Effect of ambient air pollution on hospital admission for respiratory diseases in Hanoi children during 2007-2019.

Air pollution poses a threat to children's respiratory health. This study aims to quantify the association between short-term air pollution exposure and respiratory hospital admissions among children in Hanoi, Vietnam, and estimate the population-attributable burden using local data. A case-crossover analysis was conducted based on the individual records where each case is their own control. The health data was obtained from 13 hospitals in Hanoi and air pollution data was collected from four monitoring stations from 2007 to 2019. We used conditional logistic regression to estimate Percentage Change (PC) and 95% Confidence Interval (CI) in odd of hospital admissions per 10 µg/m3 increase in daily average particulate matter (e.g. PM1, PM2.5, PM10), Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), 8-h maximum Ozone and per 1000 µg/m3 increase in daily mean of Carbon Monoxide (CO). We also calculated the number and fraction of admissions attributed to air pollution in Hanoi by using the coefficient at lag 0. A 10 µg/m3 increase in the concentration of PM10, PM2.5, PM1, SO2, NO2, O3 8-h maximum and 1000 µg/m3 increase in CO concentration was associated with 0.6%, 1.2%, 1.4%, 0.8%, 1.6%, 0.3%, and 1.7% increase in odd of admission for all respiratory diseases among children under 16 years at lag 0-2. All PM metrics and NO2 are associated with childhood admission for pneumonia and bronchitis. Admissions due to asthma and upper respiratory diseases are related to increments in NO2 and CO. For attributable cases, PM2.5 concentrations in Hanoi exceeding the World Health Organization Air Quality Guidelines accounted for 1619 respiratory hospital admissions in Hanoi children in 2019. Our findings show that air pollution has a detrimental impact on the respiratory health of Hanoi children and there will be important health benefits from improved air quality management planning to reduce air pollution in Vietnam.

Two new flavonoids with antimicrobial activity from the roots of Byttneria aspera Colebr. ex Wall (Malvaceae).

Two new flavonoids, 4',5,7-trihydroxy-5'-methoxy-6,8-dimethylisoflavone (1) and 2',5',7-trihydroxy-5-methoxy-6,8-dimethylflavanone (2) together with the known flavonoids 4´,5,7-trihydroxy-3´-methoxy-6.8-dimethylflavone (3), epigallocatechin (4), 4´-O-methylepicatechin (5) and quercetin (6) were isolated from the roots of Byttneria aspera. The structures of these compounds were determined by means of spectroscopic methods. Compounds 1-6 were submitted to cytotoxic activity assays against three cancer cell lines including KB, MCF7 and A549, as well as their antimicrobial activity against a panel of clinically significant microorganisms. Compound 6 showed moderate cytotoxic activity with IC50 values of 12.7, 56.9 and 17.5 µM against KB, MCF7 and A549. Interestingly, the new compounds 1 and 2 exhibits antimicrobial activity, with compound 1 displaying selective antifungal activity against Candida albicans giving an MIC value of 128 µg/mL, compared to cyclohexamide with 32 µg/mL, while compound 2 shows potent inhibition of the Gram-positive bacterium Enterococcus faecalis displaying an MIC of 64 µg/mL, compared to streptomycin with 256 µg/mL.

Individual-, social- and policy- factors associated with smoking cessation among adult male cigarette smokers in Hanoi, Vietnam: a longitudinal study.

BACKGROUND: Nearly one-in-two Vietnamese men smoke cigarettes placing them among the highest tobacco consumers in the world. Despite the need for smoking cessation to curb the burden of tobacco-related diseases in Vietnam, this rate remains at less than 30%. Therefore, this study examines individual-, social- and policy factors associated with smoking cessation among adult male smokers in Vietnam. METHODS: We established a longitudinal International Tobacco Control study of male smokers in Hanoi, Vietnam, in September 2018. This paper analyses 1525 men who participated in baseline and one-year follow-up. We applied a weighted multivariable logistic regression to examine the association between smoking cessation and individual-, social- and policy predictors. RESULTS: At follow-up, 14.8% of participants had quit smoking for at least 30 consecutive days during the last year. Among the persistent smokers, 56.6% expressed intention to quit smoking. Factors associated with smoking cessation included a lower number of cigarettes smoked per day (aOR = 0.96, 95% CI: 0.94, 0.99) and having several attempts to quit smoking (aOR = 2.16, 95% CI 1.13, 4.12). Intention to quit smoking was associated with multiple quit attempts, a chronic condition diagnosis, more tobacco-related knowledge, greater self-efficacy, and more worries about their future health. The perceived impact of smoke-free policy and health warning labels were positively associated with intention to quit at any stage. CONCLUSIONS: Interventions aimed at increasing smoking cessation should focus on all aspects of individual, social, and policy factors. Persistent smokers are more motivated to quit if they have made multiple quit attempts, more self-efficacy of quitting and worried about their future health, indicating that increasing smokers' beliefs and knowledge may be important for behavioural change. Health warning labels and tobacco taxation policies should be maintained and promoted as they are perceived to be particularly useful for persistent smokers' intention to quit.

Drought-Stress-Related Reprogramming of Gene Expression in Barley Involves Differential Histone Modifications at ABA-Related Genes.

Plants respond to drought by the major reprogramming of gene expression, enabling the plant to survive this threatening environmental condition. The phytohormone abscisic acid (ABA) serves as a crucial upstream signal, inducing this multifaceted process. This report investigated the drought response in barley plants (Hordeum vulgare, cv. Morex) at both the epigenome and transcriptome levels. After a ten-day drought period, during which the soil water content was reduced by about 35%, the relative chlorophyll content, as well as the photosystem II efficiency of the barley leaves, decreased by about 10%. Furthermore, drought-related genes such as HvS40 and HvA1 were already induced compared to the well-watered controls. Global ChIP-Seq analysis was performed to identify genes in which histones H3 were modified with euchromatic K4 trimethylation or K9 acetylation during drought. By applying stringent exclusion criteria, 129 genes loaded with H3K4me3 and 2008 genes loaded with H3K9ac in response to drought were identified, indicating that H3K9 acetylation reacts to drought more sensitively than H3K4 trimethylation. A comparison with differentially expressed genes enabled the identification of specific genes loaded with the euchromatic marks and induced in response to drought treatment. The results revealed that a major proportion of these genes are involved in ABA signaling and related pathways. Intriguingly, two members of the protein phosphatase 2C family (PP2Cs), which play a crucial role in the central regulatory machinery of ABA signaling, were also identified through this approach.

Noncanonical processing by animal Microprocessor.

Microprocessor (MP), DROSHA-DGCR8, processes primary miRNA transcripts (pri-miRNAs) to initiate miRNA biogenesis. The canonical cleavage mechanism of MP has been extensively investigated and comprehensively validated for two decades. However, this canonical mechanism cannot account for the processing of certain pri-miRNAs in animals. In this study, by conducting high-throughput pri-miRNA cleavage assays for approximately 260,000 pri-miRNA sequences, we discovered and comprehensively characterized a noncanonical cleavage mechanism of MP. This noncanonical mechanism does not need several RNA and protein elements essential for the canonical mechanism; instead, it utilizes previously unrecognized DROSHA dsRNA recognition sites (DRESs). Interestingly, the noncanonical mechanism is conserved across animals and plays a particularly significant role in C. elegans. Our established noncanonical mechanism elucidates MP cleavage in numerous RNA substrates unaccounted for by the canonical mechanism in animals. This study suggests a broader substrate repertoire of animal MPs and an expanded regulatory landscape for miRNA biogenesis.

Smoking Cessation, Quit Attempts and Predictive Factors among Vietnamese Adults in 2020.

OBJECTIVE: This study aims to describe the updated smoking cessation and quit attempt rates and associated factors among Vietnamese adults in 2020. METHODS: Data on tobacco use among adults in Vietnam in 2020 was derived from the Provincial Global Adult Tobacco Survey. The participants in the study were people aged 15 and older. A total of 81,600 people were surveyed across 34 provinces and cities. Multi-level logistic regression was used to examine the associations between individual and province-level factors on smoking cessation and quit attempts. RESULTS: The smoking cessation and quit attempt rates varied significantly across the 34 provinces. The average rates of people who quit smoking and attempted to quit were 6.3% and 37.2%, respectively. The factors associated with smoking cessation were sex, age group, region, education level, occupation, marital status, and perception of the harmful effects of smoking. Attempts to quit were significantly associated with sex, education level, marital status, perception of the harmful effects of smoking, and visiting health facilities in the past 12 months. CONCLUSIONS: These results may be useful in formulating future smoking cessation policies and identifying priority target groups for future interventions. However, more longitudinal and follow-up studies are needed to prove a causal relationship between these factors and future smoking cessation behaviors.

Screening for adverse childhood experiences among young people using drugs in Vietnam: related factors and clinical implications.

BACKGROUND: Research evidence shows a strong association between adverse childhood experiences (ACEs) and later-life substance use. But little is known about the prevalence and impact of ACEs among young people using drugs (YPUD) in Vietnam. METHOD: A cross-sectional study using respondent-driven sampling and peer recruitment methods was conducted among YPUD aged 16-24 in three cities in Vietnam. Eligible participants were screened for ACEs using the ACE-IQ, tested for HIV and hepatitis C, and assessed for sociodemographic and behavioral characteristics. RESULTS: Data were collected on 553 individuals whose median age was 20: 79% were male, 18.3% women and 2.7% transgender. Methamphetamine use was reported by 75.8% of participants. 85.5% reported at least one ACE and 27.5% had four ACEs or more. An ACE score of 4 or higher was associated with female and transgender, lower educational level, methamphetamine use, buying sex, depression, psychotic symptoms and expressed need for mental health support. CONCLUSIONS: ACEs were found to be very common among YPUD in Vietnam. It is therefore strongly recommended that these young people should be provided with a comprehensive and secure assessment and care that includes not only essential harm reduction and addiction treatment needs but also addresses their mental health needs.

Dissection of the Caenorhabditis elegans Microprocessor.

Microprocessor (MP) is a complex involved in initiating the biogenesis of microRNAs (miRNAs) by cleaving primary microRNAs (pri-miRNAs). miRNAs are small single-stranded RNAs that play a key role in the post-transcriptional regulation of gene expression. Thus, understanding the molecular mechanism of MP is critical for interpreting the roles of miRNAs in normal cellular processes and during the onset of various diseases. MP comprises a ribonuclease enzyme, DROSHA, and a dimeric RNA-binding protein, which is called DGCR8 in humans and Pasha in Caenorhabditis elegans. DROSHA cleaves stem-loop structures located within pri-miRNAs to generate pre-miRNAs. Although the molecular mechanism of human MP (hMP; hDROSHA-DGCR8) is well understood, that of Caenorhabditis elegans MP (cMP; cDrosha-Pasha) is still largely unknown. Here, we reveal the molecular mechanism of cMP and show that it is distinct from that of hMP. We demonstrate that cDrosha and Pasha measure ∼16 and ∼25 bp along a pri-miRNA stem, respectively, and they work together to determine the site of cMP cleavage in pri-miRNAs. We also demonstrate the molecular basis for their substrate measurement. Thus, our findings reveal a previously unknown molecular mechanism of cMP; demonstrate the differences between the mechanisms of hMP and cMP; and provide a foundation for revealing the mechanisms regulating miRNA expression in different animal species.

The Microprocessor complex that initiates miRNA biogenesis was discovered in animals in 2004. However, the molecular mechanism of C. elegans Microprocessor (cMP) has remained elusive since its discovery 18 years ago. In this study, we revealed the unique molecular mechanism of cMP by conducting high-throughput pri-miRNA cleavage assays. We demonstrated that cMP, consisting of cDrosha and Pasha, each can measure the stem lengths of pri-miRNAs. cDrosha measures ∼16 bp of the lower stem length, whereas Pasha measures ∼25 bp of the upper stem in pri-miRNAs. In addition, we identified the cleavage sites and cleavage efficiency of cMP in C. elegans pri-miRNAs. These results will be helpful for future studies of miRNA biogenesis in C. elegans.

Classification of Southeast Asian mints (Mentha spp.) based on simple sequence repeat markers.

Mentha is a complex genus encompassing many species as a consequence of their interspecific hybridization and polyploidy. Southeast Asian mints have been poorly distinguished though they are widely used for culinary and medical purposes. In this study, we have analyzed Southeast Asian mints and known varieties as well as a related Lamiaceae species (Nepeta sp.) using simple sequence repeat (SSR) markers and leaf morphology. Two types of mints were clearly distinguished based on their venation pattern and leaf shape index. We developed 12 SSR markers that allowed good amplification in the Mentha and another Lamiaceae species. In the SSR-based phylogram, the Mentha lines could be delimited into groups I-VI. The Southeast Asian mints divided into groups I and II, and the phylogram separated most of the available species, with groups I and II containing the known species M. × cordifolia and M. arvensis, respectively. The separation of the two groups was supported by a population structure analysis. The SSR markers developed in this study enabled the simultaneous classification of mints and will help improve our understanding of the genetic composition of known mint varieties and as yet unclassified Southeast Asian mints.

Circular Whole-Transcriptome Amplification (cWTA) and mNGS Screening Enhanced by a Group Testing Algorithm (mEGA) Enable High-Throughput and Comprehensive Virus Identification.

Metagenomic next-generation sequencing (mNGS) offers a hypothesis-free approach for pathogen detection, but its applicability in clinical diagnosis, in addition to other factors, remains limited due to complicated library construction. The present study describes a PCR-free isothermal workflow for mNGS targeting RNA, based on a multiple displacement amplification, termed circular whole-transcriptome amplification (cWTA), as the template is circularized before amplification. The cWTA approach was validated with clinical samples and nanopore sequencing. Reads homologous to dengue virus 2 and chikungunya virus were detected in clinical samples from Bangladesh and Brazil, respectively. In addition, the practicality of a high-throughput detection system that combines mNGS and a group testing algorithm termed mNGS screening enhanced by a group testing algorithm (mEGA) was established. This approach enabled significant library size reduction while permitting trackability between samples and diagnostic results. Serum samples of patients with undifferentiated febrile illnesses from Vietnam (n = 43) were also amplified with cWTA, divided into 11 pools, processed for library construction, and sequenced. Dengue virus 2, hepatitis B virus, and parvovirus B19 were successfully detected without prior knowledge of their existence. Collectively, cWTA with the nanopore platform opens the possibility of hypothesis-free on-site comprehensive pathogen diagnosis, while mEGA contributes to the scaling up of sample throughput. IMPORTANCE Given the breadth of pathogens that cause infections, a single approach that can detect a wide range of pathogens is ideal but is impractical due to the available tests being highly specific to a certain pathogen. Recent developments in sequencing technology have introduced mNGS as an alternative that provides detection of a wide-range of pathogens by detecting the presence of their nucleic acids in the sample. However, sequencing library preparation is still a bottleneck, as it is complicated, costly, and time-consuming. In our studies, alternative approaches to optimize library construction for mNGS were developed. This included isothermal nucleic acid amplification and expansion of sample throughput with a group testing algorithm. These methods can improve the utilization of mNGS as a diagnostic tool and can serve as a high-throughput screening system aiding infectious disease surveillance.

Biovalorization of Market Surplus Bread for Development of Probiotic-Fermented Potential Functional Beverages.

Bread wastage is a growing concern in many developed countries. This research aimed to explore the biovalorization of market surplus bread for the development of probiotic-fermented beverages in a zero-waste approach. Bread slurries with different initial total solid contents were inoculated with probiotics Lacticaseibacillus rhamnosus GG (LGG) and Saccharomyces cerevisiae CNCM I-3856, alone and in combination. Our results showed that, of all percentages tested, 5% (w/w, dry weight) initial total solid content resulted in better growth of the probiotics and higher cell counts, while the texture of bread slurries with concentrations higher than 5.0% was too thick and viscous for bread beverage developments. In addition, the development of probiotic-fermented bread beverages was feasible on various types of bread. Furthermore, food additives (sweetener and stabilizer) did not affect the growth of LGG and S. cerevisiae CNCM I-3856 in both mono- and co-culture fermentation. During shelf life measurement, co-inoculation of LGG with S. cerevisiae CNCM I-3856 significantly improved the survival of LGG compared to the mono-culture at 5 and 30 °C, demonstrating the protective effects provided by the yeast. Our study suggests the potential of using market surplus bread as raw materials to deliver live probiotics with sufficient cell counts.

Assessment of a psychiatric intervention at community level for people who inject drugs in a low-middle income country: the DRIVE-Mind cohort study in Hai Phong, Viet Nam.

BACKGROUND: Access to psychiatric care for people who inject drugs (PWID) is limited/absent and stigmatized in most low-middle-income countries (LMICs). Innovative interventions are needed. We aimed to describe and assess the impact of a community-based psychiatric intervention among PWID in Hai Phong, Vietnam. METHODS: In a cohort study with one year psychiatric follow-up, PWID diagnosed with a psychotic disorder, a major depressive episode, or suicide risk, were recruited from the wider Drug-Related Infections in ViEtnam (DRIVE) project in the city of Hai Phong. The community-based psychiatric intervention included specialized follow-up (free consultations with psychiatrists, free medication, referral to mental health department for hospitalization when necessary) and support from community-based organisations (case management, harm reduction, administrative support, linkage to HIV care, methadone maintenance treatment and mental health support). The main outcome was reduction/remission of symptoms. Access to and retention in psychiatric care, quality-of-life and stigmatization were also measured pre and post-intervention. FINDINGS: Among the 1212 participants screened from March to May 2019, 271 met the inclusion criteria, 233 (86.3%) accepted the intervention and 170 completed the follow-up (72.9%). At inclusion, 80.6% were diagnosed with current depression, 44.7% with psychotic disorder and 42.4% with suicide risk. After a one-year follow-up, these proportions dropped to 15.9%, 21.8%, and 22.9% respectively. Quality-of-life and perceived stigma related to mental health were also significantly improved, while drug use decreased only marginally. INTERPRETATION: Community-based psychiatric interventions are both feasible and efficient in the Vietnamese context. Similar interventions should be implemented and evaluated in other, different LMICs. FUNDING: : This work was supported by grants from NIDA (US) (#DA041978) and ANRS (France) (#13353). The funding agencies had no role in designing the research, data analyses, or preparation of the report.

The conserved single-cleavage mechanism of animal DROSHA enzymes.

RNase III enzymes typically cleave both strands of double-stranded RNAs (dsRNAs). We recently discovered that a human RNase III, DROSHA, exhibits a single cleavage on the one strand of primary microRNAs (pri-miRNAs). This study revealed that DROSHAs from the other animals, including worms and flies, also show the single cleavage on dsRNAs. Furthermore, we demonstrated that the mechanism of single cleavage is conserved in animal DROSHA enzymes. In addition, the dsRNA-binding domain (dsRBD) and a 3p-strand cleavage-supporting helix (3pCSH) of the DROSHA enzymes foster a weak single cleavage on one strand, which ensures their double cleavages. Disrupting the interaction of dsRBD-RNA and 3pCSH-RNA by an internal loop (IL) and a 3pCSH-loop in the lower stem of pri-miRNAs, respectively, inhibits one of the double cleavages of DROSHAs, and this results in the single cleavage. Our findings expand our understanding of the enzymatic mechanisms of animal DROSHAs. They also indicate that there are currently unknown cellular functions of DROSHA enzymes using their single cleavage activity.

A targeted approach with nanopore sequencing for the universal detection and identification of flaviviruses.

Nucleic acid test (NAT), most typically quantitative PCR, is one of the standard methods for species specific flavivirus diagnosis. Semi-comprehensive NATs such as pan-flavivirus PCR which covers genus Flavivirus are also available; however, further specification by sequencing is required for species level differentiation. In this study, a semi-comprehensive detection system that allows species differentiation of flaviviruses was developed by integration of the pan-flavivirus PCR and Nanopore sequencing. In addition, a multiplexing method was established by adding index sequences through the PCR with a streamlined bioinformatics pipeline. This enables defining cut-off values for observed read counts. In the laboratory setting, this approach allowed the detection of up to nine different flaviviruses. Using clinical samples collected in Vietnam and Brazil, seven different flaviviruses were also detected. When compared to a commercial NAT, the sensitivity and specificity of our system were 66.7% and 95.4%, respectively. Conversely, when compared to our system, the sensitivity and specificity of the commercial NAT were 57.1% and 96.9%, respectively. In addition, Nanopore sequencing detected more positive samples (n = 8) compared to the commercial NAT (n = 6). Collectively, our study has established a semi-comprehensive sequencing-based diagnostic system for the detection of flaviviruses at extremely affordable costs, considerable sensitivity, and only requires simple experimental methods.

Evaluation of the Obesity Prevention, Blood Glucose, and Blood Lipid Control of Vietnamese Rice Varieties in High-Fat Diet-Induced Obese Mice.

Five Vietnamese rice varieties, which differ in their basic chemical composition (starch content, amylose content, fiber content) including polished rices and whole grain rices, were chosen for this study. High-fat diet-induced obesity, using these rice, was subjected to in vivo experiments to evaluate the effects of body weight gain, caloric intake, postprandial blood glucose level (PBGL), and glycemic index (GI) in tested mice groups. PBGL peaks appeared at 30th minute after eating, and GI of each experimental group was ranked in order as GN > TL > HR > GM > LD and GN > LT > HR > LD > GM, respectively, in which, brown rice (LD) and germinated brown rice (GM) had low GI. Furthermore, these rice varieties caused the lowest LDL cholesterol and the ratio of LDL/HDL cholesterols in mice. In this study, the higher the amylose and fiber contents were, the lower glycemic index, triglycerides, LDL, and LDL/HDL values were. The golden flower glutinous rice (GN), with low amylose and fiber content, gave worse blood lipid parameters than that of GM and LD. Histopathological studies of white adipose and liver tissues showed that LD and GM significantly reduced the symptoms of obesity and fatty liver compared with the others, especially compared to GN. The results obtained from this study help patients with overweight, obesity, and type 2 diabetes choose the right rice variety for their daily diet to be able to control their diseases.

Daily heroin injection and psychiatric disorders: A cross-sectional survey among People Who Inject Drugs (PWID) in Haiphong, Vietnam.

BACKGROUND: Psychiatric comorbidities are frequent among people who inject drugs, they are associated with a poorer prognosis and need to be addressed. Their interaction with daily heroin injection requires clarification. METHODS: A cross-sectional survey was conducted among PWID recruited in the city of Haiphong, Vietnam, by respondent-driven sampling. The inclusion criteria were age 18 or older and current injection drug use, verified by skin marks and positive urine tests for heroin or methamphetamine. Data on socio-demographic characteristics, drug use, sexual behaviour and access to treatment were collected using face-to-face questionnaires by trained interviewers. PWID were screened by trained psychiatrists for depression, psychotic disorder and suicidality, using the MINI questionnaire. RESULTS: 418 participants were included in the analyses. All were injected heroin users, 21 % were diagnosed with a current major depressive disorder, 15 % with a current psychotic disorder and 12 % presented a suicide risk. In the bivariate analyses, regular meth use, cannabis use and ketamine use were positively associated with presenting at least one psychiatric condition while daily heroin injection and being currently treated with methadone were negatively associated. In the multivariate model, poly-substance use was positively associated with depression (methamphetamine and drinking in addition to heroin) and psychotic disorder (methamphetamine and/or hazardous drinking in addition to heroin) while daily heroin injection and current methadone treatment were negatively and independently associated with depression and psychotic syndrome. CONCLUSIONS: Our survey confirms the burden of methamphetamine use and the protective effect of methadone but also a possible protective effect of daily heroin injection.

Human disease-associated single nucleotide polymorphism changes the orientation of DROSHA on pri-mir-146a.

The Microprocessor complex of DROSHA and DGCR8 initiates the biosynthesis of microRNAs (miRNAs) by processing primary miRNAs (pri-miRNAs). The Microprocessor can be oriented on pri-miRNAs in opposite directions to generate productive and unproductive cleavages at their basal and apical junctions, respectively. However, only the productive cleavage gives rise to miRNAs. A single nucleotide polymorphism (SNP, rs2910164) in pri-mir-146a is associated with various human diseases. Although this SNP was found to reduce the expression of miRNA, it is still not known if it affects the activity of the Microprocessor directly, and how it functions. In this study, we revealed that the SNP creates an unexpected mGHG motif at the apical junction of pri-mir-146a. This mGHG motif interacts with the double-stranded RNA-binding domain (dsRBD) of DROSHA, switching its orientation on pri-mir-146a from the basal to the apical junction. As a result, the SNP facilitates Microprocessor to cleave SNP-pri-mir-146a at its unproductive sites. Our findings help to elucidate the molecular mechanism that explains how the disease-associated SNP modulates the biogenesis of pri-mir-146a and thereby affects its cellular functions.

Investigation on the Epoxidation of Piperitenone, and Structure-activity Relationships of Piperitenone Oxide for Differentiation-inducing Activity.

Piperitenone oxide, a major chemical constituent of the essential oil of spearmint, Mentha spicata, induces differentiation in human colon cancer RCM-1 cells. In this study, piperitenone oxide and trans-piperitenone dioxide were prepared as racemic forms by epoxidation of piperitenone. The relative configuration between two epoxides in piperitenone dioxide was determined to be trans by 1H NMR analysis and nuclear Overhauser effect spectroscopy (NOESY) in conjunction with density functional theory (DFT) calculations. Optical resolution of (±)-piperitenone oxide by high-performance liquid chromatography (HPLC) using a chiral stationary phase (CSP) afforded both enantiomers with over 98% enantiomeric excess (ee). Evaluation of the differentiation-inducing activity of the synthetic compounds revealed that the epoxide at C-1 and C-6 in piperitenone oxide is important for the activity, and (+)-piperitenone oxide has stronger activity than (-)-piperitenone oxide. The results obtained in this study provide new information on the application of piperitenone oxide and spearmint for differentiation-inducing therapy. Furthermore, natural piperitenone oxide was isolated from M. spicata. The enantiomeric excess of the isolated natural piperitenone oxide was 66% ee. Epoxidation of piperitenone with hydrogen peroxide proceeded in a phosphate buffer under weak basic conditions to give (±)-piperitenone oxide. These results suggest that the nonenzymatic epoxidation of piperitenone, which causes a decrease in the enantiomeric excess of natural piperitenone oxide, is accompanied by an enzymatic epoxidation in the biosynthesis of piperitenone oxide.