One-pot ligation of multiple peptide segments via N-terminal thiazolidine deprotection chemistry.

Peptide ligation chemistries have revolutionized the synthesis of proteins with site-specific modifications or proteomimetics through assembly of multiple peptide segments. In order to prepare polypeptide chains consisting of 100-150 amino acid residues or larger generally assembled from three or more peptide segments, iterative purification process that decreases the product yield is usually demanded. Accordingly, methodologies for one-pot peptide ligation that omit the purification steps of intermediate peptide segments have been vigorously developed so far to improve the efficiency of chemical protein synthesis. In this chapter, we first outline the concept and recent advances of one-pot peptide ligation strategies. Then, the practical guideline for the preparation of peptide segments for one-pot peptide ligation is described with an emphasis on diketopiperazine thioester synthesis. Finally, we disclose the explicit protocols for one-pot four segment ligation via repetitive deprotection of N-terminal thiazolidine by a 2-aminobenzamide type aldehyde scavenger.

Impact of switching to injectables cabotegravir and rilpivirine on sleep disturbances in a cohort of people living with HIV.

BACKGROUND: Recently, injectable cabotegravir/rilpivirine (ICAB/RPV) became available for HIV treatment. However, there are no real-life data on the impact of switching to ICAB/RPV on sleep disturbances (SD). Therefore, we aimed at assessing and investigating this aspect in our cohort. METHODS: A SD multidimensional assessment (Epworth Sleepiness scale, Insomnia severity Index, Berlin Questionnaire, and Pittsburg Sleep Quality Index, PSQI) was performed to all people who consented before starting ICAB/RPV and 12 wk after the switch. Demographics, life-style habits, laboratory, and clinical data were collected from medical health records. RESULTS: To June 2023, 46 people were included, 76.1% males, with a median age of 48.5 (IQR: 41-57), 50% had multimorbidity, 13% was on polypharmacy. Median age with HIV and CD4 + T cell count nadir were 10 (5-19.5) years and 360 (205-500) cell/mm3, respectively. The reason to start a long-acting strategy was person's choice in all cases. Baseline antiretroviral regimens were mostly: tenofovir alafenamide/emtricitabine/rilpivirine (39.1%) and dolutegravir/lamivudine (32.6%). No significant changes were observed in any of the scores for each questionnaire, but for a worsening PSQI. 37% people reported a subjectively improved sleep quality, even if statistically significant changes were not observed in almost all the sleep parameters. CONCLUSIONS: To the best of our knowledge, this is the first study exploring impact of switching to ICAB/RPV on SD. Despite integrase inhibitor have been associated with SD, we did not observed a negative impact on sleep quality after the switch to ICAB/RPV. More studies and with larger number of people are necessary to confirm our results.

Prenylated indole diketopiperazine alkaloids as phosphatase inhibitors from the marine-derived fungus Talaromyces purpureogenus.

Six previously undescribed prenylated indole diketopiperazine alkaloids, talaromyines A-F (1-6), were isolated from the marine-derived fungus Talaromyces purpureogenus SCSIO 41517. Their structures including absolute configurations were elucidated on the basis of comprehensive spectroscopic data including NMR, HR-ESI-MS, and electronic circular dichroism calculations, together with chemical analysis of hydrolysates. Compounds 1-5 represent the first example of spirocyclic indole diketopiperazines biosynthesized from the condensation of L-tryptophan and L-alanine. Compounds 2 and 4-5 showed selective inhibitory activities against phosphatases TCPTP and MEG2 with IC50 value of 17.9-29.7 µM, respectively. Compounds 4-5 exhibited mild cytotoxic activities against two human cancer cell lines H1975 and HepG-2.

Co-delivery of Plinabulin and Tirapazamine boosts anti-tumor efficacy by simultaneously destroying tumor blood vessels and killing tumor cells.

It is imperative to optimize chemotherapy for heightened anti-tumor therapeutic efficacy. Unrestrained tumor cell proliferation and sustained angiogenesis are pivotal for cancer progression. Plinabulin, a vascular disrupting agent, selectively destroys tumor blood vessels. Tirapazamine (TPZ), a hypoxia-activated prodrug, intensifies cytotoxicity in diminishing oxygen levels within tumor cells. Despite completing Phase III clinical trials, both agents exhibited modest treatment efficiency due to dose-limiting toxicity. In this study, we employed methoxy poly(ethylene glycol)-b-poly(D,L-lactide) (mPEG-b-PDLLA) to co-deliver Plinabulin and TPZ to the tumor site, concurrently disrupting blood vessels and eliminating tumor cells, addressing both symptoms and the root cause of tumor progression. Plinabulin was converted into a prodrug with esterase response (PSM), and TPZ was synthesized into a hexyl chain-containing derivative (TPZHex) for effective co-delivery. PSM and TPZHex were co-encapsulated with mPEG-b-PDLLA, forming nanodrugs (PT-NPs). At the tumor site, PT-NPs responded to esterase overexpression, releasing Plinabulin, disrupting blood vessels, and causing nutritional and oxygen deficiency. TPZHex was activated in response to increased hypoxia, killing tumor cells. In treating 4T1 tumors, PT-NPs demonstrated enhanced therapeutic efficacy, achieving a 92.9 % tumor suppression rate and a 20 % cure rate. This research presented an innovative strategy to enhance synergistic efficacy and reduce toxicity in combination chemotherapy.

Two-drug regimens for the treatment of HIV in Africa.

Two-drug regimens for the treatment of HIV are increasingly available. The oral regimen of dolutegravir plus lamivudine is recommended as a preferred option in multiple national guidelines but is not currently included in WHO HIV treatment guidelines nor widely used in Africa. Long-acting injectable cabotegravir and rilpivirine is being rolled out in the USA, Europe, and Australia but its use in sub-Saharan Africa is currently restricted to clinical trials. Given the increasing life expectancy, rising prevalence of non-communicable diseases, and resulting polypharmacy among people living with HIV, there are potential advantages to the use of two-drug regimens, particularly in African women, adolescents, and older adults. This Viewpoint reviews existing evidence and highlights the risks, benefits, and key knowledge gaps for the use of two-drug regimens in settings using the public health approach in Africa. We suggest that a two-drug regimen of dolutegravir and lamivudine can be safely used as a switch option for virologically suppressed individuals in settings using the public health approach once chronic hepatitis B has been excluded. Individuals with HIV who are switched to two-drug regimens should receive a full course of hepatitis B vaccinations. More efficacy data is needed to support dolutegravir plus lamivudine combination in the test and treat approach, and long-acting cabotegravir and rilpivirine in the public health system in sub-Saharan Africa.

Antimicrobial spiroketal macrolides and dichloro-diketopiperazine from Micromonospora sp. FIMYZ51.

Four compounds (1-4) featuring with an L-rhodinose and spiroketal, possess uncommon continuous hydroxy groups in the macrolide skeleton, and a dichloro-diketopiperazine (5) were isolated from a marine derived Micromonospora sp. FIMYZ51. The determination of the relative and absolute configurations of all isolates was achieved by extensive spectroscopic analyses, single-crystal X-ray diffraction analysis, and ECD calculations. According to structural characteristic and genomic sequences, a plausible biosynthetic pathway for compound 1-4 was proposed and a spirocyclase was inferred to be responsible for the formation of the rare spirocyclic moiety. Compounds 1-4 exhibited potent antifungal activities which is equal to itraconazole against Aspergillus niger. Compounds 1-5 exhibited different degree of inhibitory activities against opportunistic pathogenic bacteria of endocarditis (Micrococcus luteus) with MIC values ranging from 0.0625 µg/mL to 32 µg/mL. Compounds 2 and 3 showed moderate cytotoxicity against drug-resistant tumor cell lines (Namalwa and U266). The result not only provides active lead-compounds, but also reveal the potential of the spirocyclase gene resources from Micromonospora sp., which highlights the promising potential of the strain for biomedical applications.

Lamivudine, Doravirine, and Cabotegravir Downregulate the Expression of Human Endogenous Retroviruses (HERVs), Inhibit Cell Growth, and Reduce Invasive Capability in Melanoma Cell Lines.

This study explores the impact of antiretroviral administration on the expression of human endogenous retroviruses (HERVs), cell growth, and invasive capability of human melanoma cell lines in culture. We investigated three antiretrovirals-lamivudine, doravirine, and cabotegravir-in A375, FO-1, and SK-Mel-28, BRAF-mutated, and in MeWo, P53-mutated, melanoma cell lines. The findings indicate a general capability of these drugs to downregulate the expression of HERV-K Pol and Env genes and hinder cell viability, mobility, and colony formation capacity of melanoma cells. The antiretroviral drugs also demonstrate selectivity against malignant cells, sparing normal human epithelial melanocytes. The study reveals that the integrase inhibitor cabotegravir is particularly effective in inhibiting cell growth and invasion across different cell lines in comparison with lamivudine and doravirine, which are inhibitors of the viral reverse transcriptase enzyme. The investigation further delves into the molecular mechanisms underlying the observed effects, highlighting the potential induction of ferroptosis, apoptosis, and alterations in cell cycle regulatory proteins. Our findings showed cytostatic effects principally revealed in A375, and SK-Mel-28 cell lines through a downregulation of retinoblastoma protein phosphorylation and/or cyclin D1 expression. Signs of ferroptosis were detected in both A375 cells and FO-1 cells by a decrease in glutathione peroxidase 4 and ferritin expression, as well as by an increase in transferrin protein levels. Apoptosis was also detected in FO-1 and SK-Mel-28, but only with cabotegravir treatment. Moreover, we explored the expression and activity of the stimulator of interferon genes (STING) protein and its correlation with programmed death-ligand 1 (PD-L1) expression. Both the STING activity and PD-L1 expression were decreased, suggesting that the antiretroviral treatments may counteract the detrimental effects of PD-L1 expression activation through the STING/interferon pathway triggered by HERV-K. Finally, this study underscores the potential therapeutic significance of cabotegravir in melanoma treatment. The findings also raise the prospect of using antiretroviral drugs to downregulate PD-L1 expression, potentially enhancing the therapeutic responses of immune checkpoint inhibitors.

Chromatin damage generated by DNA intercalators leads to degradation of RNA Polymerase II.

In cancer therapy, DNA intercalators are mainly known for their capacity to kill cells by inducing DNA damage. Recently, several DNA intercalators have attracted much interest given their ability to inhibit RNA Polymerase I transcription (BMH-21), evict histones (Aclarubicin) or induce chromatin trapping of FACT (Curaxin CBL0137). Interestingly, these DNA intercalators lack the capacity to induce DNA damage while still retaining cytotoxic effects and stabilize p53. Herein, we report that these DNA intercalators impact chromatin biology by interfering with the chromatin stability of RNA polymerases I, II and III. These three compounds have the capacity to induce degradation of RNA polymerase II and they simultaneously enable the trapping of Topoisomerases TOP2A and TOP2B on the chromatin. In addition, BMH-21 also acts as a catalytic inhibitor of Topoisomerase II, resembling Aclarubicin. Moreover, BMH-21 induces chromatin trapping of the histone chaperone FACT and propels accumulation of Z-DNA and histone eviction, similarly to Aclarubicin and CBL0137. These DNA intercalators have a cumulative impact on general transcription machinery by inducing accumulation of topological defects and impacting nuclear chromatin. Therefore, their cytotoxic capabilities may be the result of compounding deleterious effects on chromatin homeostasis.

Synthesis of compounds based on the active domain of cabotegravir and their application in inhibiting tumor cells activity.

Structural modification based on existing drugs, which ensures the safety of marketed drugs, is an essential approach in developing new drugs. In this study, we modified the structure of cabotegravir by introducing the front alkyne on the core structure through chemical reaction, resulting in the synthesis of 9 compounds resembling 1,2,3-triazoles. The potential of these new cabotegravir derivatives as tumor suppressors in gastrointestinal tumors was investigated. Based on the MTT experiment, most compounds showed a reduction in the viability of KYSE30 and HCT116 cells. Notably, derivatives 5b and 5h exhibited the most significant inhibitory effects. To further explore the effects of derivatives 5b and 5h on gastrointestinal tumors, KYSE30 cells were chosen as a representative cell line. Both derivatives can effectively curtail the migration and invasion capabilities of KYSE30 cells and induce apoptosis in a dose-dependent manner. We further demonstrated these derivatives induce cell apoptosis in KYSE30 cells by inhibiting the expression of Stat3 protein and Smad2/3 protein. Based on the above results, we suggest they show promise in developing drugs for esophageal squamous cell carcinoma.

2,5-Diketopiperazines (DKPs): Promising Scaffolds for Anticancer Agents.

2,5-Diketopiperazine (2,5-DKP) derivatives represent a family of secondary metabolites widely produced by bacteria, fungi, plants, animals, and marine organisms. Many natural products with DKP scaffolds exhibited various pharmacological activities such as antiviral, antifungal, antibacterial, and antitumor. 2,5-DKPs are recognized as privileged structures in medicinal chemistry, and compounds that incorporate the 2,5-DKP scaffold have been extensively investigated for their anticancer properties. This review is a thorough update on the anti-cancer activity of natural and synthesized 2,5-DKPs from 1997 to 2022. We have explored various aspects of 2,5-DKPs modifications and summarized their structure-activity relationships (SARs) to gain insight into their anticancer activities. We have also highlighted the novel approaches to enhance the specificity and pharmacokinetics of 2,5-DKP-based anticancer agents.

Favorable Virological Outcome, Characteristics of Injection Site Reactions, Decrease in Renal Function Biomarkers in Asian People with HIV Receiving Long-Acting Cabotegravir Plus Rilpivirine.

Long-acting cabotegravir plus rilpivirine has revolutionized the concept of antiretroviral therapy, but as the causes of virological failure and satisfaction can depend on patient background, real-world data are needed. In this single-center study, we reviewed clinical records of people with HIV (PWH) who received injectable cabotegravir plus rilpivirine between June 2022 and January 2023. We assessed virological and safety outcomes, including injection site reactions (ISRs) and changes in serum creatinine and cystatin C. Seventy-four patients were included. There were no virological failures. Approximately 80% of individuals achieved HIV-RNA undetectable in all visits up to 14 months (median 13 months) after switching. Pain upon injection was significantly more common at the rilpivirine injection site, while delayed pain was significantly more common at the cabotegravir injection site. The serum creatinine (mean difference -0.12 mg/dL, p < .0001) and the cystatin C (mean difference -0.077 mg/dL, p < .0001) decreased significantly after switching, and in multivariable regression analysis, baseline characteristics did not affect the decrease in these renal function markers. Long-acting cabotegravir plus rilpivirine showed excellent antiviral efficacy and safety in PWH in Japan. ISRs were characterized differently at the cabotegravir and rilpivirine injection sites. Although cystatin C showed decrease after the regimen switch, further confirmation is needed whether cabotegravir plus rilpivirine can improve renal function.

The Bisdioxopiperazine ICRF-193 Attenuates LPS-induced IL-1ß Secretion by Macrophages.

Inhibiting pathological secretion of Interleukin-1ß has shown beneficial effects in disease models and in the clinic and thus there is interest in finding inhibitors that can reduce its release from macrophages in response to their activation by foreign pathogens. We used an in vitro human macrophage model to investigate whether ICRF-193, a Topoisomerase II inhibitor could modulate IL1B mRNA expression and IL-1ß secretion. These macrophage-like cells readily secrete IL-1ß in response to Lipopolysaccharide (LPS). Upon exposure to a non-toxic dose of ICRF-193, IL-1ß secretion was diminished by ~ 40%; however, level of transcription of IL1B was unaffected. We show that there was no Topoisomerase 2B (TOP2B) binding to several IL1B gene sites, which may explain why ICRF-193 does not alter IL1B mRNA levels. Hence, we show for the first time that ICRF-193 can reduce IL-1ß secretion. Its low cost and the development of water-soluble prodrugs of ICRF-193 warrants its further investigation in the modulation of pathological secretion of this cytokine for the treatment of inflammatory disorders. (165 words).

Unravelling the Secrets of α-Pyrones from Aspergillus Fungi: A Comprehensive Review of Their Natural Sources, Biosynthesis, and Biological Activities.

Aspergillus, one of the most product-rich and genetically robust genera, contains a diverse range of species with potential economic and ecological implications. Chemically, Aspergillus is one of the essential sources of polyketides, alkaloids, diphenyl ethers, diketopiperazines, and other miscellaneous compounds, displaying a variety of pharmacological activities. The α-pyrones are unsaturated six-membered lactones. Although α-pyrone has a small structure, it is responsible for the structural diversity of several natural and synthetic compounds and multiple biological activities. In this review, we have summarized approximately 178 α-pyrone containing metabolites derivatives identified/reported from terrestrial, marine, endophytic, and filamentous Aspergillus species, including their sources, biological properties, and biosynthetic pathways until mid-2023, for the first time. This review is the first to compile and analyze the available data on α-pyrone metabolites from Aspergillus, which could facilitate further research and innovation in this field. Additionally, it offers a valuable source of scaffolds for future bioactive drug development, as some of these metabolites have shown potent antimicrobial, anti-inflammatory, and anticancer effects. Therefore, this review has significant implications for the advancement of natural product chemistry, pharmacology, biotechnology, and medicine.

Four previously undescribed diketopiperazines from marine fungus Aspergillus puniceus FAHY0085 and their effects on liver X receptor α.

Four previously undescribed diketopiperazine-type alkaloids including one oxepin-containing diketopiperazine-type alkaloid, oxepinamide L (1), three 4-quinazolinone alkaloids, puniceloids E-G (10-12), together with 12 known analogues, protuboxepin D (2), oxepinamides D-G, J-K and I (3-9), puniceloids B-D (13-15) and protubonine B (16), were isolated from the culture of the marine-derived fungus Aspergillus puniceus FAHY0085. The structures of the previously undescribed compounds were comprehensively elucidated by detailed interpretation of their NMR and HRESIMS data. Their absolute configurations were unambiguously determined by ROESY experiments, Marfey's method, calculated ECD experiments and single-crystal X-ray diffraction analysis. Compounds (3-4, 6-8, 14-15) were evaluated for their cytotoxic activity against HepG2, MCF-7, SW1116 and HeLa cells and compound 6 and 14 showed moderate cytotoxic activity against HeLa cells with IC50 49.61 ± 2.91 and 28.38 ± 1.57 µM, respectively. Compounds (1-8, 11-15) were screened for their transcriptional activation of liver X receptor α and compound 11 with known compounds 13-15 showed significant transcriptional activation of liver X receptor α with EC50 values in the range 2-50 µM.

Photofragmentation specificity of photoionized cyclic amino acids (diketopiperazines) as precursors of peptide building blocks.

The photoionisation and photofragmentation of the two cyclic dipetides cyclo(alanyl-glycine) cGA and cyclo(glycyl-glycine) cGG, have been studied combining experiments and simulations. State selected fragments from the ionized molecules are detected using photo-electron photo-ion coincidence (PEPICO) measurements and specific fragmentation paths are identified and characterized via the use of ion-neutral coincidence maps. The simulations, performed using Quantum Chemistry methods, allow us to infer the fragmentation mechanisms of the ionized and excited molecules. We show that ring opening is followed by emission of the neutral fragments CO and HNCO. In the case of cGG the emission of neutral CO leads to a metastable structure that breaks producing small cationic fragments. The studied cyclic dipeptides evolve under ionizing radiation generating different small aziridin moieties and oxazolidinones. These two species are key reactants to elongate producing peptide chains. The corresponding mechanisms have been computed and show that the reaction requires very low energy and may occur in the presence of ionizing radiation.

New Indole Diketopiperazine Alkaloids from Soft Coral-Associated Epiphytic Fungus Aspergillus versicolor CGF 9-1-2.

Two new indole diketopiperazine alkaloids (IDAs), (+)19-epi-sclerotiamide (1) and (-)19-epi-sclerotiamide (2), along with 13 known analogs (3-15), were isolated from a soft coral-associated epiphytic fungus Aspergillus versicolor CGF 9-1-2. The structures of two new compounds were established based on the combination of HR-ESI-MS, 1D and 2D NMR spectroscopy, optical rotation measurements and quantum chemical 13 C-NMR, the absolute configurations were determined by experimental and electronic circular dichroism (ECD) calculations. The results of molecular docking showed that all the compounds had a good binding with TDP1, TDP2, TOP1, TOP2, Ache, NLRP3, EGFR, EGFR L858R, EGFR T790M and EGFR T790/L858. Biological evaluation of compounds 3, 6, 8, 11 showed that 3 exerted a strong inhibitory effect on TDP2 with a rate of 81.72 %.

Diketopiperazine and isoindolinone alkaloids from the endophytic fungus Aspergillus sp. HAB10R12.

Four previously undescribed alkaloids, aspergillinine A-D, and four known diterpene pyrones were isolated from the potato dextrose agar (PDA) culture of Aspergillus sp. HAB10R12. The chemical structures of the isolated compounds were elucidated based on a detailed analysis of their NMR and MS data. The absolute configuration of the isolated compounds was determined by Electronic Circular Dichroism analysis coupled with computational methods. Aspergillinine A represents the first example of a diketopiperazine dipeptide containing the unnatural amino acid N-methyl kynurenine. Its absolute configuration revealed that it adopts a rather unusual conformation. Aspergillinine B represents a previously unencountered skeleton containing an isoindolinone ring. Aspergillinine C and D were similar to previously isolated diketopiperazine alkaloids, namely, lumpidin and brevianamide F, respectively. The diterpene pyrones were isolated twice previously, once from a soil-derived Aspergillus species, and once from the liquid culture of Aspergillus sp. HAB10R12. The alkaloids isolated in this study showed no antiproliferative activity when tested against HepG2 and A549 cancer cell lines.

Chemical diversity and biological activities of specialized metabolites from the genus Chaetomium: 2013-2022.

Chaetomium (Chaetomiaceae), a large fungal genus consisting of at least 400 species, has been acknowledged as a promising resource for the exploration of novel compounds with potential bioactivities. Over the past decades, emerging chemical and biological investigations have suggested the structural diversity and extensive potent bioactivity of the specialized metabolites in the Chaetomium species. To date, over 500 compounds with diverse chemical types have been isolated and identified from this genus, including azaphilones, cytochalasans, pyrones, alkaloids, diketopiperazines, anthraquinones, polyketides, and steroids. Biological research has indicated that these compounds possess a broad range of bioactivities, including antitumor, anti-inflammatory, antimicrobial, antioxidant, enzyme inhibitory, phytotoxic, and plant growth inhibitory activities. This paper summarizes current knowledge referring to the chemical structure, biological activity, and pharmacologic potency of the specialized metabolites in the Chaetomium species from 2013 to 2022, which might provide insights for the exploration and utilization of bioactive compounds in this genus both in the scientific field and pharmaceutical industry.

Indole diketopiperazine alkaloids and aromatic polyketides from the Antarctic fungus Penicillium sp. SCSIO 05705.

A new indole diketopiperazine alkaloid, named penilline D (1), together with five known indole alkaloid analogues (2-5, 11), two meroterpenoids (6 and 12), and four butenolide derivatives (7-10), were isolated from the Antarctic fungus Penicillium sp. SCSIO 05705. Extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation were used to elucidate the structure of penilline D (1), including its absolute configuration. All isolated compounds (1-12) were evaluated for their cytotoxic, antibacterial and enzyme inhibitory activities against acetylcholinesterase (AChE) and pancreatic lipase (PL). Among them, compound 5 exhibited moderate in vitro cytotoxic activity against the 143B cell line with IC50 value of 12.64 ± 0.78 µM. Compound 6 showed strong inhibitory activity against AChE with IC50 value of 0.36 nM (IC50 18.7 nM for Tacrine), while compounds 6 and 11 showed weak PL enzyme inhibitory activity. Furthermore, an in silico molecular docking study was also performed between 6 and AChE.

2,5-Diketopiperazines: A Review of Source, Synthesis, Bioactivity, Structure, and MS Fragmentation.

BACKGROUND: 2,5-Diketopiperazines (DKPs), also called cyclic dipeptides, are the simplest peptide derivatives in nature that are formed by the condensation of two amino acids. They are an important category of bioactive substances with various structures. OBJECTIVE: This review focuses on the natural sources, synthetic processes, biological properties and MS fragmentation regularity of simple DKPs, in order to provide a reference for exploring future scientific and therapeutic potentials of these compounds. METHODS: Pertinent information was collected and organized from several electronic scientific databases (e.g., Web of Science, China Knowledge Resource Integrated, ScienceDirect, PubMed, Wanfang Data and Google Scholar), PhD and MS dissertations. There are 107 articles published from the early 20th century to 2021 that were reviewed in this work. RESULTS: DKPs have been obtained from a broad range of natural resources, including fungi, bacteria, plants, and animals, and have been synthesized by chemical and biological methods. DKPs have various pharmacological activities, including anticancer, antibacterial, antithrombotic, neuron protective, analgesic, and other activities. Mass spectrometry is the most common method for the structural analysis of DKPs. DKPs can be quickly screened and identified by MS according to the mass spectrum fragmentation pattern. CONCLUSION: As a category of relatively unexplored compounds, DKPs have been demonstrated to have various bioactivities, especially with antitumor and antibacterial activities. However, the existing research on DKPs is still in the early stage, and their application in drug development needs to be further studied.