Anion-Driven C-F Bond Activation of Trifluoromethyl N-Aryl Hydrazones: Application to the Synthesis of 1,3,4-Oxadiazoles.

The CF3 group attached to N-aryl hydrazone could be activated upon treatment with a suitable base, thus serving as an excellent C1 unit for the assembly of a series of 1,3,4-oxadiazoles by reaction with hydrazides. The transformation is proposed to proceed via the intermediate formation of a gem-difluorinated azoalkene. Furthermore, this reaction features simple conditions and a broad substrate scope with respect to both trifluoromethyl N-aryl hydrazones and hydrazides.

Toward more efficient ergothioneine production using the fungal ergothioneine biosynthetic pathway.

BACKGROUND: Ergothioneine (ERG) is a potent histidine-derived antioxidant that confers health-promoting effects. Only certain bacteria and fungi can biosynthesize ERG, but the ERG productivity in natural producers is low. ERG overproduction through genetic engineering represents an efficient and cost-effective manufacturing strategy. RESULTS: Here, we showed that Trichoderma reesei can synthesize ERG during conidiogenesis and hyphal growth. Co-expression of two ERG biosynthesis genes (tregt1 and tregt2) from T. reesei enabled E. coli to generate 70.59 mg/L ERG at the shaking flask level after 48 h of whole-cell biocatalysis, whereas minor amounts of ERG were synthesized by the recombinant E. coli strain bearing only the tregt1 gene. By fed-batch fermentation, the extracellular ERG production reached 4.34 g/L after 143 h of cultivation in a 2-L jar fermenter, which is the highest level of ERG production reported thus far. Similarly, ERG synthesis also occurred in the E. coli strain engineered with the two well-characterized genes from N. crassa and the ERG productivity was up to 4.22 g/L after 143 h of cultivation under the above-mentioned conditions. CONCLUSIONS: Our results showed that the overproduction of ERG in E. coli could be achieved through two-enzymatic steps, demonstrating high efficiency of the fungal ERG biosynthetic pathway. Meanwhile, this work offers a more promising approach for the industrial production of ERG.

Ultrahigh-performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry profiling and unveiling the transformation of ginsenosides by the dual conditions of citric acid and high-pressure steaming.

RATIONALE: Many methods have been reported for the production of rare ginsenosides, including heat treatment, acid hydrolysis, alkaline hydrolysis, enzymatic hydrolysis, and microbial transformation. However, the conversion of original ginsenosides to rare ginsenosides under the dual conditions of citric acid and high-pressure steam sterilization has rarely been reported. METHODS: In this study, a method involving ultrahigh-performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry was developed for analysis of chemical transformation of protopanaxatriol (PPT)-type ginsenosides Rg1 and Re, protopanaxadiol (PPD)-type ginsenoside Rb1 , and total ginsenosides in the dual conditions of citric acid and high-pressure steam sterilization. An internal ginsenoside database containing 126 known ginsenosides and 18 ginsenoside reference compounds was established to identify the transformation products and explore possible transformation pathways and mechanisms. RESULTS: A total of 54 ginsenosides have been preliminarily identified in the transformation products of PPD-type ginsenosides Rg1 and Re, PPD-type ginsenoside Rb1 , and total ginsenosides, and the possible transformation pathways were as follows: Rg1 , Re → 20(S)-Rh12 , 20(R)-Rh12 ; Rg1 , Re → 20(S)-Rh1 , 20(R)-Rh1 → Rk3 , Rh4 , Rh5 ; Rb1 → gypenoside LXXV; Rb1 → 20(S)-Rg3 , 20(R)-Rg3 → Rk1 , Rg5 ; Re → 20(S)-Rg2 , 20(R)-Rg2 → 20(S)-Rf2 , 20(R)-Rf2 , Rg4 , F4 . CONCLUSIONS: The results elucidated the possible transformation pathways and mechanisms of ginsenosides in the dual conditions of citric acid and high-pressure steam sterilization, which were helpful for revealing the mechanisms of ginsenosides and enhanced safety and quality control of pharmaceuticals and nutraceuticals. Meanwhile, a simple, efficient, and practical method was developed for the production of rare ginsenosides, which has the potential to produce diverse rare ginsenosides on an industrial scale.

Combining protein and metabolic engineering strategies for biosynthesis of melatonin in Escherichia coli.

BACKGROUND: Melatonin has attracted substantial attention because of its excellent prospects for both medical applications and crop improvement. The microbial production of melatonin is a safer and more promising alternative to chemical synthesis approaches. Researchers have failed to produce high yields of melatonin in common heterologous hosts due to either the insolubility or low enzyme activity of proteins encoded by gene clusters related to melatonin biosynthesis. RESULTS: Here, a combinatorial gene pathway for melatonin production was successfully established in Escherichia coli by combining the physostigmine biosynthetic genes from Streptomyces albulus and gene encoding phenylalanine 4-hydroxylase (P4H) from Xanthomonas campestris and caffeic acid 3-O-methyltransferase (COMT) from Oryza sativa. A threefold improvement of melatonin production was achieved by balancing the expression of heterologous proteins and adding 3% glycerol. Further protein engineering and metabolic engineering were conducted to improve the conversion of N-acetylserotonin (NAS) to melatonin. Construction of COMT variant containing C303F and V321T mutations increased the production of melatonin by fivefold. Moreover, the deletion of speD gene increased the supply of S-adenosylmethionine (SAM), an indispensable cofactor of COMT, which doubled the yield of melatonin. In the final engineered strain EcMEL8, the production of NAS and melatonin reached 879.38 ± 71.42 mg/L and 136.17 ± 1.33 mg/L in a shake flask. Finally, in a 2-L bioreactor, EcMEL8 produced 1.06 ± 0.07 g/L NAS and 0.65 ± 0.11 g/L melatonin with tryptophan supplementation. CONCLUSIONS: This study established a novel combinatorial pathway for melatonin biosynthesis in E. coli and provided alternative strategies for improvement of melatonin production.

Combining DNA Barcoding and HPLC Fingerprints to Trace Species of an Important Traditional Chinese Medicine Fritillariae Bulbus.

Fritillariae Bulbus is a precious Chinese herbal medicine that is grown at high elevation and used to relieve coughs, remove phlegm, and nourish the lungs. Historically, Fritillariae Bulbus has been divided into two odourless crude drugs: Fritillariae Cirrhosae Bulbus and Fritillariae Thunbergii Bulbus. However, now the Chinese Pharmacopoeia has described five Fritillariae Bulbus-the new additions include Fritillariae Pallidiflorae Bulbus, Fritillariae Ussuriensis Bulbus, and Fritillariae Hupehensis Bulbus. Because the morphology of dried Fritillariae Bulbus is similar, it is difficult to accurately identify the different types of Fritillariae Bulbus. In the current study, we develop a method combining DNA barcoding and high-performance liquid chromatography (HPLC) to help distinguish Fritillariae Cirrhosae Bulbus from other Fritillariae Bulbus and guarantee species traceability of the five types of Fritillariae Bulbus. We report on the validation of an integrated analysis method for plant species identification using DNA barcoding that is based on genetic distance, identification efficiency, inter- and intra-specific variation, calculated nearest distance, neighbour-joining tree and barcoding gap. Our results show that the DNA barcoding data successfully identified the five Fritillariae Bulbus by internal transcribed spacer region (ITS) and ITS2, with the ability to distinguish the species origin of these Fritillariae Bulbus. ITS2 can serve as a potentially useful DNA barcode for the Fritillaria species. Additionally, the effective chemical constituents are identified by HPLC combined with a chemical identification method to classify Fritillaria. The HPLC fingerprint data and HCA (hierarchical clustering analysis) show that Fritillariae Cirrhosae Bulbus is clearly different from Fritillariae Thunbergii Bulbus and Fritillariae Hupehensis Bulbus, but there is no difference between Fritillariae Cirrhosae Bulbus, Fritillariae Ussuriensis Bulbus, and Fritillariae Pallidiflorae Bulbus. These results show that DNA barcoding and HPLC fingerprinting can discriminate between the five Fritillariae Bulbus types and trace species to identify related species that are genetically similar.

Negative Regulation of Ectoine Uptake and Catabolism in Sinorhizobium meliloti: Characterization of the EhuR Gene.

Ectoine has osmoprotective effects on Sinorhizobium meliloti that differ from its effects in other bacteria. Ectoine does not accumulate in S. meliloti cells; instead, it is degraded. The products of the ehuABCD-eutABCDE operon were previously discovered to be responsible for the uptake and catabolism of ectoine in S. meliloti However, the mechanism by which ectoine is involved in the regulation of the ehuABCD-eutABCDE operon remains unclear. The ehuR gene, which is upstream of and oriented in the same direction as the ehuABCD-eutABCDE operon, encodes a member of the MocR/GntR family of transcriptional regulators. Quantitative reverse transcription-PCR and promoter-lacZ reporter fusion experiments revealed that EhuR represses transcription of the ehuABCD-eutABCDE operon, but this repression is inhibited in the presence of ectoine. Electrophoretic mobility shift assays and DNase I footprinting assays revealed that EhuR bound specifically to the DNA regions overlapping the -35 region of the ehuA promoter and the +1 region of the ehuR promoter. Surface plasmon resonance assays further demonstrated direct interactions between EhuR and the two promoters, although EhuR was found to have higher affinity for the ehuA promoter than for the ehuR promoter. In vitro, DNA binding by EhuR could be directly inhibited by a degradation product of ectoine. Our work demonstrates that EhuR is an important negative transcriptional regulator involved in the regulation of ectoine uptake and catabolism and is likely regulated by one or more end products of ectoine catabolism. IMPORTANCE: Sinorhizobium meliloti is an important soil bacterium that displays symbiotic interactions with legume hosts. Ectoine serves as a key osmoprotectant for S. meliloti However, ectoine does not accumulate in the cells; rather, it is degraded. In this study, we characterized the transcriptional regulation of the operon responsible for ectoine uptake and catabolism in S. meliloti We identified and characterized the transcription repressor EhuR, which is the first MocR/GntR family member found to be involved in the regulation of compatible solute uptake and catabolism. More importantly, we demonstrated for the first time that an ectoine catabolic end product could modulate EhuR DNA-binding activity. Therefore, this work provides new insights into the unique mechanism of ectoine-induced osmoprotection in S. meliloti.

Phenolic compounds from Bletilla striata.

Two new malic acid derivatives, namely eucomic acid 1-methyl ester (2) and 6'''-acetylmilitaline (7), together with ten known compounds (1, 3-6, 8-12), were isolated from the dry tubers of Bletilla striata (Thunb.) Reichb. F., a perennial traditional Chinese medicinal herb, which was used for the treatment of pneumonophthisis, pneumonorrhagia, tuberculosis, and hemorrhage of the stomach or lung. Their structures were elucidated by spectroscopic analyses, including 1D-, 2D-NMR, and HR-ESI-MS.

Cell-free ribosome display and selection of antibodies on arrayed antigens.

In vitro display technology is a powerful tool for discovery and optimisation of novel antibodies. With increasing demands on various binding molecules in proteomics studies, techniques for a large-scale generation of antibodies or antibody fragments are needed. Here, we describe a novel method for parallel generation of different antibody fragments (scFv) by integrating cell-free ribosome display with array technology. We have demonstrated the procedure by successfully isolating scFv antibodies specific to 16 different cancer biomarkers via a single process. Our results provide proof of principle for multiple production of various scFv antibodies simultaneously.

Plastic Change along the Intact Crossed Pathway in Acute Phase of Cerebral Ischemia Revealed by Optical Intrinsic Signal Imaging.

The intact crossed pathway via which the contralesional hemisphere responds to the ipsilesional somatosensory input has shown to be affected by unilateral stroke. The aim of this study was to investigate the plasticity of the intact crossed pathway in response to different intensities of stimulation in a rodent photothrombotic stroke model. Using optical intrinsic signal imaging, an overall increase of the contralesional cortical response was observed in the acute phase (≤48 hours) after stroke. In particular, the contralesional hyperactivation is more prominent under weak stimulations, while a strong stimulation would even elicit a depressed response. The results suggest a distinct stimulation-response pattern along the intact crossed pathway after stroke. We speculate that the contralesional hyperactivation under weak stimulations was due to the reorganization for compensatory response to the weak ipsilateral somatosensory input.

Design of an ectoine-responsive AraC mutant and its application in metabolic engineering of ectoine biosynthesis.

Advanced high-throughput screening methods for small molecules may have important applications in the metabolic engineering of the biosynthetic pathways of these molecules. Ectoine is an excellent osmoprotectant that has been widely used in cosmetics. In this study, the Escherichia coli regulatory protein AraC was engineered to recognize ectoine as its non-natural effector and to activate transcription upon ectoine binding. As an endogenous reporter of ectoine, the mutated AraC protein was successfully incorporated into high-throughput screening of ectoine hyper-producing strains. The ectoine biosynthetic cluster from Halomonas elongata was cloned into E. coli. By engineering the rate-limiting enzyme L-2,4-diaminobutyric acid (DABA) aminotransferase (EctB), ectoine production and the specific activity of the EctB mutant were increased. Thus, these results demonstrated the effectiveness of engineering regulatory proteins into sensitive and rapid screening tools for small molecules and highlighted the importance and efficacy of directed evolution strategies applied to the engineering of genetic components for yield improvement in the biosynthesis of small molecules.

High production of ectoine from aspartate and glycerol by use of whole-cell biocatalysis in recombinant Escherichia coli.

BACKGROUND: Recently, the compatible solute 1, 4, 5, 6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid (ectoine) has attracted considerable interest due to its great potential as a protecting agent. To overcome the drawbacks of high salinity in the traditional bioprocess of ectoine using halophilic bacteria, various attempts have been made to engineer ectoine biosynthesis in nonhalophilic bacteria. Unfortunately, the yields of ectoine in these producers are still low and hardly meet the demands of large scale production. In this paper, the whole-cell biocatalytic process using aspartate and glycerol as substrates was tried for high production of ectoine in nonhalophilic bacteria. RESULTS: The ectoine genes ectABC from the halophilic bacterium Halomonas elongata were successfully introduced into Escherichia coli K-12 strain BW25113 under the arabinose-inducible promoter. To our delight, a large amount of ectoine was synthesized and excreted into the medium during the course of whole-cell biocatalysis, when using aspartate and glycerol as the direct substrates. At the low cell density of 5 OD/mL in flask, under the optimal conditions (100 mM sodium phosphate buffer (pH 7.0), 100 mM sodium aspartate, 100 mM KCl and 100 mM glycerol), the concentration of extracellular ectoine was increased to 2.67 mg/mL. At the high cell density of 20 OD/mL in fermentor, a maximum titre of 25.1 g/L ectoine was achieved in 24 h. Meanwhile, the biomass productivity of ectoine is as high as 4048 mg per gram dry cell weight (g DCW)(-1), which is the highest value ever reported. Furthermore, it was demonstrated that the same batch of cells could be used for at least three rounds. Finally, a total yield of 63.4 g ectoine was obtained using one litre cells. CONCLUSION: Using aspartate and glycerol as the direct substrates, high production of ectoine was achieved by the whole-cell biocatalysis in recombinant E. coli. Multiple rounds of whole-cell biocatalysis were established to further improve the production of ectoine. Our study herein provided a feasible biosynthesis process of ectoine with potential applications in large-scale industrial production.

Tissue damage from chronic liver injury inhibits peripheral NK cell abundance and proinflammatory function.

One of the difficulties in the treatment of hepatocellular carcinoma is that it is impossible to eliminate the inhibitory effect of the tumor microenvironment on immune response. Therefore, it is particularly important to understand the formation process of the tumor microenvironment. Chronic inflammation is the core factor of cancer occurrence and the leading stage of inflammation-cancer transformation, and the natural killer cell subsets play an important role in it. Our study confirmed that in the stage of chronic liver injury, the local immunosuppressive microenvironment of the liver (i.e. the damaged microenvironment) has been formed, but this inhibitory effect is only for peripheral natural killer cells and has no effect on tissue-resident natural killer subsets. The markers of damage microenvironment are the same as those of tumor microenvironment.

Iridoids rich fraction from Valeriana jatamansi Jones promotes axonal regeneration and motor functional recovery after spinal cord injury through activation of the PI3K/Akt signaling pathway.

Valeriana jatamansi Jones (VJJ), renowned for its extensive history in traditional Chinese medicine and ethnomedicine within China, is prevalently utilized to alleviate ailments such as epigastric distension and pain, gastrointestinal disturbances including food accumulation, diarrhea, and dysentery, as well as insomnia and other diseases. Moreover, the Iridoid-rich fraction derived from Valeriana jatamansi Jones (IRFV) has demonstrated efficacy in facilitating the recuperation of motor functions after spinal cord injury (SCI). This study is aimed to investigate the therapeutic effect of IRFV on SCI and its underlying mechanism. Initially, a rat model of SCI was developed to assess the impact of IRFV on axonal regeneration. Subsequently, employing the PC12 cell model of oxidative damage, the role and mechanism of IRFV in enhancing axonal regeneration were explored using the phosphoinositide-3-kinase (PI3K)/protein kinase B (Akt) signaling pathway inhibitor LY294002. Ultimately, the same inhibitor was administered to SCI rats to confirm the molecular mechanism through which IRFV promotes axonal regeneration by activating the PI3K/Akt signaling pathway. The results showed that IRFV significantly enhanced motor function recovery, reduced pathological injury, and facilitated axonal regeneration in SCI rats. In vitro experiments revealed that IRFV improved PC12 cell viability, augmented axonal regeneration, and activated the PI3K/Akt signaling pathway. Notably, the inhibition of this pathway negated the therapeutic benefits of IRFV in SCI rats. In conclusion, IRFV promote promotes axonal regeneration and recovery of motor function after SCI through activation of the PI3K/Akt signaling pathway.

Mechanism of Valeriana Jatamansi Jones for the treatment of spinal cord injury based on network pharmacology and molecular docking.

Spinal cord injury (SCI) is characterized by high rates of disability and death. Valeriana jatamansi Jones (VJJ), a Chinese herbal medicine, has been identified to improve motor function recovery in rats with SCI. The study aimed to analyze the potential molecular mechanisms of action of VJJ in the treatment of SCI. The main ingredients of VJJ were obtained from the literature and the SwissADME platform was used to screen the active ingredients. The Swiss TargetPrediction platform was used to predict the targets of VJJ, and the targets of SCI were obtained from the GeneCards and OMIM databases. The intersecting genes were considered potential targets of VJJ in SCI. The protein-protein interaction network was constructed using the STRING database and the hub genes of VJJ for SCI treatment were screened according to their degree values. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed using the Metascape database. Cytoscape software was used to construct the "herb-ingredient-target-pathway" network. Preliminary validation was performed using molecular docking via Auto Dock Vina software. A total of 56 active ingredients of VJJ, mainly iridoids, were identified. There were 1493 GO items (P < .01) and 173 signaling pathways (P < .01) obtained from GO and Kyoto Encyclopedia of Genes and Genomes enrichment, including the phosphoinositide-3-kinase (PI3K)-protein kinase B (Akt) signaling pathway, hypoxia-inducible factor 1 signaling pathway, and tumor necrosis factor signaling pathway. Molecular docking revealed that 12 hub genes enriched in the PI3K/Akt signaling pathway had a high binding affinity for the active ingredient of VJJ. VJJ may exert its therapeutic effects on SCI through the iridoid fraction, acting on signal transducer and activator of transcription 3, CASP3, AKT1, tumor necrosis factor, mammalian target of rapamycin, interleukin 6, and other hub genes, which may be related to the PI3K/Akt signaling pathway.

Fluorescence-based aptasensors for small molecular food contaminants: From energy transfer to optical polarization.

Small molecular food contaminants, such as mycotoxins, pesticide residues and antibiotics, are highly probable to be passively introduced in food at all stages of its processing, including planting, harvest, production, transportation and storage. Owing to the high risks caused by the unknowing intake and accumulation in human, there is an urgent need to develop rapid, sensitive and efficient methods to monitor them. Fluorescence-based aptasensors provide a promising platform for this area owing to its simple operation, high sensitivity, wide application range and economical practicability. In this paper, the common sorts of small molecular contaminants in foods, namely mycotoxins, pesticides, antibiotics, etc, are briefly introduced. Then, we make a comprehensive review, from fluorescence resonance energy transfer (in turn-on, turn-off, and ratiometric mode, as well as energy upconversion) to fluorescence polarization, of the fluorescence-based aptasensors for the determination of these food contaminants reported in the last five years. The principle of signal generation, the advances of each sort of fluorescent aptasensors, as well as their applications are introduced in detail. Additionally, we also discussed the challenges and perspectives of the fluorescent aptasensors for small molecular food contaminants. This work will offer systematic overview and inspiration for amateurs, researchers and developers of fluorescence-based aptasensors for the detection of small molecules.

[Ribosome display screening of a novel human anti-IgE scFv fragment].

Total mRNA was extracted from lymphocytes separated from the peripheral blood of allergic patients, and then variable region of heavy chain (VH) and variable region of light chain (VL) cDNA library were constructed by RT-PCR. Human scFv templates for rabbit reticulocyte lysate ribosome display were assembled by primers and linker peptide (Gly4Ser)3. mRNA bound in antibody-ribosome-mRNA complexes was recovered using in-situ single primer RT-PCR, and three rounds of anti-IgE scFv DNA were enriched. The target DNA fragments were double enzyme digested and ligated into plasmid pET22b (+), followed by transformation in E. coli Rosseta (DE3). Positive clones were screened using clone PCR, Dot blotting and antigen ELISA. The correct lengths of VH (400 bp) and VL (710 bp) PCR products were obtained. The expected 1,000 bp ribosome display templates were also observed in agarose gel electrophoresis. After three rounds of ribosome display target sequences were effectively enriched, leading to a library of 10(13) members. Antibodies with the highest ELISA value for IgE were generated in the strain pET-IgE-6. A human anti-IgE scFv library was successfully constructed as described herein. Ribosome display using single primer in-situ RT-PCR as the recovery procedure effectively enriched target sequences. Anti-IgE scFv with high affinity and specificity were identified. The prepared human anti-IgE scFv fragment might be self-developed to a lead drug for treating asthma. Our study provides an alternative method for rapid discovery of human antibodies of therapeutic importance.

The role of γδ T17 cells in cardiovascular disease.

Due to the ability of γδ T cells to bridge adaptive and innate immunity, γδ T cells can respond to a variety of molecular cues and acquire the ability to induce a variety of cytokines such as IL-17 family, IFN-γ, IL-4, and IL-10. IL-17+ γδ T cells (γδ T17 cells) populations have recently received considerable interest as they are the major early source of IL-17A in many immune response models. However, the exact mechanism of γδ T17 cells is still poorly understood, especially in the context of cardiovascular disease (CVD). CVD is the leading cause of death in the world, and it tends to be younger. Here, we offer a review of the cardiovascular inflammatory and immune functions of γδ T17 cells in order to understand their role in CVD, which may be the key to developing new clinical applications.

Isolation and characterization of two new chroman-4-ones from the endophytic fungus Penicillium chrysogenum obtained from Eucommia ulmoides Oliver.

Two new chroman-4-ones penicichromanone A (1) and penicichromanone B (2), together with three known compounds conioxepinol C (3), emodin (4) and moniliphenone (5), were obtained from the endophytic fungus Penicillium chrysogenum, which was isolated from the bark of Eucommia ulmoides Oliver. The structures of 1 and 2 were elucidated by detailed analysis of HRESIMS, 1D/2D NMR and ECD spectra. All the compounds were evaluated for their anti-inflammatory activities using HEK293 cells, and compounds 1, 3, 4 and 5 exhibited significant inhibitory effects on TNF-α-stimulated NF-κB activation.

Complete genome sequence of Alicyclobacillus acidocaldarius strain Tc-4-1.

Alicyclobacillus acidocaldarius strain Tc-4-1 was initially isolated from a hot spring in Tengchong, China. This organism is both thermophilic and acidophilic. It can produce heat- and acid-stable enzymes, such as amylase and esterase, which may be important in industry. Here we report the whole genome sequence of the strain.

Chemical Composition, Pharmacological, and Toxicological Effects of Betel Nut.

Betel nut, the fruit of Areca catechu L, has a long medical history in Southeast Asia. It is native to Malaysia and is cultivated and processed extensively in subtropical regions, such as South China and India. Betel nut almost appears as a "snack" in various occasions in most parts of China. Clinically, betel nut can play a certain pharmacology role and was used in malaria, ascariasis, arthritis, enterozoic abdominalgia, stagnation of food, diarrhea, edema, and beriberi. The nervous excitement of betel nut chewing has made it gradually become popular. However, chewing betel nut can induce oral submucosal fibrosis (OSF) and oral cancer (OC). At the same time, long-term chewing of betel nut also causes inhaled asthma, sperm reducing, betel quid dependence (BQD), and uterine and esophageal cancers. The main components of processed betel nut are the goal of this review. This study will mainly start from the pharmacological activity and toxicology study of betel nut in recent years, aiming to seek its advantages and disadvantages. In the meantime, this study will analyze and emphasize that betel nut and arecoline are the high-risk factors for oral cancer, which should arouse attention and vigilance of the public.