Evaluation of piper cubeba extract, (-)-cubebin and its semi-synthetic derivatives against oral pathogens

Botanicals as promising antimicrobial agents for enhancing oral health: a comprehensive review

The mouth houses the second largest diversity of microorganisms in the body, harboring more than 700 bacterial species colonizing the soft mucosa and hard tooth surfaces. Microbes are the cause of several health-related problems, such as dental carries, gingivitis, periodontitis, etc., in the mouth across different age groups and socioeconomic/demographic groups. Oral infections are major health problems that affect the standard of living. Compromised oral health is related to chronic conditions and systemic disorders. Microbes responsible for dental caries are acid-producing and aciduric Gram-positive bacteria (Streptococci, Lactobacilli). Gram-negative bacteria (Porphyromonas, Prevotella, Actinobacillus, and Fusobacterium) capable of growing in anaerobic environments are responsible for periodontal diseases. Due to the high prevalence of oral diseases, negative effects associated with the use of antimicrobial agents and increased antibiotic resistance in oral pathogens, suitable alternative methods (effective, economical and safe) to suppress microbes disturbing oral health need to be adopted. Side effects associated with the chemical antimicrobial agents are vomiting, diarrhea and tooth staining. Several researchers have studied the antimicrobial properties of plant extracts and phytochemicals and have used them as indigenous practices to control several infections. Therefore, phytochemicals extracted from plants can be suitable alternatives. This review focuses on the various phytochemical/plant extracts suppressing the growth of oral pathogens either by preventing their attachment to the surfaces or by preventing biofilm formation or other mechanisms.

Integrating serum pharmacochemistry and network pharmacology to explore potential compounds and mechanisms of Alpiniae oxyphyllae fructus in the treatment of cellular senescence in diabetic kidney disease

Background

Diabetic kidney disease (DKD), one of the microvascular complications in patients with diabetes mellitus, is a common cause of end-stage renal disease. Cellular senescence is believed to be an essential participant in the pathogenesis of DKD. Although there is evidence that Alpiniae oxyphyllae fructus (AOF) can ameliorate DKD progression and organismal senescence, its ability to ameliorate renal cellular senescence in DKD as well as active components and molecular mechanisms remain to be explored.

Purpose

This study aimed to investigate the role of AOF in the treatment of cellular senescence in DKD and to explore its active components and potential molecular mechanisms.

Methods

The pharmacological efficacy of AOF in ameliorating cellular senescence in DKD was assessed by establishing DKD mouse models and HK-2 cells under high glucose stress. UHPLC-QTOF-MS was used to screen the active compounds in AOF, which were used in conjunction with network pharmacology to predict the molecular mechanism of AOF in the treatment of cellular senescence in DKD.

Results

In vivo experiments showed that AOF reduced GLU, mAlb, Scr, BUN, MDA, SOD levels, and ameliorated renal pathological damage and renal cell senescence in DKD mice. In vitro experiments showed that AOF-containing serum improved the decline in HK-2 cell viability and alleviated cellular senescence under high glucose intervention. The results of the UHPLC-QTOF-MS screened 26 active compounds of AOF. The network pharmacological analyses revealed that Cubebin, 2',6'-dihydroxy-4'-methoxydihydrochalcone, Chalcone base + 3O,1Prenyl, Batatasin IV, and Lucidenolactone were the five core compounds and TP53, SRC, STAT3, PIK3CA, and AKT1 are the five core targets of AOF in the treatment of DKD. Molecular docking simulation results showed that the five core compounds had good binding ability to the five core targets. Western blot validated the network pharmacological prediction results and showed that AOF and AOF-containing serum down-regulate the expression of TP53, and phosphorylation of SRC, STAT3, PIK3CA, and AKT.

Conclusion

Our study shows that AOF may delay the development of cellular senescence in DKD by down-regulating the levels of TP53, and phosphorylation of SRC, STAT3, PIK3CA, and AKT.

Extraction, identification and antitumor activity in cell cultures of cubebin isolated from dry seeds Piper cubeba (Piperaceae)

The Pipercubeba, it is one spice, widely consumed in Europe, which has several bioactive molecules, between those a lignan named cubebin. Cubebin has several known biological activities, such as analgesic activity and anti-inflammatory, trypanocidal activity, leishmanicidal and antitumor activity. The objective of this study was to evaluate the antiproliferative activity "in vitro" cubebin in eight different human tumor cell lines. It was fully characterized by IR analysis, NMR, mass spectrometry, DSC, TGA, residual solvent and elemental analysis. The antitumor activity of cubebin was evaluated "in vitro" on eight different human tumor cell lineages. Cubebin showed GI50≤30μg/mL for lineage cell U251 (glioma CNS), 786-0 (kidney), PC-3 (prostate), HT-29 (colon rectum). For K562 cells (leukemia), cubebin presented GI50≤to 4.0mg/mL. For the other lineages cells, MCF-7 (breast) and NCI-H460 to cubebin can be considered inactive because of GI50>250mg/mL. Analyzing the selectivity index for cubebin, it can be observed that high selectivity of cubebin to K562 lineage cells (leukemia). Analyzing the cytotoxic potential of cubebin was observed that probably acts cubebin altering metabolism, inhibiting cell growth - a cytostatic effect, showing no cytocidal effect on any lineage cell.

A review on multi-therapeutic potential of (-)-cubebin: experimental evidences

Lignans are a large category of polyphenolic compounds that have low molecular weight and are widely distributed in the plant kingdom. They have been recognized for their potential antioxidizing and antiproliferative action. One of the most important lignans is cubebin which is abundantly isolated from the leaves and seeds of Piper cubeba and Piper nigrum. Cubebin possesses numerous biological actions such as antileukemic, trypanocidal, antimycobacterial, analgesic, anti-inflammatory, histamine antagonist, antifungal, and antispasmodic. This review discusses the in vitro and in vivo pharmacological studies on cubebin related to biochemistry and pharmacological applications and it ensures that it widely shows therapeutic potential. We expect that these therapeutic actions will set a new track in the formation of novel biological agents by the derivatization of cubebin. This review will assuredly fascinate countless researchers to begin further experimentation that might lead to novel agents for the treatment and prevention of diseases.

Cubeb (Piper cubeba L.f.): A comprehensive review of its botany, phytochemistry, traditional uses, and pharmacological properties

Piper cubeba L.f. (Piperaceae), known as cubeb, is a popular traditional herbal medicine used for the treatment of many diseases, especially digestive and respiratory disorders. The plant is rich in essential oil, found mainly in fruits, and this makes it economically important. Many traditional utilizations have been also validated from the plant and its isolated compounds owing to their antioxidant, antibacterial, anti-inflammatory and anticancer effects. These biological activities are attributed to the phytochemicals (phenolic compounds, lignans and alkaloids) and the essential oil of the plant. The present work aims to provide an up-to-date review on the traditional uses, phytochemistry and pharmacology of the plant and discusses the future perspectives to promote its valorization for nutritional- and health-promoting effects.

Plant-Derived Compounds as Promising Therapeutics for Vitiligo

Vitiligo is the most common depigmenting disorder characterized by white patches in the skin. The pathogenetic origin of vitiligo revolves around autoimmune destruction of melanocytes in which, for instance, oxidative stress is responsible for melanocyte molecular, organelle dysfunction and melanocyte specific antigen exposure as well as melanocyte cell death and thus serves as an important contributor for vitiligo progression. In recent years, natural products have shown a wide range of pharmacological bioactivities against many skin diseases, and this review focuses on the effects and mechanisms of natural compounds against vitiligo models. It is showed that some natural compounds such as flavonoids, phenols, glycosides and coumarins have a protective role in melanocytes and thereby arrest the depigmentation, and, additionally, Nrf2/HO-1, MAPK, JAK/STAT, cAMP/PKA, and Wnt/β-catenin signaling pathways were reported to be implicated in these protective effects. This review discusses the great potential of plant derived natural products as anti-vitiligo agents, as well as the future directions to explore.

Lignans from Bursera fagaroides: Chemistry, Pharmacological Effects and Molecular Mechanism. A Current Review

Bursera fagaroides is a medicinal tree endemic to México, it belongs to the Burseraceae family and has proven antitumor activity. Modern research, performed principally with the bark extracts, have indicated that lignans are the main active constituents of B. fagaroides, with a high content of aryltetralin, aryldihydronaphtalene, dibenzylbutirolactone, and dibenzylbutane-type lignans as the constituents of the active extracts. In general, lignans from B. fagaroides exhibited potent anti-cancer activity, although antitumor, anti-bacterial, anti-protozoal, anti-inflammatory, and anti-viral properties have also been described. This review covers literature-reported lignans from B. fagaroides, chemical structures, nomenclature, chromatographic techniques of isolation, characterization strategies, and highlights the anti-cancer molecular mechanisms of lignans. Evaluation of the anticancer function of lignans has been extensively investigated since the cytotoxic in vitro results and in vivo assays in mice and zebrafish models to the tubulin molecular recognition by NMR. Also, we discuss the future direction for studying this important plant species and its lignan metabolites.

Phytochemicals as modifiers of gut microbial communities

A healthy gut microbiota (GM) is paramount for a healthy lifestyle. Alterations of the GM have been involved in the aetiology of several chronic diseases, including obesity and type 2 diabetes, as well as cardiovascular and neurodegenerative diseases. In pathological conditions, the diversity of the GM is commonly reduced or altered, often toward an increased Firmicutes/Bacteroidetes ratio. The colonic fermentation of dietary fiber has shown to stimulate the fraction of bacteria purported to have beneficial health effects, acting as prebiotics, and to increase the production of short chain fatty acids, e.g. propionate and butyrate, while also improving gut epithelium integrity such as tight junction functionality. However, a variety of phytochemicals, often associated with dietary fiber, have also been proposed to modulate the GM. Many phytochemicals possess antioxidant and anti-inflammatory properties that may positively affect the GM, including polyphenols, carotenoids, phytosterols/phytostanols, lignans, alkaloids, glucosinolates and terpenes. Some polyphenols may act as prebiotics, while carotenoids have been shown to alter immunoglobulin A expression, an important factor for bacteria colonization. Other phytochemicals may interact with the mucosa, another important factor for colonization, and prevent its degradation. Certain polyphenols have shown to influence bacterial communication, interacting with quorum sensing. Finally, phytochemicals can be metabolized in the gut into bioactive constituents, e.g. equol from daidzein and enterolactone from secoisolariciresinol, while bacteria can use glycosides for energy. In this review, we strive to highlight the potential interactions between prominent phytochemicals and health benefits related to the GM, emphasizing their potential as adjuvant strategies for GM-related diseases.

In Vivo and in Silico Trypanocidal Activity Evaluation of (-)-Cubebin Encapsulated in PLGA Microspheres as Potential Treatment in Acute Phase

In this study, the trypomastigotes of a Y strain of Trypanosoma cruzi were inoculated intraperitoneally into male BALB/c mice weighing approximately 25 g each, which were divided into groups for evaluation of the trypanocidal activity. For the treatment of experimental groups, encapsulated and unencapsulated (-)-cubebin, Benznidazole, and two groups as negative controls were used. The encapsulated (-)-cubebin showed a 68.1 % encapsulation efficiency. The parasitemia peak of substances remained around the 9^th day after the observed reduction in the number of circulating trypomastigotes. The encapsulated (-)-cubebin and (-)-cubebin unloaded showed a decrease of 61.3 % and 58.5 % in the number of parasites as compared to the negative control, respectively. Moreover, animals treated with encapsulated (-)-cubebin had a higher survival time as compared to the other groups. In conclusion, the results obtained were more promising for encapsulated (-)-cubebin as compared to unloaded particles.

Hinokinin alleviates high fat diet/streptozotocin-induced cardiac injury in mice through modulation in oxidative stress, inflammation and apoptosis

Type 2 diabetes, a global health concern has been considered as major risk factor for cardiovascular diseases. Hinokinin, an emerging bioactive lignin, is reported to show wide range of pharmacological activities. However, the protective role and mechanisms of Hinokinin against type 2 diabetes-mediated cardiotoxicity are still remains unknown. An experimental type 2 diabetic mice model was created by treating animals with high fat diet for four weeks and intraperitoneal injection of streptozotocin (35 mg/kg body weight). Post-type 2 diabetic induction, animals orally treated with Hinokinin (20 or 40 mg/kg body weight) for six weeks. The type 2 diabetic mice exhibited a rise in blood glucose level as well as glycated hemoglobin (HbA1c %), decrease in weekly body weights, decrease in food intake, reduction in absolute heart weight, fall in serum insulin level with altered lipid profile and cardiac functional damage. Diabetic mice treated with Hinokinin attenuated hyperglycemia, dyslipidemia and cardiac dysfunction. In addition, Hinokinin ameliorated histological alterations, fibrosis and glycated proteins in HFD/STZ-induced mice. Type 2 diabetic condition in mice exacerbated oxidative stress, inflammatory status and apoptosis. Hinokinin treatment significantly assuaged oxidative stress, inflammation and apoptosis and elevated antioxidant defenses in diabetic heart. The underlying mechanisms for such mitigation involved the modulation of Nrf2/Keap1/ARE pathway, MAPKs (JNK, p38 and ERK 1/2) and TLR4/MyD88/NF-κB mediated inflammatory pathways and mitochondrial-dependent (intrinsic) apoptosis pathway. In conclusion, the results of this study provided clear evidence that Hinokinin protects against HFD/STZ (type 2 diabetes)-induced cardiac injury by alleviating oxidative stress, inflammation and apoptosis.

In vitro anthelmintic activity of the crude hydroalcoholic extract of Piper cubeba fruits and isolated natural products against gastrointestinal nematodes in sheep

This study describes the in vitro anthelmintic activity of a hydroalcoholic extract from the fruit of Piper cubeba and its major isolated components against the eggs and larvae of gastrointestinal nematodes obtained from naturally-infected ovines. In vitro anthelmintic activity was evaluated using the egg hatch test (EHT), larval development test (LDT) and L3 migration inhibition test (LMT). The extract showed ovicidal and larvicidal activity, with an EC₅₀ of 200 μg/mL and 83.00 μg/mL in the EHT and LDT, respectively. The extract inhibited 100% of larval migration at the lowest tested concentration (95 μg/mL). The crude extract was purified using successive silica gel chromatographic columns, which revealed the lignans hinokinin, cubebin and dihydrocubebin as the major compounds that were present, which were then used in in vitro tests. Cubebin, dihydrocubebin and hinokinin showed higher activity than the crude extract, with an EC₅₀ for ovicidal activity of 150.00 μg/mL, 186.70 μg/mL and 68.38 μg/mL, respectively. In the LDT, cubebin presented an EC₅₀ of 14.89 μg/mL and dihydrocubebin of 30.75 μg/mL. Hinokinin inhibited 100% the larval development at all concentrations evaluated. In the LMT, dihydrocubebin inhibited 100% the larval migration in all concentrations evaluated while cubebin and hinokinin showed EC₅₀ values of 0.89 μg/mL and 0.34 μg/mL, respectively. P. cubeba extract is rich in several classes of active compounds, but here we demonstrate that the described anthelmintic activity may be related to the presence of these lignans, which are present in larger concentrations than other components of the extract. Our results demonstrate for first time the anthelmintic activity against gastrointestinal nematodes in sheep for this class of special metabolites that are present in P. cubeba fruit. However, future detailed studies are needed to evaluate the effectiveness of P. cubeba fruits extract and active lignans in in vivo tests.

Wound healing evaluation of self-nanoemulsifying drug delivery system containing Piper cubeba essential oil

The objective of this work was to characterize and evaluate wound healing potential of Piper cubeba oil (PO) via self-nanoemulsifying drug delivery system (SNEDDS) in comparison with standard gentamycin. PO loaded SNEDDS was prepared by low energy emulsification technique and characterized for thermodynamic stability, self-emulsification power and various physico-chemical parameters. An optimal formula of PO SNEDDS was subjected to wound healing evaluation, collagen determination and histomorphological examination in female Wistar rats as compared with pure PO and standard antibiotic/gentamycin. An optimal formula of PO SNEDDS showed significant wound healing effects in Wistar female rats in comparison with pure PO. However, wound healing effects of optimized SNEDDS were comparable with standard gentamycin. An optimized formulation also indicated significant enhancement in collagen content (0.82 mg/g) in comparison with pure PO (0.53 mg/g) and negative control (0.33 mg/g). While, the collagen content of SNEDDS (0.82 mg/g) treated rats were comparable with standard gentamycin treated animals (0.98 mg/g). Histopathological examinations of optimized SNEDDS treated animals showed no signs of inflammatory cells which indicated that prepared SNEDDS was safe and nontoxic to rats. The results obtained in this work showed the potential application of SNEDDS in enhancement of the wound healing activity of PO upon oral administration.

Development of a Validated High-Performance Liquid Chromatography Method and Optimization of the Extraction of Lignans from Piper cubeba

Piper cubeba L. f. is a food seasoning, which contains secondary metabolites displaying several biological properties, such as cytotoxic, anti-inflammatory, and antiparasitic activities. The lignans (+)-dihydroclusin, (-)-clusin, (-)-cubebin, (-)-yatein, and (-)-haplomyrfolin were isolated, with (-)-haplomyrfolin reported for the first time in P. cubeba seeds. Chromatographic standards were used to develop a reliable reverse-phase high-performance liquid chromatography analytical method according to the Agência Nacional de Vigilância Sanitária and International Conference on Harmonization guidelines to quantitate these lignans in both P. cubeba seeds and their extracts. The extraction of the lignans was also optimized, with the best conditions being ultrasound-assisted extraction, with 84% aqueous ethanol for 38 min in a single extraction. This procedure allows for the extraction of more than 80% of the total lignans, which is better in comparison to other techniques, such as maceration and Soxhlet extraction.

An Ethnopharmacological, Phytochemical and Pharmacological Review on Lignans from Mexican Bursera spp

The genus Bursera belongs to the family Burseraceae and has been used in traditional Mexican medicine for treating various pathophysiological disorders. The most representative phytochemicals isolated from this genus are terpenoids and lignans. Lignans are phenolic metabolites known for their antioxidant, apoptotic, anti-cancer, anti-inflammatory, anti-bacterial, anti-viral, anti-fungal, and anti-protozoal properties. Though the genus includes more than 100 species, we have attempted to summarize the biological activities of the 34 lignans isolated from selected Mexican Bursera plants.

Antioxidant properties and anti-mutagenic potential of Piper Cubeba fruit extract and molecular docking of certain bioactive compounds

Spices and herbs are recognized as sources of natural antioxidants and thus play an important role in the chemoprevention of diseases and aging. Piper cubeba is one among them and known for its medicinal properties for decades. Various biological activities are associated with its extract and phytocompounds. However, the anti-mutagenic activity of antioxidant rich extract is less explored. In this study, we performed the fraction-based antioxidant activity of P. cubeba using four different assays and evaluated the anti-mutagenic activity of most potent antioxidant fraction using Salmonella typhimurium tester strains against four mutagens (methyl methanesulfonate [MMS], sodium azide [SA], benzo(a)pyrene, and 2-aminoflourene) respectively. Among all tested fractions at 25-200 µg/ml, ethanolic extract revealed highest antioxidant activity and significant anti-mutagenicity against both direct and indirect acting mutagens at least one tester strain. Phytochemical analysis by gas chromatography-mass spectrometry (GC/MS) revealed the presence of various phytocompounds including copaene, isocaryophyllene, α-cubebene, etc. Molecular docking studies on DNA binding interactions of GC/MS detected phytocompounds highlight the possible mode of binding. In summary, these in vitro studies have provided the scientific basis for validation of using this plant in the traditional system of medicine and highlighted the need for exploring the role of various compounds for therapeutic efficacy. On the other hand, synergistic interaction among phytocompounds is to be explored to optimize or standardize the extracts for the exploitation in modern phytomedicine.

In vitro schistosomicidal activity of the lignan (-)-6,6'-dinitrohinokinin (DNHK) loaded into poly(lactic-co-glycolic acid) nanoparticles against Schistosoma mansoni

CONTEXT

(-)-6,6'-Dinitrohinokinin (DNHK) display remarkable antiparasitic activity and was, therefore, incorporated into a nanoparticle formulation.

OBJECTIVE

Incorporation of DNHK in poly lactic-co-glycolic acid (PLGA) nanoparticles aiming to improve its biological activities.

MATERIALS AND METHODS

Synthesis, characterization and incorporation of DNHK into glycolic acid (PLGA) nanoparticles by nanoprecipitation method. The nanoparticles were characterized by ultraviolet-visible spectroscopy, X-ray diffraction, field emission electron microscopic scanning mansoni (FESEM), and dynamic light scattering (DLS). For the in vitro test with Schistosoma mansoni, the DNHK-loaded PLGA was diluted into the medium, and added at concentrations 10-200 µM to the culture medium containing one adult worm pair. The parasites were kept for 120 h and monitored every 24 h to evaluate their general condition, including: pairing, alterations in motor activity and mortality.

RESULTS

The loaded PLGA nanoparticles gave an encapsulation efficiency of 42.2% and showed spherical characteristics in monodisperse polymeric matrix. The adult worm pairs were separated after 120 h of incubation for concentrations higher than 50 µM of DNHK-loaded PLGA. The groups incubated with 150 and 200 µM of DNHK-loaded PLGA for 24 and 120 h killed 100% of adult worms, afforded LC50 values of 137.0 ± 2.12 µM and 79.01 ± 1.90 µM, respectively, which was similar to the effect displayed by 10 µM of praziquantel.

DISCUSSION AND CONCLUSIONS

The incorporation of DNHK-loaded showed schistosomicidal activity and allowed its sustained release. The loaded PLGA system can be administered intravenously, as well as it may be internalized by endocytosis by the target organisms.

Neuroprotective effect of Cubebin: A dibenzylbutyrolactone lignan on scopolamine-induced amnesia in mice

BACKGROUND & OBJECTIVES

Acetylcholinesterase (AChE) inhibitors represent a major class of drugs which provide symptomatic relief and improvement in cognitive function in Alzheimer's disease (AD). In this study, cubebin, a dibenzylbutyrolactone lignan, was isolated from Piper cubeba and investigated for its AChE inhibitory activity in an attempt to explore its potential for memory-enhancing activities in mice.

METHODS

Molecular docking of cubebin was carried out followed by in vitro AChE activity. Mice were treated with cubebin (25 & 50 mg/kg; i.p.), for three days and memory impairment was induced by scopolamine (3 mg/kg; i.p.). Memory function was evaluated by Morris water maze (MWM) test. Biochemical parameters of oxidative stress and cholinergic function were estimated in brain.

RESULTS

Molecular docking study revealed that cubebin was well bound within the binding site of the AChE enzyme showing interactions such as π-π stacking and hydrogen bonding with residues present therein. Cubebin inhibited AChE enzyme in an in vitro assay with IC50value of 992 μM. Scopolamine administration caused a significant impairment of learning and memory in mice, as indicated by a marked decrease in MWM performance. Scopolamine administration also produced a significant enhancement of brain AChE activity and oxidative stress in mice brain. Pre-treatment of cubebin (25 and 50 mg/kg; i.p.) significantly prevented scopolamine-induced learning and memory deficits along with attenuation of scopolamine-induced rise in brain AChE activity and oxidative stress level.

INTERPRETATION & CONCLUSIONS

Cubebin showed promising protective activity in scopolamine-induced spatial memory impairment in mice. This could be attributed to its brain AChE inhibition and antioxidant activity.

Effects of Piper cubeba L. essential oil on methicillin-resistant Staphylococcus aureus: an AFM and TEM study

The increasing prevalence of antibiotic-resistant bacteria is creating a real challenge for health care systems worldwide, making the development of novel antibiotics a necessity. In addition to the development of new antibiotics, there is an urgent need for in-depth characterization of the mechanisms of bacterial resistance toward new drugs. Here, we used essential oils extracted in our laboratory from Piper cubeba against methicillin-resistant Staphylococcus aureus ATCC 43300, one of the most prominent antibiotic-resistant bacteria. Effects of the essential oils extracted from P cubeba on bacteria were mainly evaluated using 2 powerful microscopy techniques: atomic force microscopy and transmission electron microscopy. High-resolution atomic force microscopy images of the cells were obtained close to their native environment by immobilizing the cells on porous Polyether sulfone membranes, which were prepared in our laboratory with a wide range and distribution of pore sizes and depth. Inhibition zones (mm) and minimum inhibitory concentrations were determined. Two different concentrations of the oil were used to treat the cells: 50 μg/mL minimum inhibitory concentration and 25 μg/mL. The 50 μg/mL oil solution caused severe damage to the bacterial cells at microscopic levels while the 25 μg/mL solution showed no effects compared to the control. However, at nanoscopic levels, the 25 μg/mL oil solution caused significant changes in the cell wall, which could potentially impair bacterial activities. These results were also confirmed by transmission electron microscopy micrographs. Our results indicate that the extract has a good biological activity against methicillin- and oxacillin-resistant S aureus and that it acts on the cell wall and plasma (cytoplasmic) membrane.

In vitro and in vivo anthelmintic activity of (-)-6,6'-dinitrohinokinin against schistosomula and juvenile and adult worms of Schistosoma mansoni

The chemotherapy of schistosomiasis relies on the use of praziquantel. However, concerns over drug resistance have encouraged the search for new drug leads. This paper is the first report on the in vitro and in vivo activity of (-)-6,6'-dinitrohinokinin (DNK) against Schistosoma mansoni. In vitro, the lethal concentrations for 50% of parasites (LC50) of DNK against adult worms were 103.9±3.6 and 102.5±4.8μM at 24 and 72h, respectively. Scanning electron microscopy images showed extensive tegumental alterations such as peeling and smaller numbers of tubercles in the spine of adult worms. DNK also elicited high mortality of schistosomula, with LC50 values of 57.4±2.3, 32.5±0.9, and 20.4±1.2μM at 24, 48, and 72h, respectively. DNK displayed moderate activity against the juvenile liver parasite, with an LC50 value of 179.5±2.3 μM at 72h. This compound reduced the total number of eggs by over 83%, and it affected the development of eggs produced by adult worms. The selectivity index showed that at 24h, DNK was 8.5 and 15.4 times more toxic to the adult worms and schistosomula than to Chinese hamster lung fibroblast cells, respectively. Treatment of infected mice with DNK moderately decreased worm burden (33.8-52.3%), egg production (40.7-60.0%), and spleen and liver weights. Together, our results indicated that DNK presents moderate in vitro and in vivo activities against S. mansoni, and it might therefore be interesting to explore the structure-activity relationship of the antischistosomal activity of this compound.

Cytotoxic activity of Piper cubeba extract in breast cancer cell lines

This study aimed to evaluate the cytotoxicity of a crude extract of Piper cubeba against normal and breast cancer cell lines. To prepare the extract, P. cubeba seeds were ground, soaked in methanol and dichloromethane and isolated by column chromatography. Fractions were tested for cytotoxicity effects on normal fibroblast (L929), normal breast (MCF-12A) and breast cancer cell lines (MCF-7, MDA-MB-468 and MDA-MB-231). The most effective fraction was selected for DNA fragmentation assay to detect apoptotic activity. The results showed that the methanolic crude extract had a higher cytotoxic activity against MDA-MB-468 and MCF-7 than a dichloromethane crude extract. Then, the methanolic crude extract was separated into six fractions, designated A to F. Fraction C was highly active against breast cancer cell lines with an IC50 value less than 4 μg/mL. Therefore, Fraction C was further separated into seven fractions, CA to CG. The 1H-NMR profile showed that Fraction CE was long chain hydrocarbons. Moreover, Fraction CE demonstrated the highest activity against MCF-7 cells with an IC50 value of 2.69 ± 0.09 μg/mL and lower cytotoxicity against normal fibroblast L929 cells with an IC50 value of 4.17 ± 0.77 μg/mL. Finally, DNA fragmentation with a ladder pattern characteristic of apoptosis was observed in MCF-7, MDA-MB-468, MDA-MB-231 and L929 cells, but not in MCF-12A cells.

Hinokinin, an emerging bioactive lignan

Hinokinin is a lignan isolated from several plant species that has been recently investigated in order to establish its biological activities. So far, its cytotoxicity, its anti-inflammatory and antimicrobial activities have been studied. Particularly interesting is its notable anti-trypanosomal activity.

The lignan (-)-hinokinin displays modulatory effects on human monoamine and GABA transporter activities

The neurotransmitter transporters of the SLC6 family play critical roles in the regulation of neurotransmission and are the primary targets of therapeutic agents used to treat clinical disorders involving compromised neurotransmitter signaling. The dopamine and norepinephrine transporters have been implicated in clinical disorders such as attention deficit hyperactivity disorder (ADHD) and substance abuse. The GABA transporters (GATs) serve as a target for anxiolytic, antidepressant, and antiepileptic therapies. In this work, the interaction with neurotransmitter transporters was characterized for a derivative of the lignan (-)-cubebin (1), namely, (-)-hinokinin (2). Using in vitro pharmacological assays, 2 selectively inhibited the human dopamine and norepinephrine transporters, in a noncompetitive manner possibly mediated by binding to a novel site within the transporters, and displayed low affinity for the serotonin transporter. Compound 2 also specifically inhibited the GAT-1 GABA transporter subtype. Compound 2 is not a substrate of the carriers as it had no effect on the efflux of either of the neurotransmitters investigated. This compound is inactive toward glutamate and glycine transporters. These results suggest that 2 may serve as a tool to develop new therapeutic drugs for ADHD and anxiety that target the DAT, NET, and GAT-1 transporters.

In vitro schistosomicidal effects of aqueous and dichloromethane fractions from leaves and stems of Piper species and the isolation of an active amide from P. amalago L. (Piperaceae)

Dichloromethane and aqueous fractions from leaves and stems of Piper arboreum Aubl., P. aduncum L., P. amalago L., P. crassinervium H.B. & K., P. diospyrifolium Kunth, P. hispidum Sw. and P. xylosteoides (Kunth) Steud. were tested against adult worms of Schistosoma mansoni. The in vitro activity was evaluated in terms of mortality, number of separated worms and number of worms with reduced motor activity. Most dichloromethane fractions from all Piper species showed moderate schistosomicidal activity, but aqueous fractions were not active. The dichloromethane fraction of P. amalago leaves (at 100 μg/ml) showed the highest activity, resulting in worm mortality, the separation of worm pairs and reduced motor activity. Chromatographic fractionation of the dichloromethane fraction of P. amalago leaves led to the isolation of its major compound, which was also tested against adults of S. mansoni. The isolated piperamide N-[7-(3′,4′-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl] pyrrolidine, at 100 μm, resulted in the mortality of all adult worms after 24 h of incubation. The findings suggest that species of Piper are potential sources of schistosomicidal compounds.

Enantiomeric HPLC resolution and absolute stereochemistry assignment of a new poligamain derivative

A new aryltetralin lignan derivative, 1, was obtained by reacting dimethyl succinate and piperonal, furnishing the lactone 4-(3',4'-methylenedioxybenzyl)-4,5-dihydro-2(3H)-furanone, which was reacted once again with piperonal and LDA to give the dibenzylbutirolactone 7-hydroxyhinokinin. The cyclization of 7-hydroxyhinokinin into polygamain occurred in the presence of trifluoroacetic acid. The reduction of the furanic ring of polygamain was done by its reaction with DIBAL in THF, furnishing the diol functionalized lignin derivative 1 as single diastereomer. The enantiomeric fractions of 1 were obtained by preparative enantioselective HPLC. The absolute stereochemistry was assigned by electronic circular dichroism (ECD) and nuclear magnetic resonance (NMR) spectroscopy. An all-trans relative configuration was determined by NMR on the bases of ¹H coupling constants and nuclear Overhauser effect (n.O.e.) experiments. The absolute configuration at C1 was assigned on the basis of the ECD sign at 296 nm by comparison to the ECD spectra of structural analogues with defined stereochemistry. The assignment of the absolute configuration was confirmed by applying the exciton chirality method to the well-defined ECD couplets at 285 and 200 nm allied to the two electronic transitions L(b) and B(b) of the aromatic moieties, respectively. Rac-1 and its enantiomeric isomers were evaluated against important bacteria responsible for dental caries. The best results obtained for the (1R,2S,3S) isomer were against Streptococcus mutans (250 μM), Streptococcus salivarius (250 μM), Streptococcus sobrinus (280 μM) and Streptococcus mitis (280 μM). The (1S,2R,3R) isomer was active only against Streptococcus sanguinis (280 μM). The enantiomeric mixture was less active than the (1R,2S,3S) isomer.

Mutagenicity and antimutagenicity of (-)-hinokinin a trypanosomicidal compound measured by Salmonella microsome and comet assays

Background

The dibenzylbutyrolactone lignan (−)-hinokinin (HK) was derived by partial synthesis from (−)-cubebin, isolated from the dry seeds of the pepper, Piper cubeba. Considering the good trypanosomicidal activity of HK and recalling that natural products are promising starting points for the discovery of novel potentially therapeutic agents, the aim of the present study was to investigate the (anti) mutagenic∕ genotoxic activities of HK.

Methods

The mutagenic∕ genotoxic activities were evaluated by the Ames test on Salmonella typhimurium strains TA98, TA97a, TA100 and TA102, and the comet assay, so as to assess the safe use of HK in the treatment of Chagas’ disease. The antimutagenic ∕antigenotoxic potential of HK were also tested against the mutagenicity of a variety of direct and indirect acting mutagens, such as 4- nitro-o-phenylenediamine (NOPD), sodium azide (SA), mitomycin C (MMC), benzo[a]pyrene (B[a]P), aflatoxin B₁ (AFB₁), 2-aminoanthracene (2-AA) and 2-aminofluorene (2-AF), by the Ames test, and doxorubicin (DXR) by the comet assay.

Results

The mutagenicity∕genotoxicity tests showed that HK did not induce any increase in the number of revertants or extent of DNA damage, demonstrating the absence of mutagenic and genotoxic activities. On the other hand, the results on the antimutagenic potential of HK showed a strong inhibitory effect against some direct and indirect-acting mutagens.

Conclusions

Regarding the use of HK as an antichagasic drug, the absence of mutagenic effects in animal cell and bacterial systems is encouraging. In addition, HK may be a new potential antigenotoxic ∕ antimutagenic agent from natural sources. However, the protective activity of HK is not general and varies with the type of DNA damage-inducing agent used.

Antiprotozoal and Antimycobacterial Activities of Pure Compounds from Aristolochia elegans Rhizomes

We analyzed the antimycobacterial activity of the hexane extract of rhizomes from Aristolochia elegans. Some compounds of this extract were purified and tested against a group of drug-resistant Mycobacterium tuberculosis strains. We also evaluated their antiprotozoal activities. The hexane extract was active against M. tuberculosis H37Rv at a MIC = 100 μg mL(-1); the pure compounds eupomatenoid-1, fargesin, and (8R,8'R,9R)-cubebin were active against M. tuberculosis H37Rv (MIC = 50 μg mL(-1)), while fargesin presented activity against three monoresistant strains of M. tuberculosis H37Rv and a MDR clinical isolate of M. tuberculosis (MIC < 50 μg mL(-1)). Both the extract and eupomatenoid-1 were very active against E. histolytica and G. lamblia (IC(50) < 0.624 μg mL(-1)); in contrast, fargesin and (8R,8'R,9R)-cubebin were moderately active (IC(50) < 275 μg mL(-1)). In this context, two compounds responsible for the antimycobacterial presented by A. elegans are fargesin and cubebin, although others may exert this activity also. In addition to the antimycobacterial activity, the hexane extract has important activity against E. histolytica and G. lamblia, and eupomatenoid-1 is one of the compounds responsible for the antiparasite activity.

Screening of immunomodulatory activity of total and protein extracts of some Moroccan medicinal plants

Herbal and traditional medicines are being widely used in practice in many countries for their benefits of treating different ailments. A large number of plants in Morocco were used in folk medicine to treat immune-related disorders. The objective of this study is to evaluate the immunomodulatory activity of protein extracts (PEs) of 14 Moroccan medicinal plants. This activity was tested on the proliferation of immune cells. The prepared total and PEs of the plant samples were tested using MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide) assay on the splenocytes with or without stimulation by concanavalin-A (Con-A), a mitogenic agent used as positive control. The results of this study indicated different activity spectra. Three groups of activities were observed. The first group represented by Citrullus colocynthis, Urtica dioica, Elettaria cardamomum, Capparis spinosa and Piper cubeba showed a significant immunosuppressive activity. The second group that showed a significant immunostimulatory activity was represented by Aristolochia longa, Datura stramonium, Marrubium vulgare, Sinapis nigra, Delphynium staphysagria, Lepidium sativum, Ammi visnaga and Tetraclinis articulata. The rest of the plant extracts did not alter the proliferation induced by Con-A. This result was more important for the PE than for the total extract. In conclusion, this study revealed an interesting immunomodulating action of certain PEs, which could explain their traditional use. The results of this study may also have implications in therapeutic treatment of infections, such as prophylactic and adjuvant with cancer chemotherapy.

Plant polyphenols and their anti-cariogenic properties: a review

Polyphenols constitute one of the most common groups of substances in plants. Polyphenolic compounds have been reported to have a wide range of biological activities, many of which are related to their conventional antioxidant action; however, increasing scientific knowledge has highlighted their potential activity in preventing oral disease, including the prevention of tooth decay. The aim of this review is to show the emerging findings on the anti-cariogenic properties of polyphenols, which have been obtained from several in vitro studies investigating the effects of these bioactive molecules against Streptococcus mutans, as well as in vivo studies. The analysis of the literature supports the anti-bacterial role of polyphenols on cariogenic streptococci, suggesting (1) a direct effect against S. mutans; (2) an interaction with microbial membrane proteins inhibiting the adherence of bacterial cells to the tooth surface; and (3) the inhibition of glucosyl transferase and amylase. However, more studies, particularly in vivo and in situ, are necessary to establish conclusive evidence for the effectiveness and the clinical applications of these compounds in the prevention of dental caries. It is essential to better determine the nature and distribution of these compounds in our diet and to identify which of the hundreds of existing polyphenols are likely to provide the greatest effects.

Traditional Medicinal Plant Extracts and Natural Products with Activity against Oral Bacteria: Potential Application in the Prevention and Treatment of Oral Diseases

Oral diseases are major health problems with dental caries and periodontal diseases among the most important preventable global infectious diseases. Oral health influences the general quality of life and poor oral health is linked to chronic conditions and systemic diseases. The association between oral diseases and the oral microbiota is well established. Of the more than 750 species of bacteria that inhabit the oral cavity, a number are implicated in oral diseases. The development of dental caries involves acidogenic and aciduric Gram-positive bacteria (mutans streptococci, lactobacilli and actinomycetes). Periodontal diseases have been linked to anaerobic Gram-negative bacteria (Porphyromonas gingivalis, Actinobacillus, Prevotella and Fusobacterium). Given the incidence of oral disease, increased resistance by bacteria to antibiotics, adverse affects of some antibacterial agents currently used in dentistry and financial considerations in developing countries, there is a need for alternative prevention and treatment options that are safe, effective and economical. While several agents are commercially available, these chemicals can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining. Hence, the search for alternative products continues and natural phytochemicals isolated from plants used as traditional medicines are considered as good alternatives. In this review, plant extracts or phytochemicals that inhibit the growth of oral pathogens, reduce the development of biofilms and dental plaque, influence the adhesion of bacteria to surfaces and reduce the symptoms of oral diseases will be discussed further. Clinical studies that have investigated the safety and efficacy of such plant-derived medicines will also be described.

Anticariogenic properties of ent-pimarane diterpenes obtained by microbial transformation

In the present work, the anticariogenic activities of three pimarane-type diterpenes obtained by fungal biotransformation were investigated. Among these metabolites, ent-8(14),15-pimaradien-19-ol was the most active compound, displaying very promising MIC values (ranging from 1.5 to 4.0 μg mL(-1)) against the main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis, and Lactobacillus casei. Time kill assays performed with ent-8(14),15-pimaradien-19-ol against the primary causative agent S. mutans revealed that this compound only avoids growth of the inoculum in the first 12 h (bacteriostatic effect). However, its bactericidal effect is clearly noted thereafter (between 12 and 24 h). The curve profile obtained by combining ent-8(14),15-pimaradien-19-ol and chlorhexidine revealed a significant reduction in the time necessary for killing S. mutans compared with each of these two chemicals alone. However, no synergistic effect was observed using the same combination in the checkerboard assays against this microorganism. In conclusion, our results point out that ent-8(14),15-pimaradien-19-ol is an important metabolite in the search for new effective anticariogenic agents.

A mint purified extract protects human keratinocytes from short-term, chemically induced oxidative stress

Oxidative stress is strictly correlated to the pathogenesis of many diseases, and a diet rich in fruits and vegetables, or adequately integrated, is currently considered to be a protective and preventive factor. This study aimed to analyze the efficacy of a 1 h preincubation with the highest nontoxic dose of a characterized Mentha longifolia extract (80 μg/mL) in protecting human keratinocytes (NCTC2544) from chemically induced oxidative stress (500 μM H2O2 for 2, 16, and 24 h). As reference synthetic pure compounds rosmarinic acid (360.31 μg/mL), a major mint phenolic constituent, and resveratrol (31.95 mg/mL), a well-known antioxidant, were used. Cellular viability was significantly protected by mint, which limited protein and DNA damage, decreased lipid peroxidation, and preserved glutathione and superoxide dismutase activity in the shorter phases of oxidative stress induction, in extents comparable to or better than those of pure compounds. These data suggest that mint use as only a flavoring has to be revised, taking into consideration its enrichment in foodstuff and cosmetics.

Effect of the dibenzylbutyrolactone lignan (-)-hinokinin on doxorubicin and methyl methanesulfonate clastogenicity in V79 Chinese hamster lung fibroblasts

The dibenzylbutyrolactone lignan (-)-hinokinin (HK) was obtained by partial synthesis from (-)-cubebin, isolated from the dry seeds of the pepper, Piper cubeba. In view of the trypanocidal activity of HK and its potential as a lead compound for drug development, evaluation of its possible genotoxic activity is required. We have tested HK for possible genotoxicity and evaluated the compound's effect on the activity of the clastogens doxorubicin (DXR) and methyl methanesulfonate (MMS) in the micronucleus (MN) assay with Chinese hamster lung fibroblast V79 cells. HK alone did not induce MN, at concentrations up to 128microM. In combined treatments, HK reduced the frequency of MN induced by MMS. With respect to DXR, HK exerted a protective effect at lower concentrations, but at higher concentrations it potentiated DXR clastogenicity.

Hinokinin biosynthesis in Linum corymbulosum Reichenb

Due to their peculiar stereochemistry and numerous biological activities, lignans are of widespread interest. As only a few biosynthetic steps have been clarified to date, we aimed to further resolve the molecular basis of lignan biosynthesis. To this end, we first established that the biologically active lignan (-)-hinokinin could be isolated from in vitro cultures of Linum corymbulosum. Two hypothetical pathways were outlined for the biosynthesis of (-)-hinokinin. In both pathways, (+)-pinoresinol serves as the primary substrate. In the first pathway, pinoresinol is reduced via lariciresinol to secoisolariciresinol by a pinoresinol-lariciresinol reductase, and methylenedioxy bridges are formed later. In the second pathway, pinoresinol itself is the substrate for formation of the methylenedioxy bridges, resulting in consecutive production of piperitol and sesamin. To determine which of the proposed hypothetical pathways acts in vivo, we first isolated several cDNAs encoding one pinoresinol-lariciresinol reductase (PLR-Lc1), two phenylcoumaran benzylic ether reductases (PCBER-Lc1 and PCBER-Lc2), and two PCBER-like proteins from a cDNA library of L. corymbulosum. PLR-Lc1 was found to be enantiospecific for the conversion of (+)-pinoresinol to (-)-secoisolariciresinol, which can be further converted to give (-)-hinokinin. Hairy root lines with significantly reduced expression levels of the plr-Lc1 gene were established using RNAi technology. Hinokinin accumulation was reduced to non-detectable levels in these lines. Our results strongly indicate that PLR-Lc1 participates in (-)-hinokinin biosynthesis in L. corymbulosum by the first of the two hypothetical pathways via (-)-secoisolariciresinol.

Chemical constituents of Aristolochia constricta: antispasmodic effects of its constituents in guinea-pig ileum and isolation of a diterpeno-lignan hybrid

Twenty constituents were isolated from the n-hexane and chloroform extracts of Aristolochia constricta, a plant whose aerial parts have been used empirically in folk medicine for various purposes. The inhibitory effects of these constituents on smooth muscle contraction in isolated guinea-pig ileum were studied in order to observe their antispasmodic effects. 3,4-Dibenzyldihydrofuran-type lignans [(-)-cubebin, (-)-hinokinin, and (-)-pluviatolide] and a kaurene-type diterpene [(-)-kaur-16-en-19-oic acid] were isolated as active principals. They inhibited electrically induced and acetylcholine-induced contraction in the isolated guinea-pig ileum. In addition, 9- O-[(-)-kaur-15-en-17-oxyl]cubebin was isolated as a new diterpeno-lignan hybrid, although this constituent did not exhibit antispasmodic activity.