Natural Sesquiterpene Lactone as Source of Discovery of Novel Fungicidal Candidates: Structural Modification and Antifungal Activity Evaluation of Xanthatin Derived from Xanthium strumarium L

Xanthatin: A promising natural product in combating disease

With the advancement of research in Traditional Chinese Medicine (TCM), an increasing number of bioactive constituents have been identified and characterized. Xanthatin, a naturally occurring bicyclic sesquiterpene lactone, is predominantly isolated from Xanthium species within the Compositae. Xanthium strumarium is a widely distributed plant, its aerial parts, especially the leaves, are rich in xanthatin. As one of the main active components in X. sibiricum, xanthatin has many biological activities. Based on this, the research on xanthatin is gradually deepening, it has significant pharmacological effects in anti-tumor, anti-inflammatory, anti-bacterial, anti-fungal and anti-viral aspects. In this review, the pharmacological activities and underlying mechanisms of xanthatin were systematically summarized and analyzed, highlighting its significant potential as a TCM in drug discovery and development. Xanthatin exhibits diverse pharmacological activities and possesses a unique mechanism of action, offering novel insights for the treatment of various diseases and demonstrating significant potential as a promising drug candidate.

Rational search for natural antimicrobial compounds: relevance of sesquiterpene lactones

Antimicrobial resistance is one of the most pressing global health challenges, as many pathogens are rapidly evolving to evade existing treatments. Despite this urgent need for new solutions, natural plant-derived compounds remain relatively underexplored in the development of antimicrobial drugs. This report highlights an innovative approach to discovering potent antimicrobial agents through bioguided fractionation of numerous plant species from the rich Argentinean flora. By systematically screening 60 species (over 177 extracts) for antimicrobial activity against representative strains of gram-positive and gram-negative bacteria, we identified promising bioactive compounds within the Asteraceae family-particularly sesquiterpene lactones from the Xanthium genus. Building on this basis, we synthesized semi-synthetic derivatives by chemically modifying plant sub-extracts, focusing on structures incorporating heteroatoms and/or heterocycles containing oxygen and nitrogen (important for the bioavailability and bioactivity that they are capable of providing). These modifications were evaluated for their potential to enhance antimicrobial efficacy against bacteria and Candida species, including resistant strains. Our findings suggest that tailoring natural metabolites from Xanthium and related Asteraceae species can significantly improve their antimicrobial properties. This strategy offers a promising pathway for the development of novel therapeutic agents to combat bacterial and fungal infections in an era of rising drug resistance.

Antifungal phloroglucinol derivatives from Dryopteris fragrans (L.) Schott

BACKGROUND

Potatoes, a major economic crop, are significantly impacted by Fusarium dry rot, a prevalent postharvest disease. In Dryopteris fragrans, the research of phloroglucinol derivatives are mainly focused on antibacterial activity, while the inhibitory effects on phytopathogenic fungi have not been reported.

RESULTS

In our study, six new phloroglucinol derivatives, Ortho-desaspidin AA (1), Ortho-desaspidin PA (2), Ortho-desaspidin BA (3), Dryaspidin B (4), Alde-iso-methylaspidinol B (5), and Iso-methylaspidinol P (6), and nine known phloroglucinol derivatives, were isolated from D. fragrans. And Compound 10, aspidinol B, showed significant inhibitory activity against Fusarium oxysporum, Fusarium graminearum, Fusarium proliferatum with EC50 = 3.619, 6.051, and 8.221 μg/mL, respectively, outperforming the commercial fungicide hymexazol (EC50 = 34.88, 8.21, 17.91). Aspidinol B displayed potent in vivo antifungal activity against F. oxysporum, F. graminearum, and F. proliferatum at 10 μg/mL with an inhibitory rate of 83.26, 54.15 and 79.62%, respectively. Transcriptome analysis speculates that aspidinol B, by affecting the uptake of iron ions into the bacterium, and cause heme depletion that ultimately leads to changes in oxidation-related pathways.

CONCLUSION

Aspidinol B exhibits strong inhibitory effects on Fusarium, indicating its potential use in the prevention and control strategies for potato dry rot. These results indicate that aspidinol B could be a potential fungicidal lead compound against Fusarium. © 2025 Society of Chemical Industry.

Natural Biphenyl-Type Neolignans as Resources of Pesticide Candidates: Assembly, Insecticidal Potency, and Cytotoxicity of Honokiol/Magnolol Analogues of Isoxazoline Hybridization via [3 + 2] Dipolar Cycloaddition

Currently, the development of novel pesticides remains a crucial initiative to address the challenges of agricultural pest management. In pursuit of agrochemical candidates derived from plant natural products (NPs), 76 novel isoxazoline-hybridized honokiol/magnolol analogues were assembled via a [3 + 2] dipolar cycloaddition reaction, and their pesticidal potency and cytotoxicity were evaluated. Bioassays revealed that 13 compounds (5d, 6k, 7b-d, 7f, 7g, 8d-f, 13f, 15d, and 16h) exhibited superior larvicidal activity against Plutella xylostella Linnaeus with LC50 values in the range of 1.75-5.87 μg/mL, outperforming the botanical insecticide rotenone (LC50 = 26.7 μg/mL). Particularly, compounds 7c, 8d, and 15d showed over 11-fold higher larvicidal activity against P. xylostella than against rotenone. Meanwhile, compounds 5i, 6g, 7a, and 8a displayed better growth inhibitory effects on Mythimna separata Walker (LC50 = 0.13, 0.25, 0.34, and 0.35 mg/mL, respectively) compared to rotenone (LC50 = 0.53 mg/mL). Further greenhouse potted-plant assays revealed that compounds 8d and 15d showed superior in vivo control efficacy against P. xylostella compared to rotenone and comparable to tolfenpyrad and also demonstrated good protective effects on plants. Toxicity tests disclosed that these potent compounds exhibited moderate cytotoxicity to the human keratinocyte cell line (HaCaT), indicating a considerably favorable safety profile for skin exposure. Structure-activity relationship (SAR) analysis illustrated the importance of the exposed hydroxyls and newly introduced isoxazoline scaffolds in enhancing the insecticidal activity of these compounds. The novel scaffold, excellent insecticidal potency, and good safety profile position these compounds reported herein as promising leads for further pesticide candidates development. Furthermore, the present work offers valuable insights for advancing the NP-inspired agrochemical innovation.

Design and semisynthesis of novel oleanolic acid-based tertiary amide derivatives as promising antifungal agents against phytopathogenic fungi

To further explore and discover natural products-based antifungal agents, seventeen tertiary amide-oleanolic acid hybrids were designed and synthesized, and structurally confirmed by 1H NMR, 13C NMR, HRMS, and melting point. Bioassay results illustrated that derivative 4 k exhibited prominent in vitro inhibitory activity against the mycelium growth of Gaeumannomyces graminis and Valsa mali with the EC50 values of 41.77 and 43.96 μg/mL, respectively. Meanwhile, the structure-activity relationships were also summarized. Moreover, in vivo control efficacy demonstrated that derivative 4 k displayed remarkable curative effect (CE) against V. mali at 200 μg/mL with the value of 52.6%, evidently superior to that of the positive control carbendazim (41.5%). Besides, derivative 4 k also exhibited good CE against Botrytis cinerea at 200 μg/mL with the value of 33.0%. Scanning electron microscope analysis initially indicated that derivative 4 k may exert its antifungal effect by leading to abnormal morphology on the mycelium surface, resulting in the aberrant hypha growth.

Prominent Naturally Derived Oxidative-Stress-Targeting Drugs and Their Applications in Cancer Treatment

The relationship between oxidative stress and cancer has been extensively studied and highlighted, along with its role in various aspects of angiogenesis. The modulation of oxidative levels and the adaptive mechanisms of oxidative stress in cancer systems are attractive research themes for developing anti-cancer strategies. Reactive oxygen species (ROS) are involved in various pathophysiological processes and play crucial roles in DNA damage and angiogenesis. Although cancer cells have developed various adaptive defense mechanisms against oxidative stress, excessive ROS production has been proposed as an anti-cancer strategy to induce cellular apoptosis. In particular, natural-source-based antioxidants have been identified as effective against cancers, and various delivery platforms have been developed to enhance their efficacy. In this review, we highlighted the anti-cancer components (plumbagin, quercetin, resveratrol, curcumin, xanthatin, carvacrol, telmisartan, and sulforaphane) that modulate ROS levels and the recent targeting platforms used to increase the application of anti-cancer drugs and the developed delivery platforms with diverse mechanisms of action. Further, we summarized the actual doses used and the effects of these drug candidates in various cancer systems. Overall, this review provides beneficial research themes for expanding cancer-targeting fields and addressing limited applications in diverse cancer types.

Novel Pesticide Candidates Inspired by Natural Neolignan: Preparation and Insecticidal Investigation of Honokiol Analogs Containing 2-Aminobenzoxazole-Fused Core Scaffold

As a continuation of our efforts to develop new agrochemicals with typical architecture and efficient bioactivity from plant natural products, natural neolignan honokiol was used as a lead compound to prepare novel analogs bearing the core 2-aminobenzoxazole scaffold. Their insecticidal potency against two representative agricultural pests, Plutella xylostella Linnaeus and Mythimna separata (Walker), were evaluated in vivo. The pesticide bioassay results revealed that compounds 7″a, 9, 10d, and 10j exhibited prominent larvicidal activity against the larvae of P. xylostella (LC50 = 7.95, 11.85, 15.51, and 12.06 μg/mL, respectively), superior to the precursor honokiol (LC50 = 43.35 μg/mL) and two botanical insecticides, toosendanin (LC50 = 26.20 μg/mL) and rotenone (LC50 = 23.65 μg/mL). Compounds 7d, 10d, and 10j displayed a more pronounced nonchoice antifeedant effect (AFC50 = 9.48, 9.14, and 12.41 μg/mL, respectively) than honokiol (AFC50 = 54.81 μg/mL) on P. xylostella. Moreover, compounds 7b, 7″a, 9, 10d, 10f, and 10j showed better growth inhibitory activity against M. separata (LC50 = 0.36, 0.34, 0.28, 0.16, 0.26, and 0.11 mg/mL, respectively) than honokiol, toosendanin, and rotenone (LC50 = 1.48, 0.53, and 0.46 mg/mL, respectively). A potted plant assay under greenhouse conditions illustrated that compounds 10d and 10j continued to provide good control efficacy against P. xylostella and an apparent protective effect on plants. Further cytotoxicity assay revealed that the aforementioned potent compounds showed relatively moderate toxicity and a good safety profile for non-target mammalian cells. Overall, the current work provides valuable insight into the agrochemical innovation of honokiol-derived analogs for use as natural-inspired pesticides in agricultural pest management.

Development of natural perfume as potential fungicide candidates: construction and biological evaluation of vanillin analogs bearing the 1,3,4-oxadiazole/1,3-thiazolidin-4-one fragments

Two series of vanillin derivatives containing 1,3,4-oxadiazole and 1,3-thiazolidin-4-one scaffolds were prepared and evaluated for their antifungal activity. The results revealed that compounds 6j (29.73 μg/ml) and 7a (38.15 μg/ml) displayed excellent inhibitory activity against the spore of Fusarium solani. The inhibitory activity of compound 7d (10.53 μg/ml) against the spore of Alternaria solani was more than 42-fold that of vanillin. Compound 7a (37.54 μg/ml) showed better antifungal activity against the spore of B. cinerea than positive controls. The cytotoxicity assay confirmed that compounds 6k, 7a, and 7d showed good selectivity and less toxicity to normal mammalian cells.

Developmental toxicity assay of xanthatin in zebrafish embryos

Xanthatin (XAN), a xanthanolide sesquiterpene lactone, isolated from Chinese herb, Xanthium strumarium L, has various pharmacological activities, such as antitumor activity and anti-inflammatory. However, little is known about its potential toxicity and the mechanism. Here, zebrafish model was used to study the developmental toxicity in vivo. Our results indicated that xanthatin increased the mortality and led to the morphological abnormalities including pericardial edema, yolk sac edema, curved body shape and hatching delay. Furthermore, xanthatin damaged the normal structure and/or function of heart, liver, immune and nervous system. ROS elevation and much more apoptosis cells were observed after xanthatin exposure. Gene expression results showed that oxidative stress-related genes nrf2 was inhibited, while oxidative stress-related genes (keap1 and nqo1) and apoptotic genes (caspase3, caspase9 and p53) were increased after xanthatin exposure. Mitophagy related genes pink1 and parkin, and wnt pathway (β-catenin, wnt8a and wnt11) were significantly increased after xanthatin exposure. Taken together, our finding indicated that xanthatin induced developmental toxicity, and the ROS elevation, apoptosis activation, dysregulation of mitophagy and wnt pathways were involved in the toxicity caused by xanthatin.