Comparison of the antioxidant content of fruits, vegetables and teas measured as vitamin C equivalents

New Insights on Dietary Polyphenols for the Management of Oxidative Stress and Neuroinflammation in Diabetic Retinopathy

Diabetic retinopathy (DR) is a neurodegenerative and vascular pathology that is considered one of the leading causes of blindness worldwide, resulting from complications of advanced diabetes mellitus (DM). Current therapies consist of protocols aiming to alleviate the existing clinical signs associated with microvascular alterations limited to the advanced disease stages. In response to the low resolution and limitations of the DR treatment, there is an urgent need to develop more effective alternative therapies to optimize glycemic, vascular, and neuronal parameters, including the reduction in the cellular damage promoted by inflammation and oxidative stress. Recent evidence has shown that dietary polyphenols reduce oxidative and inflammatory parameters of various diseases by modulating multiple cell signaling pathways and gene expression, contributing to the improvement of several chronic diseases, including metabolic and neurodegenerative diseases. However, despite the growing evidence for the bioactivities of phenolic compounds, there is still a lack of data, especially from human studies, on the therapeutic potential of these substances. This review aims to comprehensively describe and clarify the effects of dietary phenolic compounds on the pathophysiological mechanisms involved in DR, especially those of oxidative and inflammatory nature, through evidence from experimental studies. Finally, the review highlights the potential of dietary phenolic compounds as a prophylactic and therapeutic strategy and the need for further clinical studies approaching the efficacy of these substances in DR management.

Recyclable Cu-Ag bimetallic nanocatalyst for radical scavenging, dyes removal and antimicrobial applications

An ecofriendly and cost effective green method has been used for the synthesis of recyclable, high functional nanoparticles. Bimetallic nanoparticles (BmNPs), Cu-Ag, have been synthesized using beetroot extract as reducing and capping agent. Formation of BmNPs was initially confirmed by UV-visible analysis, having distinct peaks of Ag at 429 nm and Cu at 628 nm. FTIR analysis also confirmed the association of bioactive phytochemicals with Cu-Ag nanoparticles. Crystallinity and morphology of BmNPs was determined through X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS) and energy dispersion X-ray spectroscopy (EDAX). The size of spherical shape Cu-Ag BmNPs was found to be 75.58 nm and EDAX studies confirmed the percent elemental composition of Cu and Ag in synthesized nanocatalyst. Results of different analysis provided supported evidences regarding the formation of BmNPs. Catalytic potential of BmNPs was tested for the degradation of rhodamine B (Rh-B), methylene blue (MB) and methyl orange (MO) dyes. Cu-Ag BmNPs exhibited outstanding catalytic activity for the degradation of selected organic dyes and percent degradation was recorded more than 90% for each dye. In addition, antiradical property of BmNPs was tested employing DPPH^● and ABTS^●+ assays and it was found to be promising. Synthesized BmNPs also exhibited strong antimicrobial activity against Salmonella typhimurium and Bacillus subtilis. Recyclability of nanoparticles was also evaluated and recovery from dye degradation reaction mixture was successfully achieved. The recovered nanoparticles exhibited same catalytic potential for the degradation of Rh-B. The objective of the current study was to synthesize BmNPs Cu-Ag employing a cost effective green method having promising catalytic, antiradical and antimicrobial potential. Further, BmNPs were reused after recovery from catalytic reactions, proving that BmNPs can be recycled having the same efficiency as that of a freshly prepared Cu-Ag BmNPs.

In Vitro Evaluation of Anti-Rift Valley Fever Virus, Antioxidant and Anti-Inflammatory Activity of South African Medicinal Plant Extracts

Rift valley fever virus (RVFV) is a mosquito-borne virus endemic to sub-Saharan African countries, and the first sporadic outbreaks outside Africa were reported in the Asia-Pacific region. There are no approved therapeutic agents available for RVFV; however, finding an effective antiviral agent against RVFV is important. This study aimed to evaluate the antiviral, antioxidant and anti-inflammatory activity of medicinal plant extracts. Twenty medicinal plants were screened for their anti-RVFV activity using the cytopathic effect (CPE) reduction method. The cytotoxicity assessment of the extracts was done before antiviral screening using the MTT assay. Antioxidant and reactive oxygen/nitrogen species' (ROS/RNS) inhibitory activity by the extracts was investigated using non-cell-based and cell-based assays. Out of twenty plant extracts tested, eight showed significant potency against RVFV indicated by a decrease in tissue culture infectious dose (TCID50) < 105. The cytotoxicity of extracts showed inhibitory concentrations values (IC50) > 200 µg/mL for most of the extracts. The antioxidant activity and anti-inflammatory results revealed that extracts scavenged free radicals exhibiting an IC50 range of 4.12-20.41 µg/mL and suppressed the production of pro-inflammatory mediators by 60-80% in Vero cells. This study demonstrated the ability of the extracts to lower RVFV viral load and their potency to reduce free radicals.

Evaluation of the anti-oxidant effect of ascorbic acid on apoptosis and proliferation of germinal epithelium cells of rat testis following malathion-induced toxicity

Objective(s):

The aim of this study was to determine the protective role of ascorbic acid on apoptosis and proliferation of spermatogonia and primary spermatocyte cells after malathion administration as an organophosphate pesticide in rat testis.

Materials and Methods:

Thirty male Wistar rats were randomly divided into five groups of 6 rats each, including control (no intervention), sham (normal saline 0.09%), malathion (50 mg/kg), malathion plus ascorbic acid (50 mg/kg and 200 mg/kg, respectively), and ascorbic acid (200 mg/kg) groups. Malathion and ascorbic acid were administrated via intraperitoneal injection once per day and seven times per week. After 6 weeks, animals were sacrificed, and testis tissue was used for evaluation of apoptosis and proliferation of germinal epithelium cells using the TUNEL and PCNA staining techniques.

Results:

The results of TUNEL staining showed that the numbers of apoptotic cells in spermatogonia and primary spermatocyte cells were significantly increased in the malathion 50 mg/kg group vs control group (P<0.001). Co-administration of malathion 50 mg/kg and ascorbic acid 200 mg/kg significantly decreased the apoptotic cells in both cell types in comparison with malathion 50 mg/kg group (P<0.001). The results of PCNA staining revealed that the proliferation of these cells was significantly decreased in malathion 50 mg/kg group vs control group (P<0.001), and malathion 50 mg/kg plus ascorbic acid 200 mg/kg administration increased the proliferation of cells compared with malathion 50 mg/kg group (P<0.001).

Conclusion:

The results provide evidence that ascorbic acid showed preventive effects on malathion-induced toxicity in male rat testis.

Fruit red colorants impact on the antiradical activity determined by DPPH method

This work is focused on the determination of antiradical activity (ARA) by the method of free radical scavenging of 2,2-Diphenyl-1-picrylhydrazyl (DPPH). Since the DPPH solution is intense purple-coloured and absorbs at a wavelength of 517 nm, similar to the anthocyanin colorants of fruits, the modification of the method examined the effect of the colour of the sample extracts on the result of the ARA determination. Statistical evaluation of the results of the analyses using Youden's graphing method revealed that the two compared method adjustments gave consistent results over the observed range of antiradical activity. It also showed that there was no statistically significant difference between the mean ARA values obtained by the two treatments. Investigation of the effect of the evaluated fruit components revealed a strong correlation between the content of ascorbic acid and ARA in samples containing no anthocyanin colorants. For the fruit samples studied, ARA values showed a strong correlation with polyphenol content.

Antioxidant Activity of Metabolites from Coleonema Album (Rutaceae)

Coleonema album, a member of the South African ‘Fynbos’ biome, was evaluated for its antioxidant and free radical scavenging activity. Ethanol- and acetone-based extracts from plant material obtained from two different geographical areas were analysed. A bioassay-guided fractionation methodology was followed for screening of active compounds. The 1,1-diphenyl-2-picrylhydrazyl (DPPH)-TLC method revealed the presence of a number of antioxidants which were quantified by the DPPH-spectrophotometric assay and the oxygen radical absorbance capacity (ORAC) assay. The C. album extracts possessed significant in vitro antioxidant activity, a large portion of which appeared to be contributed by the phenolic compounds. In contrast, the reducing power of the extracts could not be correlated with the observed antioxidant activity. Identification and structural information of the active components were obtained by a combination of preparative TLC and LC-MS which revealed the presence of coumarin aglycones and glycosides. The results of this study indicate that C. album contains strong antioxidants that warrant further investigation into the relationship between the structure and activity of the active coumarin metabolites.

Phytochemical screening, antioxidant activity and inhibitory potential of Ficus carica and Olea europaea leaves

It is our interest to screen Oela europaea L and Ficus carica L leaf extract for total phenolic, flavonoid contents and to evaluate their free radical scavenging and Ferric reducing power (FRAP) using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Data shows that Olea europaea and Ficus carica have strong antioxidant potency to scavenge free radical at an optimal phenolic and flavonoid concentration. Results further suggest a strong correlation between antioxidant activities, phenolic and flavonoid contents. Thus, the screening of Ficus carica and Olea europaea leaf extracts for potential antioxidants as source of drugs for several diseases especially oxidative stress and cancers is illustrated.

Nutraceutical Properties of Herbal Infusions from Six Native Plants of Argentine Patagonia

Six native plants of South America traditionally consumed in the Patagonian region (southern Argentina and Chile), namely: Adesmia boronioides Hook. f., Apium australe Thouars, Buddleja globosa Hope, Drimys andina (Reiche) R. Rodr. & Quezada, Dysphania multifida L. and Solidago chilensis Meyen were investigated to determine the nutraceutical properties of infusions of their aerial parts. The infusions were characterized in terms of their antioxidant activity, phenolic and flavonoid content, profile of phenolic compounds, general toxicity and cytotoxicity on two different human cell lines: T84 (derived from colon cancer) and HTR8/SVneo (not derived from cancer). Twenty-nine compounds, mainly phenolic acids and flavonoids, were identified. This is the first analysis of phenolic compounds in infusions from native plants of Patagonia. D. andina, B. globosa and S. chilensis showed high levels of antioxidants, even higher than those of Green Tea. The content of phenolic compounds correlated significantly with the antioxidant activity of the samples analyzed. The toxicity test indicated that the use of A. australe, B. globosa and D. multifida seems safe, but a moderate consumption is suggested for A. boronioides, D. andina and S. chilensis until more exhaustive and long-term results are available. Moreover, A. boronioides and S. chilensis showed anticancer potential due to their antiproliferative activity on human cancer cell lines.

A specific QSAR model for proteasome inhibitors from Oleaeuropaea and Ficuscarica

Oleaeuropaea and Ficuscarica are widely used in traditional medicine for the treatment of cancer. Therefore, it is of interest to develop a QSAR model for screening proteasome inhibitors from plant source. Hence, a QSAR model was developed using multiple linear regressions; partial least squares regression and principal component regression methods. Results of QSAR modeling and docking demonstrate that compounds derived from both plants have great potentiality to be proteasome inhibitors. The developed QSAR model highlights a strong structure-effect relationship. The predicted correlation of comparative molecular field analysis, and comparative molecular similarity indexes are 0.963 and 0.919, respectively. Computed absorption, distribution, metabolism, excretion and toxicity studies on these derivatives showed encouraging results with very low toxicity, distribution and absorption.

Antibacterial Activity of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica and their mechanism of action against Streptococcus mutans

Background:

Curative plants have reportedly been used to make chewing sticks/toothbrushes intended for the treatment of oral diseases.

Objective:

The in vitro antibacterial activities of Azadirachta indica, Pongamia pinnata, Psidium guajava, and Mangifera indica were evaluated against Streptococcus mutans, along with the cytotoxicity and antioxidant and synergistic potentials. The effect of M. indica on the expression of crucial virulence genes spaP and gtfB of S. mutans was determined.

Materials and Methods:

The antibacterial activity was determined using a modified microdilution method. The antioxidant potential was evaluated using diphenyl picrylhydrazyl (DPPH), Griess reagent, and nitroblue tetrazolium calorimetric assays. The synergistic activity was investigated using a modified checkerboard method, while the cytotoxicity was determined according to a cell proliferation 2,3-Bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide salt assay. Reverse transcription was the chosen method for determining the difference in expression of the spaP and gtfB genes after treatment with the plant sample.

Results:

M. indica and A. indica had the highest antibacterial activity at concentrations of 0.3 mg/ml and 6.25 mg/ml, respectively. A. indica had the best free radical scavenging of DPPH, exhibiting 50% inhibition at 28.72 μg/ml; while M. indica showed better superoxide scavenging potential than the positive control quercetin. Both M. indica and A. indica had adequate activity against the nitric oxide-free radical (12.87 and 18.89 μg/ml, respectively). M. indica selectively reduced the expression of the gtfB gene, indicating a mechanism involving Glucotranferases, specifically targeting bacterial attachment.

SUMMARY

Mangifera indica and Azadirachta indica had very good antibacterial activity against Streptococcus mutans and moderate toxicity against Vero cells

M. indica had the best antioxidant capacity overall

M. indica reduced the expression of gtfB gene at 0.5 mg/ml.

Abbreviations used: AA: Ascorbic acid; BHI: Brain–heart infusion; CHX: Chlorhexidine; DPPH: Diphenyl picrylhydrazyl; DMSO: Dimethlysulfoxide; NBT: Nitroblue tetrazolium; NO: Nitric oxide;

Areca nut extract protects against ovariectomy-induced osteoporosis in mice

Estrogen deficiency increases the generation of reactive oxygen species (ROS), which is a crucial pathogenic factor for osteoporosis. Areca nuts are rich in phenolics, which have high antioxidant activity. In the present study, an ovariectomy (OVX)-induced osteoporosis mouse model was used to investigate the protective effects of areca nut extract (ANE) on bone loss and related processes. A total of 24 8-week-old female mice were randomly divided into three groups (n=8 per group): I Sham-operated control; II, bilateral OVX; and III, bilateral OVX + ANE. Group III were treated orally with ANE at a single dose of 300 mg/kg body weight daily for 6 months. ANE supplementation for 6 months improved trabecular bone microarchitecture and significantly increased bone mineral density in the distal femur (P<0.05) compared with Group II. Furthermore, serum levels of the osteoclast differentiation-inducing factors, receptor activator of nuclear factor-κB ligand and osteoprotegerin were significantly increased and decreased, respectively (both P<0.05), in OVX mice and these effects were significantly inhibited by ANE treatment (both P<0.05). ANE supplementation also resulted in significantly decreased serum hydrogen peroxide and malondialdehyde levels compared with Group II, while the levels of glutathione and catalase activity were significantly increased (P<0.05 and P<0.01, respectively). The current study indicated that the protective effects of ANE against bone loss were mediated, at least in part, via inhibition of the release of ROS and bone resorption. These results suggested that ANE could have therapeutic value in the treatment of osteoporosis.

Anti-diabetic effect of Alpinia oxyphylla extract on 57BL/KsJ db-/db- mice

Diabetes mellitus is characterized by high blood glucose levels. Increased levels of reactive oxygen species (ROS) may disrupt insulin signaling and result in insulin resistance. The Alpinia oxyphylla extract (AOE) possesses powerful antioxidant activity and may therefore inhibit the development of insulin resistance. The objective of the present study was to determine the effects of AOE on blood glucose, insulin and lipid levels in a type II diabetic nephropathy animal model (C57BIKsj db-/db-). All experiments were performed on male C57BL/Ks DB/DB and db-/db- mice that were left to acclimatize for 1 week prior to the experimental period. AOE was administered to these mice at different dosages (100, 300 and 500 mg/kg) for 8 weeks. The results demonstrated that AOE did not affect mouse weight, while blood glucose concentrations were found to significantly decrease in a dose-dependent manner (P<0.05). The effect of administering 500 mg/kg AOE (AOE500) to db-/db- mice was tested further. Treatment with AOE500 for 8 weeks led to improved glucose tolerance and reduced plasma insulin concentrations (P<0.05), as well as a significant decrease in triglyceride concentrations (P<0.05) and levels of total cholesterol (P<0.05) in db-/db- mice. Furthermore, treatment with AOE500 decreased the concentration of malondialdehyde, elevated the concentration of glutathione and increased the activities of the antioxidant enzymes superoxide dismutase and peroxidase (P<0.05) in the livers of db-/db- mice. Meanwhile, AOE-treated mice exhibited significantly reduced urine albumin, creatinine and blood urea nitrogen excretion (P<0.05). In parallel, the upregulated expression of phosphatase and tensin homolog (PTEN) in the liver and kidneys of db-/db- mice was impaired following AOE500 treatment. The results of the present study suggest that AOE regulates blood glucose and lipid levels and improves renal function by mediating oxidative stress and PTEN expression at the onset of type II diabetes mellitus.

In vitro and In vivo antimycobacterial, hepatoprotective and immunomodulatory activity of Euclea natalensis and its mode of action

ETHNOPHARMACOLOGICAL RELEVANCE

The Natal gwarri or Natal ebony (Euclea natalensis A.DC.) is a deciduous tree found widespread throughout southern Africa, especially in Kwazulu-Natal and the southern cost. It has been widely used by indigenous communities such as the Zulus, Tsongas and Vendas for symptoms related to tuberculosis (TB). The decoctions made from the plant parts are administered for chest diseases to treat complications such as chest pains, bronchitis, pleurisy and asthma. TB is prevalent in immune-compromised patients and it is evident that TB-drugs cause hepatotoxicity. The objective of the present study was therefore to evaluate the antimycobacterial activity of the ethanolic extract of E. natalensis against TB and its hepatoprotective and immunomodulatory activities.

MATERIALS AND METHODS

The antimycobacterial, antioxidant, hepatoprotective, immunomodulatory activity and cytotoxicity of the ethanolic extract of the shoots of E. natalensis were determined in vitro. The mechanism of action of the antituberculosis activity was determined by investigating the inhibitory effect on mycothiol disulfide reductase enzyme. Furthermore, the acute, sub-acute toxicity (50-2000mg/kg) and antimycobacterial effect (300mg/kg) of E. natalensis shoot extract were investigated in Balb/c mice. Hepatoprotective activity of the extract (50-150mg/kg) was evaluated on isoniazid and rifampicin (50mg/kg; i.p.) induced hepatic damage in a rat model.

RESULTS

The minimum inhibitory concentration of the extract was found to be 125µg/ml against Mycobacterium tuberculosis. The extracts 50% inhibitory concentration (IC₅₀) against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical was found to be 22.55µg/ml. The plant showed a hepatoprotective effect (50% at 12.5µg/ml) and the ability to increase T-helper 1 cell cytokines; Interleukin 12, Interleukin 2 and Interferon α by up to 12 fold and the ability to decrease the T-helper 2 cell cytokine Interleukin 10 4 fold when compared to baseline cytokine production. No cellular toxicity was observed in primary peripheral blood mononuclear cells (PBMC's) and two secondary cell lines; U937 monocytes and Chang liver cells (a derivative of the HepG2 cell line). During mechanistic studies, the extract showed a 50% inhibition of mycothiol reductase activity at 38.62µg/ml. During the acute and sub-acute studies, E. natalensis exhibited no toxic effect and the 50% lethal dose (LD₅₀) was established to be above 2000mg/kg. The extract was able to reduce the mycobacterial load (1.5-fold reduction) in infected mice. Isoniazid and rifampicin caused significant hepatic damage in rats, and the extract was able to reduce the toxicity by 15% and 40% at 50 and 150mg/kg respectively.

CONCLUSION

The present study supports the traditional usage of the plant against tuberculosis symptoms. The study showed the ability of E. natalensis shoot extract to inhibit mycobacterial growth, stimulate an appropriate immune response and have a hepatic protective effect. Due to the extract's significant results for hepatoprotective, immunomodulatory effects and antimycobacterial activity, it may prove to be effective to serve as an adjuvant for TB-patients.

Comparison of bioactivities and phenolic composition of Choerospondias axillaris peels and fleshes

BACKGROUND

Choerospondias axillaris is both an edible and medicinal fruit. It has a growing popularity and economic importance due to its nutritive value and medicinal effects, but comprehensive information on the chemical composition and bioactivity of its fruits is still lacking. Therefore the aim of this study was to investigate the antioxidant, antimicrobial and antiproliferative effects and chemical composition of peel polyphenolic (PP) and flesh polyphenolic (FP) extracts from C. axillaris.

RESULTS

The phenolics and flavonoids of peel were significantly higher than those of flesh. Ultra-performance liquid chromatography (UPLC) and ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight-mass spectrometry (UPLC/ESI-QTOF-MS(2) ) analysis revealed that (+)-catechin and oligomeric procyanidins were the most abundant compounds in PP and FP. Both extracts exhibited strong ferric-reducing antioxidant power, total antioxidant activity and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(•) )-scavenging ability. PP showed a significantly higher antimicrobial effect against tested strains than that of FP, in a dose-dependent manner. Furthermore, both extracts inhibited the growth of HepG2 and Caco-2 cells in a dose- and time-dependent manner, with IC50 values of 39.31 and 47.49 µg mL(-1) to HepG2 cells and 101.90 and 102.61 µg mL(-1) to Caco-2 cells respectively.

CONCLUSION

This is the first detailed report on the chemical composition and bioactivities of C. axillaris fruits. © 2015 Society of Chemical Industry.

Phytochemical Constituents and Antioxidant and Antimicrobial Activity of Selected Plants Used Traditionally as a Source of Food

Many indigenous plants have also been used as a source of food and medicine in many African rural communities in the past. The study investigated the antimicrobial activity, phytochemical constituent, and antioxidant activity of selected traditional plants used traditionally as a source of food and medicine. The methanol and water extracts of different plant parts were analyzed for phytochemicals using standard phytochemical screening reagents while the broth microdilution assays were used to analyze antimicrobial activities. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenes were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging activities. The back extracts of Sclerocarya birrea and the leaf extracts of Garcinia livingstonei exhibit the best antioxidant activities, while the water and methanol back extracts of S. birrea and G. livingstonei were the most active against all the tested foodborne bacteria.

Do teas rich in antioxidants reduce the physicochemical and peroxidative risk factors for calcium oxalate nephrolithiasis in humans? Pilot studies with Rooibos herbal tea and Japanese green tea

Several experimental and animal studies have demonstrated that substances rich in antioxidants can reduce the physicochemical and peroxidative risk factors for calcium oxalate (CaOx) renal stone formation in urine and blood. However, there are very few such investigations in humans. In the present pilot study, two varieties of tea, a green one from Japan (JGT) and a herbal one from South Africa (Rooibos) (RT), both rich in antioxidants, were administered to a group of CaOx stone formers (SF) (n = 8) for 30 days. Both teas were analysed for polyphenols by high-performance liquid chromatography and for minerals by plasma atomic and optical emission spectroscopy. 24 h urines (baseline and day 30) were analysed for lithogenic factors. CaOx metastable limits and crystal nucleation and growth kinetics were also determined in each urine sample. Deposited crystals were inspected by scanning electron microscopy. Blood samples were collected (baseline and day 30). Biomarkers of oxidative stress including plasma and urinary thiobarbituric acid reactive substances (TBARS) and urinary N-acetyl-β-D-glucosaminidase (NAG) were also determined. Urinary physicochemical risk factors were also investigated after ingestion of RT for 30 days in two control groups (CG1 and CG2), the latter one of which consisted of habitual JGT drinkers. Statistical analyses were performed using Wilcoxon signed rank tests and Mann-Whitney tests for paired and independent measurements, respectively. Several flavonoids and catechins were quantified in RT and JGT, respectively, confirming that both teas are rich sources of antioxidants. Mineral content was found to be far below dietary reference intakes. There were no significant changes in any of the urinary physicochemical or peroxidative risk factors in the control groups or in SF, except for the supersaturation (SS) of brushite (Bru) which decreased in the latter group after ingestion of JGT. Crystal morphology showed a tendency to change from mixed CaOx mono- and di-hydrate to monohydrate after ingestion of each tea. Since the latter form has a stronger binding affinity for epithelial cells, this effect is not protective. Analysis of the physicochemical and peroxidative risk factors in CG1 and CG2 did not reveal any evidence of a synergistic effect between the two teas. Paradoxically, baseline risk factors in the habitual JGT control group were significantly raised relative to those in CG1. Our preliminary results suggest that ingestion of RT and JGT does not reduce the risk factors for CaOx stone formation in humans, but these findings need to be tested in further studies involving much larger sample sizes.

Extract from Ceratonia siliqua Exhibits Depigmentation Properties

Skin hyper-pigmentation is a condition initiated by the overproduction of melanin existing in the melanocytes. Melanin pigment is responsible for the colour of skin in humans. It is formed through a series of oxidative reactions involving the amino acid tyrosine in the presence of the key enzyme tyrosinase. In continuation with our efforts to identify tyrosinase inhibitors from plants sources, the methanol extract from leaf, bark and fruit of Ceratonia siliqua were screened for tyrosinase inhibition and diphenolase activity. The bark extract exhibited significant inhibition on mushroom tyrosinase using L-tyrosine as a substrate and showed diphenolase activity. The extract further significantly lowered tyrosinase mRNA levels in B16-F10 mouse melanocytes. Bioassay-guided fractionation led to the isolation of six compounds. Compounds (-)-epicatechin-3-O-gallate, 1,2,3,6-tetra-O-galloyl-ß-D-glucose and gallocatechin-3-O-gallate showed tyrosinase inhibitions with the IC50 values of 27.52, 83.30 and 28.30 µg/mL, respectively. These compounds also exhibited L-DOPA activities with IC50 values of >200, 150 and 200 µg/mL, respectively. A clinical study was conducted using 20 volunteers in a patch testing trial for irritancy potential and skin depigmentation. The clinical results showed the sample to be non-irritant with irritancy potential of -34.21 and depigmentation trial showed an improvement in the even skin tone of UV induced pigmentation at 3% after 28 days of application.

Extraction optimization and nanoencapsulation of jujube pulp and seed for enhancing antioxidant activity

The aim of this study was to optimize extraction conditions for jujube pulp and seed in order to obtain maximum active ingredient yield and antioxidant activity, as well as to prepare chitosan nanoparticles loaded with jujube pulp and seed extracts for enhancing stability. The extraction conditions, i.e. temperature, time, and ethanol concentration, were optimized at the following respective values: 61.2 °C, 38 h, and 60.4% for pulp, and 58 °C, 34 h, and 59.2% for seed. The jujube nanoparticle size significantly increased with a higher chitosan/sodium tripolyphosphate ratio and extract concentration. Entrapment efficiency was greater than 80% regardless of preparation conditions. The stabilities of jujube pulp and seed extract in terms of total phenolic content and antioxidant activity were effectively enhanced by nanoencapsulation. In conclusion, jujube pulp and seed extracts prepared using optimal conditions could be useful as a natural functional food ingredient with antioxidant activity, and nanoencapsulation can be used to improve the stability of jujube extract. Therefore, these results could be used to promote the utilization of not only jujube pulp but also seed, by product.

Some Strychnos spinosa (Loganiaceae) leaf extracts and fractions have good antimicrobial activities and low cytotoxicities

BACKGROUND

Strychnos spinosa Lam. is a deciduous tree used in traditional medicine to treat infectious diseases. This study is designed to determine the antimicrobial, antioxidant and cytotoxic activities of extracts and fractions from leaves of S. spinosa.

METHODS

Extracts were obtained by maceration with acetone, methanol and dichloromethane/methanol (1/1) while fractions were prepared by liquid-liquid fractionation of the acetone extract. A broth serial microdilution method with tetrazolium violet as growth indicator was used to determine the minimum inhibitory concentration (MIC) against fungi, Gram-positive and Gram-negative bacteria. The antioxidant activity was determined using free-radical-scavenging assays, and the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide reduction assay was used to determine cytotoxicity.

RESULTS

Four extracts and five fractions had good to weak antimicrobial activity with MICs ranging from 0.04 to >1.25 mg/ml against both fungi and bacteria. The chloroform and ethyl acetate fractions had an MIC of 0.08 mg/ml against Aspergillus fumigatus. The n-butanol fraction had an MIC of 0.04 mg/ml against Cryptococcus neoformans. The hexane and chloroform fractions had an MIC of 0.08 mg/ml against Staphylococcus aureus. The antioxidant activities were much lower than that of the positive controls. Except for the alkaloid extract, all the extracts and fractions had free-radical-scavenging activity (IC50 ranging from 33.66 to 314.30 μg/ml). The cytotoxicity on Vero cells was reasonable to low with LC50 values ranging between 30.56 and 689.39 μg/ml.

CONCLUSION

The acetone extract and the chloroform fraction had the highest antibacterial activity. By solvent-solvent fractionation it was possible to increase the activity against A. fumigatus and to decrease the cytotoxicity leading to a potentially useful product to protect animals against aspergillosis. Our results therefore support the use of S. spinosa leaves in traditional medicine to treat infectious diseases.

Antimicrobial and anti-inflammatory activities of Pleurostylia capensis Turcz (Loes) (celastraceae)

BACKGROUND

Pleurostylia capensis is a large tree that can reach the maximum height of 20 m long, and it have been traditionally used as cosmetic, for steam bath, ritual body wash, and as a purgative to treat symptoms of witchcraft. Using ethanol, chloroform, dichloromethane (DCM), ethyl acetate (EA), and water extracts, leaves, bark and roots of Pleurostylia capensis were investigated scientifically for their effectiveness in antimicrobial, antioxidant and anti-inflammatory activities using standard methods.

MATERIALS AND METHODS

The extracts were evaluated for antimicrobial activity against Gram positive (Staphylococcus aureus, Bacillus cereus, and Mycobacterium smegmatis), Gram negative (Escherichia coli, Klebsiella pneumonia, Klebsiella oxytoca, Streptococcus pyogenes, Pseudomonas aeruginosa and Salmonella typhimurium), and Candida albicans. The antioxidant activity was investigated using 2, 2-diphenlyl-1-picrylhadrazyl (DPPH), free radical scavenging assay. The anti-inflammatory activity of P. capensis extracts was evaluated against both cyclooxygenase enzymes (COX 1 and 2).

RESULTS

The ethyl acetate extracts of P. capensis showed a strong antimicrobial activity against B. cereus, K. pneumonia, S. pyogenes, and M. smegmatis with MIC value of 0.39 and 0.78 mg/ml. While the ethanol bark extract was most active against M. smegmatis with MIC value of 0.78 mg/ml; the least potent activity was observed with dichloromethane, chloroform and water extracts, with an MIC value ranging from 1.56 mg/ml to 50.0 mg/ml. The plant extracts proved to be good antioxidant agent, whereas extracts of ethanol were the most active, with IC50 ranging from 1.00 to 1.74 µg/ml, which is lower, and in close range to Vitamin C (1.40 µg/ml).

CONCLUSIONS

Its moderation to potent inhibitory activity was observed in all extracts. Ethanol and dichloromethane extracts were among the most potent when compared to water and petroleum ether extracts. The water extracts showed to be nontoxic on the Hek cell line with an IC50 value of 204.0, and 207.3 µg/ml (roots and bark) respectively. The dichloromethane, ethyl acetate, chloroform and ethanol extracts showed to be toxic on the Hek cell, with IC50 range from 5.94 to 42.91µg/ml. The results obtained indicate the effectiveness of these plants.

Antioxidant property and storage stability of quince juice phenolic compounds

The aim of this study was to characterise, in depth, 11 quince cultivars to provide data for their industrial processing into high-quality juices. Polyphenolic composition analyses (identification and quantification), soluble fraction of procyanidins, antioxidant capacity assays and cluster analysis were measured. A total of 19 kinds of polyphenolic compounds were the following in the juices: before and after 6 month of storage time at 4 and 30 °C. Large variations in polyphenolic compounds content were found as affected by quince cultivar. The total phenolics determined by UPLC ranged from 4045 mg to 721 mg/100 mL of juices, and was high correlated with antioxidant activity. During 6 months of storage a significant change was observed in the content of polyphenols, especially in procyanidins (37% and 55%, respectively). This result may be useful for the juice industry as a starting point for the development of tasty quince juices with high levels of bioactive compounds.

Antibacterial and anti-inflammatory effects of Syzygium jambos L. (Alston) and isolated compounds on acne vulgaris

BACKGROUND

Acne vulgaris is a chronic skin disorder leading to inflammation as a result of the production of reactive oxygen species due to the active involvement of Propionibacterium acnes (P. acnes) in the infection site of the skin. The current study was designed to assess the potential of the leaf extract of Syzygium jambos L. (Alston) and its compounds for antibacterial and anti-inflammatory activity against the pathogenic P. acnes.

METHODS

The broth dilution method was used to assess the antibacterial activity. The cytotoxicity investigation on mouse melanocyte (B16-F10) and human leukemic monocyte lymphoma (U937) cells was done using sodium 3'-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitrobenzene sulfonic acid hydrate (XTT) reagent. The non-toxic concentrations of the samples was investigated for the suppression of cytokines interleukin 8 (IL 8) and tumour necrosis factor (TNF α) by testing the supernatants in the co-culture of the human U937 cells and heat killed P. acnes using enzyme immunoassay kits (ELISA). The statistical analysis was done using the Graph Pad Prism 4 program.

RESULTS

Bioassay guided isolation of ethanol extract of the leaves of S. jambos led to the isolation of three known compounds namely; squalene, an anacardic acid analogue and ursolic acid which are reported for the first time from this plant. The ethanol extract of S. jambos and one of the isolated compound namely, anacardic acid analogue were able to inhibit the growth of P. acnes with a noteworthy minimum inhibitory concentration (MIC) value of 31.3 and 7.9 μg/ml, respectively. The ethanol extract and three commercially acquired compounds namely; myricetin, myricitrin, gallic acid exhibited significant antioxidant activity with fifty percent inhibitory concentration (IC50) ranging between 0.8-1.9 μg/ml which was comparable to that of vitamin C, the reference antioxidant agent. The plant extract, compounds ursolic acid and myricitrin (commercially acquired) significantly inhibited the release of inflammatory cytokines IL 8 and TNF α by suppressing them by 74 - 99%. TEM micrographs showed the lethal effects of selected samples against P. acnes.

CONCLUSIONS

The interesting antibacterial, antioxidant and anti-inflammatory effects of S. jambos shown in the present study warrant its further investigation in clinical studies for a possible alternative anti-acne agent.

Thyme oil vapour and modified atmosphere packaging reduce anthracnose incidence and maintain fruit quality in avocado

BACKGROUND

Postharvest application of prochloraz fungicide is commercially practiced to control anthracnose, a postharvest disease in avocado. Increasing consumer concern regarding food safety and demand for organically produced fruits make it necessary to search for natural environmentally friendly alternative products and processes for the fruit industry.

RESULTS

A combination of modified atmosphere packaging (MAP; ∼8% CO₂, 2% O₂) plus thyme oil (TO) was evaluated on the incidence and severity of anthracnose, physiological disorders (grey pulp, vascular browning), fruit quality parameters (L*, h°, firmness, weight loss) and sensory parameters (taste, texture, flavour and overall acceptance), phenylalanine ammonia-lyase (PAL) enzyme activity, total phenolic compounds, flavonoid contents and antioxidant activity in avocados ('Fuerte' and 'Hass' cultivars) held at 10 °C cold storage for 18 days and thereafter, ripened at 25 °C for 5-10 days. Stand-alone MAP, commercial treatment (prochloraz 0.05%) and untreated (control) fruit were included for comparison. MAP + TO treatment significantly (P < 0.05) reduced the incidence and severity of anthracnose, grey pulp, vascular browning, weight loss and loss of fruit firmness, and showed acceptable taste, flavour, texture and higher overall acceptance, increased PAL activity, total phenolic compounds, flavonoid contents and antioxidant activity, after ripening at 25 °C followed by cold storage at 10 °C.

CONCLUSION

This investigation recommends MAP + TO combination treatment as a suitable alternative to the currently adopted prochloraz application.

The comparative effects of atorvastatin and quince leaf extract on atherosclerosis

Background

This study investigates the ability of quince leaf extract to prevent progression of atherosclerosis and to determine the lipid-lowering effect of it.

Objectives

This study suggested that quince leaf effects on progression of atherosclerosis, and performed comparison with atorvastatin as a standard medication.

Materials and Methods

The effect of 50mg/kg of the quince leaf extract on lipid profiles was assessed by measuring the levels of totalcholesterol, triglyceride, LDL, HDL, and liver enzymes (AST, ALT, and AP) in plasma and were evaluated the thickness of aortic plaques in the hypercholesterolemic rabbits after stopping. These assessments were performed using 0.5 mg/kg of atorvastatin.

Results

Oral administration of cholesterol for 8 weeks resulted in a significant increase (P < 0.05) in plasma markers. Treatment with the extract at dose of 50 mg/kg and 0.5 mg/kg of atorvastatin not only were reduced lipid profile in plasma (P < 0.05) but also were increased HDL-cholesterol levels. There were decrease (P = 0.04) in the liver enzymes in extract treated rabbits. However, plaque thickness had no significant difference in the aorta of treated rabbits compared with studied control.

Conclusions

These results indicate the lipid-lowering effects of quince leaf similar to atorvastatin and it can probably serve as a new potential natural product for atherosclerosis treatment.

Antioxidant activity of ripe and unripe pepino fruit (Solanum muricatum Aiton)

Ripe and unripe exotic pepino fruit were evaluated for antioxidant activity, total phenols, and flavonoid content. The antioxidant potency was investigated by employing various established in vitro systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2-2'-azinobis(3-ethylbenthiazoline-6-sulphonic acid (ABTS), hydroxyl radical scavenging, reducing power, ferrous ion chelation, ferric reducing antioxidant power (FRAP), and lipid peroxidation. The EC(50) values of ripe ethanolic extract on DPPH radical, reducing power, ferrous ion chelation, ABTS radical, FRAP, hydroxyl radical, lipid peroxidation (brain), and lipid peroxidation (liver) were obtained to be 2.20, 2.81, <5.00, 34.06, 8.53, 1.30, 1.75, and 0.51 mg/mL, respectively. However, the EC(50) values for unripe fruit extract were noted to be 3.75, 3.40, 11.25, 40.12, 9.75, 0.80, 1.91, and 0.63 mg/mL, respectively. Ripe fruit exhibited the highest values of antioxidant activity in all the scavenging assays except for hydroxyl radical scavenging assay. Ripe pepino had higher total phenol and flavonoid content than unripe fruit. This study suggests that possible mechanism of the biological activities may be due to free radical scavenging and antioxidant characteristics, which may be due to the presence of polyphenols in the fruit extracts.

PRACTICAL APPLICATION

The ripe and unripe pepino fruit have excellent antioxidant properties, so the results obtained in this study clearly indicate that pepino fruit has a significant potential to use as a natural antioxidant agent and possibly as a food supplement.

Anticancer Activity of Certain Herbs and Spices on the Cervical Epithelial Carcinoma (HeLa) Cell Line

Acetone extracts of selected plant species were evaluated for their in vitro cytotoxicity against a noncancerous African green monkey kidney (Vero) cell line and an adenocarcinoma cervical cancer (HeLa) cell line. The plants studied were Origanum vulgare L. (Oregano), Rosmarinus officinalis L. (Upright and ground cove rosemary), Lavandula spica L. (Lavender), Laurus nobilis L. (Bay leaf), Thymus vulgaris L. (Thyme), Lavandula x intermedia L. (Margaret Roberts Lavender), Petroselinum crispum Mill. (Curly leaved parsley), Foeniculum vulgare Mill. (Fennel), and Capsicum annuum L. (Paprika). Antioxidant activity was determined using a quantitative DPPH (1,1-diphenyl-2-picryl hydrazyl) assay. The rosemary species exhibited effective radical scavenging capacity with 50% inhibitory concentration (IC(50)) of 3.48 ± 0.218 μg/mL and 10.84 ± 0.125 μg/mL and vitamin C equivalents of 0.351 g and 1.09 g for McConnell's Blue and Tuscan Blue, respectively. Cytotoxicity was measured using XTT (Sodium 3'-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate) colorimetric assay. Only L. nobilis and O. vulgare exhibited pronounced effects on the HeLa cell line. Dose-dependent studies revealed IC(50) of 34.46 ± 0.48 μg/mL and 126.3 ± 1.00 μg/mL on the HeLa cells and on the Vero cells 124.1 μg/mL ± 18.26 and 163.8 μg/mL ± 2.95 for L. nobilis and O. vulgare, respectively. Light (eosin and haematoxylin staining) and confocal microscopy (Hoechst 33342, acridine orange, and propidium iodide staining) were used to evaluate the cytotoxic mechanism of action for L. nobilis and O. vulgare.

Evaluation of the effect of green tea extract on mouth bacterial activity in the presence of propylene glycol

BACKGROUND

Compounds present in green tea have proved to inhibit the growth and activity of bacteria associated with infections.

OBJECTIVES

To assess the effects of green tea leaves extract in presence of propylene glycol on the aerobic mouth bacteria load.

MATERIALS AND METHODS

Saliva of 25 volunteer girl students aging 20-25 years were selected and evaluated by a mouthwash sample containing 1% tannin, as the most effective antibacterial complex in green tea. Comparative studies were also conducted between green tea mouthwashes containing 1% tannin and a similar sample with 10% propylene glycol added during extraction. This comparison was applied for a chlorhexidine 0.2% sample as a chemical mouthwash brand, too.

RESULTS

There was a meaningful difference between the green tea mouthwashes containing 10% propylene glycol and the simple green tea extract (P < 0.05). Significant difference was also seen between the herbal and chemical mouthwashes (P < 0.05). The extract 1% tannin containing 10% propylene glycol reduced the aerobic mouth bacterial load of the student salvia about 64 percent. The pH monotonousness in different days and temperatures approved the stability of tannin in liquid water medium.

CONCLUSIONS

Using green tea extract as a herbal mouthwash is safe and harmless specially for children and pregnant women. This result led us to suppose that green tea may prevent plaque formation on teeth, coming over halitosis due to mouth infection, too. These effects need to be approved in an in vivo trial as a second study.

In vitro chemo-preventative activity of Crotalaria agatiflora subspecies agatiflora Schweinf

ETHNOPHARMACOLOGICAL RELEVANCE

Crotalaria species have been widely used in Chinese traditional medicine to treat several types of internal cancers. Crotalaria agatiflora is used as a medicinal plant in several African countries for the treatment of bacterial and viral infections as well as for cancer.

MATERIALS AND METHODS

Water and ethanol extracts of the leaves of Crotalaria agatiflora were evaluated for cytotoxicity on four cancerous and one noncancerous cell lines, using XTT (Sodium 3'-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate) colorimetric assay. Antioxidant activity was determined using DPPH (1,1-diphenyl-2-picryl hydrazyl). Light microscopy (eosin and haematoxylin staining) and flow cytometry (Annexin-V and propidium iodide) were used to evaluate the mechanism of action of the ethanol extract and one of the isolated compounds.

RESULTS

The 50% inhibitory concentration (IC(50)) of the ethanol extract was found to be 73.9 μg/mL against leukemic U-937 cells. Good antioxidant activity (IC(50)=18.89 μg/mL) of the ethanol extract indicated the potential of Crotalaria agatiflora as chemo-preventative supplement. A bioassay guided fractionation of the ethanol extract led to the isolation of two pure compounds, namely madurensine and doronenine. Madurensine and doronenine showed moderate cytotoxicity on cancerous U-937 cells (IC(50) values: 47.97 and 29.57 M respectively). The crude extract treated U-937 cells showed definite signs of cell death during light microscopic investigation, while little apoptosis (10-20%) and necrosis (<2%) were detected in cells treated with the extract or madurensine.

CONCLUSIONS

The results indicated that Crotalaria agatiflora possesses potential chemopreventative and therapeutic properties. The exact mechanism of action should still be determined in future studies. It is hypothesized that the ethanolic extract as well as madurensine induces autophagy, which in prolonged circumstances may lead to autophagic cell death.

Tyrosinase activity of Greyia flanaganii (Bolus) constituents

Hyper-pigmentation of the skin is a common problem that is prevalent in middle aged and elderly people. It is caused by over production of melanin. Tyrosinase is known to be the key enzyme in melanin production. Ethanolic extract of Greyia flanaganii leaves showed significant (P<0.05) antityrosinase activity exhibiting the IC₅₀ of 32.62 μg/ml. The total extract was further investigated for its toxicity and effect on melanin production by melanocytes cells, and showed significant inhibition (P<0.05) (20%) of melanin production at 6.25 μg/ml and low levels of cytotoxicity (IC₅₀<400 μg/ml). The amount of antioxidants necessary to decrease the initial DPPH absorbance by 50% (EC₅₀) by the total ethanolic extract was found to be 22.01 μg/ml. The effect of G. flanaganii against acne causing bacteria, Propionibacterium acnes, was investigated using microdilution assay. The MIC of the extract of G. flanaganii was found to be 250 μg/ml. Bioassay-guided fractionation led to the isolation of (3S)-4-hydroxyphenethyl 3-hydroxy-5-phenylpentanoate (1), 2',4',6'-trihydroxydihydrochalcone (2), 2',6',4-trihydroxy-4'-methoxydihydrochalcone (3), 2',6'-dihydroxy-4'-methoxydihydrochalcone (4), 5,7-dihydroxyflavanone [(2S)-pinocembrin] (5), 2',6'-dihydroxy-4',4-dimethoxy dihydrochalcone (6) and (2R,3R)-3,5,7-trihydroxy-3-O-acetylflavanone (7). The isolated compounds were tested for their antioxidant, cytotoxicity, tyrosinase inhibition and antibacterial activities. Compound 2 exhibited significant (P<0.05) antityrosinase activity exhibiting the IC₅₀ of 69.15 μM. The isolated compounds showed low toxicity of the cells with reduction of melanin content of the cells. All compounds tested showed good radical scavenging activity. These data indicates that G. flanaganii extract and its isolated phenolic constituents could be possible skin lightening agents.