Ethnobotany, phytochemistry, pharmacology and quality control of Peucedanum decursivum (Miq.) Maxim: A critical review.

ETHNOPHARMACOLOGICAL RELEVANCE: Dried roots of Peucedanum decursivum, a traditional Chinese medicine (TCM), has historically respiratory diseases such as cough, thick phlegm, headache, fever, and gynecological diseases, rheumatoid arthritis, and nasopharyngeal carcinoma. AIM OF THE STUDY: Made an endeavor to evaluate the research trajectory of P. decursivum, comprehensively discern its developmental status, and offer a guideline for future investigations. MATERIALS AND METHODS: A meticulous search of literatures and books from 1955 to 2024 via databases like PubMed, Web of Science and CNKI was conducted, including topics and keywords of " P. decursivum" "Angelica decursivum" and "Zihua Qianhu". RESULTS: P. decursivum and its prescriptions have traditionally been used for treating phlegm-heat cough, wind-heat cough, gastrointestinal diseases, pain relief and so on. It contains 234 identified compounds, encompassing coumarins, terpenes, volatile oils, phenolic acids, fatty acids and derivatives. It exhibits diverse pharmacological activities, including anti-asthmatic, anti-inflammatory, antioxidant effects, anti-hypertensive, anti-diabetic, anti-Alzheimer, and anti-cancer properties, primarily attributed to coumarins. Microscopic identification, HPLC fingerprinting, and bioinformatics identification are the primary methods currently used for the quality control. CONCLUSION: P. decursivum demonstrates anti-asthmatic, anti-inflammatory, and antioxidant effects, aligning with its traditional use. However, experimental validation of its efficacy against phlegm and viruses is needed. Additionally, analgesic effects mentioned in historical texts lack modern pharmacological studies. Numerous isolated compounds exhibit highly valuable medicinal properties. Future research can delve into exploring these substances further. Rigorous of heavy metal contamination, particularly Cd and Pb, is necessary. Simultaneously, investigating its pharmacokinetics and toxicity in humans is crucial for the safety.

Selective Hydrodeoxygenation of Lignin-Derived Phenolic Monomers to Cyclohexanol over Tungstated Zirconia Supported Ruthenium Catalysts.

The selective hydrodeoxygenation (HDO) of lignin-derived methoxyphenols to cyclohexanol is one of the most significant transformation in biomass conversion since cyclohexanol is an important industrial raw material. This study has disclosed a series of tungstated zirconia with different Zr/W ratio supported Ru catalysts (Ru/xZrW, x means the molar ration of Zr/W) for the hydrodeoxygenation (HDO) of guaiacol to cyclohexanol. Among these catalysts, Ru/16ZrW has the best catalytic activity, which can achieve 92 % yield of cyclohexanol under the conditions of 180 °C and 1 MPa H2 pressure for 2 h (TOF 231 h-1). Compared with Ru/ZrO2, Ru/16ZrW has smaller particles, more dispersed and electron-rich Ru species, significant hydrogen spillover and more acid sites, which are the main reason for its excellent performance on this reaction. Apart from guaiacol, other methoxy substitution phenols and organosolv lignin can also be converted into cyclohexanol via hydrodeoxygenation reactions over this catalyst.

Liquid- liquid (Cyclohexanone: Cyclohexanol) separation using augmented tight nanofiltration membrane: A sustainable approach.

Organic solvent nanofiltration (OSN) is an incipient technology in the field of organic liquid-liquid separation. The incomplete separations and complexity involved in these, forces many organic liquids to be released as effluents and the adverse effects of these on environment is enormous and irreparable. The work prominences on the complete separation of industrially significant cyclohexanone: cyclohexanol (keto-alcohol oil) and heptane: toluene mixtures. The separations of these above-mentioned organic liquid mixtures were carried out using the fabricated Lewis acid modified graphitic carbon nitride (Cu2O@g-C3N4) incorporated polyvinylidene difluoride (PVDF) composite membranes. These fabricated membranes showed a separation factor of 18.16 and flux of 1.62 Lm-2h-1 for cyclohexanone: cyclohexanol mixture and separation of heptane and toluene mixture (with heptane flux of 1.52 Lm-2h-1) showed a separation factor of 9.9. The selectivity and productivity are based on the polarity and size of the organic liquids. The role of Cu2O@g-C3N4 is influencing the pore size distribution, increased divergence from solubility parameters, polarity, solvent uptake and porosity of the composite membranes. The developed composite membranes are thus envisioned to be apt for a wide range of liquid-liquid separations due to its implicit nature.

Constituents of Chimaphila japonica and Their Diuretic Activity.

Three new phenols (1-3), one new cyclohexanol (4), two known phenols (5-6), and six known flavonoids (7-12) were isolated from the n-butanol of the 75% ethanol extract of all plants of Chimaphila japonica Miq. Among them, compound 5 was named and described in its entirety for the first time, and compounds 9 and 10 were reported in C. japonica for the first time. The structures of all compounds were confirmed using a comprehensive analysis of 1D and 2D NMR and HRESIMS data. Biological results show that compounds 4, 7, and 11 exhibited potent diuretic activity. The modes of interaction between the selected compounds and the target diuretic-related WNK1 kinase were investigated in a preliminary molecular docking study. These results provided insight into the chemodiversity and potential diuretic activities of metabolites in C. japonica.

Phenol Hydrogenation to Cyclohexanol Catalysed by Palladium Supported on CuO/CeO2.

Hydrogenation of phenol to cyclohexanone/cyclohexanol is an important reaction in production of nylon-6, nylon-66 and in petroleum industry. Liquid phase phenol hydrogenation over Pd-CuO/CeO2 was carried out under mild conditions. Palladium impregnated over CuO/CeO2 synthesized by co-precipitation method showed excellent catalytic activity for phenol hydrogenation (99% conversion with 80% cyclohexanol yield) at 90 °C and 10 bar H2 pressure in water. Commercial 10%Pd/C showed only 8% phenol conversion under identical conditions. The detailed characterization revealed significant improvement in surface area of ceria after addition of CuO and decrease in crystallite size with creation of defects in CeO2 lattice. XPS analysis showed Pd loading on CuO/CeO2 to cause hydrogen spillover on the surface leading to increase in the oxygen vacancies. The interaction of phenol with catalyst surface studied by detailed FTIR analysis, revealed activation of phenol on oxygen vacancy of ceria as phenoxide ion with perpendicular orientation of aromatic ring on catalyst surface.

Mitigating carcinogenic smoke opacity in a light-duty diesel engine by utilizing cyclohexanol, polyethylene glycol, and 2-methoxyethanol.

Diesel fuel reformulation is an attractive method to reduce hazardous smoke emissions because it does not require modifications to the existing engine infrastructure. As the concerns about global warming and air pollution are mounting, high-efficiency diesel engines with low smoke emissions have become more attractive. This study demonstrates that three alcohols, viz. cyclohexanol, polyethylene glycol, and 2-methoxyethanol, can be added to fossil diesel up to 3% by vol. to reduce carcinogenic smoke emissions in a one-cylinder, common rail direct injection (CRDI) diesel engine. The experimental investigations revealed that smoke could be reduced by up to 66.2%, 39.6% and 14% using 3% by vol. addition of cyclohexanol, polyethylene glycol, and 2-methoxyethanol to diesel, respectively, when compared to pure diesel operation. 1% addition by vol. of cyclohexanol and 2-methoxyethanol could reduce NOx and smoke emissions under all load conditions. CO emissions are slightly higher for all alcohol at high load conditions. HC emissions for the test fuels are lower than pure diesel operation at low load conditions, increasing at high loads. These emissions, however, can be reduced by using suitable after-treatment devices.

Cobalt-Graphene Catalyst for Selective Hydrodeoxygenation of Guaiacol to Cyclohexanol.

Herein, cobalt-reduced graphene oxide (rGO) catalyst was synthesized with a practical impregnation-calcination approach for the selective hydrodeoxygenation (HDO) of guaiacol to cyclohexanol. The synthesized Co/rGO was characterized by transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), and H2 temperature-programmed reduction (H2-TPR) analysis. According to the comprehensive characterization results, the catalyst contains single Co atoms in the graphene matrix and Co oxide nanoparticles (CoOx) on the graphene surface. The isolated Co atoms embedded in the rGO matrix form stable metal carbides (CoCx), which constitute catalytically active sites for hydrogenation. The rGO material with proper amounts of N heteroatoms and lattice defects becomes a suitable graphene material for fabricating the catalyst. The Co/rGO catalyst without prereduction treatment leads to the complete conversion of guaiacol with 93.2% selectivity to cyclohexanol under mild conditions. The remarkable HDO capability of the Co/rGO catalyst is attributed to the unique metal-acid synergy between the CoCx sites and the acid sites of the CoOx nanoparticles. The CoCx sites provide H while the acid sites of CoOx nanoparticles bind the C-O group of reactants to the surface, allowing easier C-O scission. The reaction pathways were characterized based on the observed reaction-product distributions. The effects of the process parameters on catalyst preparation and the HDO reaction, as well as the reusability of the catalyst, were systematically investigated.

New Alk(en)ylhydroxycyclohexanes with Tyrosinase Inhibition Potential from Harpephyllum caffrum Bernh. Gum Exudate.

This work presents the first report on the phytochemical investigation of Harpephyllum caffrum Bernh. gum exudate. A known cardanol, 3-heptadec-12'-Z-enyl phenol (1) and three new alk(en)ylhydroxycyclohexanes, namely, (1R,3R)-1,3-dihydroxy-3-[heptadec-12'(Z)-enyl]cyclohexane (2) (1S,2S,3S,4S,5R)-1,2,3,4,5-pentahydroxy-5-[octadec-13'(Z)-enyl]cyclohexane (3) and (1R,2S,4R)-1,2,4-trihydroxy-4-[heptadec-12'(Z)-enyl]cyclohexane (4) were isolated from the gum. The structures of the compounds were determined by extensive 1D and 2D NMR spectroscopy and HR-ESI-MS data. The ethanolic extract of the gum was found to be the most potent tyrosinase inhibitor with IC50 of 11.32 µg/mL while compounds 2 and 3, with IC50 values of 24.90 and 26.99 µg/mL, respectively, were found to be potential anti-tyrosinase candidates from the gum. Gum exudate may be a potential source for non-destructive harvesting of selective pharmacologically active compounds from plants. The results also provide evidence that H. caffrum gum may find application in cosmetics as a potential anti-tyrosinase agent.

Recent progress on selective hydrogenation of phenol toward cyclohexanone or cyclohexanol.

Phenol is considered as an important platform molecule for synthesizing value-added chemical intermediates and products. To date, various strategies for phenol transformation have been developed, and among them, selective hydrogenation of phenol toward cyclohexanone (K), cyclohexanol (A) or the mixture KA oil has been attracted great interest because they are both the key raw materials for the synthesis of nylon 6 and 66, as well as many other chemical products, including polyamides. However, until now it is still challengeable to realize the industrilized application of phenol hydrogenation toward KA oils. To better understand the selective hydrogenation of phenol and fabricate the enabled nanocatalysts, it is necessary to summarize the recent progress on selective hydrogenation of phenol with different catalysts. In this review, we first summarize the selective hydrogenation of phenol toward cyclohexanone or cyclohexanol by different nanocatalysts, and simultaneously discuss the relationship among the active components, type of supports and their performances. Then, the possible reaction mechanism of phenol hydrogenation with the typical metal nanocatalysts is summarized. Subsequently, the possible ways for scale-up hydrogenation of phenol are discussed. Finally, the potential challenges and future developments of metal nanocatalysts for the selective hydrogenation of phenol are proposed.

Condensation derivatives of 4-isopropylbenzaldehyde with acetophenone from the red alga Laurencia tristicha.

Seven undescribed condensation derivatives of 4-isopropylbenzaldehyde with acetophenone, including one 1,3,5-trisubstituted pentane-1,5-dione, two 1,3,4,5,7-pentasubstituted heptane-1,7-diones and four 1,2,3,4,5-pentasubstituted cyclohexanols, together with two known flavonoids, were obtained from the red alga Laurencia tristicha. The relative configurations were elucidated by extensive spectroscopic data analysis of MS, 1D and 2D NMR, while the absolute configurations were determined by comparing the experimental and calculated electronic circular dichroism spectra. All the isolates were proven to be naturally occurring in the red alga by LC-MS analysis, and these 1,3,5-trisubstituted-pentane-1,5-dione, 1,3,4,5,7-pentasubstituted-heptane-1,7-diones and 1,2,3,4,5-pentasubstituted-cyclohexanols were reported from natural sources for the first time. The proposed biogenetic pathway of the isolates was also discussed.

Impaired neuromuscular function by conjoint actions of organophosphorus insecticide metabolites omethoate and cyclohexanol with implications for treatment of respiratory failure.

BACKGROUND: Ingestion of agricultural organophosphorus insecticides is a significant cause of death in rural Asia. Patients often show acute respiratory failure and/or delayed, unexplained signs of neuromuscular paralysis, sometimes diagnosed as "Intermediate Syndrome". We tested the hypothesis that omethoate and cyclohexanol, circulating metabolites of one agricultural formulation, cause muscle weakness and paralysis. METHODS: Acetylcholinesterase activity of insecticide components and metabolites was measured using purified enzyme from eel electroplaque or muscle homogenates. Mechanomyographic recording of pelvic limb responses to nerve stimulation was made in anaesthetized pigs and isometric force was recorded from isolated nerve-muscle preparations from mice. Omethoate and cyclohexanol were administered intravenously or added to physiological saline bathing isolated muscle. We also assessed the effect of MgSO4 and cooling on neuromuscular function. RESULTS: Omethoate caused tetanic fade in pig muscles and long-lasting contractions of the motor innervation zone in mouse muscle. Both effects were mitigated, either by i.v. administration of MgSO4 in vivo or by adding 5 mM Mg2+ to the medium bathing isolated preparations. Combination of omethoate and cyclohexanol initially potentiated muscle contractions but then rapidly blocked them. Cyclohexanol alone caused fade and block of muscle contractions in pigs and in isolated preparations. Similar effects were observed ex vivo with cyclohexanone and xylene. Cyclohexanol-induced neuromuscular block was temperature-sensitive and rapidly reversible. CONCLUSIONS: The data indicate a crucial role for organophosphorus and solvent metabolites in muscle weakness following ingestion of agricultural OP insecticide formulations. The metabolites omethoate and cyclohexanol acted conjointly to impair neuromuscular function but their effects were mitigated by elevating extracellular Mg2+ and decreasing core temperature, respectively. Clinical studies of MgSO4 therapy and targeted temperature management in insecticide-poisoned patients are required to determine whether they may be effective adjuncts to treatment.

Tuning a bi-enzymatic cascade reaction in Escherichia coli to facilitate NADPH regeneration for ε-caprolactone production.

ε-Caprolactone is a monomer of poly(ε-caprolactone) which has been widely used in tissue engineering due to its biodegradability and biocompatibility. To meet the massive demand for this monomer, an efficient whole-cell biocatalytic approach was constructed to boost the ε-caprolactone production using cyclohexanol as substrate. Combining an alcohol dehydrogenase (ADH) with a cyclohexanone monooxygenase (CHMO) in Escherichia coli, a self-sufficient NADPH-cofactor regeneration system was obtained. Furthermore, some improved variants with the better substrate tolerance and higher catalytic ability to ε-caprolactone production were designed by regulating the ribosome binding sites. The best mutant strain exhibited an ε-caprolactone yield of 0.80 mol/mol using 60 mM cyclohexanol as substrate, while the starting strain only got a conversion of 0.38 mol/mol when 20 mM cyclohexanol was supplemented. The engineered whole-cell biocatalyst was used in four sequential batches to achieve a production of 126 mM ε-caprolactone with a high molar yield of 0.78 mol/mol.

The Six Isomers of the Cyclohexanol Dimer: A Delicate Test for Dispersion Models.

The cyclohexanol homodimer acts as a delicate test model of the role of dispersion forces in intermolecular association. Whereas phenol produces a single dimer, the suppression of π interactions and the larger conformational flexibility in cyclohexanol results in multiple isomerism, with six competing dimers of the free molecule being observed in a supersonic jet expansion. Rotational spectroscopy reveals accurate structural data, specifically the formation of homo- and heterochiral diastereoisomers and the presence of both equatorial and axial forms in the dimers. Four dispersion-corrected density-functional molecular orbital calculations were tested against the experiment, with B3LYP-D3(BJ) offering good structural reproducibility with an Alrich's triple-ζ basis set. However, the prediction of the dimer energetics is largely model-dependent, thus offering a testbed for the validation of dispersion-corrected computational models.

Transition Metal Oxodiperoxo Complex Modified Metal-Organic Frameworks as Catalysts for the Selective Oxidation of Cyclohexane.

In this work, a series of modified metal-organic frameworks (MOFs) have been prepared by pre- and post-treatment with transition metal oxodiperoxo complexes (MoO(O2)2, WO(O2)2, and KVO(O2)2). The obtained materials are characterized by XRD, FTIR, SEM, TEM, inductively coupled plasma atomic emission spectrometry (ICP-AES), and X-ray photoelectron spectroscopy (XPS), as well as by N2 adsorption/desorption measurement. The characterization results show that transition metal oxodiperoxo complexes are uniformly incorporated into the MOF materials without changing the basic structures. The performance of cyclohexane oxidation on metal oxodiperoxo complex modified MOFs are evaluated. UiO-67-KVO(O2)2 shows the best performance for cyclohexane oxidation, with 78% selectivity to KA oil (KA oil refers to a cyclohexanol and cyclohexanone mixture) at 9.4% conversion. The KA selectivity is found to depend on reaction time, while hot-filtration experiments indicates that the catalytic process is heterogeneous with no leaching of metal species.

Synthesis of Terpyridines: Simple Reactions-What Could Possibly Go Wrong?

The preparation of 24-functionalized 12,22:26,32-terpyridines (4'-functionalized 3,2:6',3''-terpyridines) by the reaction of three 4-alkoxybenzaldehydes with 3-acetylpyridine and ammonia was investigated; under identical reaction conditions, two (R = nC4H9, C2H5) gave the expected products whereas a third (R = nC3H7) gave only a cyclohexanol derivative derived from the condensation of three molecules of 3-acetylpyridine with two of 4-(n-propoxy)benzaldehyde. A comprehensive survey of ''unexpected'' products from reactions of ArCOCH3 derivatives with aromatic aldehydes is presented. Three different types of alternative product are identified.

Alkylphenol inverse agonists of HCN1 gating: H-bond propensity, ring saturation and adduct geometry differentially determine efficacy and potency.

BACKGROUND AND PURPOSE: In models of neuropathic pain, inhibition of HCN1 is anti-hyperalgesic. 2,6-di-iso-propyl phenol (propofol) and its non-anesthetic congener, 2,6-di-tert-butyl phenol, inhibit HCN1 channels by stabilizing closed state(s). EXPERIMENTAL APPROACH: Using in vitro electrophysiology and kinetic modeling, we systematically explore the contribution of ligand architecture to alkylphenol-channel coupling. KEY RESULTS: When corrected for changes in hydrophobicity (and propensity for intra-membrane partitioning), the decrease in potency upon 1-position substitution (NCO∼OH >> SH >>> F) mirrors the ligands' H-bond acceptor (NCO > OH > SH >>> F) but not donor profile (OH > SH >>> NCO∼F). H-bond elimination (OH to F) corresponds to a ΔΔG of ∼4.5 kCal mol-1 loss of potency with little or no disruption of efficacy. Substitution of compact alkyl groups (iso-propyl, tert-butyl) with shorter (ethyl, methyl) or more extended (sec-butyl) adducts disrupts both potency and efficacy. Ring saturation (with the obligate loss of both planarity and π electrons) primarily disrupts efficacy. CONCLUSIONS AND IMPLICATIONS: A hydrophobicity-independent decrement in potency at higher volumes suggests the alkylbenzene site has a volume of ≥800 Å3. Within this, a relatively static (with respect to ligand) H-bond donor contributes to initial binding with little involvement in generation of coupling energy. The influence of π electrons/ring planarity and alkyl adducts on efficacy reveals these aspects of the ligand present towards a face of the channel that undergoes structural changes during opening. The site's characteristics suggest it is "druggable"; introduction of other adducts on the ring may generate higher potency inverse agonists.

Influence of Hydronium Ions in Zeolites on Sorption.

In the presence of sufficient concentrations of water, stable, hydrated hydronium ions are formed in the pores and at the surface of solid acids such as zeolites. For a medium-pore zeolite, such as zeolite MFI, hydrated hydronium ions consist of eight water molecules and have an effective volume of 0.24 nm3 . In their presence, larger organic molecules can only adsorb in the portions of the pore that are not occupied by hydronium ions. As a consequence, the available pore volume decreases proportionally to the concentration of the hydronium ions. The higher charge density (the increasing ionic strength) that accompanies an increasing concentration of hydronium ions leads to an increase in the activity coefficients of the adsorbed substrates, thus, weakening the interactions between the organic part of the molecules and the zeolite and favoring the interactions with polar groups. The quantitative understanding of these interactions makes it possible to link a collective property such as hydrophilicity and hydrophobicity of zeolites to specific interactions on molecular level.

Determination of cyclohexanol in urine by headspace solid-phase microextraction coupled with gas chromatography / 中华劳动卫生职业病杂志

Objective@#To establish a method for determining cyclohexanol in urine by headspace solid-phase microextraction (HS/SPME) coupled with gas chromatography (GC) .@*Methods@#After the urine sample was hydrolyzed by β-glucuronidase, 2.0 g of NaCl was added, then the analyte in urine was adsorbed by a CAR/PDMS solid phase micro-extraction head in a water bath at 50 ℃ for 20 min. And the extraction head was inserted into the gas chromatograph gasification chamber to desorb, the analyte was detected after separated by the capillary through the flame ionization detector.@*Results@#The linear range of the method was 0.1-5.0 mg/L with the correlation coefficients (r) 0.999. The average recovery was 84.5%-96.3%, the inter-day precision was 3.81%-6.00%, and the detection limit was 0.03 mg/L.@*Conclusion@#The method is founded to be low detection limit, simple operation and no need of organic solvent. So it is suitable for the detection of cyclohexanol in urine of occupational exposure to cyclohexanone.

Serotonin-1A receptor dependent modulation of pain and reward for improving therapy of chronic pain.

Chronic pain conditions such as low back pain and osteoarthritis are the most prominent causes of disability worldwide. Morphine and other opioid drugs are the gold standard treatment for severe pain, including surgical pain, but the use of these drugs for chronic pain is limited largely because long term use of these drugs is associated with drug abuse and hyperalgesia which produces a negative impact on the treatment. Non-addictive treatments for chronic pain are, therefore, highly needed. Commonly used opioid drugs activate mu opioid receptors, resulting in an inhibition of tonic activity of nociceptive neurons. The rewarding effects of opioid drugs are also mediated via activation of mu opioid receptors and inhibition of GABA mediated control of the activity of dopamineregic neurons. Enhanced glutamate release and greater activity of NMDA glutamate receptors is linked to the hyperalgesic effects of opioid drugs. Evidence suggests that activation of serotonin (5-hydroxytryptamine; 5-HT)-1 A receptors modulates dopamine neurotransmission to inhibit rewarding effects of drugs of abuse. Activation of these receptors inhibits glutamate release from the sensory neurons to reduce pain transmission. To help develop strategies for improving therapeutics in chronic pain, and draw research interest in the synthesis of non-addictive opioid drugs which do not predispose to hyperalgesia, the present article concerns the potential mechanism involved in 5-HT-1 A receptor mediated inhibition of pain and reward.

Emission and combustion profile study of unmodified research engine propelled with neat biofuels.

The current work focuses on the experimental investigation to analyze the combustion and emission characteristics of a direct injection diesel engine fueled with neat biodiesel (BD100) and different proportions of cyclohexanol blends as a fuel additive in various volume fractions. Cyclohexanol is dispersed into a neat biodiesel in a volume fraction of 10, 20, and 30 vol%. The biodiesel is produced from neem oil by the conventional transesterification process. The experimental results revealed that with the increased cyclohexanol fraction, the combustion was found smooth. The addition of cyclohexanol has a positive influence on various physical and chemical properties of neat biodiesel. The in-cylinder pressure is comparatively low for diesel followed by cyclohexanol and biodiesel blends when compared with neat biodiesel. This is due to shorter ignition delay period. The heat-release rate of neat biodiesel is the highest among all fuels. The overall HC emission of BD70COH30 is 12.19% lower than BD100 and 16.34% lower than diesel. The overall CO2 emission of BD70COH30 is 13.91% higher than BD100 and 19.5% higher than diesel. The overall NOx emission of BD70COH30 is 5.31% lower than BD100 at all load engine operations. The presence of 10, 20, and 30% of cyclohexanol in biodiesel decreased smoke emissions as compared with neat biodiesel and diesel. The overall smoke emission of BD70COH30 is 19.23% lower than BD100 and 25.51% lower than diesel. The overall CO emission of cyclohexanol blended with biodiesel by 30 vol% (BD70COH30) is 17% lower than neat biodiesel and 21.8% lower than diesel. Based on the outcome of this study, neem oil biodiesel and cyclohexanol blends can be employed as a potential alternative fuel for existing unmodified diesel engines owing to its lesser emission characteristics.