative medicine. It thrives even in polluted areas, like Puchuncaví Valley, Chile. Therefore, the study aimed to assess the impact of industrial pollution in Puchuncaví Valley, Chile, on the phytoconstituent content, as well as the antioxidant and cytotoxic activities, of S. fistulosus. Phenols, flavonoids, and anthraquinones content were measured, alongside the assessment of antioxidant activities. Additionally, a GC-MS analysis was conducted to profile the phytoconstituents, while the cytotoxic potential was evaluated in HT-29 and MCF-7 and cell line non-tumorigenic MCF-10. The Wild sample exhibited a greater concentration of phytoconstituents (0 to 169.48 mg·L-1) compared to the Commercial control (0 to 95.38 mg·L-1), directly correlating with its antioxidant activity. While the Wild species showed cytotoxic activity, the Commercial control demonstrated cytotoxic effects on MCF-10 and MCF-7. Noteworthy compounds identified were hexadecanoic acid (12.76 to 19.57% relative area) and (Z,Z,Z)-9,12,15-octadecatrienoic acid (18.36% relative area), with anticancer properties. In conclusion, the abiotic stress experienced by S. fistulosus led to higher phytoconstituent content and improved antioxidant activity when contrasted with the Commercial control. The Commercial species showed increased cytotoxic activity against both tumorigenic and non-tumorigenic cell lines.

Cytotoxic Activity, Topoisomerase I Inhibition and In Silico Studies of New Sesquiterpene-aryl Ester Derivatives of (-) Drimenol.

In this study, we aimed to evaluate two sets of sesquiterpene-aryl derivatives linked by an ester bond, their cytotoxic activities, and their capacity to activate caspases 3/7 and inhibit human topoisomerase I (TOP1). A total of 13 compounds were synthesized from the natural sesquiterpene (-)-drimenol and their cytotoxic activity was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and an immortalized non-tumoral cell line (MCF-10). From the results, it was observed that 6a was the most promising compound due to its cytotoxic effect on three cancer cell lines and its selectivity, 6a was 100-fold more selective than 5-FU in MCF-7 and 20-fold in PC-3. It was observed that 6a also induced apoptosis by caspases 3/7 activity using a Capsase-Glo-3/7 assay kit and inhibited TOP1. A possible binding mode of 6a in a complex with TOP1-DNA was proposed by docking and molecular dynamics studies. In addition, 6a was predicted to have a good pharmacokinetic profile for oral administration. Therefore, through this study, it was demonstrated that the drimane scaffold should be considered in the search of new antitumoral agents.

Study of Cannabis Oils Obtained from Three Varieties of C. sativa and by Two Different Extraction Methods: Phytochemical Characterization and Biological Activities.

Currently, much effort is being placed into obtaining extracts and/or essential oils from Cannabis sativa L. for specific therapeutic purposes or pharmacological compositions. These potential applications depend mainly on the phytochemical composition of the oils, which in turn are determined by the type of C. sativa and the extraction method used to obtain the oils. In this work, we have evaluated the contents of secondary metabolites, delta-9-tetrahydrocannabinol (THC), and cannabidiol (CBD), in addition to the total phenolic, flavonoids, and anthraquinone content in oils obtained using solid-liquid extraction (SLE) and supercritical fluid extraction (SCF). Different varieties of C. sativa were chosen by using the ratio of THC to CBD concentrations. Additionally, antioxidant, antifungal and anticancer activities on different cancer cell lines were evaluated in vitro. The results indicate that oils extracted by SLE, with high contents of CBD, flavonoids, and phenolic compounds, exhibit a high antioxidant capacity and induce a high decrease in the cell viability of the tested breast cancer cell line (MCF-7). The observed biological activities are attributed to the entourage effect, in which CBD, phenols and flavonoids play a key role. Therefore, it is concluded that the right selection of C. sativa variety and the solvent for SLE extraction method could be used to obtain the optimal oil composition to develop a natural anticancer agent.

Synthesis of fluorescent chalcones, photophysical properties, quantitative structure-activity relationship and their biological application.

The development of fluorescent pigments is an area of interest in several research fields due to their high sensitivity. In the current study-eight known and three new N,N-dimethylamino-chalcones (12a-k) were synthesized with good yields using the Claisen-Schmidt reaction. For each molecular system, the photophysical properties, including the maximum absorption wavelength (λAbsorption), molar absorption coefficient (ε), maximum excitation wavelength (λExcitation), maximum emission wavelength (λEmission), Stokes Shift (Δλ), fluorescence quantum yield (Φfl), fluorescence lifetime (τfl), radiative and non-radiative rate constants (kR and kNR, respectively) were evaluated. Variations in each of these properties were analyzed depending on the substituents present on each compound. To relate the chemical structures of the synthesized compounds to their photophysical properties, Hansch analysis (2D-QSPR) was applied. As a result of Hansch analysis, we found different photophysical properties related to molecular orbitals and the energy of their derivatives (Highest Occupied Molecular Orbital-HOMO, Lowest Unoccupied Molecular Orbital-LUMO, Difference between LUMO-HOMO-ΔLH, Chemical potential-µ, Hardness-η, Softness-S, and electrophilic global index-ω) as well as to the atomic charges on atoms C5, Cα, Cß, and CO. The application of this type of analysis has made it possible to understand and subsequently design new molecules with defined photophysical properties. Finally, the compounds were use as fluorescent pigment to get living cell imaging on breast cancer cells, obtaining the compound 12a as promissory alternative.

Antitumoral Activity of Leptocarpha rivularis Flower Extracts against Gastric Cancer Cells.

Leptocarpha rivularis is a native South American plant used ancestrally by Mapuche people to treat gastrointestinal ailments. L. rivularis flower extracts are rich in molecules with therapeutic potential, including the sesquiterpene lactone leptocarpin, which displays cytotoxic effects against various cancer types in vitro. However, the combination of active molecules in these extracts could offer a hitherto unexplored potential for targeting cancer. In this study, we investigated the effect of L. rivularis flower extracts on the proliferation, survival, and spread parameters of gastric cancer cells in vitro. Gastric cancer (AGS and MKN-45) and normal immortalized (GES-1) cell lines were treated with different concentrations of L. rivularis flower extracts (DCM, Hex, EtOAc, and EtOH) and we determined the changes in proliferation (MTS assay, cell cycle analysis), cell viability/cytotoxicity (trypan blue exclusion assay, DEVDase activity, mitochondrial membrane potential MMP, and clonogenic ability), senescence (ß-galactosidase activity) and spread potential (invasion and migration assays using the Boyden chamber approach) in all these cells. The results showed that the DCM, EtOAc, and Hex extracts display a selective antitumoral effect in gastric cancer cells by affecting all the cancer parameters tested. These findings reveal an attractive antitumoral potential of L. rivularis flower extracts by targeting several acquired capabilities of cancer cells.

Evaluation of Antioxidant and Cytotoxic Activity of Hydro-Ethanolic Extracts Obtained from Steiractinia aspera Cuatrec.

In this work, the antioxidant activity of the hydro-ethanolic extracts of the leaves, flowers, and aerial parts of Steiractinia aspera Cuatrec, both fresh and post-distillation, was evaluated by ABTS+·, FRAP, H2O2 and DPPH assays. The cytotoxic activity was evaluated in MCF-7, MCF-10A and HT-29 cell lines. The hydro-ethanolic extracts were obtained by matrix solid-phase dispersion (MSPD) and ultrasound-assisted solvent extraction (SE). The fresh-leaf MSPD extract had the highest antioxidant activity, and the post-distillation leaf ultrasound-assisted SE extract had the highest cytotoxicity in the MCF-7 breast cancer cell line, although not selective, which was evaluated by sulforhodamine B assay. On the other hand, ROS was evaluated by flow cytometry which showed that post-distillation leaf extract is pro-oxidant. Chlorogenic acid, kaempferol-3-glucoside and quercetin were found in the fresh leaves' extracts, according to HPLC-DAD. PLC-DAD permitted the isolation of p-coumaric acid, E-3-(4-(((E)-3-(3,4-dihydroxyphenyl) acryloyl) oxy)-3-hydroxyphenyl) acrylic acid and a diglucosylated derivative of ursolic acid, which were analyzed by 1H and 13C NMR. Our results suggest that the fresh leaf extract of Steiractinia aspera Cuatrec has potential use for antioxidant applications.

Resveratrol Decreases the Invasion Potential of Gastric Cancer Cells.

The cancer-preventive agent Resveratrol (RSV) [3,5,4'-trihydroxytrans-stilbene] is a widely recognized antioxidant molecule with antitumoral potential against several types of cancers, including prostate, hepatic, breast, skin, colorectal, and pancreatic. Herein, we studied the effect of RSV on the cell viability and invasion potential of gastric cancer cells. AGS and MKN45 cells were treated with different doses of RSV (0-200 µM) for 24 h. Cell viability was determined using the Sulphorhodamine B dye (SRB) assay. For invasion assays, gastric cells were pre-treated with RSV (5-25 µM) for 24 h and then seeded in a Transwell chamber with coating Matrigel. The results obtained showed that RSV inhibited invasion potential in both cell lines. Moreover, to elucidate the mechanism implicated in this process, we analyzed the effects of RSV on SOD, heparanase, and NF-κB transcriptional activity. The results indicated that RSV increased SOD activity in a dose-dependent manner. Conversely, RSV significantly reduced the DNA-binding activity of NF-κB and the enzymatic activity of heparanase in similar conditions, which was determined using ELISA-like assays. In summary, these results show that RSV increases SOD activity but decreases NF-kB transcriptional activity and heparanase enzymatic activity, which correlates with the attenuation of invasion potential in gastric cancer cells. To our knowledge, no previous study has described the effect of RSV on heparanase activity. This article proposes that heparanase could be a key effector in the invasive events occurring during gastric cancer metastasis.

Inhibition of Caco-2 and MCF-7 cancer cells using chalcones: synthesis, biological evaluation and computational study.

Cancer is the second death cause worldwide, with breast and colon cancer among the most prevalent types. Traditional treatment strategies have several side effects that inspire the development of novel anticancer agents derived from natural sources, like chalcone derivatives. For this investigation, twenty-three chalcones (4a-w) were synthesized and evaluated as antiproliferative agents against MCF-7 and Caco-2 cells, finding three and two compounds with similar or higher antiproliferative activity than daunorubicin, while only two chalcones showed better selectivity indexes than daunorubicin on MCF-7. From these results, we developed good-performance QSAR models (r > 0.850, q2>0.650), finding several structural features that could modify chalcone activity and selectivity. According to these models, chalcones 4w and 4t have high potency and selectivity against Caco-2 and MCF-7, respectively, which make them attractive candidates for hit-to-lead development of ROS-independent pro apoptotic agents.

Ultrasound assisted synthesis and cytotoxicity evaluation of known 2',4'-dihydroxychalcone derivatives against cancer cell lines.

This work reports on the development of an efficient and ecofriendly ultrasound assisted method for the high yield synthesis (70.0-94.0%) of eighteen oxyalkylated derivatives of 2',4'-dihydroxychalcone. Synthesized compounds were subjected to in vitro biological assays against HT-29 (colorectal), MCF-7 (breast), and PC-3 (prostate) human tumor cell lines, these cell lines are among the ten most aggressive malignancies diagnosed in the world. Cytotoxicity evaluations showed that four of the synthesized compounds exhibited moderate to very high toxic activity against MCF-7 (IC50 = 8.4-34.3 µM) and PC-3 (IC50 = 9.3-29.4 µM) - comparable to 5-fluorouracil (IC50 16.4-22.3 µM). The same compounds only showed moderate activity against HT-29 (IC50 15.3-36.3 µM), closer to daunorubicin (IC50 15.1 µM). Next, although selectivity index (SI) of compounds was weak, compound 18 exhibited a remarkable and selective cytotoxic activity (5.8-10.57) against cancer cells. Outside of these, most compounds significantly reduced cell survival, increased reactive oxygen species (ROS) and caspase activity, and decreased mitochondrial membrane permeability. In this sense, a portion of anti-proliferative activity is due to apoptosis. Notwithstanding, due to its remarkable response, chalcone 18 may be a potential alternative as a chemotherapeutic anti-carcinogen.

Chemical Composition, Antioxidant and Anticancer Activities of Leptocarpha rivularis DC Flower Extracts.

An evaluation of antioxidant and anticancer activity was screened in Leptocarpha rivularis DC flower extracts using four solvents (n-hexane (Hex), dichloromethane (DCM), ethyl acetate (AcOEt), and ethanol (EtOH)). Extracts were compared for total extract flavonoids and phenol contents, antioxidant activity (2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric reducing antioxidant potential (FRAP), total reactive antioxidant properties (TRAP) and oxygen radical absorbance capacity (ORAC)) across a determined value of reduced/oxidized glutathione (GSH/GSSG), and cell viability (the sulforhodamine B (SRB) assay). The most active extracts were analyzed by chromatographic analysis (GC/MS) and tested for apoptotic pathways. Extracts from Hex, DCM and AcOEt reduced cell viability, caused changes in cell morphology, affected mitochondrial membrane permeability, and induced caspase activation in tumor cell lines HT-29, PC-3, and MCF-7. These effects were generally less pronounced in the HEK-293 cell line (nontumor cells), indicating clear selectivity towards tumor cell lines. We attribute likely extract activity to the presence of sesquiterpene lactones, in combination with other components like steroids and flavonoids.

Antioxidant and Anti-Proliferative Activity of Essential Oil and Main Components from Leaves of Aloysia polystachya Harvested in Central Chile.

The aim of this study was to determine, first, the chemical composition of Aloysia polystachya (Griseb) Moldenke essential oil, from leaves harvested in central Chile; and second, its antioxidant and cytotoxic activity. Eight compounds were identified via gas chromatography-mass spectrometry (GC-MS) analyses, with the most representative being R-carvone (91.03%), R-limonene (4.10%), and dihydrocarvone (1.07%). For Aloysia polystachya essential oil, antioxidant assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, ferric reducing antioxidant power (FRAP), and total reactive antioxidant potential (TRAP)) showed good antioxidant activity compared to commercial antioxidant controls; and anti-proliferative assays against three human cancer cell lines (colon, HT-29; prostate, PC-3; and breast, MCF-7) determined an IC50 of 5.85, 6.74, and 9.53 µg/mL, and selectivity indices of 4.75, 4.12, and 2.92 for HT-29, PC-3, and MCF-7, respectively. We also report on assays with CCD 841 CoN (colon epithelial). Overall, results from this study may represent, in the near future, developments for natural-based cancer treatments.

Actividad citotóxica de extractos crudos y fracciones de Blepharocalyx cruckshanksii contra líneas celulares de cáncer humano seleccionadas / Cytotoxic activity of crude extracts and fractions from Blepharocalyx cruckshanksii against selected human cancer cell lines

El presente estudio tiene como objetivo explorar las posibles aplicaciones de los extractos de corteza y hoja de Blepharocalyx cruckshanksii como agente citotóxico contra líneas celulares de cáncer in vitro ((MCF-7, PC-3 y HT-29) mediante el uso de ensayo de sulforhodamine B (SRB). El ensayo de citotoxicidad reveló que el extracto de acetato de etilo de la corteza exhibía una actividad anticancerígena marcada. El extracto activo se sometió a un reparto líquido-líquido usando hexano y acetato de etilo para obtener fracciones basadas en su polaridad. Sin embargo, la Fracción 4 (F4) fue identificado como el más efectivo de la serie al mostrar contra todas las líneas celulares de cáncer una citotoxicidad cercana a los agentes antineoplásicos ensayados. Luego, F4 se analizó por cromatografía de gasesespectrometría de masas (GC-MS) para identificar sus componentes principales y relacionar estos componentes con el efecto citotóxico. Los resultados obtenidos indicaron que la corteza de B. cruckshanksii tiene una excelente actividad citotóxica y amerita estudios adicionales para aislar nuevos compuestos para quimioterapia.

The present study aims to explore the potential applications of Blepharocalyx cruckshanksii bark and leaf extracts as a cytotoxic agent against in vitro cancer cell lines (MCF-7, PC-3 and HT-29) by using sulforhodamine B (SRB) assay. The cytotoxicity assay revealed that the ethyl acetate extract from the bark exhibited marked anticancer activity. The active extract was subjected to liquid-liquid partitioning by using hexane and ethyl acetate to obtain fractions based on their polarity. However, Fraction 4 (F4) was identified as the most effective of the series by displaying against all cancer cell lines a cytotoxicity close to antineoplastic agents assayed. Then, F4 was analyzed by gas chromatography­mass spectrometry (GC-MS) to identify their major components and to relate these components to the cytotoxic effect. The results obtained indicated that B. cruckshanksii bark have excellent cytotoxic activity and warrant further studies to isolate novel compounds for chemotherapeutic use.

Antigrowth activity and induction of apoptosis in human melanoma cells by Drymis winteri forst extract and its active components.

Melanoma is a highly invasive cancer that resists most conventional treatments. Therefore, there is an urgent need to identify alternative anticancer agents able to affect new molecular targets. Drimys winteri (Winteraceae) is a medicinal plant, employed in Brazil and many countries, in folk medicine against a variety of ailments, especially for the treatment of fevers, ulcers, pains, affections of respiratory tract and cancers. Previous phytochemical studies have isolated and identified the presence of diverse classes of secondary metabolites in this plant such as sesquiterpenes. In an ongoing to identify new natural anticancer compounds for the treatment and/or prevention of melanoma, we study the effects of Drimys winteri bark ethyl acetate extract and its sesquiterpenes drimenol, nordrimenone, isonordrimenone and polygodial on human melanoma cells. The treatment of melanoma cells with extract, drimenol, isordrimenone and polygodial resulted in a significant reduction in cell viability. But, polygodial showed the highest inhibitory growth activity. In addition, we reported an apoptotic response after treatment with drimenol, isordrimenone and polygodial that probably involves the reduction of Hsp70 expression and reactive oxygen species production. Alternatively, the inhibition of caspase cascade at higher concentrations, correlated with additional reactive oxygen species increase, probably switches natural product-induced cell death from apoptosis to necrosis. Therefore, this evidence provides a scientific support for the anticancer employ of Drimys winteri in traditional medicinal and suggests that active molecules can be considered potential candidates to be tested also in in vivo models, alone or in combination with chemotherapy agents, for the management of melanoma.

In vitro antioxidant and antiproliferative effect of the extracts of Ephedra chilensis K Presl aerial parts.

BACKGROUND: Ephedra chilensis K Presl, known locally as pingo-pingo, is a Chilean endemic plant used in traditional medicine as an anti-inflammatory and used in other treatments. However, unlike for the other Ephedra species, there have been no reports on the antioxidant and cytotoxic effects of this plant. The present study aims to explore the potential applications of E. chilensis extract as a cytotoxic agent against in vitro cancer cell lines and to explore the relationship between this extract and antioxidant activity. METHODS: Total anthraquinone, flavonoid, and phenolic contents, as well as antioxidant activity (DPPH, FRAP, and TRAP assays) and cytotoxic effect on several cancer cell lines (MCF-7, PC-3, DU-145, and HT-29) were measured for the hexane, dichloromethane and ethanol extracts of E. chilensis. In addition, several correlations among the phytochemical content, antioxidant activity, and cytotoxic effect were evaluated. Finally, GC-MS analyses of the most active extracts were carried out to identify their major components and to relate these components to the cytotoxic effect. RESULTS: Antioxidant activity was found in the EtOH extracts of Ephedra, and the results were correlated with the phenolic content. For the cytotoxic activity, the non-polar extracts of E. chilensis had the highest antiproliferative effect for the MCF-7 and PC-3 cancer lines; the extract was shown to be up to three times more selective than doxorubicin. However, the cytotoxic effect was not correlated with the antioxidant activity. Lastly, the GC-MS analysis showed a high concentration of saturated fatty acids (mainly n-hexadecanoic acid) and terpenoids (mainly 4-(hydroxy-ethyl)-γ-butanolactone). CONCLUSION: The cytotoxic activity and selectivity of the non-polar extracts of E. chilensis for the MCF-7 and PC-3 cell lines could be related to the terpenic compounds and fatty acids of the extracts or to the synergistic effect of all of the compounds in the extracts. These non-polar extracts can be used for the development of new drugs against breast and prostate cancer.

Synthesis and Antiproliferative Activity of New Cyclodiprenyl Phenols against Select Cancer Cell Lines.

Six new cyclodiprenyl phenols were synthesized by direct coupling of perillyl alcohol and the appropriate phenol. Their structures were established by IR, HRMS and mainly NMR. Three human cancer cell lines-breast (MCF-7), prostate (PC-3) and colon (HT-29)-were used in antiproliferative assays, with daunorubicin and dunnione as positive controls. Results described in the article suggest that dihydroxylated compounds 2⁻4 and monohydroxylated compound 5 display selectivity against cancer cell lines, cytotoxicity, apoptosis induction, and mitochondrial membrane impairment capacity. Compound 2 was identified as the most effective of the series by displaying against all cancer cell lines a cytotoxicity close to dunnione antineoplastic agent, suggesting that the cyclodiprenyl phenols from perillyl alcohol deserve more extensive investigation of their potential medicinal applications.

(-)-Shikimic Acid as a Chiral Building Block for the Synthesis of New Cytotoxic 6-Aza-Analogues of Angucyclinones.

We describe the syntheses of nine new angucyclinone 6-aza-analogues, achieved through a hetero Diels-Alder reaction between the shikimic acid derivative-azadiene 13, with different naphthoquinones. The cytotoxic activity of the new synthesized compounds and five angucyclinones, previously reported, was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and one non-tumoral cell line, human colon epithelial cells (CCD841 CoN). Our results showed that most 6-azadiene derivatives exhibited significant cytotoxic activities, which was demonstrated by their IC50 values (less than 10 µM), especially for the most sensitive cells, PC-3 and HT-29. From a chemical point of view, depending on the protected group of ring A and the pattern of substitution on ring D, cytotoxicity elicited these compounds, in terms of their potency and selectivity. Therefore, according to these chemical features, the most promising agents for every cancer cell line were 7a, 17, and 19c for PC-3 cells; 7a, 17, and 20 for HT-29 cells, and 19a for MCF-7 cells.

Structure-Activity Relationship of Dialkoxychalcones to Combat Fish Pathogen Saprolegnia australis.

To investigate the anti-Saprolegnia activities of chalconic compounds, nine dialkoxychalcones 2⁻10, along with their key building block 2',4'-dihydroxychalcone 1, were evaluated for their potential oomycide activities against Saprolegnia australis strains. The synthesis afforded a series of O-alkylated derivatives with typical chalcone skeletons. Compounds 4⁻10 were reported for the first time. Interestingly, analogue 8 with the new scaffold demonstrated remarkable in vitro growth-inhibitory activities against Saprolegnia strains, displaying greater anti-oomycete potency than the standard drugs used in the assay, namely fluconazole and bronopol. In contrast, a dramatic loss of activity was observed for O-alkylated derivatives 2, 3, 6, and 7. These findings have highlighted the therapeutic potential of the natural compound 1 scaffold to be exploitable as a drug lead with specific activity against various Saprolegnia strains.