Isolation and in vitro antibacterial activity of astilbin, the bioactive flavanone from the leaves of Harungana madagascariensis Lam. ex Poir. (Hypericaceae)

Attenuative effect of astilbin on polystyrene microplastics induced testicular damage: Biochemical, spermatological and histopathological-based evidences

Polystyrene microplastics (PS-MPs) are the potential environmental pollutants that possess the ability to induce testicular damage. Astilbin (ASB) is a dihydroflavonol, abundantly reported in multiple plants that has various pharmacological properties. This research elucidated the mitigative potential of ASB against PS-MPs-instigated testicular toxicity. 48 adult male rats (200 ± 10 g) were distributed into 4 groups (n = 12): control, PS-MPs received (0.01 mg/kg), PS-MPs + ASB received (0.01 mg/kg + 20 mg/kg) and ASB supplemented group (20 mg/kg). After 56th day of the trial, animals were sacrificed and testes were harvested for the estimation of biochemical, hormonal, spermatogenic, steroidogenic, apoptotic and histological profiles. PS-MPs intoxication significantly (P < 0.05) lowered glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione reductase (GSR) as well as catalase (CAT) activities, whereas elevated MDA as well as ROS levels. Besides, the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), nuclear factor kappa-B (NF-κB) along with cyclooxygenase-2 (COX-2) activity were raised. PS-MPs treatment reduced luteinizing hormone (LH), plasma testosterone and follicle-stimulating hormone (FSH) level besides decreased epididymal sperm number, viability, motility as well as the count of HOS coil-tailed spermatozoa and increased sperm morphological irregularities. PS-MPs exposure lowered steroidogenic enzymes (17β-HSD, 3β-HSD and StAR protein along with Bcl-2 expression, besides increasing Caspase-3 and Bax expressions and histopathological alterations in testicular tissues. However, ASB treatment significantly reversed PS-MPs mediated damage. In conclusion, ASB administration is protective against PS-MPs-instigated testicular damage owing to its anti-inflammatory, anti-apoptotic, antioxidant and androgenic nature.

Smilax glabra Roxb.: A Review of Its Traditional Usages, Phytochemical Constituents, Pharmacological Properties, and Clinical Applications

Smilax glabra Roxb. (SGB) is a medicinal plant widely distributed in 17 countries worldwide. It is the primary raw material of the world-famous and best-selling functional food and beneficial tea. SGB was first recorded in Ben Cao Jing Ji Zhu of the Southern and Northern Dynasties (420–589 AD) and was reported for nutritional and medicinal properties for thousands of years. This review searched PubMed, Web of Science, and other databases for relevant literature on SGB species until April 2022. It aims to provide more integrated thinking, detailed awareness, and better knowledge of SGB. More than 200 chemical components have been discovered, including flavonoids, phenolic, phenolic acids, stilbenes, organic acids, phenylpropanoids, and others. Previous studies have demonstrated that SGB and its active ingredients show a wide range of pharmacological effects, including anti-infective, anti-cancer, anti-inflammatory, antioxidant, cardiovascular protection, etc. However, many studies on the biological activity of this plant were mainly based on crude extracts and active ingredients, and there is a lack of clinical studies and toxicity studies to support the development of drug design, development, and therapy. In summary, this review will provide specific and valuable suggestions and guidelines for further research and application of this plant in the medicinal field.

The natural source, physicochemical properties, biological activities and metabolism of astilbin

Astilbin is a dihydroflavanol found in many plants and processed foods. Astilbin possesses multiple health-beneficial bioactivities and has received great attention. Hence, the natural source, physicochemical properties, biological activities and metabolism of astilbin are summarized in the present article. Engelhardia roxburghiana Wall. and Smilax glabra Roxb. are the main resource for astilbin purification because of high content. Because of chemical instability, astilbin amount in foods is dependent on the processing and storage conditions. The degradation of astilbin includes isomerization and decomposition. The interconversion of astilbin and its isomers occurs through a chalcone intermediates, which significantly affects the taste of wine during storage. Many factors such as temperature, pH, metal ions and food additives could affect the chemical stability of astilbin. Astilbin exhibits very novel selective immunosuppressive activity, which is not found in other compounds. The rhamnose moiety of astilbin is essential for this bioactivity. After digestion, astilbin was mainly absorbed and transported in circulatory blood in its intact form, and only one metabolite, 3'-O-methylastilbin, was found. Although having many bioactivities, astilbin faces the challenge of poor bioavailability. Some promising strategies were developed for improving its bioavailability, particularly through fabrication the zein nanoparticles.

Advances in biochemistry and the biotechnological production of taxifolin and its derivatives

Taxifolin (dihydroquercetin) and its derivatives are medicinally important flavanonols with a wide distribution in plants. These compounds have been isolated from various plants, such as milk thistle, onions, french maritime, and tamarind. In general, they are commercially generated in semisynthetic forms. Taxifolin and related compounds are biosynthesized via the phenylpropanoid pathway, and most of the biosynthetic steps have been functionally characterized. The knowledge gained through the detailed investigation of their biosynthesis has provided the foundation for the reconstruction of biosynthetic pathways. Plant- and microbial-based platforms are utilized for the expression of such pathways for generating taxifolin-related compounds, either by whole-cell biotransformation or through reconfiguration of the genetic circuits. In this review, we summarize recent advances in the biotechnological production of taxifolin and its derivatives.

The interaction between gut microbiota and flavonoid extract from Smilax glabra Roxb. and its potent alleviation of fatty liver

Fatty liver is associated with intestinal microbiota dysbiosis and low-grade chronic inflammation. Herein we report the interaction of the flavonoid extract from Smilax glabra Roxb. (FSGR) with gut microbiota. Then, FSGR's function of modulating microbiota in a rat model of high-fat diet (HFD) induced fatty liver has been explored. These investigations indicated that the main compound in FSGR, such as astilbin and its isomers, could be metabolized to aglycone, while further splitting resulted in some phenolic acid compounds through a redox reaction. The data obtained clearly showed that FSGR not only alleviated the steatosis degree of liver cells and modulated the contents of short chain fatty acids (SCFAs) in the intestinal tract, but also reversed gut dysbiosis induced by HFD as prognosticated by the decreased ratio of Firmicutes/Bacteroidetes (F/B) and altered gene expression. The results demonstrated that FSGR probably could be used as a prebiotic agent to impede gut dysbiosis and fatty liver-related metabolic disorders.

Medicinal plants used in managing diseases of the respiratory system among the Luo community: an appraisal of Kisumu East Sub-County, Kenya

BACKGROUND

Poor access to healthcare in rural communities causes many people to seek herbalists who use medicinal plants for the treatment of various disease conditions. Most knowledge of traditional herbal medicine makes use of indigenous remedies which are often undocumented and are at risk of being lost. The preservation of this knowledge may facilitate scientific inquiry into promising new therapeutic molecules.

METHODS

Semi-structured questionnaires were used to collect the sociodemographic information of 30 herbalists in Kisumu East Sub County. The local names of medicinal plants used in managing illnesses of the respiratory system, their habit, active parts, indications, methods of preparation, routes of administration, scientific identity, and conservation status were also recorded. Other reported traditional uses, pharmacological activities, and toxicological data were identified via a literature search.

RESULTS

Most herbalists were female (86.7%), aged between 61 and 70 years (43.3%) with no formal education (56.7%), and had 21-30 years of practice (30%). 44 plant species, belonging to 43 genera and 28 families were identified. Leguminosae and Rutaceae plant families were predominant, leaves were frequently used (33%), and trees were the most common habit (44.4%). Most plants were collected in the wild (79.2%), preparation was mainly by decoction (68.8%), and the administration was mainly orally. The main indication was cough and 79.5% of all documented plant species had previously been reported to have a pharmacological activity relevant to the mitigation of respiratory illnesses. Toxicological data was available for 84.1% of the plant species identified.

CONCLUSIONS

The predominant use of roots, root barks, and root tubers by herbalists in Kisumu East Sub County threatens to negatively impact the ecological survival of some plant species. The preservation of herbalists' knowledge of medicinal plants in the study area is a pressing concern considering their advanced age and little formal education. There is a need to conserve some of the medicinal plants documented in this study. The medicinal claims made by herbalists also warrant scientific scrutiny.

ASTILBIN: A PROMISING UNEXPLORED COMPOUND WITH MULTIDIMENSIONAL MEDICINAL AND HEALTH BENEFITS

BACKGROUND

Many flavonoids have various beneficial actions like anti-inflammatory, anti-carcinogenic properties and many other clinical conditions. Astilbin is one such flavanoid compound having many physiological as well as pharmacological actions.

PURPOSE

To summarize the important findings from the research conducted using astilbin having significance to its physiological and pharmacological activities as well as the patents filed using astilbin.

STUDY DESIGN

Systematic review and compilation of the collected literature.

METHOD

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct and Google Scholar etc. All the article available in the English language that used our compound of interest i.e. astilbin, on the basis of inclusion criteria decided were retrieved from these databases, thoroughly reviewed and were summarized.

RESULT

It has been established that astilbin can play a vital in the management of diseases associated with immune system. It also possesses antibacterial, anti-oxidative and hepatoprotective activity.

CONCLUSION

These researches provide evidence that astilbin possesses great potential and thus can be utilized in the management of various disorders, thus establishing itself as a potential candidate for novel drug development. Also, there is still room for research on astilbin like it can be evaluated for anticancer potential, protective effect in various diabetic complications and many more. Overall observations from data suggested that astilbin is a promising compound and proved its efficacy in every preclinical study which is conducted till date. Some of the pharmacological activity is still unexplored. After successful preclinical trials, astilbin can go for further clinical trials.

Metabolism, Excretion, and Tissue Distribution of Astilbin-Zein Nanoparticles in Rats

The excretion, tissue distribution, and metabolic profile of astilbin in rat were studied by HPLC and UPLC-QTOF-MS. Astilbin underwent isomerization in the small intestine, and its four isomers were found in feces. Besides, taxifolin, the aglycone of astilbin, and its further metabolites by gut microbes through hydrogenation, dehydration, and ring-fission were found. The total feces excretion of astilbin was about 14.4% of administration. The forming of zein-caseinate nanoparticles can significantly delay and reduce the feces excretion of astilbin. Astilbin and its isomers were absorbed in their intact form. The main metabolites found in plasma and tissues were the methylated products. Astilbin was rapidly distributed in various tissues including brain and maintained relatively high concentration in heart. Compared with other tissues, significantly higher concentration and longer duration of astilbin were found in the gastrointestinal tract. Astilbin and its isomers were excreted in their intact and methylated form in urine.

Bioassay-Guided Isolation and in Silico Study of Antibacterial Compounds From Petroleum Ether Extract of Peperomia blanda (Jacq.) Kunth

Bioassay-guided isolation protocol was performed on petroleum ether extract of Peperomia blanda (Jacq.) Kunth using column chromatographic techniques. Five compounds were isolated and their structures were elucidated via one-dimensional (1D) and two-dimensional (2D) NMR, gas chromatography mass sectroscopy (GCMS), liquid chromatography mass spectroscopy (LCMS), and ultraviolet (UV) and infrared (IR) analyses. Dindygulerione E (a new compound), and two compounds isolated from P. blanda for the first time-namely, dindygulerione A and flavokawain A-are reported herein. Antimicrobial activity was screened against selected pathogenic microbes, and minimum inhibitory concentrations (MIC) were recorded within the range of 62-250 μg/mL. Assessment of the pharmacotherapeutic potential has also been done for the isolated compounds, using the Prediction of Activity spectra for Substances (PASS) software, and different activities of compounds were predicted. Molecular docking, molecular dynamics simulation and molecular mechanics/Poisson-Boltzmann Surface Area (MM-PBSA) calculations have proposed the binding affinity of these compounds toward methylthioadenosine phosphorylase enzyme, which may explain their inhibitory actions.

IN VITRO EFFICACY OF EXTRACTS FROM PLANTS USED BY SMALL-HOLDER FARMERS IN THE TREATMENT OF DERMATOPHILOSIS IN CATTLE

Background:

Bovine dermatophilosis, an important skin disease of cattle caused by Dermatophilus congolensis, negatively impacts the livelihoods of small-holder farmers in Zimbabwe. This impact is through, morbidity, loss of draught animal power, costs incurred to manage the disease, losses associated with devalued damaged hides and the resultant culling of some of the affected cattle. Due to the inaccessibility of conventional drugs to manage bovine dermatophilosis, farmers have been reported to use local medicinal plants to manage the disease. The aim of the study was to evaluate the in vitro antimicrobial activities of three plants that small-holder farmers in Zimbabwe used to manage bovine dermatophilosis.

Methods:

Dried plant materials were ground into powder and extracted individually using, water, 80 % acetone and 80 % methanol. The antimicrobial properties of the plants were evaluated against two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and one Gram-positive (Staphylococcus aureus) reference bacterial strains. They were further evaluated against a field isolate of Dermatophilus congolensis. The assays used were the disc diffusion, minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC).

Results:

Acetone and methanol extracts had superior inhibitory activities than did those of water. Pterocarpus angolensis DC extracts had better inhibitory properties with absolute MIC values of 0.156 – 5 mg/ml, Cissus Quadrangularis L had MIC values in the range 0.156 – 5 mg/ml while that of Catunaregam spinosa Thunb, Terveng was 0.156 – 10 mg/ml. Dermatophilus congolensis was more sensitive to Pterocarpus angolensis DC average MIC = 0.63 mg/ml than to Cissus quadrangularis L average MIC = 1.25 mg/ml and Catunaregam. spinosa Thunb, Terveng average MIC = 2.08 mg/ml.

Conclusion:

These results suggest the potential antibacterial activities of extracts of the three plants and hence farmers are, in a way, justified in using the plants. Better results (lower MIC) could be obtained by extracting and evaluating pure active compounds of the plants.

The Effects of Astilbin on Cognitive Impairments in a Transgenic Mouse Model of Alzheimer's Disease

Bioflavonoids are being utilised as neuroprotectants in the treatment of various neurological disorders, including Alzheimer's disease (AD). Astilbin, a bioflavanoid, has been reported to have potent neuroprotective effects, but its preventive effects on amyloid-β (Aβ)-induced, Alzheimer's disease-related, cognitive impairment, and the underlying mechanisms of these effects have not been well characterised. Five-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group and two astilbin (either 20 or 40 mg/kg per day, intraperitoneally) groups. After 8 weeks of treatment, we observed beneficial effects of astilbin (40 mg/kg per day), including lessening learning and memory deficits and reducing plaque burden and Aβ levels. Furthermore, the expressions of both the cAMP responsive element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were significantly increased and the disturbance of AKT/GSK-3β signalling pathway was markedly ameliorated in the hippocampus of astilbin-treated (40 mg/kg per day) group. Our data suggest that astilbin might be a potential therapeutic agent against AD.

Antimicrobial and antioxidant activity and chemical characterisation of Erythrina stricta Roxb. (Fabaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The bark of Erythrina stricta Roxb. (Fabaceae) has been used in Indian indigenous systems as a remedy for rheumatism, stomach-ache, asthma, dysentery, contact dermatitis, eczema and skin infections. However, there have been limited phytochemical or biological studies on the bark of E. stricta and there are no studies that align with its traditional medicinal uses.

AIM OF THE STUDY

The aim of this study was to assess the antimicrobial and antioxidant activity of the stem bark of E. stricta to support its topical use in the treatment of contact dermatitis, eczema and skin infections and to isolate and identify any bioactive compounds.

MATERIALS AND METHODS

MTT microdilution and disc diffusion assays were used to determine the antimicrobial activities of n-hexane, dichloromethane, ethyl acetate, methanol and water extracts of the bark of E. stricta. Column and preparative thin layer chromatography were used for the purification of the dichloromethane extract. The structures of the compounds isolated were elucidated by extensive 1D and 2D NMR spectroscopic techniques and comparison with published data. The antioxidant activities of the extracts were determined by DPPH free radical scavenging and FRAP assays and the antioxidant activity of the pure compounds by dot-blot and DPPH staining methods.

RESULTS

The dichloromethane, ethyl acetate, and n-hexane extracts showed the most significant activity with MIC values of 7.8µg/mL, 125µg/mL, and 125µg/mL against a sensitive strain of Staphylococcus aureus. The dichloromethane and ethyl acetate extracts also showed significant activity against Candida albicans with MIC values of 125µg/mL and 1mg/mL respectively. GC-MS analysis of the n-hexane extract showed the presence of the antibacterial and antifungal compounds β-caryophyllene, caryophyllene oxide, α-selinene, β-selinene, selin-11-en-4-α-ol, α-copaene and δ-cadenine. Phytochemical studies of the dichloromethane extract led to the isolation of the novel compound erynone (1), together with six known compounds; wighteone (2), alpinum isoflavone (3), luteone (4), obovatin (5), erythrinassinate B (6) and isovanillin (7). Luteone (4) exhibited the most significant antibacterial activity with minimum inhibitory quantity (MIQ) values of 1.88µg, 1.88µg and 3.75µg, respectively, against sensitive (MSSA) and resistant strains (MRSA and MDRSA) of S. aureus using a TLC bioautography assay. Erynone (1) exhibited the greatest DPPH free radical scavenging activity.

CONCLUSIONS

Seven compounds, including a new chromanone, were isolated from the antimicrobial dichloromethane extract of the stem bark of E. stricta. Six of the seven compounds showed antibacterial and/or antioxidant activities. These findings provide support for the customary (traditional and contemporary) use of E. stricta bark for the treatment of skin and wound infections.

Ethnomedical and ethnobotanical investigations on the response capacities of Guinean traditional health practioners in the management of outbreaks of infectious diseases: The case of the Ebola virus epidemic

ETHNOPHARMACOLOGICAL RELEVANCE

The recent outbreak of Ebola virus infections has mostly remained confined to the West African countries Guinea-Conakry, Sierra-Leone and Liberia. Due to intense national and international mobilizations, a significant reduction in Ebola virus transmission has been recorded. While international efforts focus on new vaccines, medicines and diagnostics, no coherent national or international approach exists to integrate the potential of the traditional health practitioners (THPs) in the management of infectious diseases epidemics. Nevertheless, the first contact of most of the Ebola infected patients is with the THPs since the symptoms are similar to those of common traditionally treated diseases or symptoms such as malaria, hemorrhagic syndrome, typhoid or other gastrointestinal diseases, fever and vomiting.

MATERIALS AND METHODS

In an ethnomedical survey conducted in the 4 main Guinean regions contacts were established with a total of 113 THPs. The socio-demographic characteristics, the professional status and the traditional perception of Ebola Virus Disease (EVD) were recorded.

RESULTS

The traditional treatment of the main symptoms was based on 47 vegetal recipes which were focused on the treatment of diarrhea (22 recipes), fever (22 recipes), vomiting (2 recipes), external antiseptic (2 recipes), hemorrhagic syndrome (2 recipes), convulsion and dysentery (one recipe each). An ethnobotanical survey led to the collection of 54 plant species from which 44 identified belonging to 26 families. The most represented families were Euphorbiaceae, Caesalpiniaceae and Rubiaceae. Literature data on the twelve most cited plant species tends to corroborate their traditional use and to highlight their pharmacological potential.

CONCLUSIONS

It is worth to document all available knowledge on the traditional management of EVD-like symptoms in order to evaluate systematically the anti-Ebola potential of Guinean plant species.

New α-glucosidase inhibiting anthracenone from the barks of Harungana madagascariensis Lam

Two new 10-hydroxy-9(10H)-anthracenone, madagascenone A (1) and B (2), were isolated from the barks of Harungana madagascariensis Lam. The structures of the compounds were determined using 1D- and 2D-NMR and mass spectroscopic techniques. Both of the compounds showed an in vitro α-glucosidase inhibition with IC₅₀ = 69.9 ± 4.21 and 122.3 ± 1.13 μM, respectively, more potent than the standard acarbose (IC₅₀ = 840 ± 1.23 μM).

Induction of TGF-β and IL-10 production in dendritic cells using astilbin to inhibit dextran sulfate sodium-induced colitis

Astilbin, a major bioactive compound from Rhizoma smilacis glabrae, has been reported to possess anti-inflammatory properties. Our study first evaluated astilbin on dextran sulfate sodium (DSS)-induced acute colitis in mice. By intraperitoneal injection of astilbin, the severity of colitis was attenuated, and the serum levels of IL-10 and TGF-β were increased. Using flow cytometry, a higher number of IL-10(+) dendritic cells (DCs) and TGF-β(+) DCs and a lower number of CD86(+) DCs, IL-12 p40(+) DCs, and IL-1β(+) DCs were detected in the spleen of mice with colitis after astilbin treatment. The administration of astilbin also resulted in the upregulation of CD103(+) expression in colonic DCs. In a coculture system, murine bone marrow-derived DCs pretreated with astilbin resulted in an enhanced production of CD4(+)CD25(+)Foxp3(+) T cells. The results of this study show that astilbin could be a candidate drug for inflammatory bowel disease by mediating the regulatory functions of DCs.

Aqueous stability of astilbin: effects of pH, temperature, and solvent

The influence of temperature, pH value, and solvent on the degradation behavior of astilbin was studied by HPLC. Results showed that the degradation of astilbin was pH and temperature dependent, and the isomerization of astilbin to its three stereoisomers was found. The degradation process followed the first-order kinetics model, and the degradation rate k values increased, whereas half-life (t1/2) values declined with the rise of pH and temperature. The stability of astilbin was related to its B-ring substitution. Engeletin with a 4'-hydroxy-substituted B-ring was more stable than astilbin with a 3',4'-dihydroxy-substituted B-ring. The stability of astilbin differed depending on the solvent and followed the order 50% ethanol > ethanol > methanol > 50% methanol > water. In cultural media, astilbin was less stable than in water, which may be related to the presence of metal ions. The stability results of astilbin were confirmed in the extraction of dihydroflavonols from Rhizoma Smilacis Glabrae and may have a guiding function in turtle jelly production.

Efficacy of Plectranthus amboinicus (Lour.) Spreng in a Murine Model of Methicillin-Resistant Staphylococcus aureus Skin Abscesses

The present work aimed to evaluate the effectiveness of Plectranthus amboinicus (Lour.) Spreng against MRSA clinical isolates. The in vitro antimicrobial activity of the hydroalcoholic extract (HE), the ethyl acetate (EA) fraction and its subfractions were determined by broth microdilution and bioautography against MRSA clinical isolates. The microdilution checkerboard method was used to assess in vitro drug combination studies. To induce abscess formation, bacterial suspensions were added to Citodex and inoculated subcutaneously into male Swiss mice. The treatment protocol consisted of 2 doses of HE, the EA fraction or vancomycin introduced intraperitoneally into mice 3 and 12 h after infection. The EA fraction and its subfractions presented the lowest minimal inhibitory concentrations (MIC, 0.25 to 0.5 mg/mL). The plant samples were bacteriostatic at 2x and 4x MIC and bactericidal at 100 mg/mL. The EA fraction presented synergism with vancomycin and an additive effect with ciprofloxacin. A significant reduction of abscess volume, bacterial cell counts in abscess slurries, and inflammatory scores was observed in the HE and EA fraction-treated groups. The samples were effective in treating the animals in a dose-dependent fashion. The present study proved the effectiveness of P. amboinicus fractions against MRSA using in vitro and in vivo assays.

PVP and surfactant combined carrier as an effective absorption enhancer of poorly soluble astilbin in vitro and in vivo

CONTEXT

Astilbin is considered to be a new and promising immunosuppressant for immune related diseases, but limited in clinical application due to its poor water solubility, difficult oral absorption and low bioavailability.

OBJECTIVE

The present work studied the effect of PVP and surfactant combined carrier on its capability to improve drug absorption.

MATERIALS AND METHODS

PVP K30-Tween 80 combined carries was applied into the astilbin solid dispersions, tested both in vivo in beagle dogs and in vitro in transport experiments across Caco-2 cell monolayers.

RESULTS AND DISCUSSION

In the animal studies a many fold increase in plasma AUC was observed for the solid dispersions of drug in PVP K30-Tween 80 combined carries compared to active pharmaceutical ingredient (API). The applicability of Caco-2 monolayers as a tool for predicting the in vivo transport behavior of Astilbin in combination with a solubility enhancing carries was shown. In vitro transport studies confirmed the effect of combined carries on the absorption behavior of the astilbin. MTT studies showed the cell viability gradually decreased with the increase of the drug concentration in a dose dependent manner for astilbin and that in solid dispersions. The permeability and apparent permeability coefficients (Papp) increased with drug in the Caco-2 cell.

CONCLUSION

In this study, it was found that PVP K30 and Tween 80 promoted the permeability of drugs best within a certain amount. For astilbin PVP K30 and surfactant combined carrier had a strong potential to improve oral bioavailability.

Aqueous solubility and stability enhancement of astilbin through complexation with cyclodextrins

The complexation of astilbin with α-, β-, and γ-cyclodextrin (CD) was studied by phase solubility test and UV-vis spectral titration. Complexation with CDs gradually decreased the absorbance of astilbin at 291 nm and obviously increased its water solubility. The formation constant (K(a)) between astilbin and the three CDs was calculated. The stability of astilbin complexes increased in the order α-CD < γ-CD < β-CD, attributed to the CDs' cavity size. Temperature studies showed that the K(a) value decreased along with the rise of temperature. The negative values of enthalpy and entropy during complexation indicated that the complexation process was enthalpy-controlled. In alkaline medium isomerization and decomposition of astilbin were found; however, the addition of CDs significantly improved its stability through complexation. The solubility of astilbin in β-CD microcapsules prepared by the freeze-drying method was enhanced by 122.1-fold, and its dissolution profile was improved.

Body malodours and their topical treatment agents

Body malodour, including foot odour, suppresses social interaction by diminishing self-confidence and accelerating damage to the wearer's clothes and shoes. Most treatment agents, including aluminium anti-perspirant salts, inhibit the growth of malodourous bacteria. These metallic salts also reduce sweat by blocking the excretory ducts of sweat glands, minimizing the water source that supports bacterial growth. However, there are some drawback effects that limit the use of aluminium anti-perspirant salts. In addition, over-the-counter anti-perspirant and deodourant products may not be sufficiently effective for heavy sweaters, and strong malodour producers. Body odour treatment agents are rarely mentioned in the literature compared with other cosmetic ingredients. This review briefly summarizes the relationship among sweat, skin bacteria, and body odour; describes how odourous acids, thiols, and steroids are formed; and discusses the active ingredients, including metallic salts and herbs, that are used to treat body odour. A new class of ingredients that function by regulating the release of malodourants will also be described. These ingredients do not alter the balance of the skin flora.

2-(4-Bromo-phen-yl)-6-methyl-4H-1-benzopyran-4-one (4'-bromo-6-methyl-flavone)

Planar (r.m.s. deviation from the plane through all non-H atoms = 0.036 Å) mol-ecules of the title compound, C(16)H(11)BrO(2), form a layered structure stabilized by C-H⋯O hydrogen bonds and π-π stacking inter-actions.

Permeation of astilbin and taxifolin in Caco-2 cell and their effects on the P-gp

This study was designed to understand the transport profiles of astilbin and taxifolin in Caco-2 cell model and their effects on the function and expression of P-glycoprotein. The transport studies were examined using Caco-2 cells cultured on Transwell inserts. Their effects on the function and expression of P-glycoprotein were detected using Western Blot and RT-PCR. The transport was concentration and temperature dependent. The apparent permeability (P(app)) of these two compounds in the secretory direction was larger than that in the absorptive direction in the concentration range of 10-1000 microM. Those compounds had no effects on the P-glycoprotein-mediated transport of Rhodamine 123. Caco-2 cells exposed to astilbin or taxifolin for 36 h exhibited higher P-glycoprotein activity through up-regulating P-glycoprotein expression at protein and mRNA levels. These results indicated that P-glycoprotein and Multidrug Resistance Protein 2 might play important roles in limiting the bioavailability of those compounds. Drugs which are the inhibitors of P-glycoprotein or Multidrug Resistance Protein 2 may increase the oral bioavailability of astilbin or taxifolin and the possibility of unwanted drug-food interactions. The increased expression of P-glycoprotein in Caco-2 cells may serve as an adaptation and defense mechanism in limiting the entry of xenobiotics into the body.

Antibacterial activities of Dodonaea viscosa using contact bioautography technique

The crude ethanolic extract and n-hexane, dichloromethane, ethyl acetate, n-butanol and aqueous fractions of Dodonaea viscosa were analyzed for antibacterial potential against four Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, and three Gram negative bacteria: Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa. Preliminary screening showed inhibition against Staphylococcus aureus, Micrococcus luteus, Escherichia coli and Pseudomonas aeruginosa. The thin layer chromatograms of the fractions were then subjected to contact bioautography, which showed inhibition zone at different R(f) values against Bacillus subtilis, Micrococcus luteus, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa, indicating the presence of antibacterial components. The MIC of each fraction was determined through a 96-well micro-titer plate method. The non-viability of the organisms was ascertained by determining the MBC of the fractions.

Naturally Occurring Flavanones: An Overview

Flavanones are one of the most interesting naturally occurring flavonoids in view of their structural pattern as well as biological and pharmacological potentials. The present review deals with natural flavanones reported from 1998 to mid 2007, along with their biological and pharmacological activities. The review includes more than 160 new naturally occurring flavanones from 135 references. The reported flavonoids belong to thirty-six plant families.

Anti-protozoan activities of Harungana madagascariensis stem bark extract on trichomonads and malaria

AIM OF THE STUDY

The ethanolic stem bark extract of Harungana madagascariensis (Hypericaceae), (Choisy) Poir were evaluated for their activities on Trichomonas gallinae (Rivolta) Stabler isolated from the pigeon (Columba livia). It was also tested for their anti-malarial activity on N67 Plasmodium yoelii nigeriensis (in vivo) in mice and on Plasmodium falciparum isolates in vitro.

MATERIALS AND METHODS

The anti-trichomonal screening was performed in vitro using Trichomonas gallinae culture. The minimum lethal concentration (MLC) is the lowest concentration of the test extract in which no motile organisms were observed. The anti-malarial effects were determined in-vivo for suppressive, curative and prophylactic activities in mice receiving a standard inoculum size of 1 x 10(7) (0.2 ml) infected erythrocytes of Plasmodium yoelii nigeriensis intraperitoneally, and the in vitro was performed against 3 isolates of Plasmodium falciparum in a candle jar procedures.

RESULTS

The IC(50) of the extract and metronidazole (MDZ) (Flagyl) on Trichomonas gallinae at 48 h are 187 and 1.56 microg/ml. The IC(50) of the extract, chloroquine (CQ) and artemether (ART) on Plasmodium falciparum are between 0.052 and 0.517 microg/ml for the extract and 0.021 and 0.0412 microg/ml for ART and CQ, respectively. The actions of the extract in in vivo study on Plasmodium yoelii nigeriensis showed that in both suppressive and prophylactic tests the percentages chemo-suppressive were between 28.6-44.8% and 30.2-78.2% respectively, while only 80 mg/kg of the extract reduced the parasitaemia level when compared to the control and the standard drugs in curative test.

CONCLUSIONS

Harungana madagascariensis stem bark extract therefore exhibited significant anti-protozoan effects against Trichomonas and Plasmodium both in vivo and in vitro.

Antibacterial C-geranylflavonoids from Paulownia tomentosa Fruits

Eight C-6-geranylflavonoids ( 1- 8) were isolated from an ethanol extract of Paulownia tomentosa fruits. Tomentodiplacone ( 1), 3'- O-methyl-5'-hydroxydiplacone ( 2), 3'- O-methyl-5'- O-methyldiplacone ( 3), and tomentodiplacone B ( 4) were obtained as new compounds, and 3'- O-methyldiplacol ( 5) was isolated for the first time from a natural source. The structures of these new compounds were determined by using mass spectrometry (including HRMS) and 1D and 2D NMR spectroscopy, and the absolute configurations of the compounds were determined by circular dichroism. The antibacterial activities of 1- 8 against seven bacteria and yeast were evaluated.

Antimalarial activity of some plants traditionally used in treatment of malaria in Kwale district of Kenya

Methanolic and water extracts of five medicinal plant species used for treatment of malaria in traditional/cultural health systems of Kwale people in Kenya were tested for antimalarial activity against Plasmodium falciparum and Plasmodium berghei, respectively and for their cytotoxic effects. The most active extracts (IC(50)<10 microg/ml) screened against chloroquine (CQ) sensitive (D6) and resistant (W2) P. falciparum clones, were the water and methanol extracts of Maytenus undata (Thunb.) Blakelock (Celasteraceae), methanol extracts of Flueggea virosa (Willd.) Voigt (Euphorbiaceae), Maytenus putterlickioides (Loes.) Excell and Mendoca (Celastraceae), and Warburgia stuhlmannii Engl. (Canellaceae). These extracts showed various cytotoxic levels on Vero E6 cells with the water extract of M. undata exhibiting least cytotoxicity. At least one of the extracts of the plant species exhibited a high chemo suppression of parasitaemia >70% in a murine model of P. berghei infected mice. These results indicate that there is potential for isolation of a lead compound from the extracts of the five plants. W. stuhlmannii and M. putterlickioides have not been reported before for antiplasmodial activity.

In vitro antimicrobial assay of plants used in traditional medicine in Bukoba Rural district, Tanzania

Plants used in traditional medicine in Bukoba Rural district in Tanzania were evaluated for their in vitro antimicrobial activities. Plant materials from eight plant species (Harungana madagascariensis (Lam) Poir., Jatropha curcas L., Lantana trifolia L., Plectranthus barbatus Andr., Pseudospondias microcarpa Engl., Psorospermum febrifugum Spach, Teclea nobilis Del. and Vernonia adoensis [Warp.] SL) were collected based on ethnomedical information provided by traditional herbal practitioners. Results of the study indicate that extracts from the eight plant species were active against at least one or more of the test organisms (Bacillus subtilis, Staphylococcus aureus [gram positive], Escherichia coli, Pseudomonas aeruginosa [gram negative] and Candida albicans [Yeast]). A profile of secondary metabolites (alkaloids, terpenoids, triterpenes, phenolics, tannins, flavonoids, anthraquinones, flavonols/flavones and /or chalcones, sterols and saponins) was obtained for three plant species (Jatropha curcas L., Plectranthus barbatus Andr., and Pseudospondias microcarpa Engl.). The paper discusses the probable therapeutic basis of these traditional plants based on their secondary metabolite profiles and for the first time draws research attention to Bukoba Rural district as a source for plants with potential pharmaceutical applications.

Flavanone and 2'-OH flavanone inhibit metastasis of lung cancer cells via down-regulation of proteinases activities and MAPK pathway

Flavanones richly exist in citrus and have been well characterized to have various bioactive properties. However, the anti-metastasis properties of flavanones remain unclear. The anti-metastatic effects of six flavanones including flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone, naringin, and naringenin were investigated in lung cancer cells. Despite little influence on cell viability, flavanone and 2'-OH flavanone markedly inhibited the invasion, motility, and cell-matrix adhesion of A549 cells. This was associated with a reduced expression of matrix metalloproteinase (MMP)-2 and urokinase-type plasminogen activator (u-PA) in treated cells. Treatment with flavanone and 2'-OH flavanone also potently attenuated the phosphorylations of extracellular signal-regulated kinase 1/2 (ERK 1/2) and p38(MAPK), as well as the activations of NF-kappaB and AP-1. The reduced expressions of MMP-2 and u-PA, as well as inhibition of cell invasion were obtained in the cultures treated with U0126 (ERK 1/2 inhibitor) and SB203580 (p38(MAPK) inhibitor). Thus, the inhibitory effects of flavanone and 2'-OH flavanone on the expression of MMP-2 and u-PA may be at least partly through inactivation of ERK 1/2 and p38(MAPK) signaling pathways. Finally, oral administration of flavanone and 2'-OH flavanone were evidenced by its inhibition on the metastasis of A549 cells and Lewis lung carcinoma (LLC) cells in vivo. In conclusion, flavanone and 2'-OH flavanone perturb the invasion and metastasis of lung cancer cells, thereby constituting an adjuvant treatment for metastasis control.

The tumor-growth inhibitory activity of flavanone and 2′-OH flavanone in vitro and in vivo through induction of cell cycle arrest and suppression of cyclins and CDKs

Natural products, including flavonoids, are suggested to be involved in the protective effects of fruits and vegetables against cancer. However, studies concerning the effect of flavonoids frequently lacked data regarding to flavanones. In this study, we investigated the inhibitory effect of flavanone compounds, including flavanone, 2'-OH flavanone, 4'-OH flavanone, 6-OH flavanone, naringin and naringenin, on cell growth of various cancer cells. We determined that flavanone and 2'-OH flavanone inhibited cell growth of A549, LLC, AGS, SK-Hepl and HA22T cancer cells, while other flavanones showed little or no inhibition. We evaluated growth-inhibitory activity of flavanone and 2'-OH flavanone against highly proliferative human lung cancer cells (A549) via anchorage-independent and -dependent colony formation assay, and further showed that treatment of flavanone resulted in a G1 cell cycle arrest with reduction of cyclin D, E and cyclin-dependent kinase (CDK) 2, while treatment of 2'-OH flavanone led to a G2/M phase accumulation with reduction of cyclin B, D and Cdc2. Moreover, we demonstrated the improvement effect of flavanone and 2'-OH flavanone with anti-cancer drug, doxorubicin, on A549 cells. Finally, flavanone and 2'-OH flavanone were evidenced by its inhibition on the growth of A549 and Lewis lung carcinoma cells in vivo.