Acetylcholinesterase inhibitory activity of volatile oil from Peltophorum dasyrachis Kurz ex Bakar (yellow batai) and Bisabolane-type sesquiterpenoids

Anti-Neuroinflammatory and Neuroprotective Effect of Intermedin B Isolated from the Curcuma longa L. via NF-κB and ROS Inhibition in BV2 Microglia and HT22 Hippocampal Cells

Compounds derived from Curcuma longa L. (C. longa) have been extensively studied and reported to be effective and safe for the prevention and treatment of various diseases, but most research has been focused on curcuminoids derived from C. longa. As neurodegenerative diseases are associated with oxidation and inflammation, the present study aimed to isolate and identify active compounds other than curcuminoids from C. longa to develop substances to treat these diseases. Seventeen known compounds, including curcuminoids, were chromatographically isolated from the methanol extracts of C. longa, and their chemical structures were identified using 1D and 2D NMR spectroscopy. Among the isolated compounds, intermedin B exhibited the best antioxidant effect in the hippocampus and anti-inflammatory effect in microglia. Furthermore, intermedin B was confirmed to inhibit the nuclear translocation of NF-κB p-65 and IκBα, exerting anti-inflammatory effects and inhibiting the generation of reactive oxygen species, exerting neuroprotective effects. These results highlight the research value of active components other than curcuminoids in C. longa-derived compounds and suggest that intermedin B may be a promising candidate for the prevention of neurodegenerative diseases.

An indole diketopiperazine alkaloid and a bisabolane sesquiterpenoid with unprecedented skeletons from Aspergillus fumigatus

Fumitryprostatin A (1), the first example of an indole diketopiperazine alkaloid with a tricyclic 5/6/5 skeleton characterized by a dipyrrolo[1,2-a:1',2'-d]pyrazine-5,10-dione ring system decorated with a prenylated indole moiety, and fuminoid A (2), a sesquiterpenoid with a bicyclo[3.2.1]octane ring featuring a novel carbon skeleton via the transformation of the methyl, were isolated from the fungus Aspergillus fumigatus along with six known diketopiperazine alkaloids. The structure with the absolute configuration of 1 was determined based on spectroscopic analyses and X-ray crystallographic analysis, while the configuration of 2 was assigned tentatively by ¹³C NMR data with DP4+ probability analyses and ECD calculations. A plausible biosynthetic pathway for 1 was proposed starting from L-Trp and L-Pro via normal indole diketopiperazine. Compound 1 exhibited moderate cytotoxic activity with an IC₅₀ value of 14.6 μM, while compound 8 exhibited moderate immunosuppressive activity in vitro.

Bisabolane-type sesquiterpenoids: Structural diversity and biological activity

Bisabolane-type sesquiterpenoids, a class of monocyclic sesquiterpenoids, are widely distributed in nature and have a variety of biological activities. To provide a reference for the further research and development of these compounds, the phytochemical and biological properties of natural bisabolane-type sesquiterpenoids (356 compounds in total) isolated between 1985 and 2020 from 24 families, primarily Compositae, Zingiberaceae, Aspergillaceae, Halichondriidae, and Aplysiidae were reviewed. In vitro and in vivo studies have indicated that antibacterial, anti-inflammatory, and cytotoxic effects are the most commonly reported pharmacological properties of bisabolane-type sesquiterpenoids. Owing to their extensive significant effects, a lot of traditional medicines containing this type of compounds have been used for a long history. Thus, bisabolane-type sesquiterpenoids are a rich source of important natural products, which show great potential for the development of new drugs.

Two new organic acids from Portulaca oleracea L. and their anti-inflammatory and anticholinesterase activities

Two new organic acids, identified as (7E,9E,12E)-pentadecyl-7,9,12-trienoic acid, named Oleraceacid A (1), and 6,7-dihydroxy-4-(4-hydroxy-3,5-dimethoxyphenyl)-2-naphthoic acid, named Oleraceacid B (2), were isolated from Portulaca oleracea L.. The structures were verified by spectroscopic methods, including UHPLC-ESI-QTOF/MS, 1 D and 2 D NMR. Both Oleraceacid A (1) and Oleraceacid B (2) at 20 μM inhibited the inflammatory factor, IL-1β in the RAW 264.7 cells induced by LPS, moreover, Oleraceacid A (1) can inhibit cholinesterase activity.

Antimicrobial and cytotoxic phenolic bisabolane sesquiterpenoids from the fungus Aspergillus flavipes 297

Phenolic bisabolane-type sesquiterpenoids (PBS) represent a rare class of natural products with diverse biological activities. In this study, chemical investigations of the fungus Aspergillus flavipes 297 resulted in the isolation and identification of seven PBS, including a pair of new enantiomers (+)-1a and (-)-1b, a new derivative 2, and five previously reported ones 3-7. The chemical structures of the isolated PBS were determined by extensive NMR and HRESIMS spectroscopic analysis. The absolute configurations of the separated enantiomers (+)-1a and (-)-1b were solved by comparison of the experimental ECD spectra with those of the TDDFT-ECD calculated spectra. The new compounds 1 and 2 represent rare cases of PBS bearing a methylsulfinyl group, which was distinct from the commonly-observed PBS structurally. All the isolated compounds 1-7 were evaluated their antimicrobial and cytotoxic activities. As a result, the tested compounds showed selective antimicrobial activity against several pathogenic bacteria and fungi with the MIC (minimum inhibiting concentrations) values ranging from 2 to 64 μg/mL. Moreover, enantiomers (+)-1a and (-)-1b, together with compound 2, exhibited promising cytotoxicity against MKN-45 and HepG2 cell lines, respectively, indicating that the methylsulfinyl substituent enhanced cytotoxicity to a certain degree.

Acetylcholinesterase Inhibitory Potential of Various Sesquiterpene Analogues for Alzheimer's Disease Therapy

Alzheimer's disease (AD) is a gradually growing irreversible illness of the brain that almost affects every fifth person (aged > 80 years) in the world. World Health Organization (WHO) also revealed that the prevalence of this disease will enhance (upto double) significantly upto 2030. The poor cholinergic transmission at the synapse is considered to be one of the main reasons behind the progression and occurrence of this disorder. Natural inhibitors of acetylcholine (ACh) such as galanthamine and rivastigmine are used commercially in the treatmentof AD. The biomolecules such assesquiterpenes, possess a great structural diversity and are responsible for a plethora of pharmacological properties. The potential of various sesquiterpenes as anticholinesterase has been reviewed in this article. For this purpose, the various databases, mainly PubMed, Scopus, and Web of Science were investigatedwith different keywords such as "sesquiterpenes+acetylcholinesterase" and "sesquiterpenes+cholinesterase+inhibitors" in the surveyed time frame (2010-2020). A vast literature was evident in the last decade, which affirms the potential of various sesquiterpenes in the improvement of cholinergic transmission by inhibiting the AChE. After data analysis, it was found that 12 compounds out of a total of 58 sesquiterpenes were reported to possess IC50 < 9μM and can be considered as potential candidates for the improvement of learning and memory. Sesquiterpene is an important category of terpenoids, found to possess a large spectrum of biological activities. The outcome of the review clearly states that sesquiterpenes (such as amberboin, lipidiol,etc) from herbs could offer fresh, functional compounds for possible prevention and treatment of AD.

Chemical constituents and anticholinesterase activity of the essential oil of Algerian Elaeoselinum thapsioides (Desf.) maire

Elaeoselinum thapsioides (Desf.) Maire (Apiaceae) is an Algerian medicinal plant used in traditional medicine to treat different diseases. The essential oil obtained by hydrodistillation from the aerial parts of Elaeoselinum thapsioides growing wild in Algeria, was analyzed by GC-MS for the first time. Forty-five compounds were detected, accounting for 93.8% of the total oil, which was characterized by a high content of hydrocarbons derivatives of monoterpenes (75.9%). Myrcene (61.0%) was the principal constituent of the essential oil, followed by germacrene D (10.3%), α-pinene (6.5%) and β-pinene (2.9%). In vitro anticholinesterase activity of the essential oil was investigated by the Ellman method that evidenced a low acetylcholinesterase and butyrylcholinesterase inhibitory effect.

Application of The Dess-Martin Oxidation in Total Synthesis of Natural Products

Dess-Martin periodinane (DMP), a commercially available chemical, is frequently utilized as a mild oxidative agent for the selective oxidation of primary and secondary alcohols to their corresponding aldehydes and ketones, respectively. DMP shows several merits over other common oxidative agents such as chromiumand DMSO-based oxidants; thus, it is habitually employed in the total synthesis of natural products. In this review, we try to underscore the applications of DMP as an effective oxidant in an appropriate step (steps) in the multi-step total synthesis of natural products.

Terpenes, Phenylpropanoids, Sulfur and Other Essential Oil Constituents as Inhibitors of Cholinesterases

Essential oils constituents are a diverse family of low molecular weight organic compounds with comprehensive biological activity. According to their chemical structure, these active compounds can be divided into four major groups: terpenes, terpenoids, phenylpropenes, and "others". In addition, they may contain diverse functional groups according to which they can be classified as hydrocarbons (monoterpenes, sesquiterpenes, and aliphatic hydrocarbons); oxygenated compounds (monoterpene and sesquiterpene alcohols, aldehydes, ketones, esters, and other oxygenated compounds); and sulfur and/or nitrogen containing compounds (thioesters, sulfides, isothiocyanates, nitriles, and others). Compounds that act as cholinesterase inhibitors still represent the only pharmacological treatment of Alzheimer´s disease. Numerous in vitro studies showed that some compounds, found in essential oils, have a promising cholinesterase inhibitory activity, such as α-pinene, δ-3-carene, 1,8-cineole, carvacrol, thymohydroquinone, α- and β-asarone, anethole, etc. This review summarizes the most relevant research published to date on essential oil constituents and their acetylcholinesterase/butyrylcholinesterase inhibitory potential as well as their structure related activity, synergistic and antagonistic effects.

Phytochemical and biological studies on rare and endangered plants endemic to China. Part XV. Structurally diverse diterpenoids and sesquiterpenoids from the vulnerable conifer Pseudotsuga sinensis

An extensive phytochemical investigation on the chemical constituents from the needles and twigs of the vulnerable conifer Pseudotsuga sinensis yielded 19 diterpenoids and 21 sesquiterpenoids with various carbocyclic skeletons. Among them, 13 (named pseudosinins A-M, resp.) were undescribed compounds. Their structures with absolute configurations were characterized by a combination of spectroscopic methods, calculated and experimental electronic circular dichroism (ECD) data, quantum chemical calculations of the chemical shifts, and single crystal X-ray diffraction analyses. In particular, an array of labdane-derived norditerpenoids with C₁₉-, C₁₈-, and C₁₆-skeletons, and related drimane-type sesquitepenoids with C₁₅- and C₁₃-skeletons were found in the title plant. The possible biogenetic relationships of these degraded terpenoids were briefly discussed. Among the isolates, pseudosinin D, cis-communic acid, and 4β,15-dihydroxy-19-norabieta-8,11,13-trien-7-one showed moderate inhibitory activities against the enzyme ATP-citrate lyase (ACL), a potential drug target for the treatment of hyperlipidemia and hypercholesterolemia.

Structure elucidation and NMR assignments of a new sesquiterpene of volatile oil from Artemisia frigida Willd

A new sesquiterpene, artefrigin (5), together with four known sesquiterpenes were isolated from the volatile oil of Artemisia frigida Willd. The structure of five was elucidated by spectroscopic methods, including UV, IR, HR-ESI-MS and extensive 1D and 2D NMR techniques.

Structure elucidation and antimicrobial activities of five compounds from Artemisia integrifolia L

A new compound, integracid (1), together with four known compounds were isolated from the dichloromethane (CH2Cl2) extract from Artemisia integrifolia L. The structures of compounds (1-5) were elucidated by spectroscopic methods, including ultraviolet, infrared (IR), high resolution-electrospray ionization-mass spectrometry (HR-ESI-MS) and extensive one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) techniques, and by comparison with data reported in the references. Antibacterial activities of the compounds were evaluated against various bacteria.

Bisabolane sesquiterpenes from Clausena sanki with their potential anti-inflammatory activities

The investigation on the stems and leaves of Clausena sanki led to the isolation of a previously undescribed bisabolane sesquiterpene, clausemargic A (1), together with six known analogues (2-7). The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparisons with data reported in the literature. All known compounds (2-7) were isolated from C. sanki for the first time. All isolated compounds were evaluated for their anti-inflammatory activities via examining the inhibitory activity on nitric oxide (NO) production induced by lipopolysaccharide in mouse macrophage RAW 264.7 cells in vitro. Compounds 1-7 showed significant inhibitory activities with IC₅₀ values comparable to that of hydrocortisone.

Evaluation of the Anti-Trypanosomal Activity of Vietnamese Essential Oils, with Emphasis on Curcuma longa L. and Its Components

Human African trypanosomiasis (HAT), known as sleeping sickness and caused by Trypanosoma brucei, is threatening low-income populations in sub-Saharan African countries with 61 million people at risk of infection. In order to discover new natural products against HAT, thirty-seven Vietnamese essential oils (EOs) were screened for their activity in vitro on Trypanosoma brucei brucei (Tbb) and cytotoxicity on mammalian cells (WI38, J774). Based on the selectivity indices (SIs), the more active and selective EOs were analyzed by gas chromatography. The anti-trypanosomal activity and cytotoxicity of some major compounds (isolated or commercial) were also determined. Our results showed for the first time the selective anti-trypanosomal effect of four EOs, extracted from three Zingiberaceae species (Curcuma longa, Curcuma zedoaria, and Zingiber officinale) and one Lauraceae species (Litsea cubeba) with IC₅₀ values of 3.17 ± 0.72, 2.51 ± 1.08, 3.10 ± 0.08, and 2.67 ± 1.12 nL/mL respectively and SI > 10. Identified compounds accounted for more than 85% for each of them. Among the five major components of Curcuma longa EO, curlone is the most promising anti-trypanosomal candidate with an IC₅₀ of 1.38 ± 0.45 µg/mL and SIs of 31.7 and 18.2 compared to WI38 and J774 respectively.

α-Glucosidase Inhibitors: Diphenyl Ethers and Phenolic Bisabolane Sesquiterpenoids from the Mangrove Endophytic Fungus Aspergillus flavus QQSG-3

Two new diphenyl ethers (1 and 2) and four new phenolic bisabolane sesquiterpenoids (3–6), together with five known related derivatives, were isolated from the culture of the endophytic fungus Aspergillus flavus QQSG-3 obtained from a fresh branch of Kandelia obobata, which was collected from Huizhou city in the province of Guangdong, China. The structures of compounds 1–6 were determined by analyzing NMR and HRESIMS data. The absolute configurations of 5 and 6 were assigned by comparing their experimental ECD spectra with those reported for similar compounds in the literature. All isolates were evaluated for their α-glucosidase inhibitory activity, of which compounds 3, 5, 10, and 11 showed strong inhibitory effects with IC₅₀ values in the range of 1.5–4.5 μM.

Alkyl Ethers as Traceless Hydride Donors in Brønsted Acid Catalyzed Intramolecular Hydrogen Atom Transfer

A new protocol for the deoxygenation of alcohols and the hydrogenation of alkenes under Brønsted acid catalysis has been developed. The method is based on the use of either a benzyl or isopropyl ether as a traceless hydrogen-atom donor, and involves an intramolecular hydride transfer as a key step, which is achieved in a regio- and stereoselective manner.

Phenolic bisabolane sesquiterpenoids from a Thai mangrove endophytic fungus, Aspergillus sp. xy02

Seven new phenolic bisabolane sesquiterpenoids, (7R,10S)-7,10-epoxysydonic acid (1), (7S,10S)-7,10-epoxysydonic acid (2), (7R,11S)-7,12-epoxysydonic acid (3), (7S,11S)-7,12-epoxysydonic acid (4), 7-deoxy-7,14-didehydro-12-hydroxysydonic acid (5), (Z)-7-deoxy-7,8-didehydro-12-hydroxysydonic acid (6), and (E)-7-deoxy-7,8-didehydro-12-hydroxysydonic acid (7), along with five known analogues (8-12), were obtained from the culture of an endophytic fungus Aspergillus sp. xy02 isolated from the leaves of a Thai mangrove Xylocarpus moluccensis. All structures were assigned on the basis of detailed spectroscopic analyses. The absolute configurations of 1-4, being two pairs of epimers, were established by TDDFT-ECD calculations. Compound 12 showed mild antioxidative activity to scavenge DPPH radical with an IC₅₀ of 72.1 μM, whereas 2, 3, 5, 7, 9, 11, and 12 displayed moderate inhibitory activities against Staphylococcus aureus ATCC 25923 with IC₅₀ values ranging from 31.5 to 41.9 μM.

A Stereoselective Reductive Hosomi-Sakurai Reaction

A novel reductive variant of the classical Hosomi-Sakurai reaction is reported. This transformation hinges on a redox-neutral, stereoselective internal reduction event under mild conditions. This operationally simple reaction relies on readily available starting materials and leads to useful products in diastereoselectivities of up to 7:1. The versatility of this new method is demonstrated through the stereoselective one-step synthesis of an AChE inhibitor.

Molecular Targets for Components of Essential Oils in the Insect Nervous System-A Review

Essential oils (EOs) are lipophilic secondary metabolites obtained from plants; terpenoids represent the main components of them. A lot of studies showed neurotoxic actions of EOs. In insects, they cause paralysis followed by death. This feature let us consider components of EOs as potential bioinsecticides. The inhibition of acetylcholinesterase (AChE) is the one of the most investigated mechanisms of action in EOs. However, EOs are rather weak inhibitors of AChE. Another proposed mechanism of EO action is a positive allosteric modulation of GABA receptors (GABArs). There are several papers that prove the potentiation of GABA effect on mammalian receptors induced by EOs. In contrast, there is lack of any data concerning the binding of EO components in insects GABArs. In insects, EOs act also via the octopaminergic system. Available data show that EOs can increase the level of both cAMP and calcium in nervous cells. Moreover, some EO components compete with octopamine in binding to its receptor. Electrophysiological experiments performed on Periplaneta americana have shown similarity in the action of EO components and octopamine. This suggests that EOs can modify neuron activity by octopamine receptors. A multitude of potential targets in the insect nervous system makes EO components interesting candidates for bio-insecticides.

Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae

Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically-based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type-I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co-delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1-h knockdown and the 24-h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1-h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.

Interaction of plant essential oil terpenoids with the southern cattle tick tyramine receptor: A potential biopesticide target

An outbreak of the southern cattle tick, Rhipicephalus (Boophilus) microplus, (Canestrini), in the United States would have devastating consequences on the cattle industry. Tick populations have developed resistance to current acaricides, highlighting the need to identify new biochemical targets along with new chemistry. Furthermore, acaricide resistance could further hamper control of tick populations during an outbreak. Botanically-based compounds may provide a safe alternative for efficacious control of the southern cattle tick. We have developed a heterologous expression system that stably expresses the cattle tick's tyramine receptor with a G-protein chimera, producing a system that is amenable to high-throughput screening. Screening an in-house terpenoid library, at two screening concentrations (10 μM and 100 μM), has identified four terpenoids (piperonyl alcohol, 1,4-cineole, carvacrol and isoeugenol) that we believe are positive modulators of the southern cattle tick's tyramine receptor.

Inhibitory Activities of Essential Oil Obtained from Turmeric and Its Constituents against β-Secretase

The need for a preventive agent against dementia led us to screen natural plant resources. Among the herbs and spices tested, turmeric, from rhizomes of Curcuma longa, showed high potency against β-secretase. The active principles were determined as α-turmerone, β-turmerone and ar-turmerone, with IC50 values of 39, 62 and 92 μM respectively. In this study, the efficiency of collecting the essential oil using steam distillation of the volatile substance was disclosed. The active principles were explored, and four sesquiterpenoids and five monoterpenoids were revealed as active principles against β-secretase. On the other hand, α-turmerone, β-turmerone and ar-turmerone were also investigated in a pharmacokinetic absorption experiment. After oral administration, these compounds were detected in an intact form in the brain and serum. These results suggest that consumption of turmeric constituents may prevent dementia.

Subchronic exposure to leachate activates key markers linked with neurological disorder in Wistar male rat

The linking of various environmental chemicals exposure to neurodegenerative disorders is current. This study was undertaken to elucidate the toxic effects and the underlying biochemical mechanism of leachate obtained from Elewi Odo municipal battery recycling site (EOMABRL) using key markers of neuronal damage in rat via an oral route. Analysis of the concentrations of heavy metals showed that lead, cadmium, nickel, chromium, manganese, and iron were higher than the acceptable limits set by the regulatory authority-the World Health Organization. Whereas, copper, zinc, and cobalt were lower than permissible limits. EOMABRL was administered at 0, 20, 40, 60, 80, and 100% concentrations to adult male rats for 60 days. An in vitro study was also carried out in the cerebellum to assess cholinesterase biochemistry assays. Following exposure, brain was collected to determine the antioxidant status. EOMABRL administration significantly increased superoxide dismutase (SOD) and catalase (CAT) activities, and a sequential decrease in reduced glutathione (GSH) level with a concomitant increase in the accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA) level was observed, when compared with the control. The treated rat had a significant (P < 0.05) increase in the activities of acetycholinesterase (AChE) and butyrylcholinesterase (BuChE). Taken together, these findings conclude that some possible mechanisms by which EOMABRL elicits neuronal disorder in male rat could be through the activation of AChE and BuChE and induction of oxidative stress with necrosis of neuronal cells.

Absolute Configurations and NO Inhibitory Activities of Terpenoids from Curcuma longa

Curcuma longa L., belonging to the Zingiberaceae family, is a perennial herb and has been used as a spice and a pigment in the food industry. In the ongoing search for inhibitory reagents of NO production and survey of the chemical composition of natural vegetable foods, the chemical constituents of C. longa used as spice were investigated. This investigation resulted in the isolation of 2 new terpenoids and 14 known analogues. Their structures were established on the basis of the extensive analyses of 1D and 2D NMR spectroscopic data, and the absolute configurations of 1-4 were elucidated by comparison of the calculated and experimental ECD spectra. Among them, compound 1 is a rare norditerpene with an ent-labdane skeleton, and 2 is a skeletally novel sesquiterpene having an eight-membered ring. All of the compounds were found to possess NO inhibitory activities in murine microglial BV-2 cells. The discovery of two new compounds in this chemical investigation further disclosed the chemical composition of C. longa used a food spice, and the bioassay implied that the natural food spice C. longa, containing terpenoids with NO inhibitory activities, may be potentially promotive to human health.

Antimicrobial Phenolic Bisabolanes and Related Derivatives from Penicillium aculeatum SD-321, a Deep Sea Sediment-Derived Fungus

Three new phenolic bisabolane sesquiterpenes, peniciaculins A (1) and B (2) and (7S)-(-)-10-hydroxysydonic acid (3), together with a new nor-bisabolane derivative, 1-hydroxyboivinianin A (4), as well as six known bisabolanes (5-10), were identified from the culture of Penicillium aculeatum SD-321, a fungus isolated from deep-sea sediments. The structures of these compounds were mainly determined by analysis of spectroscopic data, and the absolute configurations of compounds 1-4 were established by comparing their ECD spectra with those of known analogues or by TDDFT-ECD calculations. Compound 1 represents the first example of a bisabolane analogue linked to a diphenyl ether moiety via an ether bond, while compound 2 appears to be the first dimeric bisabolane analogue where the two monomers are coupled to each other via an ester bond. The isolated compounds were evaluated for antimicrobial activity against 10 human and aquatic pathogenic bacteria and three plant-pathogenic fungi.

Chemical composition and acetylcholinesterase inhibitory activity of Artemisia maderaspatana essential oil

CONTEXT

To date, there are no reports to validate the Indian traditional and folklore claims of Artemisia maderaspatana L. (syn. Grangea maderaspatana L.) (Asteraceae) for the treatment of Alzheimer's disease.

OBJECTIVE

The present study characterizes the volatile components (non-polar compounds) of A. maderaspatana and evaluates its acetylcholinesterase inhibition potential.

MATERIALS AND METHODS

The essential oils (yield 0.06% v/w) were obtained from fresh aerial part of A. maderaspatana. The characterization of volatile components (non-polar compounds) was performed by GC-MS data and with those of reference compounds compiled in the spectral library of in-house database. The in vitro acetylcholinesterase (AChE) inhibition of the volatile organic constituents (VOC's) of A. maderaspatana aerial part was evaluated in varying concentration ranges (0.70-44.75 µg/mL) with Ellman's method.

RESULTS

The major components were α-humulene (46.3%), β-caryophyllene (9.3%), α-copaene (8.2%), β-myrcene (4.3%), Z(E)-α-farnesene (3.7%), and calarene (3.5%). Chemical variability among other Artemisia spp. from different climatic regions of India and countries namely Iran and France was observed. The experimental results showed that diverse volatile organic constituents of A. maderaspatana have significant acetylcholinesterase inhibitory activity (an IC50 value of 31.33 ± 1.03 µg/mL). This is the first report on the inhibition of acetylcholinesterase properties of essential oil of A. maderaspatana obtained from fresh aerial part.

CONCLUSIONS

The present results indicate that essential oil of A. maderaspatana isolated from the northern region of India could inhibit AChE moderately. Therefore, the possibility of novel AChE inhibitors might exist in VOCs of this plant.

Suppression of Inflammatory cytokine production by ar-Turmerone isolated from Curcuma phaeocaulis

Rhizomes of Curcuma phaeocaulis Valeton (Zingiberaceae) have traditionally been used for controlling inflammatory conditions. Numerous studies have aimed to isolate and characterize the bioactive constituents of C. phaeocaulis. It has been reported that its anti-inflammatory properties are a result of cyclooxygenase-2 inhibition; however, its effect on the T-cell function remains to be elucidated. In this study, four known sesquiterpenoids, viz., ar-turmerone (TM), germacrone (GM), (+)-(4S,5S)-germacrone-4,5-epoxide (GE), and curzerenone (CZ), were isolated from C. phaeocaulis rhizomes and evaluated for their effects on the CD4(+) T-cell function. While GM, GE, and CZ had no effect on the activation of splenic T cells or CD4(+) T cells, TM suppressed the interferon (IFN)-γ production, without affecting the interleukin (IL)-4 expression. TM also decreased the expression of IL-2 in CD4(+) T cells, but did not change their cell-division rates upon stimulation. These results suggest that TM, a major constituent of C. phaeocaulis rhizomes selectively exerts potent anti-inflammatory effects via suppression of the inflammatory cytokines IFN-γ and IL-2.

New apoptosis-inducing sesquiterpenoids from the mycelial culture of Chinese edible fungus Pleurotus cystidiosus

Two new bisabolane-type sesquiterpenoids, pleuroton A (1) and pleuroton B (2), and three clitocybulol derivatives, clitocybulol D (3), clitocybulol E (4), and clitocybulol F (5), were obtained from the mycelial culture of edible fungus Pleurotus cystidiosus O. K. Mill by repeated column chromatography over RP-18, Sephadex LH-20, and silica gel. Their structures were determined according to nuclear magnetic resonance data, high-resolution electron impact mass spectrometry, and circular dichroism spectra. These new sesquiterpenoids exhibited significant cytotoxicity against two human prostate cancer DU-145 and C42B cells in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The median inhibitory concentration (IC50) of compounds 1, 2, 3, 4, and 5 was 174, 28, 233, 162, and 179 nM, respectively, against the DU-145 cell and was 104, 52, 163, 120, and 119 nM, respectively, against the C42B cell. Especially, pleuroton B (2) exhibited the strongest cytotoxity among these sesquiterpenoids, which was confirmed by the colony formation assay. Furthermore, pleuroton B (2) could trigger the apoptosis of DU-145 cells through the detection of apoptosis cells using annexin V-FITC staining by flow cytometry, the observation of condensed nuclei in the apoptosis cells, and the western blot analysis for the expression of apoptosis-related proteins Bcl-2, Bak, and Bax. Analysis of structure-activity relationships of these sesquiterpenoids revealed that the unusual functional moiety of pleuroton B should contribute to its significant bioactivity. These results display the pharmacological potential of P. cystidiosus.

Marsupellins A-F, ent-longipinane-type sesquiterpenoids from the Chinese liverwort Marsupella alpine with acetylcholinesterase inhibitory activity

Acetylcholinesterase (AChE) inhibitory activity-guided fractionation of the Chinese liverwort Marsupella alpine afforded six new [marsupellins A-F (1-6)] and three known (7-9) ent-longipinane-type sesquiterpenoids. The structures were determined from MS and NMR spectroscopic data, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1-9 exhibited moderate to weak AChE inhibitory activity.

Curcumin-free turmeric exhibits anti-inflammatory and anticancer activities: Identification of novel components of turmeric

Turmeric, a dried powder derived from the rhizome of Curcuma longa, has been used for centuries in certain parts of the world and has been linked to numerous biological activities including antioxidant, anti-inflammatory, anticancer, antigrowth, anti-arthritic, anti-atherosclerotic, antidepressant, anti-aging, antidiabetic, antimicrobial, wound healing, and memory-enhancing activities. One component of turmeric is curcumin, which has been extensively studied, as indicated by more than 5600 citations, most of which have appeared within the past decade. Recent research has identified numerous chemical entities from turmeric other than curcumin. It is unclear whether all of the activities ascribed to turmeric are due to curcumin or whether other compounds in turmeric can manifest these activities uniquely, additively, or synergistically with curcumin. However, studies have indicated that turmeric oil, present in turmeric, can enhance the bioavailability of curcumin. Studies over the past decade have indicated that curcumin-free turmeric (CFT) components possess numerous biological activities including anti-inflammatory, anticancer, and antidiabetic activities. Elemene derived from turmeric is approved in China for the treatment of cancer. The current review focuses on the anticancer and anti-inflammatory activities exhibited by CFT and by some individual components of turmeric, including turmerin, turmerone, elemene, furanodiene, curdione, bisacurone, cyclocurcumin, calebin A, and germacrone.

Functional food quality of Curcuma caesia, Curcuma zedoaria and Curcuma aeruginosa endemic to Northeastern India

Curcuma spp. (Zingiberaceae) is one of the significant ingredients in food and traditional medicines. The current study was to investigate health-benefits of the rhizomes of endemic Curcuma caesia, Curcuma zedoaria and Curcuma aeruginosa using in vitro antioxidant, antiinflammatory and human tumor cell proliferation inhibitory activities. Among these, C. caesia (black turmeric) showed the best overall biological activities based on [3-(4, 5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and lipid peroxidation (LPO), cyclooxygenase (COX-1 and -2) enzymes, and tumor cell growth inhibitory assays. The hexane and methanolic extracts of C. caesia (CCH and CCM) showed LPO inhibition by 31 and 43 %, and COX-2 enzyme by 29 and 38 %, respectively, at 100 μg/ml. Eleven terpenoids were isolated and identified. The MTT antioxidant assay revealed that the extracts of three Curcuma spp. at 250 μg/ml and isolates at 5 μg/ml demonstrated activity comparable to positive controls vitamin C and t-butyl hydroquinone (TBHQ) at 25 μg/ml. The extracts inhibited LPO by 40 % at 250 μg/ml whereas pure isolates 1-11 by about 20 %. The extracts and isolates inhibited COX-1 and -2 enzymes between the ranges of 3-56 and 5-30 %, respectively. The in vitro biological activity exhibited by the extracts and isolates of C. caesia rhizome further supported its use in traditional medicine.

Antibacterial bisabolane-type sesquiterpenoids from the sponge-derived fungus Aspergillus sp

Four new bisabolane-type sesquiterpenoids, aspergiterpenoid A (1), (−)-sydonol (2), (−)-sydonic acid (3), and (−)-5-(hydroxymethyl)-2-(2′,6′,6′-trimethyltetrahydro-2H- pyran-2-yl)phenol (4) together with one known fungal metabolite (5) were isolated from the fermentation broth of a marine-derived fungus Aspergillus sp., which was isolated from the sponge Xestospongia testudinaria collected from the South China Sea. Four of them (1–4) are optically active compounds. Their structures and absolute configurations were elucidated by using NMR spectroscopic techniques and mass spectrometric analysis, and by comparing their optical rotations with those related known analogues. Compounds 1–5 showed selective antibacterial activity against eight bacterial strains with the MIC (minimum inhibiting concentrations) values between 1.25 and 20.0 µM. The cytotoxic, antifouling, and acetylcholinesterase inhibitory activities of these compounds were also examined.

Antioxidant and antiacetylcholinesterase activities of some commercial essential oils and their major compounds

The commercial essential oils of Citrus aurantium L., Cupressus sempervirens L., Eucalyptus globulus Labill., Foeniculum vulgare Mill. and Thymus vulgaris L., isolated by steam distillation by a company of Morocco were evaluated in terms of in vitro antioxidant activity through several methods. In vitro acetylcholinesterase inhibitory activity was also determined. Citrus limon (L.) Burm. f. oil was also studied, but it was obtained by peel expression. The best antioxidant was T. vulgaris oil, independent of the method used, mainly due to the presence of the phenolic monoterpenes thymol and carvacrol, which when studied as single compounds also presented the best activities. Concerning the acetylcholinesterase inhibition activity, E. globulus was the most effective. Nevertheless its main components 1,8-cineole and limonene were not the most active, a feature that corresponded to δ-3-carene.

Biotransformation of turmerones by Aspergillus niger

Biotransformation studies conducted on (+)-(S)-ar-turmerone (1) and (+)-(S)-dihydro-ar-turmerone (2) by the fungus Aspergillus niger have revealed that 1 was metabolized to give four oxidized metabolites, (+)-(7S)-hydroxydehydro-ar-todomatuic acid (3), (+)-(7S,10E)-12-hydroxydehydro-ar-todomatuic acid (4), (+)-(7S,10E)-7,12-dihydroxydehydro-ar-todomatuic acid (5), and (+)-(7S)-15-carboxy-9,13-epoxy-7-hydroxy-9,13-dehydro-ar-curcumene (6), and (+)-(S)-dihydro-ar-turmerone (2) was metabolized to (+)-7,11-dihydroxy-ar-todomatuic acid (7). Metabolites 3-7 were characterized using spectroscopic techniques. Metabolites 3-7 inhibited acetylcholinesterase (AChE) although less so than the parent substrates.

Natural products as a source of Alzheimer's drug leads

This review focuses on recent developments in the use of natural products as therapeutics for Alzheimer's disease. The compounds span a diverse array of structural classes and are organized according to their mechanism of action, with the focus primarily on the major hypotheses. Overall, the review discusses more than 180 compounds and summarizes 400 references.