Isolation and identification of antiplasmodial N-alkylamides from Spilanthes acmella flowers using centrifugal partition chromatography and ESI-IT-TOF-MS

In Vitro and in Vivo Antimalarial Activity, Cytotoxicity and Phytochemical HRMS2 Profile of Plants from the Western Pará State, Brazilian Amazonia

Ethnopharmacology and botanical taxonomy are valid criteria used to selecting plants for antimalarial bioprospection purposes. Based on these two criteria, ethanol extracts of 11 plants from Santarém City vicinities, Western Pará State, Brazilian Amazonia, had their in vitro antiplasmodial activity against chloroquine-resistant Plasmodium falciparum (W2 clone) assessed by the PfLDH method, whereas their cytotoxicity to HepG2-A16 cells was assessed through MTT assay. Acmella oleracea, Siparuna krukovii and Trema micrantha extracts disclosed the highest rate of parasite growth inhibition (90 %) in screening tests. In vivo antimalarial assays were conducted with these extracts against Plasmodium berghei (NK 65 strain) infected mice. Inhibition rate of parasite multiplication ranged from 41.4 % to 60.9 % at the lowest extract dose (25 mg/kg). HPLC-ESI-HRMS2 analyses allowed the putative identification of alkylamides, fatty acids, flavonoid glycosides and alkaloids in ethanol extracts deriving from these three plant species. Results pointed towards A. oleracea flowers ethanol extract as the most promising potential candidate to preclinical studies aiming the development of antimalarial phytomedicine.

Acmella oleracea extracts as green pesticides against eight arthropods attacking stored products

Developing sustainable control tools for managing noxious pests attacking stored foodstuffs is a timely research challenge. Acmella oleracea (L.) R. K. Jansen is a crop widely cultivated for its multiple usages on an industrial level. In this study, the extracts prepared with A. oleracea aerial parts were applied on wheat kernels for the management of eight important arthropod pests attacking stored products, i.e., Cryptolestes ferrugineus, Tenebrio molitor, Oryzaephilus surinamensis, Trogoderma granarium, Tribolium castaneum, Tribolium confusum, Alphitobius diaperinus (adults/larvae), and Acarus siro (adults/nymphs). Extraction of A. oleracea was optimized on the base of the yield and content of spilanthol and other N-alkylamides which were analysed by HPLC-DAD-MS. Two concentrations of n-hexane or methanol extracts (500 ppm and 1000 ppm), obtained through Soxhlet extraction, were tested to acquire mortality data on the above-mentioned pests after 4, 8, and 16 h and 1 to 7 days of exposure. Both extracts achieved complete mortality (100.0%) of C. ferrugineus adults. In the case of A. diaperinus adults, mortalities were very low at any concentrations of both extracts. In general, the n-hexane extract was more efficient than methanol extract against almost all species and stages. Considering both extracts, the susceptibility order, from most to least susceptible species/stage, was C. ferrugineus adults > A. diaperinus larvae > C. ferrugineus larvae > T. granarium adults > T. molitor larvae > O. surinamensis adults > O. surinamensis larvae > T. confusum larvae > T. castaneum larvae > A. siro adults > T. molitor adults > A. siro nymphs > T. granarium larvae > T. castaneum adults > T. confusum adults > A. diaperinus adults. Our research provides useful knowledge on the efficacy of N-alkylamides-rich A. oleracea extracts as grain protectants, pointing out the importance of targeting the most susceptible species/ developmental stages.

Extraction, Purification, Quantification, and Stability of Bioactive Spilanthol from Acmella oleracea

Acmella oleracea is an ethnobotanically significant plant with a relatiwely high content of spilanthol. Due to its broad spectrum of activity, including anti-inflammatory, antioxidant, analgesic, antifungal, and bacteriostatic properties, it is considered a valuable bioactive natural product. In addition, spilanthol as its main bioactive component inhibits facial muscle contractions, making it an attractive ingredient in anti-wrinkle and anti-aging cosmetics. Due to its muscle paralyzing effects, it is called herbal botox. The commercial interest in spilanthol encourages the development of effective methods of isolating it from plant material. The methodology used in this paper allows for the obtaining of extracts from Acmella oleracea with a relatively high content of spilanthol. An effective method of spilanthol extraction from all aerial parts of Acmella oleracea as well as methods of enriching spilanthol concentration in extracts achieved by removing polar and acidic substances from crude extracts was developed. To quantify the concentration of spilanthol, a simple, fast and economically feasible quantification protocol that uses nuclear magnetic resonance (HNMR) was developed. In addition, it has been proven, that oxidation of spilanthol by air gives (2E,7Z)-6,9-endoperoxy-N-(2-methylpropyl)-2,7-decadienamide. The studies on spilanthol solutions stability were carried out and the conditions for the long-time storage of spilanthol solutions have also been developed. Additionally, for confirmation of obtained results a sensitive (LOQ=1 ng/mL), precise (RSD lower than 7%) and accurate (RE lower than 7.5%), new HPLC-MS/MS method was applied.

Main Bioactive Components and Their Biological Activities from Natural and Processed Rhizomes of Polygonum sibiricum

Polygonatum sibiricum (Asparagaceae) is often used as an herbal drug in the traditional medicine of Southeast Asia. Its rhizome, called “Huang Jing”, is used in traditional Chinese medicine as an immune system stimulant, hypolipidemic agent, anti-aging agent, anti-fatigue agent, and cardiovascular protectant. We investigated the antioxidant, anti-acetylcholinesterase (AChE), anti-inflammatory, and anti-α-glucosidase effects of various solvent extracts and major bioactive components of Polygonatum sibiricum (PS) and processed Polygonatum sibiricum (PPS). Dichloromethane extract of PS showed stronger antioxidant effects by DPPH, ABTS, and FRAP assays, and EtOAc extract displayed relatively high antioxidant activity by a superoxide radical scavenging test. Moreover, acetone, EtOAc, and dichloromethane extracts displayed a significant anti-α-glucosidase effect. EtOH and CH₂Cl₂ extracts showed effective AChE inhibitory activity. In addition, dichloromethane extract showed the best inhibition against lipopolysaccharide (LPS)-induced nitric oxide (NO) accumulation in RAW264.7 macrophages. HPLC analysis was used to investigate and compare the content of major active components of various solvent extracts of PS and PPS. Rutin showed the most effective scavenging of DPPH and ABTS free radicals, while scopoletin and isoquercetin displayed the strongest anti-α-glucosidase and anti-AChE effect, respectively. Rutin showed the best inhibition against LPS-induced NO production and also inhibited inducible nitric oxide synthase (iNOS) expression in Western blot. The molecular docking of AChE and iNOS revealed that active components could have a better antagonistic effect than positive controls (common inhibitors). This study shows that the active extracts and components of Polygonatum sibiricum have the potential to be further developed as a natural anti-AChE, anti-α-glucosidase, antioxidant and anti-inflammatory agent.

Comparison of Various Solvent Extracts and Major Bioactive Components from Portulaca oleracea for Antioxidant, Anti-Tyrosinase, and Anti-α-Glucosidase Activities

Portulaca oleracea is a well-known species for traditional medicine and food homology in Taiwan. In traditional medicine, P. oleracea is also used to treat gastrointestinal disorders, liver inflammation, fever, severe inflammation, and headaches. We investigated antioxidant, anti-tyrosinase, and anti-α-glucosidase activities of various solvent extracts and major bioactive components from P. oleracea. Ethanol and acetone extracts showed potent DPPH, ABTS, and hydroxyl radical scavenging activities. Chloroform and n-hexane extracts displayed significant superoxide radical scavenging activity. Furthermore, ethyl acetate and acetone extracts of P. oleracea showed potent anti-tyrosinase and anti-α-glucosidase activities. Examined and compared to the various solvent extracts for their chemical compositions using HPLC analysis, we isolated seven major compounds and analyzed their antioxidant, anti-tyrosinase, and anti-α-glucosidase activities. Seven active compounds of P. oleracea, especially quercetin, rosmarinic acid, and kaempferol, exhibited obvious antioxidant, anti-tyrosinase, and anti-α-glucosidase activities. The molecular docking model and the hydrophilic interactive mode of tyrosinase and α-glucosidase revealed that active compounds might have a higher antagonistic effect than commonly inhibitors. Our result shows that the active solvent extracts and their components of P. oleracea have the potential as natural antioxidants, tyrosinase and α-glucosidase inhibitors. Our results suggest that the active solvent extracts of P. oleracea and their components have potential as natural antioxidants, tyrosinase and α-glucosidase inhibitors.

Comparison of Various Solvent Extracts and Major Bioactive Components from Unsalt-Fried and Salt-Fried Rhizomes of Anemarrhena asphodeloides for Antioxidant, Anti-α-Glucosidase, and Anti-Acetylcholinesterase Activities

The rhizome of Anemarrhena asphodeloides Bunge (AA, family Liliaceae) is a famous and frequently used herbal drug in the traditional medicine of Northeast Asia, under vernacular name “zhimu”. A. asphodeloides has been used as an anti-inflammatory, antipyretic, anti-platelet aggregation, anti-depressant, and anti-diabetic agent in traditional Chinese medicine. We examined the antioxidant, anti-acetylcholinesterase (AChE), and anti-α-glucosidase activities of various solvent extracts and the main bioactive compounds from the rhizome of A. asphodeloides. Acetone extract exhibited comparatively high antioxidant activities by 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, and ferric-reducing antioxidant power (FRAP) assays. A water extract exhibited relatively strong antioxidant activity by superoxide radical scavenging test. Furthermore, dichloromethane, chloroform, and n-hexane extracts showed significant anti-α-glucosidase activities. Finally, ethanol and dichloromethane extracts exhibited relatively strong AChE inhibitory activity. HPLC analysis was used to examine and compare various solvent extracts for their compositions of isolates. We isolated four major chemical constituents and analyzed their antioxidant, anti-α-glucosidase, and AChE inhibitory activities. The bioactivity assays showed that mangiferin displayed the most potential antioxidant activities via FRAP, ABTS, DPPH, and superoxide assays and also exhibited the most effective anti-AChE and anti-α-glucosidase activities among all the isolates. The present study suggests that A. asphodeloides and its active extracts and components are worth further investigation and might be expected to develop as a candidate for the treatment or prevention of oxidative stress-related diseases, AChE inhibition, and hyperglycemia.

Acmella oleracea extract increases collagen content and organization in partially transected tendons

Acmella oleracea contains spilanthol as the main active compound, which possesses analgesic and anti-inflammatory effects that can favor tendon reorganization. To analyze the effect of A. oleracea on the content and organization of collagen in injured tendons, the calcaneal tendon of male Lewis rats was partially transected and treated at the site of injury with a topical application of 20% A. oleracea ointment (AO group) or with the ointment base without the plant extract (B group). The animals were euthanized 21 days after partial transection. Higher collagen concentration was observed in the AO group than in the B group, and morphological analysis using polarization microscopy showed higher birefringence in the AO group than in the B group, indicating higher collagen organization. No difference was observed in the number of fibroblasts, blood vessels, proteoglycan distribution, and maximum load between the B and AO groups. In conclusion, topical application of 20% A. oleracea ointment increased the molecular organization and content of collagen, thus indicating a potential application in tendon repair. Studies on the later phases of the tendon healing process are necessary to demonstrate the possible biomechanical changes after the application of A. oleracea ointment.

Potential Antioxidant and Anti-Inflammatory Effects of Spilanthes acmella and Its Health Beneficial Effects: A Review

Oxidative stress and inflammation are two common risk factors of various life-threatening disease pathogenesis. In recent years, medicinal plants that possess antioxidant and anti-inflammatory activities were extensively studied for their potential role in treating and preventing diseases. Spilanthes acmella (S. acmella), which has been traditionally used to treat toothache in Malaysia, contains various active metabolites responsible for its anti-inflammatory, antiseptic, and anesthetic bioactivities. These bioactivities were attributed to bioactive compounds, such as phenolic, flavonoids, and alkamides. The review focused on the summarization of in vitro and in vivo experimental reports on the antioxidant and anti-inflammatory actions of S. acmella, as well as how they contributed to potential health benefits in lowering the risk of diseases that were related to oxidative stress. The molecular mechanism of S. acmella in reducing oxidative stress and inflammatory targets, such as inducible nitric oxide synthase (iNOS), transcription factors of the nuclear factor-κB family (NF-κB), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) signaling pathways were discussed. Besides, the antioxidant potential of S. acmella was measured by total phenolic content (TPC), total flavonid content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and superoxide anion radical scavenging (SOD) and thiobarbituric acid reactive substance (TBARS) assays. This review revealed that S. acmella might have a potential role as a reservoir of bioactive agents contributing to the observed antioxidant, anti-inflammatory, and health beneficial effects.

Amine Derivative from the Aerial Part of Spilanthes acmella Murr. and their Alkaline Phosphatase Activity

Background:

Spilanthes acmella Murr. is included in Asteraceae family which is used as a traditional remedy for tooth-aches, and originated from Africa, America, Borneo, India, Sri Lanka, Bangladesh, China, Japan, Thailand, and Indonesia. The present research aims to isolate the amine derivative from the ethyl acetate layer of this plant and to evaluate the isolated compounds of alkaline phosphatase activity as a sign of bone formation.

Methods:

The air-dried plants of Spilanthes acmella Murr. were extracted with methanol, then partitioned with n-hexane and ethyl acetate successively by using liquid-liquid extraction, and then the chromatographic techniques were repeated, such as silica gel, octadecyl silylated silica gel, and HPLC. The isolated compounds were determined by spectrometric analysis using ultraviolet, infrared, high-resolution electrospray ionization mass spectrometry, 1D and 2D NMR.

Results:

Benzenepropanoic acid, 4 hydroxy-2-oxo-3 piperidinyl ester (1), was isolated from the ethyl acetate layer of the whole plants of Spilanthes acmella Murr. together with dendranthemoside A (2), uridine (3), icariside B2 (4), chicoriin (5), dendranthemoside B (6), and ampelopsisionoside (7) from their butanol layer.

Conclusion:

An amine derivative, a benzenepropanoic acid that determined as 4 hydroxy-2-oxo-3 piperidinyl ester (1) was isolated and reported for the first time from the ethyl acetate layer of Spilanthes acmella naturally. All the isolated compounds from this plant stimulated alkaline phosphatase activity as a mark of bone formation up to 128%.

Comparison of Biostimulant Treatments in Acmella oleracea Cultivation for Alkylamides Production

Acmella oleracea is a promising cosmetic, nutraceutical, and pharmaceutical ingredient, and plants with high levels of active compounds are needed in the market. Cultivation can be valuable if sufficient levels of alkylamides are present in plant material. In this regard the application of biostimulants can be an innovative approach to increase yield of cultivation or bioactive compound levels. A. oleracea plants were cultivated in Northern Italy in an experimental site using three different types of biostimulants, triacontanol-based mixture (Tria), an extract from plant tissues (LL017), and seaweed extract (Swe). Plants were grown in the field in two different growing seasons (2018 and 2019). After treatments inflorescences were harvested and the quali-quantitative analysis of alkylamides and polyphenols was performed. Treated and control plants were compared for yields, morphometric measurements, quali-quantitative composition in secondary metabolites. Overall results show that both triacontanol-based mixture and the LL017 positively influenced plant growth (Tria >+ 22%; LL017 >+ 25%) and flower production (Tria >+ 34%; LL017 >+ 56%). The amount of alkylamides and polyphenols in flowers were between 2.0–5.2% and 0.03–0.50%, respectively. Biostimulant treatments ensure higher cultivation yields and allow maintenance of the alkylamide and polyphenol levels based on % (w/w), thus offering an advantage in the final quantity of extractable chemicals. Furthermore, data revealed that samples harvested in late season show a decrease of polyphenols.

Acmella oleracea for pain management

Despite advances in medicine and numerous agents that counteract pain, millions of patients continue to suffer. Attention has been given to identify novel botanical interventions that produce analgesia by interacting with nociceptive-transducing channels. The aim of this review is to provide an overview of the actual knowledge of Acmella oleracea (L.) and its activities, particularly those that are anti-inflammatory, anti-oxidant, and painkiller. These activities are attributed to numerous bioactive compounds, such as phytosterols, phenolic compounds and N-alkylamides (spilanthol, responsible for many activities, primarily anesthetic). This review includes 99 eligible studies to consider the anti-inflammatory, anti-oxidant, and painkiller of Acmella. Studies reported in this review confirmed anti-inflammatory and anti-oxidant activities of Acmella, postulating that transcription factors of the nuclear factor-κB family (NF-κB) trigger the transcription iNOS and COX-2 and several other pro-inflammatory mediators, such as IL-6, IL-1β, and TNF-α. The antinociceptive effects has been demonstrated and have been related to different processes, including inhibition of prostaglandin synthesis, activation of opioidergic, serotoninergic and GABAergic systems, and anesthetic activity through blockage of voltage-gated Na Channels. acmella oleracea represents a promise for pain management, particularly in chronic degenerative diseases, where pain is a significant critical issue.

Identification of α-glucosidase inhibitors from Clinacanthus nutans leaf extract using liquid chromatography-mass spectrometry-based metabolomics and protein-ligand interaction with molecular docking

The present study used in vitro and in silico techniques, as well as the metabolomics approach to characterise α-glucosidase inhibitors from different fractions of Clinacanthus nutans. C. nutans is a medicinal plant belonging to the Acanthaceae family, and is traditionally used to treat diabetes in Malaysia. n-Hexane, n-hexane: ethyl acetate (1:1, v/v), ethyl acetate, ethyl acetate: methanol (1:1, v/v), and methanol fractions were obtained via partitioning of the 80% methanolic crude extract. The in vitro α-glucosidase inhibitory activity was analyzed using all the fractions collected, followed by profiling of the metabolites using liquid chromatography combined with mass spectrometry. The partial least square (PLS) statistical model was developed using the SIMCA P⁺14.0 software and the following four inhibitors were obtained: (1) 4,6,8-Megastigmatrien-3-one; (2) N-Isobutyl-2-nonen-6,8-diynamide; (3) 1′,2′-bis(acetyloxy)-3′,4′-didehydro-2′-hydro-β, ψ-carotene; and (4) 22-acetate-3-hydroxy-21-(6-methyl-2,4-octadienoate)-olean-12-en-28-oic acid. The in silico study performed via molecular docking with the crystal structure of yeast isomaltase (PDB code: 3A4A) involved a hydrogen bond and some hydrophobic interactions between the inhibitors and protein. The residues that interacted include ASN259, HID295, LYS156, ARG335, and GLY209 with a hydrogen bond, while TRP15, TYR158, VAL232, HIE280, ALA292, PRO312, LEU313, VAL313, PHE314, ARG315, TYR316, VAL319, and TRP343 with other forms of bonding.

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The antidiabetic potential of various extracts of C. nutans leaf has been evaluated.

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Multivariate data analysis identified 4 α-glucosidase inhibiting compounds.

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In silico study predicted the protein-inhibitors interaction.

Development of Validated and Stability-Indicating LC-DAD and LC-MS/MS Methods for Determination of Avanafil in Pharmaceutical Preparations and Identification of a Novel Degradation Product by LCMS-IT-TOF

Avanafil (AVA), one of the most effective drugs prescribed for erectile dysfunction, is a pyrimidine-derivative PDE5 inhibitor. In the current work, new LC methods were developed and validated for quantitative determination of avanafil and qualitative determination of its degradation products. The quantitative determination of avanafil was carried out using liquid chromatography with photodiode array detection (LC-DAD) and liquid chromatography-tandem mass spectrometry LC-MS/MS methods, and fully validated according to the ICH Q2 (R1) guideline, while qualitative determination was performed using a liquid chromatography mass spectrometry-ion trap-time of flight (LCMS-IT-TOF) instrument. The separation of avanafil and its degradation products was carried out using the same reversed-phase chromatographic conditions, in which a second-generation C₁₈-bonded monolithic silica column (Chromolith^® High Resolution RP-18e, 100 × 4.6 mm, Merck KGaA) was used as stationary phase. Briefly, the methods enable quantitation of avanafil with high accuracy (recovery > 95%) and precision (RSD% < 2.0), within the ranges of 0.5–20 μg/mL for LC-DAD and 150–6000 ng/mL for LC-MS/MS. In the forced degradation studies, over and above currently existing data, a new oxidation-based degradation product, whose predicted m/z is 367.1168, was identified and its structure was confirmed by high-resolution mass spectrometric analysis. As the main advantage, either an LC-DAD or LC-MS/MS instrument can be chosen for interference-free quantitation of AVA, according to the facilities in quality-control laboratories.

One-step isolation of carnosic acid and carnosol from rosemary by centrifugal partition chromatography

Carnosic acid and carnosol are the main bioactive components responsible for the significant antioxidant activity of Rosmarinus officinalis. Nevertheless, they are known for their instability in solutions. Separation of both compounds from crude rosemary extract was successfully achieved by one-step centrifugal partition chromatography without any degradation. A two-phase solvent system, hexane/ethyl acetate/methanol/water (3:2:3:2 v/v) was run on a preparative scale applying the elution-extrusion technique in descending mode. A 900 mg quantity of the crude extract containing 39.7% carnosic acid and 12.3% carnosol was loaded onto a 500 mL column, rotating at 1800 rpm. Carnosic acid and carnosol were obtained at purities of 96.1 ± 1% and 94.4 ± 0.9%, with recoveries of 94.3 ± 4.4% and 94.8 ± 2.3%, respectively. The compounds were identified by mass spectrometry, tandem mass spectrometry, and comparison with authentic standards.

Spilanthol from Acmella Oleracea Lowers the Intracellular Levels of cAMP Impairing NKCC2 Phosphorylation and Water Channel AQP2 Membrane Expression in Mouse Kidney

Acmella oleracea is well recognized in Brazilian traditional medicine as diuretic, although few scientific data have been published to support this effect. Aim of this study was to determine the molecular effect of Acmella oleracea extract and its main alkylamide spilanthol on two major processes involved in the urine concentrating mechanism: Na-K-2Cl symporter (NKCC2) activity in the thick ascending limb and water channel aquaporin 2 accumulation at the apical plasma membrane of collecting duct cells. Phosphorylation of NKCC2 was evaluated as index of its activation by Western blotting. Rate of aquaporin 2 apical expression was analyzed by confocal laser microscopy. Spilanthol-induced intracellular signalling events were dissected by video-imaging experiments. Exposure to spilanthol reduced the basal phosphorylation level of NKCC2 both in freshly isolated mouse kidney slices and in NKCC2-expresing HEK293 cells. In addition, exposure to spilanthol strongly reduced both desmopressin and low Cl⁻-dependent increase in NKCC2 phosphorylation in mouse kidney slices and NKCC2-expressing HEK293 cells, respectively. Similarly, spilanthol reduced both desmopressin- and forskolin-stimulated aquaporin 2 accumulation at the apical plasma membrane of collecting duct in mouse kidney slice and MCD4 cells, respectively. Of note, when orally administered, spilanthol induced a significant increase in both urine output and salt urinary excretion associated with a markedly reduced urine osmolality compared with control mice. Finally, at cellular level, spilanthol rapidly reduced or reversed basal and agonist-increased cAMP levels through a mechanism involving increases in intracellular [Ca²⁺]. In conclusion, spilanthol-induced inhibition of cAMP production negatively modulates urine-concentrating mechanisms thus holding great promise for its use as diuretic.

Fast Centrifugal Partition Chromatography Fractionation of Concentrated Agave (Agave salmiana) Sap to Obtain Saponins with Apoptotic Effect on Colon Cancer Cells

Separation of potentially bioactive components from foods and plant extracts is one of the main challenges for their study. Centrifugal partition chromatography has been a successful technique for the screening and identification of molecules with bioactive potential, such as steroidal saponins. Agave is a source of steroidal saponins with anticancer potential, though the activity of these compounds in concentrated agave sap has not been yet explored. In this study, fast centrifugal partition chromatography (FCPC) was used coupled with in vitro tests on HT-29 cells as a screening procedure to identify apoptotic saponins from an acetonic extract of concentrated agave sap. The three most bioactive fractions obtained by FCPC at partition coefficients between 0.23 and 0.4 contained steroidal saponins, predominantly magueyoside b. Flow cytometry analysis determined that the fraction rich in kammogenin and manogenin glycosides induced apoptosis, but when gentrogenin and hecogenin glycosides were also found in the fraction, a necrotic effect was observed. In conclusion, this study provides the evidence that steroidal saponins in concentrated agave sap were potential inductors of apoptosis and that it was possible to separate them using fast centrifugal partition chromatography.

Ethnopharmacological evaluation of medicinal plants used against malaria by quilombola communities from Oriximiná, Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria is the most important parasitic disease in the world, including in the Amazon region, due to its high incidence. In addition, malaria is difficult to control because of the geographical characteristics of the endemic Amazon region. The quilombola communities of Oriximina, located in remote rainforest areas, have extensive experience with medicinal plants due to their close contact with and dependence on local biodiversity as a therapeutic resource. To search for active bioproducts against malaria, based on in vitro tests using blood culture-derived parasites and plants selected by an ethno-directed approach in traditional quilombola communities of Oriximiná, in the Amazon region of Brazil.

MATERIALS AND METHODS

Ethnobotanical data were collected from 35 informants in the quilombola communities of Oriximiná, Brazil, by a free-listing method for the survey of species locally indicated to be effective against malaria and related symptoms. Data were analyzed by salience index (S) and major use agreement. The activity of extracts from 11 plants, selected based on their Salience values (four plants with S>1; seven plants with S<0.1), was measured in vitro in cultures of W2 clone Plasmodium falciparum parasites resistant to chloroquine.

RESULTS

Thirty-five ethnospecies comprising 40 different plants belonging to 23 botanical families and 37 genera were listed as antimalarials by the ethno-directed approach. Among these, 11 species selected based on their S values were assayed against P. falciparum. The most active plant extracts, with an IC50 as low as 1.6μg/mL, were obtained from Aspidosperma rigidum (Apocynaceae), Bertholletia excelsa (Lecythidaceae) and Simaba cedron (Simaroubaceae), all of which displayed an S value>1.

CONCLUSION

A strong correlation between the consensus of the informants from quilombola communities living in a malaria endemic area and the salience index indicating antiplasmodial activity was observed, where the ethnospecies mostly cited to be effective against malaria produced the most active plant extracts in vitro. It was also evident from the data that these groups approached the treatment of malaria with an holistic view, making use of purgative, depurative, emetic and adaptogen plants.

Countercurrent Separation of Natural Products: An Update

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489-1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.

The traditional use of plants to manage candidiasis and related infections in Venda, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

This paper presents results of an ethnobotanical survey of medicinal plants used for the management of candidiasis and related fungal infections in the Venda area, South Africa.

MATERIALS AND METHODS

Ethnobotanical data about the uses of plants were gathered from eleven rural traditional healers using semi-structured interviews.

RESULTS

A total of 45 species belonging to 24 different families were identified, of which the dominant family was the Fabaceae with 13 species (28.9%) followed by the Asteraceae and Solanaceae with 3 species each (6.7 %). A total of 28 of these plant species (62.2%) have been shown to have anticandidal activity and 14 species (31%) have been recorded for antifungal uses in the literature. Amongst the 45 species recorded, 51% were trees, 33% were shrubs, and 16% were herbs. The most widely used plant species were Acacia caffra, Clerodendrum glabrum, Croton gratissimus, Elaeodendron transvaalense, Faurea saligna, Hippocratea longipetiolata, Osyris lanceolata, Richardia brasiliensis, Schkuhria pinnata, Schotia brachypetala, Spilanthes acmella, Strychnos potatorum, Vangueria infausta subsp. infausta and Withania somnifera. The plant parts mostly used in the therapeutic preparations were roots (27.7%), bark (23.2%), and a combination of roots, bark (18.7%) and leaves (14.3%). Decoctions (44.4%), infusions (20%), macerations (17.7%), burning (11.4%) and paste (6.5%) were used. Most of the herbal remedies were administered orally. The main factors threatening the conservation status of these plants are unsustainable methods of harvesting, logging for firewood, building materials and crafts.

CONCLUSION

The Venda area is rich in plant diversity and local indigenous knowledge of medicinal plants can play an important role as a model for low cost primary health care. Further studies are in progress to validate the indigenous plants recorded as traditional remedies in this area.

Effect of Spilanthes acmella hydroethanolic extract activity on tumour cell actin cytoskeleton

Numerous natural products have pharmacological activity such that many biologically active compounds have led to the development of cancer chemotherapy drugs. Spilanthes acmella (Asteraceae) is widely cultivated in the State of Pará, Brazil, being employed in folk medicine for its anti-inflammatory, antimicrobial, antioxidant, analgesic, insecticide, and larvicidal properties. However, its cytotoxicity and influence on actin cytoskeleton organisation in tumour cell lines are practically nonexistent. We have verified the cytotoxicity of a hydroethanolic extract of the inflorescence of S. acmella, and examined its effects on the cytoskeleton of tumour cells. Decreasing concentrations of the extract (250, 500 and 1,000 µg/mL) were given to cultures of neoplastic cells (HEp-2). Cytotoxicity was assessed by the MTT test, and the influence on cytoskeleton organisation was examined by fluorescence microscopy. The IC50 of the hydroethanolic extract was 513 µg/mL, confirming the data obtained from the MTT assay that gave high cytotoxicity. The actin cytoskeleton arrangement of HEp2 cells at 500 and 1,000 µg/mL showed depolymerisation of the filaments, causing loss of morphology and consequently compromising cell adhesion.

An introduction to hybrid ion trap/time-of-flight mass spectrometry coupled with liquid chromatography applied to drug metabolism studies

Metabolism studies play an important role at various stages of drug discovery and development. Liquid chromatography combined with mass spectrometry (LC/MS) has become a most powerful and widely used analytical tool for identifying drug metabolites. The suitability of different types of mass spectrometers for metabolite profiling differs widely, and therefore, the data quality and reliability of the results also depend on which instrumentation is used. As one of the latest LC/MS instrumentation designs, hybrid ion trap/time-of-flight MS coupled with LC (LC-IT-TOF-MS) has successfully integrated ease of operation, compatibility with LC flow rates and data-dependent MS(n) with high mass accuracy and mass resolving power. The MS(n) and accurate mass capabilities are routinely utilized to rapidly confirm the identification of expected metabolites or to elucidate the structures of uncommon or unexpected metabolites. These features make the LC-IT-TOF-MS a very powerful analytical tool for metabolite identification. This paper begins with a brief introduction to some basic principles and main properties of a hybrid IT-TOF instrument. Then, a general workflow for metabolite profiling using LC-IT-TOF-MS, starting from sample collection and preparation to final identification of the metabolite structures, is discussed in detail. The data extraction and mining techniques to find and confirm metabolites are discussed and illustrated with some examples. This paper is directed to readers with no prior experience with LC-IT-TOF-MS and will provide a broad understanding of the development and utility of this instrument for drug metabolism studies.

Antiplasmodial Activity of the Ethnobotanical Plant Cassia fistula

In our ongoing investigation of new compounds with activity against malaria parasites, we tested the in vitro antiplasmodial activity of fractions and purified compounds from Cassia fistula L., a plant traditionally used by native populations of Tanzania, Zimbabwe, Mozambique and Brazil to treat malaria or symptoms associated with this disease. Crude extracts from leaves, bark and fruits were tested for their antiplasmodial activity against the chloroquine-sensitive strain of Plasmodium falciparum(D10), where leaf extracts showed the highest activity. The chloroform extract of the leaves was further bioassay-guided fractionated using a combination of centrifugal partition chromatography and flash column chromatography. Three main antiplasmodial principles, phytol (1) (IC50 18.9 ± 0.60 μM), lutein (2) (IC50 12.5 ± 0.35 μM), and di-lineolylgalactopyranosyl-glycerol (DLGG) (IC50 5.8 ± 0.27 μM) (3), were isolated and identified using spectroscopic methods. When the three active principles were tested for their cytotoxicity using a Chinese Hamster Ovarian (CHO) cell line, compound 3 showed very weak toxicity (IC50 75.9 ± 0.28 μM), while the other two compounds were nontoxic, even at the highest concentration tested. The study provides evidence to support the use of Cassia fistula as an antimalarial remedy and describes the antiplasmodial constituents from the leaves.

Alkamid database: Chemistry, occurrence and functionality of plant N-alkylamides

ETHNOPHARMACOLOGICAL RELEVANCE

N-Alkylamides (NAAs) are a promising group of bioactive compounds, which are anticipated to act as important lead compounds for plant protection and biocidal products, functional food, cosmeceuticals and drugs in the next decennia. These molecules, currently found in more than 25 plant families and with a wide structural diversity, exert a variety of biological-pharmacological effects and are of high ethnopharmacological importance. However, information is scattered in literature, with different, often unstandardized, pharmacological methodologies being used. Therefore, a comprehensive NAA database (acronym: Alkamid) was constructed to collect the available structural and functional NAA data, linked to their occurrence in plants (family, tribe, species, genus).

MATERIALS AND METHODS

For loading information in the database, literature data was gathered over the period 1950-2010, by using several search engines. In order to represent the collected information about NAAs, the plants in which they occur and the functionalities for which they have been examined, a relational database is constructed and implemented on a MySQL back-end.

RESULTS

The database is supported by describing the NAA plant-, functional- and chemical-space. The chemical space includes a NAA classification, according to their fatty acid and amine structures.

CONCLUSIONS

The Alkamid database (publicly available on the website http://alkamid.ugent.be/) is not only a central information point, but can also function as a useful tool to prioritize the NAA choice in the evaluation of their functionality, to perform data mining leading to quantitative structure-property relationships (QSPRs), functionality comparisons, clustering, plant biochemistry and taxonomic evaluations.

In vitro antiplasmodial activity of indole alkaloids from the stem bark of Geissospermum vellosii

ETHNOPHARMACOLOGICAL RELEVANCE

The stem bark of Geissospermum vellosii has been traditionally used by the native population of northern South America to treat malaria. Indole alkaloids have been previously isolated from this plant, but the antiplasmodial constituents have not yet been described. As part of our ongoing investigations of new bioactive compounds with activity against malaria parasites, we tested the in vitro antiplasmodial activity of isolated fractions and purified alkaloids from Geissospermum vellosii.

MATERIALS AND METHODS

Indole alkaloids were isolated and identified from a methanolic crude extract of Geissospermum vellosii bark using a combination of high performance counter current chromatography, mass spectrometry and nuclear magnetic resonance technologies. The methanolic extract, the crude alkaloid fractions and the purified compounds were tested for in vitro antiplasmodial activity against the chloroquine-sensitive strain of Plasmodium falciparum (D10).

RESULTS

An indole alkaloid (4) along with four known indole alkaloids, geissolosimine (1), geissospermine (2), geissoschizoline (3), and vellosiminol (5) were isolated and structure elucidated. The antiplasmodial activity (IC(50)) of the methanolic crude extract was 2.22 μg/mL, while for the isolated compounds it ranged from 0.96 μM to 13.96 μM except for (5) which showed a low activity (157 μM). Geissolosimine (1) showed the highest antiplasmodial activity (0.96 μM).

CONCLUSIONS

This study provides evidence to support the use of Geissospermum vellosii as an antimalarial agent, as used by the native populations. Geissolosimine (1) is a lead molecular structure for possible antimalarial drug development.

Isolation and structural elucidation of indole alkaloids from Geissospermum vellosii by mass spectrometry

Alkaloids from the stem bark of Geissospermum vellosii possess a variety of therapeutic properties including antimalarial activities, activity as a sexual stimulant and inhibition of the proliferation of HIV and herpes viruses. Methods currently used to isolate the active components from G. vellosii are time-consuming, labor intensive, and result in low recovery. In addition, there is a lack of sensitive and accurate analytical methods for the structural characterization and identification of alkaloid components in minor quantities. A combination of high performance counter-current chromatography and ESI tandem mass spectrometry (MS(n)) was established to isolate alkaloids from the stem bark of G. vellosii, and study their electrospray ionization mass spectrometry fragmentation behavior. Five indole alkaloids were successfully isolated and identified by nuclear magnetic resonance and mass spectrometry. The multi-stage tandem mass spectrometric data were used to study their fragmentation pattern and set a model for detailed structure characterization of related indole alkaloids. The presence of the even mass fragment ion suggestive of an odd number of nitrogen at m/z 144 corresponding to C(10)H(9)N was characteristic to indole alkaloids. The results of the experiments demonstrated that the combination of high performance counter current chromatography and ESI-MS(n) is a sensitive, selective and effective approach for rapid isolation and characterization of alkaloids from G. vellosii.

Liquid chromatography coupled with time-of-flight and ion trap mass spectrometry for qualitative analysis of herbal medicines

With the expansion of herbal medicine (HM) market, the issue on how to apply up-to-date analytical tools on qualitative analysis of HMs to assure their quality, safety and efficacy has been arousing great attention. Due to its inherent characteristics of accurate mass measurements and multiple stages analysis, the integrated strategy of liquid chromatography (LC) coupled with time-of-flight mass spectrometry (TOF-MS) and ion trap mass spectrometry (IT-MS) is well-suited to be performed as qualitative analysis tool in this field. The purpose of this review is to provide an overview on the potential of this integrated strategy, including the review of general features of LC-IT-MS and LC-TOF-MS, the advantages of their combination, the common procedures for structure elucidation, the potential of LC-hybrid-IT-TOF/MS and also the summary and discussion of the applications of the integrated strategy for HM qualitative analysis (2006-2011). The advantages and future developments of LC coupled with IT and TOF-MS are highlighted.