Lipoxygenase inhibition by anadanthoflavone, a new flavonoid from the aerial parts of Anadenanthera colubrina

Anadenanthera colubrina (Vell) Brenan: Ethnobotanical, phytochemical, pharmacological and toxicological aspects

ETHNOPHARMACOLOGICAL RELEVANCE

Anadenanthera colubrina (Vell.) Brenan is an endemic tree to South America and different parts of it are used by the population for the treatment of various diseases, as well as in indigenous rituals. This species has high pharmacological potential but may present toxic potential due to the presence of psychotropic compounds.

AIM OF THE STUDY

To review published studies with the species A. colubrina regarding ethnobotanical, phytochemical, pharmacological and toxicological aspects, as well as discuss perspectives for new research and protection of this species.

MATERIALS AND METHODS

A literature review was performed by accessing published articles on databases such as: PubMed, Science Direct, Scielo, Scopus, Taylor and Francis online, Springer Link, National Center for Biotechnology Information (NCBI), ACS Publications, Chemspider and Google Scholar. The keywords used were: "Anadenanthera colubrina" or "Mimosa colubrina" or "Piptadenia colubrina" or "Piptadenia macrocarpa" or "Piptadenia grata" or "Anadenanthera macrocarpa" and "medicinal plants" or "pharmacological" or "phytochemicals" or "traditional use" or "toxicological" or "ethnobotanical" or "pre-clinical trial" or "clinical". Articles found by database searches and search engines were screened at four stages: (i) title screening, (ii) locality screening, (iii) abstract screening, and (iv) full text. Other articles found through supplementary searches were screened in the full text whenever available. Each article was assessed by three reviewers at the title and abstract screening stages, except for those found in Portuguese databases that were assessed by the native reviewer.

RESULTS

This robust tree has been popularly useful for agroeconomic, medicinal and as a hallucinogen in religious rituals. According to the published studies, the main parts of the plant are the bark and seeds that are mostly used for respiratory conditions and as entheogens, respectively. It is a rich traditional herbal medicine with many pharmacological properties such as anti-inflammatory, antinociceptive, antidiarrheal, wound healing, antimicrobial, antitumoral, antioxidant, antiaddictive, insecticide and allelopathic that were described in in vitro and in vivo assays, and approximately 56 compounds were identified, suggesting a therapeutic potential for this species. Although most relate to medicinal uses, these are preliminaries and do not show the mechanism of action. The phytochemical assays showed the presence of phenolic compounds, flavonoids, triterpenes, steroids and alkaloids. Some of the compounds are anadanthoflavone, which is exclusive to this species, and no pharmacological or toxicological studies have yet demonstrated this compound. Another important compound is bufotenine which was isolated from seeds and is related to hallucinogenic and antiviral activity. The extracts made from leaves, bark, gum, and fruits appear to be safe, according to both in vivo and in vitro toxicology testing, which all shown low toxicity. Due to the presence of bufotenine in the seeds, it can be toxic, however, it was not found in toxicological assays with the seed extracts.

CONCLUSIONS

Therefore, part of the studies confirms the popular use of A. colubrina, however, more assays with isolated compounds and with the different extracts are necessary to corroborate other uses and the mechanism of action of their pharmacological effects needs to discuss in more detail. Therefore, the present review would be identified the gaps and suggests further studies oriented to validate the popular use. Thus, it must be noted that the use of this species must be controlled in order to minimize the environmental impact, as most of the pharmacological potential was shown with the bark and seeds. Due to its wide use in folk medicine, it is part of the Brazilian medicinal species with priority for conservation.

Taste and chemical composition as drives for utilitarian redundancy and equivalence: a case study in local medical systems in Northeastern Brazil

BACKGROUND

We aimed to verify whether the taste and chemical composition influence the selection of plants in each medicinal category, whether within a socio-ecological system or between different socio-ecological systems. To this end, we use the theoretical bases of the Utilitarian Redundancy Model and the Utilitarian Equivalence Model. We studied the local medical systems of four rural communities in northeastern Brazil, used as models to test our assumptions.

METHODS

The data on medicinal plants and local therapeutic function were obtained from semi-structured interviews associated with the free-listing method, allowing to generate indexes of similarity of therapeutic use between the plants cited in each region. During the interviews, each informer was also asked to report the tastes of the plants cited. Subsequently, we classified each plant in each region according to the most cited taste. The data about the chemical composition of each plant were obtained from a systematic review, using Web of Knowledge and Scopus databases.

RESULTS

Pairs of plants with similar tastes are 1.46 times more likely to have the same therapeutic function within a local medical system (redundancy), but not between medical systems (equivalence). We also find that chemical compounds are not primarily responsible for utilitarian redundancy and equivalence. However, there was a tendency for alkaloids to be doubly present with greater expressiveness in pairs of equivalent plants.

CONCLUSIONS

The results indicate that each social group can create its means of using the organoleptic characteristics as clues to select new species as medicinal. Furthermore, this study corroborates the main prediction of the Utilitarian Equivalence Model, that people in different environments choose plants with traits in common for the same functions.

Ethnopharmacology, biological activities and chemical compounds of Canarium strictum: An important resin-yielding medicinal tree in India

The resin of Canarium strictum Roxb. is used for rheumatism and asthma; the bark is used as a mosquito repellent. The major compounds in the resin are triterpenoids, but as no studies have been performed on the bark, this study investigated this economically important resource. Ten folk healers were interviewed about their medicinal uses of C. strictum. Resin and bark were extracted with dichloromethane followed by methanol using accelerated solvent extraction. The extracts were fractionated using different chromatographic methods, and isolated compounds were identified by NMR spectroscopy and GC-MS. Resin and bark extracts were investigated for DPPH radical scavenging, 15-lipoxygenase inhibition, effects on nitric oxide (NO) production in LPS-activated dendritic D2SC/I cells and toxicity against Artemia salina nauplii. Traditional healers used resin to treat colds, airway afflictions and rheumatoid arthritis. α-Amyrin and β-amyrin were identified as the major constituents in the dichloromethane resin extract. From the stem bark, procyanidins, gallic acid, methyl gallate, scopoletin, 3,3'-di-O-methylellagic acid 4-O-α-arabinofuranoside and elephantorrhizol (3,3',4',5,6,7,8-heptahydroxyflavan) were isolated and identified. By GC-MS, α-amyrin and β-amyrin and their acetates, lupeol, and taraxasterol were identified. Radical scavenging, 15-lipoxygenase inhibitory activity and inhibition of NO production was observed from resin and bark extracts, and no toxicity towards Artemia salina nauplii was found. Triterpenoids and procyanidins are the major compounds in C. strictum resin and stem bark, respectively. The high content of triterpenoids might contribute to anti-inflammatory effects and give a rationale for the widespread usage of the resin in India.

Disclosing the composition of unknown historical drug formulations: an emblematic case from the Spezieria of St. Maria della Scala in Rome

This paper reports a pioneering study of an unknown historical drug formulation preserved in the Spezieria of Santa Maria della Scala in Rome, founded at the end of the seventeenth century by the Discalced Carmelites. Due to limited literature related to pharmaceutical remedies and drugs of the Early Modern Era (between the XV and XVIII centuries) and the complexity in their formulations, the study of these drugs represents a great challenge. The untargeted nature of the selected drug required a multi-analytical approach with complementary techniques to formulate a compositional hypothesis: FT-IR spectroscopy, gas chromatography-associated/mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) were successfully employed to identify different organic compounds. Systematic archaeobotanical research was performed as well, allowing us to acquire data related to the possible genus of plants from which these natural compounds derive and their geographical origin. The unknown drug formulation turned out to be a complex mixture used as an ointment with an anti-inflammatory purpose. It mainly contains a mixture of Venetian turpentine; a Pine resin (colophony) from the Pinaceae family; an exudate of a plant from South America, whose identified components are triterpenic compounds such as alpha- and beta-amyrins, betulin and lupeol; and saturated fatty acids which act as carriers and/or to reduce the viscosity of abovementioned exudates and resins. The study of historical drugs is important not only in order to know the practices handed down by the speziali in the past but also to reconstruct historical recipes, which can inspire new dermatological, cosmetic, hygienic and current healing products.Graphical abstract.

In vitro and in vivo evaluation of anti-inflammatory activity and free radical scavenging potential of leaves extract from Anadenanthera colubrina

The present study highlights the antioxidant and anti-inflammatory activities from Anadenanthera colubrina leaves ethanolic extract (EEAc) and its phytochemical profile. The chemical profile of EEAc was determined and in vitro free radical scavenging potential, cell viability in RAW 264.7 and in vitro and in vivo anti-inflammatory activity were evaluated. The analysis of EEAc showed several phenolic compounds such as tannins and phenolic acids. The high antioxidant potential observed is possibly due to its high phenolic content. The EEAc (500 mg kg^-1) showed an in vivo effect at the same level of dexamethasone; in vitro, at 50 μg mL^-1, inhibited approximately 80% of nitric oxide production concentration, showed an inhibition of more than 50% of TNF-α production and presented high cell viability. The results show that A. colubrina leaves are an important source of phytochemicals that possesses antioxidant and anti-inflammatory properties.

Stylosin and some of its synthetic derivatives induce apoptosis in prostate cancer cells as 15-lipoxygenase enzyme inhibitors

Overexpression of 15-lipoxygenase-1 (15-LOX-1) enzyme has been reported in prostate tumors, and its expression levels are associated with the degree of cancer malignancy. The aim of this study was to investigate inhibitory effects of stylosin and some similar synthetic monoterpenoids on 15-LOX and also their cytotoxic and anti-cancer activities on prostate cancer cells. Cytotoxicity of compounds was evaluated on prostate cancer cell line "PC-3" and normal human fibroblast "HFF3" cells using AlamarBlue reduction test. The inhibitory effects of the compounds against soybean 15-LOX, a commercially available enzyme, were also assessed. Finally, mechanism of cell death was investigated by flow cytometry. Some of these terpenoids had cytotoxic effects on PC-3 cells, and strong positive correlation was observed between the 15-LOX-1 inhibition potential and the cytotoxicity of the compounds. Moreover, flow cytometry results indicated that apoptosis was the predominant mechanism of induced cell death, which emphasizes the potential of these compounds in prostate cancer therapy. Among studied terpenoids, "fenchyl ferulate" exhibited about three times more cytotoxicity than cisplatin. Strong positive correlation observed between 15-LOX inhibition potential and cytotoxicity of the compounds indicates selective anti-cancer properties of the compounds might be exerted via inhibition of 15-LOX-1 in PC-3 cells. Furthermore, observed cytotoxicity is mediated through apoptosis, which is probably triggered via 15-LOX-1 inhibition.

Bioassay-Guided Isolation of Fungistatic Compounds from Mimosa caesalpiniifolia Leaves

A bioassay-guided phytochemical study of a Mimosa caesalpiniifolia leaf extract with antifungal activity permitted the identification of 28 compounds, including the new 6-(β-boivinopyranosyl)apigenin (1), 8-(β-oliopyranosyl)apigenin (2), (E)-6-(2-carboxyethenyl)apigenin (3), (E)-8-(2-carboxyethenyl)apigenin (4), and 7,5″-anhydro-6-(α-2,6-dideoxy-5-hydroxyarabinohexopyranosyl)apigenin (5). The structures of the new compounds were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, and by mass spectrometry. Compound 3 showed promising activity and selectivity against Candida krusei (IC₅₀ 44 nM), which exhibits resistance to azoles. The association of the major components 3-β-d-glucopyranosyloxysitosterol (8) and ethyl gallate (10) was synergistic against C. krusei, especially the IC values of compound 10, which were reduced by more than 100-fold.

An Improved Scalable Synthesis of α- and β-Amyrin

The synthesis of α- and β-amyrin was accomplished starting from easily accessible starting materials, oleanolic, and ursolic acid. The procedures allow the preparation of β-amyrin in an exceptionally short scalable manner via selective iodation and reduction. For α-amyrin, a different synthetic approach had to be chosen providing access to α-amyrin in medium-to-large scale.

In vitro antioxidant, antilipoxygenase and antimicrobial activities of extracts from seven climbing plants belonging to the Bignoniaceae

OBJECTIVES

This study aimed to evaluate the in vitro antioxidant capacity, to determine the anti-inflammatory effect due to lipoxygenase inhibition and to test the antimicrobial activity of ethanolic extracts from leaves of seven climbing species belonging to the Bignoniaceae family. These species are Adenocalymma marginatum (Cham.) DC., Amphilophium vauthieri DC., Cuspidaria convoluta (Vell.) A. H. Gentry, Dolichandra dentata (K. Schum.) L. G. Lohmann, Fridericia caudigera (S. Moore) L. G. Lohmann, Fridericia chica (Bonpl.) L. G. Lohmann and Tanaecium selloi (Spreng.) L. G. Lohmann.

METHODS

The antioxidant activity was evaluated using three methods, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power. Lipoxygenase-inhibiting activity was assayed spectrophotometrically; the result was expressed as percent inhibition. The antimicrobial activity was assessed using the agar disk diffusion method. Minimal inhibitory concentration (MIC) and minimal bactericidal/fungicidal concentration were also determined for each extract against 12 pathogenic bacterial strains of Staphylococcus aureus and seven fungal strains of the Candida genus. The identification of the major compounds present in the most promising extract was established by high-performance liquid chromatography-tandem mass spectrometry.

RESULTS

C. convoluta, F. caudigera, and F. chica exhibited the best antioxidant activity by scavenging DPPH and ABTS⁺ radicals and reducing Fe³⁺ ion. These extracts showed a notable inhibition of lipoxygenase. F. caudigera was found to have the lower MIC value against S. aureus strains and six Candida species. The extracts of F. caudigera and C. convoluta were active even against methicillin-resistant S. aureus. C. convoluta had higher total phenol content, better antioxidant activity and superior anti-inflammatory and antimicrobial activity. The main phenolic compounds found in this extract were coumaric and hydroxybenzoic acid derivatives and glycosylated and nonglycosylated flavones.

CONCLUSION

Most of the extracts exhibited antioxidant activity as well as in vitro inhibition of lipoxygenase. The excellent antimicrobial activity of T. selloi and F. chica supports their use in traditional medicine as antiseptic agents. The extracts of F. caudigera and C. convoluta, both with notable biological activities in this study, could be used as herbal remedies for skin care. In addition, this study provides, for the first time, information about phenolic compounds present in C. convoluta.

Delineation of Platelet Activation Pathway of Scutellarein Revealed Its Intracellular Target as Protein Kinase C

Erigeron breviscapus has been widely used in traditional Chinese medicine (TCM) and its total flavonoid component is commonly used to treat ischemic stroke, coronary heart disease, diabetes and hypertension. Scutellarin is the major ingredient of E. breviscapus and scutellarein is one of the main bioactive metabolites of scutellarin in vivo, but the latter's pharmacological activities have not been fully characterized. Provided evidence that could inhibit platelet aggregation, the effect of scutellarein on rat washed platelets and its underlying mechanisms were evaluated in our research. Scutellarein inhibited platelet adhesion and aggregation induced by multiple G protein coupled receptor agonists such as thrombin, U46619 and ADP, in a concentration-dependent manner. Furthermore, the mild effect of scutellarein on intracellular Ca(2+) mobilization and cyclic AMP (cAMP) level was observed. On the other hand, the role of scutellarein as potential protein kinase C (PKC) inhibitor was confirmed by PKC activity analysis and molecular docking. The phorbol myristate acetate-induced platelets aggregation assay with or without ADP implied that the scutellarein takes PKC(s) as its primary target(s), and acts on it in a reversible way. Finally, scutellarein as a promising agent exhibited a high inhibition effect on ADP-induced platelet aggregation among its analogues. This study clarifies the PKC-related signaling pathway involved in antiplatelet action of scutellarein, and may be beneficial for the treatment of cardiovascular diseases.

Derivatives form better lipoxygenase inhibitors than piperine: in vitro and in silico study

Piperine is a secondary metabolite of black pepper. Its uses in medicine were already studied. However, its derivatives have not gained considerable attention. In the presented study, the Lipoxygenase (LOX) inhibitory activity of piperine and its derivatives, piperonylic acid, piperic acid, and piperonal have been assessed and compared by enzyme kinetics, ITC and molecular modeling experiments. The presented investigations expressed that all the studied compounds inhibited LOX by binding at its active site. The IC(50) values of these compounds were deduced from the kinetics data and found to be 85.79, 43.065, 45.17, and 50.78 μm for piperine, piperonylic acid, piperic acid, and piperonal, respectively. The binding free energies obtained from ITC experiments were -7.47, -8.33, -8.09, and -7.86 kcal/mol for piperine, piperonylic acid, piperic acid, and piperonal, respectively. Similarly, the glide scores obtained for piperine, piperonylic acid, piperic acid, and piperonal were -7.28, -10.32, -10.72, and -9.57 kcal/mol, respectively. The results of ITC and molecular modeling experiments suggested that piperonylic acid and piperonal exhibit stronger binding at the active site than piperine does. From the presented studies, it could be concluded that derivatives of piperine may be of higher significance than piperine for certain medicinal applications, implicating (Ayurvedic) fermented herbal drugs with piperine in them.

Anadenanthera colubrina (Vell.) Brenan produces steroidal substances that are active against Alternaria alternata (Fr.) Keissler and that may bind to oxysterol-binding proteins

BACKGROUND

In previous studies, the extract from Anadenanthera colubrina was active against Alternaria alternata in vitro and reduced the disease caused by this fungus on Murcott tangor fruits to levels that have been obtained using commercial fungicides. Therefore, the goal of the present work was to isolate and identify the active substances in this extract and identify in silico their protein target in the fungus.

RESULTS

The bioguided fractionation of the methanol extract from the fruits of A. colubrina resulted in the isolation of β-sitosterol and β-sitosteryl linoleate, which had minimal inhibitory concentrations (MICs) of 250 and 500 µg mL(-1) , respectively, against A. alternata. Under the same conditions, the MICs for two commercial fungicides were 1250 and 19 µg mL(-1) . In silico studies showed that these steroidal substances bind well to oxysterol-binding proteins from Saccharomyces cerevisiae.

CONCLUSION

β-Sitosterol and β-sitosteryl linoleate, produced by A. colubrina, are active against A. alternata. In silico studies suggest that these substances may act by binding to oxysterol-binding proteins. Therefore, both substances and these proteins have potential use in the development of new steroidal structures and analogues to control the disease caused by A. alternata.

Bioassay-guided isolation, identification and molecular ligand-target insight of lipoxygenase inhibitors from leaves of Anisomeles malabarica R.Br

Background:

Anisomeles malabarica R. Br. (Lamiaceae) is extensively used in traditional medicine in major parts of India for several medicinal purposes, including their use in rheumatism.

Materials and Methods:

The air-dried leaves of A. malabarica were extracted with ethanol, defatted with n-hexane and then successively partitioned into chloroform and n-butanol fractions. Bioassay-guided fractionation and purification of chloroform fraction from A. malabarica lead to the isolation of lipoxygenase (LOX) inhibitors. The structures of isolated compounds were elucidated by ultraviolet, infrared, ¹H nuclear magnetic resonance (NMR), ¹³C NMR and mass spectrometry spectroscopic techniques and assessed further by in vitro soybean lipoxygenase (sLOX) assay. In addition, the enzyme type inhibition was evaluated through molecular docking technique as a part of computational study.

Results:

The bioactive compounds 3, 4 dihydroxy benzoic acid (1) and 4’, 5, 7-trihydroxyflavone (2) were isolated from chloroform fraction of A. malabarica, whose bioactivity was observed to be dose-dependent compared to n-butanol fraction. Among the compounds, 3, 4 dihydroxy benzoic acid showed significant sLOX inhibitory activity with 74.04% ±2.6% followed by 4’, 5, 7-trihydroxyflavone (34.68% ±1.9%). The computational analysis of compounds showed their molecular interaction with important amino acid residues and nonheme iron atom in the catalytic site of LOX by enlightening their potential binding mode at molecular level.

Conclusions:

The LOX inhibitory constituents were identified from A. malabarica by means of bioassay-guided fractionation process. The results derived from in vitro and computational experiments confirm the potential of the isolated compounds and provide additional evidence for its traditional use in inflammatory disorders.

Cuminaldehyde as a lipoxygenase inhibitor: in vitro and in silico validation

The search for lipoxygenase (LOX) inhibitors has been carried out for decades due to its importance in inflammatory diseases. In the present study, it was observed that the methanolic extract of Cuminum cyminum L. inhibited LOX activity. Activity-guided screening of the C. cyminum crude extracts helped the identification and isolation of cuminaldehyde as a 15-LOX inhibitor. The enzyme kinetics analysis suggested cuminaldehyde to be a competitive inhibitor and the IC 50 value derived from LB plots is 1,370 μM. Binding constants of cuminaldehyde on LOX was deduced by isothermal titration calorimetry. The combined thermodynamics and molecular modeling analyses suggested cuminaldehyde as a competitive LOX inhibitor. It is proposed from the present study that the coordinate bond between the Fe(2+) atom in the active site of the enzyme and the cuminaldehyde may be responsible for the enzyme inhibition. The study suggests that cuminaldehyde may be acting as an anti-inflammatory compound and may be therefore included in the category of leads for developing dual COX-LOX inhibitors as non-steroidal anti-inflammatory drugs (NSAIDs).

Mycorrhizal technology and phosphorus in the production of primary and secondary metabolites in cebil (Anadenanthera colubrina (Vell.) Brenan) seedlings

BACKGROUND

The application of arbuscular mycorrhizal fungi (AMF) can increase the growth and concentration of primary and secondary metabolites in several plant species. Cebil (Anadenanthera colubrina), a medicinal plant, benefits from mycorrhizal association, but the influence of the symbiosis on the production of its bioactive compounds is unknown. In this study the effect of mycorrhizal inoculation and phosphorus (P) supply on the production of primary and secondary metabolites in cebil seedlings was determined.

RESULTS

The production of proteins and carbohydrates in terms of both concentration and content was enhanced by inoculation with AMF, but this benefit was mitigated at higher levels of P (30 and 50 mg dm(-3) soil). The concentration of phenols, flavonoids and total tannins was favoured by mycorrhizal inoculation even at the highest levels of P (30 and 50 mg dm(-3) soil).

CONCLUSION

The production of primary and secondary metabolites in leaves of A. colubrina can be maximised by mycorrhization, with the benefit depending on supplementation of soil phosphate.

The Heck Reaction of Protected Hydroxychromones: on route to Natural Products

The Heck reaction has been successfully extended to the bromochromones with an adjacent protected phenolic hydroxy group which offers a new methodology to various naturally occurring derivatives including tricyclic O-heterocycles. Phosphine-free coupling conditions are found to be effective. Surprisingly, the methoxymethyl protecting group is unstable in several cases but benzyl proved to be an ideal protecting group which could be selectively cleaved by boron trihalides in good yields.

Medicinal plants with bioprospecting potential used in semi-arid northeastern Brazil

OBJECTIVES

Many species of the Caatinga flora are used as medicines in local communities. In recent decades, the knowledge and use of these species has been expanding within this region. We attempted to record the local diversity of medicinal plants used to treat various diseases in a rural community in the state of Ceará, Brazil, and to evaluate the promising medicinal species for bioprospecting studies.

METHODS

An ethnobotanical survey was conducted using free list and semi-structured interviews. To indicate medicinal plants that stood out, the relative importance (RI) of species mentioned by key-informants (20), by general informants in the community (71) and by all informants (91), was analyzed. The group of species that stood out for human body systems based on the informant consensus factor (ICF) was also evaluated.

RESULTS

A total of 119 species were recorded that were associated with 92 health problems. Of these species, 100 were cited by key-informants and 86 were cited by general informants. Nineteen species showed a great versatility of use, including the following: Myracrodruon urundeuva Allemão, Bauhinia cheilanta (Bong.) Steud., Hymenaea courbaril L., Mentha x villosa Huds., Ziziphus joazeiro Mart., and Ruta graveolens L. Key-informants cited 33 exclusive species, from which nine presented greater relative importance. General informants cited 19 exclusive species, 2 with greatest relative importance. The therapeutic properties were grouped into 16 body system categories. These grouping categories included skin diseases and diseases of the subcutaneous tissue; sensory system (ears) disorders; respiratory disorders; and injuries, poisoning and other external symptoms.

CONCLUSION

The great diversity of medicinal plants used in the community is evident. Some species had both high relative importance and high consensus factors among the informants; these particular species are recommended for bioprospecting studies.

Lupeol, a novel anti-inflammatory and anti-cancer dietary triterpene

In the Western world, an average of 250 mg per day of triterpenes (member of phytosterol family), largely derived from vegetable oils, cereals, fruits and vegetables is consumed by humans. During the last decade, there has been an unprecedented escalation of interest in triterpenes due to their cholesterol-lowering properties and evidence of this phenomenon include at least 25 clinical studies, 20 patents and at least 10 major commercially triterpene-based products currently being sold all around the world. Lupeol a triterpene (also known as Fagarsterol) found in white cabbage, green pepper, strawberry, olive, mangoes and grapes was reported to possess beneficial effects as a therapeutic and preventive agent for a range of disorders. Last 15 years have seen tremendous efforts by researchers worldwide to develop this wonderful molecule for its clinical use for the treatment of variety of disorders. These studies also provide insight into the mechanism of action of Lupeol and suggest that it is a multi-target agent with immense anti-inflammatory potential targeting key molecular pathways which involve nuclear factor kappa B (NFkappaB), cFLIP, Fas, Kras, phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/beta-catenin in a variety of cells. It is noteworthy that Lupeol at its effective therapeutic doses exhibit no toxicity to normal cells and tissues. This mini review provides detailed account of preclinical studies conducted to determine the utility of Lupeol as a therapeutic and chemopreventive agent for the treatment of inflammation and cancer.

Structure-activity relationship studies of flavonoids as potent inhibitors of human platelet 12-hLO, reticulocyte 15-hLO-1, and prostate epithelial 15-hLO-2

Human lipoxygenase (hLO) isozymes have been implicated in a number of disease states and have attracted much attention with respect to their inhibition. One class of inhibitors, the flavonoids, have been shown to be potent lipoxygenase inhibitors but their study has been restricted to those compounds found in nature, which have limited structural variability. We have therefore carried out a comprehensive study to determine the structural requirements for flavonoid potency and selectivity against platelet 12-hLO, reticulocyte 15-hLO-1, and prostate epithelial 15-hLO-2. We conclude from this study that catechols are essential for high potency, that isoflavones and isoflavonones tend to select against 12-hLO, that isoflavons tend to select against 15-hLO-1, but few flavonoids target 15-hLO-2.

Free radical scavenging activity and lipoxygenase inhibition of Mahonia aquifolium extract and isoquinoline alkaloids

Roots and stem-bark of Mahonia aquifolium (Oregon grape) (Berberidaceae) are effectively used in the treatment of skin inflammatory conditions.

In the present study, the effect of Mahonia aquifolium crude extract and its two representative alkaloid fractions containing protoberberine and bisbenzylisoquinoline (BBIQ) alkaloids on activity of 12-lipoxygenase (12-LOX), was studied. The reactivity with 1,1-diphenyl-2-picryl-hydrazyl (DPPH), a free stable radical, was evaluated to elucidate the rate of possible lipid-derived radical scavenging in the mechanism of the enzyme inhibition.

The results indicate that although the direct radical scavenging mechanism cannot be ruled out in the lipoxygenase inhibition by Mahonia aquifolium and its constituents, other mechanisms based on specific interaction between enzyme and alkaloids could play the critical role in the lipoxygenase inhibition rather than non-specific reactivity with free radicals.

Antioxidant and 15-lipoxygenase inhibitory activity of rotenoids, isoflavones and phenolic glycosides from Sarcolobus globosus

From Sarcolobus globosus, two rotenoids (villosinol and 6-oxo-6a,12a-dehydrodeguelin), one isoflavone (genistin) and four phenolic glycosides (vanillic acid 4-O-beta-d-glucoside, glucosyringic acid, tachioside and isotachioside) were identified for the first time from this species. Extracts and compounds from S. globosus were evaluated for their DPPH radical scavenging and 15-lipoxygenase (15-LO) inhibitory activities. All tested rotenoids were found to inhibit 15-LO, while they lacked DPPH radical scavenging effect.

Use patterns and knowledge of medicinal species among two rural communities in Brazil's semi-arid northeastern region

The present work seeks to quantify the knowledge of two rural communities in the semi-arid region of the state of Pernambuco (northeastern Brazil) concerning two species of native medicinal plants: "aroeira do sertão", Myracrodruon urundeuva (Engl.) Fr. All. (Anacardiaceae) and "angico", Anadenanthera colubrina (Vell.) Brenan (Mimosaceae). Semi-structured interviews were carried out, combined with a checklist/inventory method, which yielded different indexes for quantifying knowledge and use of these species. In addition, the reliability of local knowledge was tested using analytical techniques to determine actual tannin concentrations. Although both communities possess knowledge concerning these two species, one of them stood out in terms of the diversity of information presented (P < 0.05), a difference that may be related to its lower degree of modernization. In general, older people had a greater variety of information about these plants, although both men and women demonstrated similar knowledge. Of the 101 people interviewed in Riachão, 85% stated that they knew of uses for both species studied; in Ameixas, of the 55 interviewees, 63% responded that they knew of uses for Myracrodruon urundeuva, and 45% knew of uses for Anadenanthera colubrina. A total of 97 different uses were reported by all informants for the two species studied. Of these, 62 were mentioned in only a single community, confirming our hypothesis of differences in knowledge between them. Informants from both communities knew of a great variety of uses for these plants as well as a number of different collection techniques. We expected that knowledge about the two species would differ in relation to both gender and age, but this was only true for one of the communities. Greater concentrations of tannins were expected to be found consistently in the tree bark, but experimental data demonstrated that tannin concentrations can vary among plant parts during the year.

Baicalein is a potent in vitro inhibitor against both reticulocyte 15-human and platelet 12-human lipoxygenases

Lipoxygenases (LO) have been implicated in asthma, immune disorders, and various cancers and as a consequence, there is great interest in isolating selective LO isozyme inhibitors. Currently, there is much use of baicalein as a selective human platelet 12-LO (12-hLO) inhibitor, however, our current steady-state inhibition data indicate that baicalein is not selective against 12-hLO versus human reticulocyte 15-LO-1 (15-hLO-1) (15/12=1.3), in vitro. However, in the presence of detergents baicalein is slightly more selective (15/12=7) as seen by the steady-state inhibition kinetics, which may imply greater selectivity in a cell-based assay but has yet to be proven. The mechanism of baicalein inhibition of 15-hLO-1 is reductive, which molecular modeling suggests is through direct binding of the catecholic moiety of baicalein to the iron. A structurally related flavonoid, apigenin, is not reductive, however, molecular modeling suggests a hydrogen bond with Thr591 may account for its inhibitor potency.