Antibacterial and Antifungal Survey in Plants used in Indigenous Herbal-Medicine of South East Regions of Iran

Antibacterial Activity of Juglone Revealed in a Wound Model of Staphylococcus aureus Infection

A serious problem currently facing the field of wound healing is bacterial infection, especially Staphylococcus aureus (S. aureus) infection. Although the application of antibiotics has achieved good effects, their irregular use has resulted in the emergence of drug-resistant strains. It is thus the purpose of this study to analyze whether the naturally extracted phenolic compound, juglone, can inhibit S. aureus in wound infection. The results show that the minimum inhibitory concentration (MIC) of juglone against S. aureus was 1000 μg/mL. Juglone inhibited the growth of S. aureus by inhibiting membrane integrity and causing protein leakage. At sub-inhibitory concentrations, juglone inhibited biofilm formation, the expression of α-hemolysin, the hemolytic activity, and the production of proteases and lipases of S. aureus. When applied to infected wounds in Kunming mice, juglone (50 μL juglone with a concentration of 1000 μg/mL) significantly inhibited the number of S. aureus and had a significant inhibitory effect on the expression of inflammatory mediators (TNF-α, IL-6 and IL-1β). Moreover, the juglone-treated group promoted wound healing. At the same time, in animal toxicity experiments, juglone had no obvious toxic effects on the main tissues and organs of mice, indicating that juglone has good biocompatibility and has the potential to be used in the treatment of wounds infected with S. aureus.

Herbal Arsenal against Skin Ailments: A Review Supported by In Silico Molecular Docking Studies

Maintaining healthy skin is important for a healthy body. At present, skin diseases are numerous, representing a major health problem affecting all ages from neonates to the elderly worldwide. Many people may develop diseases that affect the skin, including cancer, herpes, and cellulitis. Long-term conventional treatment creates complicated disorders in vital organs of the body. It also imposes socioeconomic burdens on patients. Natural treatment is cheap and claimed to be safe. The use of plants is as old as mankind. Many medicinal plants and their parts are frequently used to treat these diseases, and they are also suitable raw materials for the production of new synthetic agents. A review of some plant families, viz., Fabaceae, Asteraceae, Lamiaceae, etc., used in the treatment of skin diseases is provided with their most common compounds and in silico studies that summarize the recent data that have been collected in this area.

GC-MS and molecular docking analyses of phytochemicals from the underutilized plant, Parkia timoriana revealed candidate anti-cancerous and anti-inflammatory agents

Plants are excellent sources of functionally bioactive compounds and essential nutrients. The phytochemical constituents have enormous potential in treating both plant and human diseases. Parkia timoriana (Yongchak/Zawngtah), one of the most important underutilized plants popularly consumed in Manipur and Mizoram states of Northeastern region of India, is known for its ethnobotanical and ethnomedicinal values. A significant DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), and Phosphomolybdate scavenging activity corresponding to high antioxidant potentials was shown by the extracts from different edible parts of P. timoriana. P. timoriana extract showed significant antibacterial potential against Bacillus pumilus, Bacillus subtillis, Escherichia coli and Pseudomonas aeruginosa. Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry (GC-MS) analyses of the extracts revealed the functional groups and bioactive compounds present in different edible parts of the plant. Characteristic peaks of phenols, carboxylic acids, alkenes, glycogen, alkyl halides, halogen, aliphatic amines, primary and secondary amines, esters, ether, aromatics, lipids, triglycerides, nitro compounds that had antimicrobial, anti-cancer and anti-inflammatory properties etc. were observed. The GC-MS analysis also revealed the occurrence of 49 bioactive compounds that are known to possess a variety of pharmacological activities. Subsequently, in silico molecular docking studies of the identified bioactive compounds predicted potential anticancer and anti-inflammatory properties. To the best of our knowledge, this is the first-hand report on the bioactive compounds of edible parts of P. timoriana extracts showing antioxidant, antimicrobial and pharmacological significance. This study can lead to the production of new herbal medicines for various diseases employing P. timoriana and perhaps leading to the creation of new medications.

Investigating the Effects of Aqueous and Alcoholic Extracts of Allium Hirtifolium and Allium Jesdianum on Keratinase Activity of Trichophyton Mentagrophytes

Background:

Trichophyton spp., as pathogenic species to humans and animals, cause different forms of dermatophytosis through the production of particular enzymes, playing an essential role in tissue invasion. Among these, herein, keratinase was investigated, for the specific case of Trichophyton mentagrophytes, as a target of the effects of Allium hirtifolium and Allium jesdianum extracts, thus pharmacological potential of these plants was studied against keratinase activity.

Methodology:

Sampling was carried out on 20 bald patients from medical diagnostic laboratories and mycology centers, with suspected dermatophytosis of scalp. For confirming the presence of Trichophyton mentagrophytes in the specimens, different laboratory procedures were applied. Trichophyton mentagrophytes isolates were cultured on a screening medium containing keratin to verify production of the keratinase enzyme. The best enzyme-producing isolate was selected by measuring diameter of transparent halo around colony to be used in subsequent stages. Afterwards, the optimized conditions maximizing enzyme production and activity were determined. Finally, the inhibitory effect of different dilutions of aqueous and alcoholic extracts of Allium jesdianum and Allium hirtifolium on extracellular keratinase activity was studied.

Results :

Sixteen out of 20 fungal isolates were identified as the Trichophyton mentagrophytes. The most desirable reduction on keratinase activity was reported for dilution values of 50 and 100 mg/ml of both aqueous and ethanolic extracts of A.jesdianum, though much more significant decrease belonged to the latter, and for dilution values of 25 and 100 mg/ ml of both aqueous and ethanolic extracts of A.hirtifolium.

Conclusion :

Concerning our results, it is suggested that paying special attention to these natural compounds for the treatment of dermatophytosis could be remarkably effective, considering significant production of keratinase observed in T. mentagrophytes, and they are beneficial, as they have no side effects and offer an alternative to currently available medications, which are under the restriction of drug resistance.

The Effects of Nutraceuticals and Herbal Medicine on Candida albicans in Oral Candidiasis: A Comprehensive Review

Candida albicans is part of the healthy flora in the oral cavity. It can also cause opportunistic infection, which can be deleterious. The most typical type of chronic oral candidiasis is denture stomatitis, and C. albicans is identified as the most crucial organism in this situation. Due to the development of the resistant form of candida, using conventional drugs can sometimes be ineffective. Herbs and naturally imitative bioactive compounds could become a new source for antimycotic therapy. Several review studies suggest that herbal medicine and natural bioactive compounds have antibacterial, antiviral and antifungal effects. Thus, it is hypothesized that these natural products might have beneficial effects on pathogenic oral fungal flora such as C. albicans. Although the effects of herbs have been investigated as antifungal agents in several studies, to the best of our knowledge, the effects of these natural products on C. albicans have not yet been reviewed. Thus, the aim of this study was to review the anti-candida activity (especially C. albicans in oral candidiasis) of herbal medicines and natural bioactive compounds. It is concluded that, in general, medicinal plants and nutraceuticals such as garlic, green tea, propolis, curcumin, licorice root, cinnamon, resveratrol, ginger, and berberine are useful in the treatment of C. albicans in oral candidiasis and could be considered as a safe, accessible, and inexpensive management option in an attempt to prevent and treat oral diseases. However, most of the evidence is based on the in vitro and animal studies, so more clinical trials are needed.

Enhanced antibacterial and antiparasitic activity of multifunctional polymeric nanoparticles

Due to the resistance to drugs, studies involving the combination and controlled release of different agents are gradually increasing. In this study, two different active ingredients, known to have antibacterial and antiparasitic activities, were encapsulated into single polymeric nanoparticles. After co-encapsulation their antibacterial and antileishmanial activity was enhanced approximately 5 and 250 times, respectively. Antibacterial and antileishmanial activities of caffeic acid phenethyl ester and juglone loaded, multifunctional nanoformulations (CJ4-CJ6-CJ8) were also evaluated for the first time in the literature comparatively with their combined free formulations. The antibacterial activity of the multifunctional nanoformulation (CJ8) were found to have a much higher activity (MIC values 6.25 and 12.5 μg ml^-1 for S. aureus and E. coli, respectively) than all other formulations. Similar efficacy for CJ8 was obtained in the antiparasitic study against the Leishmania promastigotes and the IC₅₀ was reduced to 0.1263 μg ml^-1. The high activity of multifunctional nanoparticles is not only due to the synergistic effect of the active molecules but also by the encapsulation into polymeric nanoparticles. Therefore, it has been shown in the literature for the first time that the biological activity of molecules whose activity is increased by the synergistic effect can be improved with nanosystems.

Cytotoxic and mutagenic potential of juglone: a comparison of free and nano-encapsulated form

Despite its evidenced beneficial herbicidal, antibacterial, antiviral, antifungal, and antioxidant effects, the application of juglone (5-hydroxy-1,4,-naphthoquinone) is limited due to its low water solubility and allelopathic and toxic effects. In recent years, research has aimed to overcome these limitations by increasing its solubility and controlling its release through nanoparticular systems. This is the first study to have synthesised and characterised juglone-loaded polymeric nanoparticles and compared them with free juglone for cytotoxicity in mouse (L929 fibroblasts) and alfalfa cells and for mutagenic potential in Salmonella typhimurium TA98/100. Mouse and plant cells treated with free and nano-encapsulated juglone showed a decrease in cell viability in a dose and time-dependent manner, but this effect was significantly lower with the nano-encapsulated form at lower doses. In the TA98 strain with S9, nano-encapsulated juglone did not exhibit mutagenic effects, unlike the free form. Since all results show that juglone encapsulation with polymeric nanoparticles reduced the toxic and mutagenic effects, it has a promising potential to be applied in medicine, food safety, and agriculture.

An ethnobotanical study of medicinal plants used to treat skin diseases in northern Pakistan

Background

Skin diseases are a major health concern especially in association with human immune deficiency syndrome and acquired an immune deficiency. The aim of this study was to document the ethnomedicinal information of plants used to treat skin diseases in Northern Pakistan. This is the first quantitative ethnobotanical study of therapeutic herbs utilized by the indigenous people of Northern Pakistan for skin diseases.

Methods

Interviews were taken to obtain information from 180 participants. Quantitative methods including fidelity level (FL), Frequency of citation (FC), Use-value (UV), Jaccard indices (JI), Family importance value (FIV), Relative frequency of citation (RFC) and Chi-square test were applied. Medicinal plants uses are also compared with 50 national and international publications.

Results

In this study, we recorded 106 plant species belonged to 56 floral families for treatment of skin ailments. The dominant life form reported was herb while the preferred method of utilization was powder, along with leaf as the most used plant part. RFC ranges from 0.07 to 0.25% whereas the highest FIV was recorded for family Pteridaceae. FL values range from 36.8 to 100%. The study reported 88% of new plant reports for the treatment of skin diseases.

Conclusion

The present study revealed the importance of several plants used to treat skin diseases by the local communities of Northern Pakistan. The available literature supported the evidence of plant dermatological properties. Plants having high UV and RFC can be considered for further scientific analysis. There is dire need to create awareness among local, government and scientific communities for the preservation of medicinal species and ethnomedicinal knowledge in Northern Pakistan.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2605-6) contains supplementary material, which is available to authorized users.

Juglone in Oxidative Stress and Cell Signaling

Juglone (5-hydroxyl-1,4-naphthoquinone) is a phenolic compound found in walnuts. Because of the antioxidant capacities of phenolic compounds, juglone may serve to combat oxidative stress, thereby protecting against the development of various diseases and aging processes. However, being a quinone molecule, juglone could also act as a redox cycling agent and produce reactive oxygen species. Such prooxidant properties of juglone may confer health effects, such as by killing cancer cells. Further, recent studies revealed that juglone influences cell signaling. Notably, juglone is an inhibitor of Pin1 (peptidyl-prolyl cis/trans isomerase) that could regulate phosphorylation of Tau, implicating potential effects of juglone in Alzheimer’s disease. Juglone also activates mitogen-activated protein kinases that could promote cell survival, thereby protecting against conditions such as cardiac injury. This review describes recent advances in the understanding of the effects and roles of juglone in oxidative stress and cell signaling.

Assessment of the Impact of Different Treatments on the Technological and Antifungal Properties of Papyrus (Cyperus Papyrus L.) Sheets

In the present work, sheets of Papyrus (Cyperus papyrus L.), manufactured by lamination from strips pre-treated with different treatments, were evaluated for their technological and fungal infestation properties (Aspergillus flavus AFl375, A. niger Ani245 and Colletotrichum gloeosporioides Cgl311). The results showed that the highest values of tensile strength, tear strength, burst index and double-fold number were observed in papyrus sheets produced from strips treated with nano-cellulose (0.25%), dimethyl sulfoxide (DMSO 10%), Tylose (0.25%) and nano-cellulose (0.5%), with values of 98.90 N·m/g, 2343.67 mN·m²/g, 1162 kpa·m²/g and 8.33, respectively. The percentage of brightness ranged from 49.7% (strips treated with KOH 2% + 100 mL NaClO) to 9.6% (strips treated with Eucalyptus camaldulensis bark extract 2%), while the percentage of darkness ranged from 99.86% (strips treated with Salix babylonica leaf extract 2% or E. camaldulensis bark extract 0.5%) to 67.26% (strips treated with NaOH (2%) + 100 mL NaClO). From the SEM examination, sheets produced from treated strips with extracts from P. rigida and E. camaldulensis or S. babylonica showed no growths of A. flavus and C. gloeosporioides. Additionally, other pre-treatments, such as Nano-cellulose+Tylose 0.5% (1:1 v/v) and Tylose 0.5%, were also found to have no growth of A. niger. In conclusion, strips pre-treated with nanomaterials and extracts were enhanced in terms of the technological and antifungal properties of produced Papyrus sheets, respectively.

Ethnobotany of the genus Taraxacum-Phytochemicals and antimicrobial activity

Plants belonging to the genus Taraxacum have been used in traditional healthcare to treat infectious diseases including food-borne infections. This review aims to summarize the available information on Taraxacum spp., focusing on plant cultivation, ethnomedicinal uses, bioactive phytochemicals, and antimicrobial properties. Phytochemicals present in Taraxacum spp. include sesquiterpene lactones, such as taraxacin, mongolicumin B, and taraxinic acid derivatives; triterpenoids, such as taraxasterol, taraxerol, and officinatrione; and phenolic derivatives, such as hydroxycinnamic acids (chlorogenic, chicoric, and caffeoyltartaric acids), coumarins (aesculin and cichoriin), lignans (mongolicumin A), and taraxacosides. Aqueous and organic extracts of different plant parts exhibit promising in vitro antimicrobial activity relevant for controlling fungi and Gram-positive and Gram-negative bacteria. Therefore, this genus represents a potential source of bioactive phytochemicals with broad-spectrum antimicrobial activity. However, so far, preclinical evidence for these activities has not been fully substantiated by clinical studies. Indeed, clinical evidence for the activity of Taraxacum bioactive compounds is still scant, at least for infectious diseases, and there is limited information on oral bioavailability, pharmacological activities, and safety of Taraxacum products in humans, though their traditional uses would suggest that these plants are safe.

Green synthesis and characterisation of CuNPs: insights into their potential bioactivity

The current investigation involves the green synthesis of copper nanoparticles (CuNPs) from an aqueous plant extract of Moringa oleifera Lam by two methods: (I) time‐based approach and (II) heat treatment of aqueous solution. Prepared CuNPs were characterised via Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy and transmission EM. The study also reveals the potential bioactivity of the prepared CuNPs. In vitro anti‐microbial efficiency of CuNPs was estimated against bacterial and fungal strains by the agar well diffusion method. Anti‐oxidant capacity of CuNPs was determined using ferric reducing ability of plasma (FRAP), lipid peroxidation (LPO) and peroxidase assays, while the antiplatelet potential was determined by measuring two haemostatic parameters (PT & APTT assay). The minimum inhibitory concentration was observed at 60 µg/ml against Streptomyces griseus and Aspergillus niger when NPs were prepared by method II. CuNPs prepared by the method I showed higher FRAP and LPO activities, while increased POX activity was found in CuNPs prepared by method II. CuNPs prepared using method I also showed better anti‐oxidant and antiplatelet potential. It was observed that M. oleifera ‐derived CuNPs exhibits strong anti‐microbial, anti‐oxidant and APTT potential. This indicates potential utilization of green synthesized NPs for various industrial and therapeutic strategies.

Synthesis, characterization and antibacterial activity of juglone encapsulated PLGA nanoparticles

AIMS

The aim of the study was to examine the effect of different process parameters which including; initial juglone amount, initial poly(d,l-lactide co-glycolide) amount, polyvinyl alcohol volume and polyvinyl alcohol concentration on encapsulation of juglone to poly(d,l-lactide co-glycolide) nanoparticles.

METHODS AND RESULTS

The synthesized nanoparticle formulations were analyzed for reaction yield, encapsulation efficiency, particle size, polydispersity, zeta potential and juglone release. In conjunction with the highest encapsulation rate, the highest amount of juglone release was obtained for F4 formulation, which has 281·8 nm particle size, 0·217 polydispersity index, and -19·55 mV zeta potential. After the detailed physicochemical characterization of this formulation, the four different kinetic models were used and it was found that juglone release mechanism controlled by Fickian diffusion method. According to antimicrobial activity results, minimal inhibitory concentration (MIC) values of both F4 and free juglone is higher for Gram negative bacteria than Gram positive bacteria. Inhibition zone diameters in the quantitative methods are found 15 and 16 mm for Staphylococcus aureus, 9 and 7 mm for Bacillus cereus, respectively, for F4 and free juglone. Moreover, the MIC values for qualitative methods were found 31·5 μg ml^-1 for two bacteria strains.

CONCLUSIONS

It was found that the antibacterial activity of the juglone nanoparticles was higher and longer than the free juglone. Additionally, a similar antimicrobial effect with a lower juglone amount (obtained from controlled release study) indicates that nanoparticle formulation is more effective.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of nanoparticle formulations of juglone in biological systems and applications could be more beneficial than its free form due to its toxicity.

Evaluation of the proximate composition, antioxidant potential, and antimicrobial activity of mango seed kernel extracts

After pulp extraction in fruit processing industry, a significant quantity of mango seed kernels are discarded as solid wastes. These seed kernels can be ideal raw materials for obtaining extracts rich in bioactive compounds with good antioxidant properties. The conversion of these wastes into utilizable food ingredients would help in reducing environmental problems associated with processing waste disposal. In order to determine their potential use, this study evaluated some of the biochemical characteristics and antimicrobial potential of mango seed kernel extracts on medically important human bacterial and fungal pathogens. Four mango varieties (Apple, Ngowe, Kent and Sabine) from Makueni and Embu counties in Kenya were used for this study. The analyzed mango seed kernel powders were found to contain on average, 6.74-9.20% protein content. Apple and Ngowe mango seed kernels had significantly higher fat content of 13.04 and 13.08, respectively, while Sabine from Makueni had the least fat content of 9.84%. The ash, fiber, and carbohydrate contents ranged from 1.78 to 2.87%, 2.64 to 3.71% and 72.86 to 75.92%, respectively. The mean percentage scavenging ability of mango kernel extracts at the concentration of 20 mg/mL was 92.22%. Apple and Sabine mango kernel extracts had significantly high inhibition zones of 1.93 and 1.73 compared to Kent and Ngowe with 1.13 and 1.10, respectively, against E. coli. For C. albicans, the inhibition of Kent mango kernel extract, 1.63, was significantly lower than that of Ngowe, Apple, and Sabine with 2.23, 2.13, and 1.83, respectively. This study demonstrates that mango seed powder is an abundant and cost-effective potential natural antibiotic and antifungal that can be utilized in addressing the challenge of food poisoning and infections caused by pathogenic microorganisms in the food industry.

Enhancement of Antifungal Activity of Juglone (5-Hydroxy-1,4-naphthoquinone) Using a Poly(d,l-lactic-co-glycolic acid) (PLGA) Nanoparticle System

This study aimed to synthesize and characterize juglone-entrapped poly(d,l-lactic-co-glycolic acid) (PLGA) nanoparticles and compare the antifungal properties of free juglone with its PLGA nanoparticle formulation for the first time. The juglone-loaded nanoparticles prepared using the oil-in-water (o/w) single-emulsion solvent evaporation method were characterized by the reaction yield (RY), encapsulation efficiency (EE), polydispersity index (PDI), particle size, zeta potential (ZP), FT-IR, and in vitro release properties and evaluated for their morphological features using SEM. The nanoparticle formulation had size, RY, ZP, EE, and PDI values of 212 nm, 66.91 ± 2.4%, -16.3 ± 0.7 mV, 70.66 ± 3.1%, and 0.083 ± 0.024, respectively. In vitro release showed a triphasic pattern with initial burst followed by sustained release and dormant phase over the study period, releasing about 72.8% in total after 42 days. The antifungal studies against Aspergillus flavus, Candida albicans, and Fusarium spp. using agar dilution and top agar dilution methods indicated that the juglone-encapsulated nanoparticle was more effective than free juglone. This study showed that the top agar method, which was applied for the first time on antifungal activity, is more suitable for the nanoparticular system based on sustained release. Therefore, PLGA nanoparticle formulations may be an important tool for application in many areas for the effective and beneficial use of hydrophobic compounds such as juglone.

Comparative effect of propolis of honey bee and some herbal extracts on Candida albicans

OBJECTIVES

To determine the effect of propolis on Candida albicans and to compare it with the effects of some other herbal extracts and antibiotics on this pathogenic fungi.

METHODS

The extracts of propolis, Thymus vulgaris, Caryophillium aromaticus, Echinophora platyloba, Allium cepa and Cinnamomum zeylanicum were prepared and the antifungi effects of the extracts were examined on Candida albicans ATCC10231 using disc-diffusion assay and micro-broth dilution. The minimum fungicidal concentration (MFC) and minimum inhibitory concentrations (MIC) as well as inhibition zone were evaluated and the anti fungi effects of herbal extracts were compared with amphotricin B and nystatin at the times of 24, 48 and 72 h. Data analysis was performed using t test.

RESULTS

Obtained results showed that propolis extract with MIC₉₀ and MFC equal to 39 and 65 μg/mL, respectively, possess the highest antifungal activity when compared with other studied extracts. The extracts of Allium cepa and Thymus vulgaris, with MFC of 169 and 137 μg/mL, respectively, showed the lowest effects on the fungi. Also nystatin and amphotricin B yielded better effects on the tested fungi compared with the effects of all studied extracts on Candida albicans.

CONCLUSION

Propolis extract is effective in controlling Candida albicans. However, the issue requires further investigation on samples in animals and performing toxicological examinations.

The comparative study of antifungal activity of Syzygium aromaticum, Punica granatum and nystatin on Candida albicans; an in vitro study

AIM

Candida species are opportunistic fungi, among which, Candida albicans is the most important species responsible for infections in immunocompromised patients with invasive fungal disease. Resistance of Candida species to antifungal drugs has led scientists to pay more attention to traditional medicine herbs. Due to the limitations in the treatment of fungal diseases such as shortages, high prices, antifungal side effects and drug resistance or reduced susceptibility to fungal drugs we decided to study the antifungal effects of herbal extracts of Syzygium aromaticum and Punica granatum.

METHODS

Twenty-one isolates of oral C. albicans in patients with denture stomatitis referred to prosthesis department, Dental faculty of Tehran University of Medical Sciences were prepared and cultured. Plant extracts were prepared from the herbs market. Tests on patient samples and standard strains 5027ATCC (PTCC10231) yeast C. albicans were performed via well diffusion method. In addition, nystatin and methanol were used as positive and negative control, respectively. Finally, the antifungal effect of extracts using Statistical Repeated measurement ANOVA test was investigated.

RESULTS

Both S. aromaticum and P. granatum showed noticeable antifungal activity in well method. Syzygium aromaticum showed better anti candida activity than nystatin (P<0.001).

CONCLUSION

Due to increasing problems with fungal diseases, these findings suggest that the plant extracts of S. aromaticum and P. granatum showed good antifungal effects (P-value<0.001). S. aromaticum (inhibition zone diameter: 29.62) showed better antifungal effects than nystatin (inhibition zone diameter: 28.48).

Trifolium pratense L. as a potential natural antioxidant

The essential oils of three different growth stages of Trifolium pratense L. (TP1, TP2 and TP3) were investigated by gas chromatography-mass spectrometry and tested for their antioxidant and antimicrobial activities. The highest content of volatile compounds was found in the essential oil sample TP1, where terpenes such as β-myrcene (4.55%), p-cymene (3.59%), limonene (0.86%), tetrahydroionone (1.56%) were highlighted due to their biological activity. The antioxidant activity was determined by following the scavenging capacity of the essential oils for the free radicals DPPH·, NO· and O2·-, as well as effects of the investigated oils on lipid peroxidation (LP). In all three cases, the sample TP1 showed the best radical-capturing capacity for DPPH· (27.61±0.12 µg/mL), NO· (16.03±0.11 µg/mL), O2·- (16.62±0.29 µg/mL) and also had the best lipid peroxidation effects in the Fe2+/ascorbate induction system (9.35±0.11 µg/mL). Antimicrobial activity was evaluated against the following bacteria cultures: Escherichia coli (ATCC10526), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 11632) and Bacillus cereus (ATCC 10876). None of the examined essential oil samples showed inhibitory effects on the tested bacterial strains.

Antimicrobial activity and phytochemical analyses of Polygonum aviculare L. (Polygonaceae), naturally growing in Egypt

Polygonum aviculare (Polygonaceae) is an herb commonly distributed in Mediterranean coastal regions in Egypt and used in folkloric medicine. Organic and aqueous solvent extracts and fractions of P. aviculare were investigated for antimicrobial activities on several microorganisms including bacteria and fungi. Phytochemical constituents of air-dried powered plant parts were extracted using aqueous and organic solvents (acetone, ethanol, chloroform and water). Antimicrobial activity of the concentrated extracts was evaluated by determination of the diameter of inhibition zone against both Gram-negative and Gram-positive bacteria and fungi using paper disc diffusion method. Results of the phytochemical studies revealed the presence of tannins, saponins, flavonoids, alkaloids and sesquiterpenes and the extracts were active against both Gram-negative and Gram-positive bacteria. Chloroform extract gave very good and excellent antimicrobial activity against all tested bacteria and good activity against all tested fungi except Candida albicans. Structural spectroscopic analysis that was carried out on the active substances in the chloroform extract led to the identification of panicudine (6-hydroxy-11-deoxy-13 dehydrohetisane). Evaluation of the antimicrobial activity of panicudine indicated significant activity against all tested Gram-negative and Gram-positive organisms. Panicudine displayed considerable activity against the tested fungi with the exception of C. albicans. Antimicrobial activity of the extracts was unaffected after exposure to different heat treatments, but was reduced at alkaline pH. Studies of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panicudine on the tested organisms showed that the lowest MIC and the MBC were demonstrated against Salmonella paratyphi, Bacillus subtilis and Salmonella typhi and the highest MIC and MBC were against Staphylococcus aureus.

Effect of Schinus terebinthifolius on Candida albicans growth kinetics, cell wall formation and micromorphology

OBJECTIVE

To evaluate the anti-fungal activity of a tincture from Schinus terebinthifolius (Brazilian pepper tree) on Candida albicans (ATCC 289065), a micro-organism associated with fungal infections of the oral cavity.

MATERIALS AND METHODS

Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) were determined through microdilution technique, as well as the microbial growth curve of C. albicans promoted by S. terebinthifolius. In addition, this study investigated a possible activity of the product on the fungal cell wall and its biological activity on fungal morphology. Nystatin was used as control and all tests were performed in triplicate.

RESULTS

S. terebinthifolius showed MIC of 312.5 µg/mL and MFC of 2500 µg/mL upon the strain tested, while Nystatin showed MIC and MFC of 6.25 µg/mL. As regards the microbial growth curve, S. terebinthifolius was able to significantly reduce the number of CFU/mL when compared to growth control until the time of 60 min. In the times 120 and 180 min there was no statistically significant difference between the growth control and the experimental product. S. terebinthifolius possibly acts on the fungal cell wall, once the sorbitol test indicated a MIC of 1250 µg/mL. In the fungal morphology, a reduction was observed of pseudo-hyphae, chlamydoconidia and blastoconidia in the presence of the experimental product.

CONCLUSION

S. terebinthifolius showed anti-fungal activity against C. albicans, inhibiting, probably, the fungal cell wall formation.

Comparison of headspace solid-phase microextraction, headspace single-drop microextraction and hydrodistillation for chemical screening of volatiles in Myrtus communis L

INTRODUCTION

Headspace solid-phase microextraction (HS-SPME) and headspace single-drop microextraction (HS-SDME) methods have never been used for the extraction and analysis of the volatile compounds of Myrtus communis. For that reason, in this work, these two techniques were compared with the traditional hydrodistillation (HD) extraction technique.

OBJECTIVE

To compare SPME and SDME with HD for the extraction and analysis of Myrtus communis volatiles.

METHODOLOGY

Three extraction methods, i.e. SPME, SDME and HD, coupled to gas chromatography-mass spectrometry were used and optimised for the analysis of Myrtus communis volatiles. The SPME extraction was performed on a 100 µm PDMS fibre and for SDME a drop of n-octadecane containing 0.7% of menthol as internal standard was used as extracting solvent. The results were compared from different viewpoints including efficiency of extraction, different kinds of species extracted and quantity of extracted compounds with HD.

RESULTS

The main analytes extracted by SPME were found to be α-pinene, limonene, 1,8-cineole, linalool, linalyl acetate, α-terpinyl acetate and geranyl acetate, whereas for SDME α-pinene, limonene, 1,8-cineole, linalool, linalyl acetate and β-myrcene were extracted as major components. Hydrodistillation could extract α-pinene, limonene, 1,8-cineole, linalool, α-terpineol, linalyl acetate, α-terpinyl acetate, geranyl acetate and cis-isoeugenol better than other volatiles from Myrtus communis.

CONCLUSION

The results demonstrated that HS-SPME and HS-SDME can be applied successfully for the extraction and separation of volatiles in aromatic plants, and these techniques are easier to perform, and more effective than HD for collection of more volatile compounds.

Isolation of antibacterial compounds from Quercus dilatata L. through bioassay guided fractionation

Background

Four medicinal plants (Chrozophora hierosolymitana Spreng, Chrysanthemum leucanthemum L., Ephedra gerardiana Wall. ex Stapf, and Quercus dilatata L.) used by indigenous healers to treat various infectious diseases were selected for the present study. The major objective of the present study was isolation and characterization of antimicrobial components from the crude plant extracts using bioassay guided fractionation.

Methods

Seven methanolic extracts of the four plants were screened to identify any antimicrobial agents present in them. The active crude plant extract was fractionated first by solvent partitioning and then by HPLC. Characterization of the active fractions was done by using spectrophotometer.

Results

All the seven methanolic extracts showed low antifungal activity, however, when these extracts were tested for antibacterial activity, significant activity was exhibited by two extracts. The extract of aerial parts of Q. dilatata was most active and therefore, was selected for further analysis. Initially fractionation was done by solvent-solvent partitioning and out of six partitioned fractions, ethanol fraction was selected on the basis of results of antibacterial activity and phytochemical analysis. Further, fractionation was carried out by RP- HPLC and purified active subfractions were characterized by comparing their absorption spectra with that of the known natural products isolated from the plants of Quercus genus.

Discussion and conclusion

The results suggest that this is the first report of the isolated antibacterial compounds from this genus.

Assessment of selected Yemeni medicinal plants for their in vitro antimicrobial, anticancer, and antioxidant activities

CONTEXT

The role of natural products as a source for remedies has been recognized since the beginning of mankind. Nevertheless, a minority of folkloricly used medicinal plants have been evaluated for their pharmacological activities.

OBJECTIVES

The purpose of this study is to evaluate 33 selected Yemeni plants for their in vitro anticancer, antimicrobial, and antioxidant activities.

MATERIALS AND METHODS

The plants were extracted with methanol and hot water. The obtained 66 extracts were tested for their in vitro cytotoxic activity using the neutral red uptake assay against two cancer cell lines (5637 and MCF-7). The antimicrobial activity was determined using the agar diffusion method and MIC-determination. The DPPH radical method was used for the determination of antioxidant activity.

RESULTS

Interesting cytotoxic activity was observed for Hypoestes forskalei (Vahl) R. Br. (Acanthaceae), Lycium shawii Roem. & Schult. (Solanaceae), Pergularia tomentosa L. (Asclepiadaceae), Psiadia punctulata (DC.) Vatke (Compositae), Pulicaria petiolaris Jaub. & Spach (Compositae) and Rosmarinus officinalis L. (Labiatae) (IC(50) values < 50 μg/mL). Antimicrobial activity with MIC values ≤ 125 μg/mL was exhibited against Gram-positive bacteria by Chrozophora oblongifolia (Del.) A.Juss. ex Spreng. (Euphorbiaceae), Myrtus communis L. (Myrtaceae), Phragmanthera regularis (Steud. ex Sprague) M.G. Gilbert (Loranthaceae) and R. officinalis. Antioxidant activity was observed for C. oblongifolia, M. communis, and P. regularis.

CONCLUSION

The results justified the use of some investigated plants in the Yemeni ethnomedicine. These findings demonstrated that some of the investigated plants could be a source of new cytotoxic and antibiotic compounds; however, further work is needed.

An investigation on the anticandidal activity of some traditional medicinal plants in Turkey

Methanol and chloroform extracts obtained from eight plant species belonging to six families, which were selected depending on their use in Turkish folk medicine, including Mentha longifolia L. (Labiatae), Mentha piperita L. Hudson (Labiatae), Prongos ferulaceae (Umbelliferae), Galium verum L. (Rubiaceae), Salvia limbata C. A Meyer (Labiatae), Artemisia austriaca Jacq. (Artemiceae), Plantago lanceolata L. (Plantaginaceae) and Urtica dioica L. (Urticaceae) were evaluated for their in vitro anticandidal activity. The anticandidal activity of extracts against 99 human pathogenic clinical isolates belonging to 35 Candida albicans, 33 Candida tropicalis and 31 Candida glabrata and standard strains of Candida spp. (C. albicans ATCC 10231, C. glabrata ATCC 80030 and C. tropicalis ATCC 22019) were tested by disc diffusion method and the active extracts were assayed for the minimal inhibitory concentration (MIC). Chloroform extracts of plants have no inhibitory effect against both clinical and standard strains of Candida spp., whereas methanol extracts exhibited good activity. Among the plants tested, M. piperita showed the highest anticandidal activity with 12.3 mm inhibition zone and 1.25 mg ml(-1) MIC value against C. albicans, M. longifolia, P. lanceolata and A. austriaca also displayed activity against C. albicans and C. tropicalis.