Screening of selected indigenous plants of Lebanon for antimicrobial activity

Study on Chemical Composition and Biological Activity of Psidium guajava Leaf Extracts

Guava (Psidium guajava) is a plant widely distributed in tropical and subtropical regions. Its leaves contain a large amount of physiological molecules such as flavonoid, sesquiterpene, triterpenoid, coumarin, alkaloid, and tannin molecules with antioxidative and anti-inflammatory effects. In this study, the use of concentrated P. guajava leaf extract molecules as a functional natural material was evaluated by confirming the extract's antioxidative, antibacterial, tyrosinase activity inhibition, and collagenase activity inhibition effects and its trans-2-nonenal removal ability. As a result of the analysis of the antioxidant and antibacterial components of concentrated P. guajava leaf extract molecules through GC-MS, a large amount of aromatic hydrocarbon molecules were detected. When different concentrations of ethanol were used for extraction, the leaf extract concentrated with 70% ethanol showed the most effective active molecules. As a result of measuring DPPH radical scavenging activity, a concentration-dependent antioxidant activity was confirmed. The antioxidant activity tended to increase when the ethanol content used for extraction was increased. Molecules such as 2,4-di-tert-butylphenol, caryophyllene oxide, and γ-muurolene in P. guajava leaf extract concentrate appeared to have antibacterial activities against S. aureus bacteria known to cause atopy. As ethanol content increased, the inhibitory effect on tyrosinase activity was increased. In addition, when ethanol content was 50%, the concentrated leaf extract was able to remove trans-2-nonenal by 52.4%. As a result of determining the concentrated leaf extract's collagenase inhibition activity, an inhibition rate close to that of ascorbic acid, a positive control, was confirmed. The concentrated guajava leaf extract molecules were confirmed to have whitening and wrinkle-improving functionality. Thus, the P. guajava leaf extract has high potential as a food and natural cosmetic material.

A review of the traditional uses, phytochemistry, pharmacology, and clinical evidence for the use of the genus Alchemilla (Rosaceae)

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Alchemilla L. (lady's mantle) comprises 1000 species, of which more than 300 have been characterized from Europe. Notably, as folk medicines, Alchemilla species have long been prescribed for the treatment of dysmenorrhea, pruritus vulvae, menopausal complaints, and related diseases in women. This review summarizes the traditional uses, highlights promising plant species, and focuses on phytochemical and biological studies to highlight future areas of research.

AIM OF THE REVIEW

This literature review aims to provide a comprehensive overview of Alchemilla species, covering their botany, traditional uses, phytochemistry, and biological and pharmacological activities, and to summarize the current research status to better understand the application value of Alchemilla plants in modern phytotherapy.

MATERIALS AND METHODS

The search strategy utilized the major thematic platforms Reaxys, Web of Science, Google Scholar, Scopus, ScienceDirect, PubMed, the USDA Plant Database and Kew Science (Royal Botanic Gardens) and was performed with the term Alchemilla. These platforms were systematically searched for articles published from 1960 to 2023.

RESULTS AND DISCUSSION

Alchemilla species, as members of the Rosaceae family, produce tannins, phenolic acids, flavonoids, anthocyanins, coumarins, triterpenes and violet compounds. Effort has been made with this comprehensive review of Alchemilla plants to highlight the recent developments and milestones achieved in modern phytochemistry and phytotherapy, underlaying a broad spectrum of the activities of these plants, such as antioxidant, anti-inflammatory, neuroprotective, antimicrobial, antiobesity, cardiovascular, anticancer, and wound healing effects.

CONCLUSIONS

An increasing number of studies on the plants in the Alchemilla genus have provided data about the main constituents and their importance in modern medicine. Both in vitro and in vivo studies have indicated that Alchemilla plants possess an extensive spectrum of biological activities. Regardless of the remarkable medical potential of Alchemilla extracts, clinical studies are limited and need to be performed to produce safer and less expensive plant-based drugs.

Maximizing the extraction yield of plant gum exudate using response surface methodology and artificial neural networking and pharmacological characterization

Prunus armeniaca gum is used as food additive and ethno medicinal purpose. Two empirical models response surface methodology and artificial neural network were used to search for optimized extraction parameters for gum extraction. A four-factor design was implemented for optimization of extraction process for maximum yield which was obtained under the optimized extraction parameter (temperature, pH, extraction time, and gum/water ratio). Micro and macro-elemental composition of gum was determined by using laser induced breakdown spectroscopy. Gum was evaluated for toxicological effect and pharmacological properties. The maximum predicted yield obtained by response surface methodology and artificial neural network was 30.44 and 30.70% which was very close to maximum experimental yield 30.23%. Laser induced breakdown spectroscopic spectra confirmed the presence Calcium, Potassium, Magnesium, Sodium, Lithium, Carbon, Hydrogen, Nitrogen and Oxygen. Acute oral toxicity study showed that gum is non-toxic up to 2000 mg/Kg body weight in rabbits, accompanied by high cytotoxic effects of gum against HepG2 and MCF-7cells by MTT assay. Overall, Aqueous solution of gum showed various pharmacological activities with significant value of antioxidant, antibacterial, anti-nociceptive, anti-cancer, anti-inflammatory and thrombolytic activities. Thus, optimization of parameters using mathematical models cans offer better prediction and estimations with enhanced pharmacological properties of extracted components.

Antibacterial and Anti-Glucosyltransferase Activity of Verbascum speciosum Against Cariogenic Streptococci

Objectives

Dental caries is a prevalent chronic human infection worldwide and several plants have shown anticariogenic properties through antibacterial activity against oral pathogens. The present study aimed to assess anticariogenic activity of Verbascum speciosum, in search of novel agents for the prevention and treatment of dental caries.

Methods

Hydro-alcoholic extracts from flowers and total aerial parts of the plant were prepared by maceration. Antibacterial activity of the extracts against Streptococcus mutans (ATCC 35668) and Streptococcus sobrinus (ATCC 27607) was investigated by agar diffusion and microdilution techniques. Inhibitory concentration-fifty values of the flowers' extract against Streptococcus mutans glucosyltransferase enzymes were determined. The total flavonoid content of the extracts was determined using an aluminum chloride reaction.

Results

Verbascum speciosum flowers' extract showed significantly higher flavonoid content and antibacterial activity; with minimum inhibitory concentrations of 100 and 200 µg/mL for Streptococcus mutans and Streptococcus sobrinus, respectively. The extract inhibited the synthesis of glucan by cell-associated and extracellular glucosyltransferase enzymes in a dose-dependent manner with higher activity against the extracellular enzyme.

Conclusion

This study indicated effective anticariogenic activity of Verbascum speciosum flowers extract. This extract can be considered as an alternative to current anticaries therapies or an additive to dental care products.

Origanum vulgare ethanolic extracts as a promising source of compounds with antimicrobial, anti-biofilm, and anti-virulence activity against dental plaque bacteria

Dental caries and periodontal diseases remain a challenge for oral health, especially given the lack of effective and safe treatment options that are currently available. Against the backdrop of an ongoing antimicrobial resistance crisis, a renewed interest in traditional medicinal plants as a potential source of new bioactive compounds has surfaced. In this context, we systematically screened the antimicrobial and anti-biofilm activities of both ethanolic and aqueous extracts of nine Algerian medicinal plants (Artemisia herba alba, Centaurium erythraea, Juglans regia, Laurus nobilis, Matricaria recutita, Mentha pulegium, Mentha piperita, Origanum vulgare and Taraxacum officinale). To evaluate the activity spectrum of the extracts, the screening was carried out against an extensive collection of Streptococcus, Enterococcus and Lacticaseibacillus isolates recovered from dental plaques of Algerian patients. Broad-spectrum antimicrobial and anti-biofilm properties were observed, especially among ethanolic extracts, which marks them as a promising source for bioactive compounds to control oral biofilms. The ethanolic extract of O. vulgare, which showed the most promising effects in the initial screening, was further characterized. We first verified the biocompatibility of this extract using human oral keratinocytes and selected a range of non-cytotoxic concentrations (0.195-0.781 mg/ml) to further validate its anti-biofilm and anti-virulence potential. At these concentrations, the extract not only prevented biofilm formation (10.04 ± 0.75-87.91 ± 9.08% of reduction) of most dental plaque isolates on a polystyrene surface, but also significantly reduced their adherence to hydroxyapatite (34.58 ± 9.09-62.77 ± 0.95%). Moreover, the extract showed curative potential against mature biofilms grown under conditions mimicking the oral niche. In addition to its anti-biofilm properties, we observed an inhibition of glucosyltransferase activity, a reduction in acidogenesis and a downregulation in the expression of multiple virulence-associated genes for extract-treated samples. Since anti-virulence properties are more robust to the development of resistance, they provide an attractive complementation to the antimicrobial activities of the extract. Thymol was identified as an important active compound of the extract using GC-MS analysis, but synergy with other compounds was also detected, suggesting a potential advantage of using the whole extract over purified thymol. Further research into the bioactive compounds of the O. vulgare ethanolic extract could yield novel products to fight dental caries.

Therapeutic Potential of Ranunculus Species (Ranunculaceae): A Literature Review on Traditional Medicinal Herbs

The genus Ranunculus includes approximately 600 species and is distributed worldwide. To date, several researchers have investigated the chemical and biological activities of Ranunculus species, and my research team has found them to have antimalarial effects. This review is based on the available information on the traditional uses and pharmacological studies of Ranunculus species. The present paper covers online literature, particularly from 2010 to 2021, and books on the ethnopharmacology and botany of Ranunculus species. Previous studies on the biological activity of crude or purified compounds from Ranunculus species, including R. sceleratus Linn., R. japonicus Thunb., R. muricatus Linn., R. ternatus Thunb., R. arvensis Linn., R. diffusus DC., R. sardous Crantz, R. ficaria Linn., R. hyperboreus Rotlb., and R. pedatus Waldst. & Kit., have provided new insights into their activities, such as antibacterial and antiprotozoal effects as well as antioxidant, immunomodulatory, and anticarcinogenic properties. In addition, the anti-inflammatory and analgesic effects of plants used in traditional medicine applications have been confirmed. Therefore, there is a need for more diverse studies on the chemical and pharmacological activities of highly purified molecules from Ranunculus species extracts to understand the mechanisms underlying their activities and identify novel drug candidates.

Ethnobotanical and antibacterial study of Primula plants traditionally used in the indigenous communities of Western Himalaya, Pakistan

Background

The upper belt of Azad Kashmir is a hilly, mountainous, and remote area where the indigenous communities mainly believe in traditional medicines for the treatment of different ailments. This study aimed to conserve scientifically and culturally important medicinal knowledge of Primula species in Azad Kashmir, Western Himalaya, Pakistan. The additional objective was to evaluate the antibacterial activity of these plants against pathogenic bacteria.

Methods

The ethnomedicinal data of Primula species was explored by conducting structured interviews with 40 informants of the study area, especially asking about the medicinal uses of Primula species. The indigenously used Primula species were further analyzed for their antibacterial activity against both gram-positive and gram-negative bacteria by using disc diffusion assay supplemented with a more robust minimum inhibitory concentration assay.

Results

Ethnomedicinal data revealed that indigenous communities living in upper regions of Azad Kashmir use 5 Primula species for the treatment of various disorders. The highly cited disease category was ophthalmic disorders. P. denticulata and P. macrophylla were the most cited plant species with higher use reports such as 104 and 93, respectively. One or more extracts of different parts of Primula species showed a noteworthy antibacterial activity against one or more tested bacteria.

Conclusion

This study provides novel information regarding several categories of traditional uses and antibacterial activity of Primula species in Azad Kashmir, Western Himalaya. The need for novel and more effective drugs derived from natural products is more important than ever, making future studies on herbal remedies both justified and urgently required.

Ethnopharmacology, phytochemistry, and bioactivities of Hieracium L. and Pilosella Hill (Cichorieae, Asteraceae) species

ETHNOPHARMACOLOGICAL RELEVANCE

Species of the genera Hieracium and Pilosella have been used in folk medicine for centuries in many parts of the world. The most wiedly used species is P. officinarum Vaill., included in the British and French Pharmacopoeias and sold as part of different commercial products.

AIM OF THE STUDY

This review critically appraises the state-of-art of ethnopharmacology, specialised metabolites, bioactivities, and toxicity of members of Hieracium and Pilosella. Thus, gaps in scientific knowledge can be identified, also focusing on the development of products with pharmacological applications.

MATERIALS AND METHODS

Literature data of Hieracium and Pilosella species were mainly retrieved using different electronic databases such as Web of Science, Google Scholar, SciFinder, and PubMed. Other electronic resources included worldwide databases on ethnobotany, ethnopharmacology, and phytochemistry as well as government reports. Additionally, ancient texts and local information such as PhD and MSc theses, and books were consulted.

RESULTS

A comprehensive analysis of the above mentioned sources revealed that only 34 out of the about 850 described species within the genera Hieracium and Pilosella have been reported in the context of traditional medicinal and ethnobotanical knowledge. The most often mentioned species is P. officinarum which has been widely used due to its diuretic effects. Other popular uses of Hieracium and Pilosella species include the treatment of skin, gastric, and intestinal diseases as well as respiratory and vascular ailments. Moreover, taxa of the two genera have been used as antiobiotics, antiseptics, antidiabetics, tonics, antiepileptics, antiphlogistics, emetics, wound healing drugs, astringents, haemostatics, and detoxificants. Finally, uses as a wild vegetable, fodder, plant for hunting and for charming rituals have also been mentioned. Phytochemical research revealed a richness in phenolic compounds and flavonoids. Moreover, coumarins, sesquiterpene lactones, terpenoids, and phytosterols were found in Hieracium and Pilosella. Experimental research conducted to support traditional uses mainly include in vitro tests, while assays based on in vivo models (including humans) are rather limited. Also, the vast majority of the studies did not identify the compounds responsible for the detected bioactivities. These established bioactivities include antidiabetic, anti-inflammatory, antibacterial, antimycotic, antiviral, cytotoxic and antiproliferative, diuretic, gastroprotective, antiepileptic, hypotensive, anti-obesity, arthropodicidal, and skin rejuvenating activities. Finally, limited toxicity studies have been conducted on members of Hieracium and Pilosella.

CONCLUSION

Taxa belonging to Hieracium and Pilosella have been confirmed to exert diuretic, anti-inflammatory, and antimicrobial effects, which is in line with their long traditional use. Moreover, the above mentioned fields of application hint to the most promising routes for the development of new marketable products. Nonetheless, additional data from an in-depth research on bio-active specialised metabolites such as sesquiterpenoids, sesquiterpene lactones, and coumarines, their bioactivities and toxicity, and their biosynthesis are still warranted.

Screening of the Potential Bioactivities of Pennyroyal (Mentha pulegium L.) Essential Oil

Increasing resistance of pathogens towards conventional antibiotics presents a major threat to public health because it reduces the effectiveness of antibiotic treatment. Mentha pulegium L., also known as pennyroyal, is an aromatic herb that belongs to the family Lamiaceae. Its essential oil has been traditionally used in medicine, aromatherapy, and cosmetics. The purpose of this work was to study the chemical composition of a pennyroyal essential oil and to evaluate their bioactivities, specifically, antioxidant, antimicrobial, anti-quorum sensing, and anti-inflammatory. A special focus was given to the antibacterial activity of the essential oil against Acinetobacter baumannii. The chemical composition of the essential oil was studied by GC-MS/GC-FID. The DPPH free radical scavenging assay and the β-carotene/linoleic acid system were used to evaluate the antioxidant properties. The antimicrobial and anti-quorum sensing activities were evaluated by disk diffusion assays and complemented with optical microscopy observations. The results showed that pulegone was the major compound (88.64%) of the pennyroyal essential oil. Regarding the antimicrobial activity, the action against Acinetobacter baumannii stands out, which, together with the capacity of the essential oil to inhibit the quorum sensing mechanisms, may suggest the use of the pennyroyal essential oil to further develop surface disinfectants for hospitals.

The Effect of Different Ester Chain Modifications of Two Guaianolides for Inhibition of Colorectal Cancer Cell Growth

Several sesquiterpene lactones (STLs) have been tested as lead drugs in cancer clinical trials. Salograviolide-A (Sal-A) and salograviolide-B (Sal-B) are two STLs that have been isolated from Centaurea ainetensis, an indigenous medicinal plant of the Middle Eastern region. The parent compounds Sal-A and Sal-B were modified and successfully prepared into eight novel guaianolide-type STLs (compounds 1-8) bearing ester groups of different geometries. Sal-A, Sal-B, and compounds 1-8 were tested against a human colorectal cancer cell line model with differing p53 status; HCT116 with wild-type p53 and HCT116 p53^-/- null for p53, and the normal-like human colon mucosa cells with wild-type p53, NCM460. IC₅₀ values indicated that derivatization of Sal-A and Sal-B resulted in potentiation of HCT116 cell growth inhibition by 97% and 66%, respectively. The effects of the different molecules on cancer cell growth were independent of p53 status. Interestingly, the derivatization of Sal-A and Sal-B molecules enhanced their anti-growth properties versus 5-Fluorouracil (5-FU), which is the drug of choice in colorectal cancer. Structure-activity analysis revealed that the enhanced molecule potencies were mainly attributed to the position and number of the hydroxy groups, the lipophilicity, and the superiority of ester groups over hydroxy substituents in terms of their branching and chain lengths. The favorable cytotoxicity and selectivity of the potent molecules, to cancer cells versus their normal counterparts, pointed them out as promising leads for anti-cancer drug design.

Phytomedicine from Middle Eastern Countries: An Alternative Remedy to Modern Medicine against Candida spp Infection

Candida spp are capable of infecting both normal and immunocompromised individuals. More recently, Candida infections have spread considerably in healthcare settings, especially in intensive care units, where it is the most frequently encountered pathogen. Candida albicans is the commonest species encountered, although infections by non-albicans species have also risen in the past few years. The pathogenicity of Candida is credited to its aptitude to change between yeast and hyphal modes of growth. Candida spp produce biofilms on synthetic materials that protect them and facilitate drug resistance and act as a source for chronic and recurrent infections. Primarily, azoles antifungal agents are utilized to treat Candida infection that targets the ergosterol synthesis pathway in the cell wall. The development of antifungal resistance in Candida species is a major reason for treatment failure, and hence, there is a need to develop newer antifungal molecules and/or modifications of existing antifungals to make them more effective and less toxic. This has led researchers to oversee the plants to discover newer antimicrobials. Middle Eastern countries are well known for their landscape ranging from dry and sandy deserts to snow-capped mountains. However, they comprise enormous plant diversity with over 20,000 different species showing various types of bioactivities, such as anticancer, antidiabetic, and antimicrobial activities. Especially, the antifungal potential of these phytoproducts could be exploited in the clinical setting for therapy. The present review examines some of the promising alternative natural compounds that have been tested and found effective in treating Candida infections in vitro in some Middle Eastern countries.

Acylated Flavone O-Glucuronides from the Aerial Parts of Nepeta curviflora

Nepeta curviflora Boiss. (Syrian catnip) is native to the Middle East. This medicinal plant is commonly used against nervous disorders, rheumatic pains, and high blood pressure. Herbal infusions prepared from various Nepeta spp. are extensively consumed as functional food. However, limited information has been known about the phenolic constituents of Syrian catnip. In this study, two acylated flavone 7-O-glucuronides, apigenin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (1) and luteolin 7-O-(2″-O-(2‴-(E-caffeoyl)-β-glucuronopyranosyl)-β-glucuronopyranoside) (2), along with the known phenolic compounds rosmarinic acid, caffeic acid, apigenin, and apigenin 7-O-β-glucopyranoside were isolated from the aerial parts of N. curviflora. The characterizations of these compounds were based on high-resolution mass spectrometry, UV, and extensive use of multidimensional NMR spectroscopy. The new compounds (1 and 2) were identified in the unmodified state and as dimethylesters.

The antidiarrhoeal evaluation of Psidium guajava L. against enteropathogenic Escherichia coli induced infectious diarrhoea

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Psidium guajava L. (Myrtaceae), commonly used as an edible fruit is traditionally used worldwide in treatment of various gastrointestinal problems including diarrhoea. The leaves of the plant have also been evaluated for antidiarrhoeal activity in various chemical induced diarrhoea models.

OBJECTIVE

The main objective of the present study was to evaluate the potency of P. guajava leaves and its major biomarker quercetin against enteropathogenic Escherichia coli (EPEC) induced infectious diarrhoea using preclinical and computational model.

MATERIAL AND METHODS

P. guajava alcoholic leaf extract (PGE) was initially standardized using HPLC taking quercetin as a biomarker and was then subjected to antidiarrhoeal evaluation on rats in an EPEC induced diarrhoea rat model. The study included assessment of various behavioral parameters, initially for 6 h and then for up to 24 h of induction which was followed by estimation of stool water content, density of EPEC in stools and blood parameters evaluation. The colonic and small intestinal tissues of the treated animals were subjected to various biochemical estimations, in vivo antioxidant evaluation, estimation of ion concentration, Na⁺/K⁺-ATPase activity, assessment of pro-inflammatory cytokines and histopathological studies. Further, the major biomarker off PGE, quercetin was subjected to molecular docking studies with Na⁺/K⁺-ATPase and EPEC.

RESULTS

The results demonstrated a significant antidiarrhoeal activity of quercetin (50 mg/kg), PGE at 200 and 400 mg/kg, p.o., where quercetin and PFGE at 200 mg/kg, p.o. were found to be more prominent, as confirmed through higher % protection, water content of stools and density of EPEC in stools. PGE and its biomarker quercetin also significantly recovered the WBC, Hb, platelets loss and also revealed a significant restoration of altered antioxidants level, pro-inflammatory cytokines (IL-1β and TNF-α) expression and had positive influence on Na⁺/K⁺-ATPase activity. The docking studies of quercetin with Na⁺/K⁺-ATPase showed favourable interactions and residues Glu 327, Ser 775, Asn 776, Glu 779 and Asp 804 of Na⁺/K⁺-ATPase were adequately similar to quercetin for donating ligands for binding, while quercetin was also found to terminate the linkage between mammalian cells and EPEC thus, preventing further infection from EPEC.

CONCLUSION

Inhibition in intestinal secretion, reduced nitric oxide production and inflammatory expression along with reactivation of Na⁺/K-ATPase activity could be attributed to the observed antidiarrhoeal potential of PGE against infectious diarrhoea, where quercetin was confirmed to be the main contributing factor.

Reduction of sterigmatocystin biosynthesis and growth of food-borne fungi by lactic acid

Food contamination by fungi and mycotoxins presents a problem for food safety even today. Since lactic acid (LA) has Generally Recognized As Safe (GRAS) status, the aim of this research was to determine its potential in protection of food against mycological and mycotoxicological contamination. In this study, LA showed an inhibitory effect on the growth of food-borne fungi (Penicillium aurantiogriseum K51, Aspergillus parasiticus KB31, Aspergillus versicolor S72, and Aspergillus niger K95) and on biosynthesis of sterigmatocystin (STE). For the antifungal effect of LA on the growth of food-borne fungi, the disc diffusion and microdilution methods were performed. The effect of LA on the STE biosynthesis by A. versicolor was determined using an LC-MS/MS technique. The largest inhibition zone was observed for A. versicolor (inhibition zone of 24 ± 0.35 mm), while there were no inhibition zones for A. niger and A. parasiticus at all tested LA concentrations. The minimal inhibitory concentration (MIC) of LA on fungi ranged from 25.0 mg/mL to 50.0 mg/mL, while the minimum fungicidal concentrations (MFCs) ranged from 50.0 mg/mL to 100.0 mg/mL. Complete inhibition of STE biosynthesis by A. versicolor was observed at an LA concentration of 50.0 mg/mL. The obtained results showed that LA could be efficient for protection of food against mycological and STE contamination.

Evaluation of antimicrobial activity of chondrillasterol isolated from Vernonia adoensis (Asteraceae)

BACKGROUND

Bacteria have developed resistance to most of the current antibiotics. There is evidence suggesting that plant-derived compounds have a potential for interacting with biological processes. One of the plants commonly used in African ethnomedicine is Vernonia adoensis from the Asteraceae family. The leaves of the plant have been reported to have antimicrobial activity. Hence, the aim of this study was to isolate the bioactive compounds from the leaf extract and evaluate their antibacterial activity on Staphylococcus aureus, Klebsiella pneumoniae and Pseudomonas aeruginosa. In addition, the effect of the isolated compound on biofilms of P. aeruginosa was determined.

METHODS

Isolation of phytochemicals from the leaves of V. adoensis was done using column chromatography. Preparative TLC was used to further isolate mixed compounds in the fractions. Nuclear magnetic resonance spectroscopy and mass spectrometry was used to identify the isolated pure compounds. The broth microdilution assay was carried out to evaluate the antibacterial activity of the isolated compound on P. aeruginosa, S. aureus and K. pneumoniae. Crystal violet staining technique was used to evaluate the effect of the isolated compound on biofilms of P. aeruginosa.

RESULTS

The compound isolated from V. adoensis was identified as chondrillasterol. Chondrillasterol exhibited 25, 38 and 65% inhibition of growth on S. aureus, K. pneumoniae and P. aeruginosa respectively. At 1.6 μg/mL chondrillasterol completely disrupted mature biofilm of P. aeruginosa while at 100 μg/mL the compound completely inhibited formation of biofilms of the bacteria.

CONCLUSION

Chondrillasterol isolated from V. adoensis has antibacterial properties against S. aureus, K. pneumoniae and P. aeruginosa. The compound also has biofilm inhibition and disruption activity against P. aeruginosa biofilms. Thus, the active phytochemical could be a useful template for the development of new antimicrobial agents with both antibacterial and antibiofilm activity.

Promising activity of Anthemis austriaca Jacq. on the endometriosis rat model and isolation of its active constituents

Anthemis austriaca Jacq. flowers are traditionally used to alleviate abdominal pain, hemorrhoids, ovary diseases and pneumonia. This study aimed to investigate the effects of A. austriaca flowers, which are frequently used in gynecological disorders, on the rat endometriosis model. The rat endometriosis model was used to evaluate the potential activity of the plant in endometriosis. The dried plant material was extracted with n-hexane, ethyl acetate (EtOAc), and methanol (MeOH), successively. The obtained extracts from A. austriaca flowers were applied to the rats. The adhesion scores, endometrial foci areas, and cytokine levels of the peritoneal fluids were measured on surgical induction of endometriosis in rats. The adhesion scores, endometriotic volume, and cytokine levels of the peritoneal fluids were reduced in the EtOAc, MeOH, and buserelin acetate-treated (reference) groups. The MeOH extract reduced the adhesion scores and endometrial foci areas from 3.1 to 1.1 (p < 0.01) and from 86.4 to 40.5 (p < 0.01), respectively and also the MeOH extract reduced tumor necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), and interleukin (IL)-6 levels of the peritoneal fluids from 13.7 to 3.8 (p < 0.01), from 28.4 to 16.3 (p < 0.05) and from 50.2 to 24.3 (p < 0.01), respectively. Therefore, isolation studies were conducted on the EtOAc and MeOH extracts. After the MeOH extract was fractionated using RP-18 column, the obtained subfractions were evaluated again on the endometriosis rat model. Subfractions A and C of the MeOH extract displayed statistically significant activity on the endometriosis rat model. Phytochemical investigation resulted in the isolation of 4-β-D-glucopyranosyloxy-6-methyl-2H-pyran-2-one (1) from Fr. A and quercetin (2), apigenin-7-O-(3″-O-acetyl)-β-D-glucopyranoside (3), apigenin-7-O-(6″-O-acetyl)-β-D-glucopyranoside (4), apigenin-7-O-β-D-glucopyranoside (5), quercetin-7-O-β-D-glucopyranoside (6) from Fr. C. Moreover, β-sitosterol-3-O-β-D-glucopyranoside (7) was isolated from the EtOAc extract. As a conclusion, the MeOH extract obtained from A. austriaca flowers contributed to the regression of endometriosis. In addition, flavonoids and sterols of the plant were detected as the possible compounds responsible for the activity.

The potency of eriosematin E from Eriosema chinense Vogel. against enteropathogenic Escherichia coli induced diarrhoea using preclinical and molecular docking studies

The main objective of the present study was to evaluate the potential of eriosematin E (ECM) isolated from the roots of Eriosema chinense against enteropathogenic Escherichia coli (EPEC) induced diarrhoea. ECM isolated from the bioactive chloroform fraction of E. chinense was subjected to antidiarrhoeal evaluation on rats against diarrhoea, induced by the oral suspension of EPEC. The study included evaluation of behavioral parameters for 6 h and up to 24 h of induction, followed by estimation of water content, the density of EPEC in stools and evaluation of various blood parameters. Further, the colonic and small intestinal tissues were subjected to biochemical estimations, antioxidant evaluation, determination of ion concentration, Na⁺/K⁺ -ATPase activity, pro-inflammatory cytokines assessment and histopathology. Finally, the impact of ECM on Na⁺/K⁺-ATPase was studied through molecular docking studies. Significant antidiarrhoeal potential of ECM was demonstrated at 5 and 10 mg/kg, p.o., however, ECM at 10 mg/kg, p.o. was found to be more effective, as confirmed through higher % protection, density of EPEC in stools and water content of stools. ECM also significantly increased the level of WBC, Hb, platelets and revealed restoration of altered antioxidants, pro-inflammatory cytokines (IL-1β and TNF-α) status and also reactivated the suppressed Na⁺/K⁺-ATPase activity, which was also confirmed through docking studies showing H-bonding of hydroxyl group of ECM with amino acids Asp 190, Asn 167 and Glu 169 thus, maintaining proper electrolyte balance and also prevented epithelial tissue damage. The overall effect of ECM may be attributed to the decline in the elevated level of cytokines, inhibition in nitric oxide production and reactivation of Na⁺/K⁺-ATPase activity resulting in reduced intestinal secretion.

Antibacterial interactions, anti-inflammatory and cytotoxic effects of four medicinal plant species

Background

The constant emergence of antibiotic resistant species and the adverse side effects of synthetic drugs are threatening the efficacy of the drugs that are currently in use. This study was aimed at investigating the possible antibacterial interactions, anti-inflammatory and cytotoxic effects of selected medicinal plants based on their traditional usage.

Methods

The acetone extracts of four plant species were assessed independently and in combination for antibacterial activity using microdilution assay and the sum of the fractional inhibitory concentration (FIC) was calculated. The ability of Dombeya rotundifolia and Schkuhria pinnata extracts to inhibit the production of reactive oxygen species (ROS) in LPS induced RAW 264.7 macrophage cells was evaluated using Dichloro-dihydro-fluorescein diacetate (H₂DCF-DA) assay to determine anti-inflammatory potential and the toxicity on African green monkey kidney (Vero) cells was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.

Results

The antibacterial efficacies of the different combinations of Schkuhria pinnata (A), Commelina africana (B), Dombeya rotundifolia (C) and Elephantorrhiza elephantina (D) plants varied from combination to combination. Synergistic effects were only exhibited against P. aeruginosa, while the antagonistic effects were only observed against E. coli. Both S. pinnata and D. rotundifolia demonstrated anti-inflammatory potential by inhibiting the production of ROS in a dose dependant manner. The cytotoxicity of the plants (LC₅₀ values) ranged from < 25.0 to 466.1 μg/mL. S pinnata extract was the most toxic with the lowest LC₅₀ value of < 25.0 μg/mL.

Conclusions

The synergistic interaction observed indicates that combinational therapy may improve biological activity. This report highlights the anti-inflammatory potential of S. pinnata and D. rotundifolia; which could be exploited in the search for anti-inflammatory agents. However, the cytotoxicity of S. pinnata highlights the importance of using this plant with caution.

Plant-based remedies for wolf bites and rituals against wolves in the Iberian Peninsula: Therapeutic opportunities and cultural values for the conservation of biocultural diversity

ETHNOPHARMACOLOGICAL RELEVANCE

Combined approaches to local knowledge and folk plant use improve awareness and promote effective strategies for the conservation of significant biocultural patrimony. Moreover, the information reported might be the basis for further appropriate phytochemical and pharmacological research. Therefore we provide an insight into traditional herbal remedies and practices for healing bite injuries in humans and domestic animals caused by the Iberian wolf. Wolf bites are associated with inflammatory processes and rabies is a potential complication AIMS: This paper describes and summarises the medicinal-veterinary empirical and ritual uses of the Iberian flora for wolf injuries and reviews the ethnopharmacological data of specific plants that are already published. The Iberian wolf is a critically endangered subspecies of the grey wolf. Livestock attacks attributed to wolves are increasingly frequent in the Iberian Peninsula, resulting in serious social problems. Interesting strategies for Iberian wolf conservation might be related to traditional grazing practices that are deeply linked with empirical knowledge and local practices passed on by oral tradition, which are also vulnerable now.

MATERIALS AND METHODS

Based on documentary sources from the beginning of the twentieth century to the present, we systematically searched old monographs, regional documents, technical papers, project reports, as well as the international and national databases and the available scientific literature, without restrictions regarding the language of the publications consulted.

RESULTS

A total of 39 remedies for healing wolf bite injuries in humans and domestic animals was reported, highlighting the medicinal use of 33 species of vascular plants, mostly wild herbs, belonging to 18 botanical families. The use of wood ashes was also reported. The number of use-reports found represents a very high number considering similar European studies. Leaves were the predominant plant part mentioned. Boiling plant materials in water for topical uses was the most frequent method of preparation found. Some traditional remedies combined two or more plant species in order to potentiate their effects. Moreover, some plant-based traditional practices and rituals to ward off wolves and to prevent wolf attacks were also documented. In these practices eleven other species (belonging to seven more families) were used.

CONCLUSIONS

Despite the decline of the Iberian wolf over the last few decades, wolves are still in the imaginary of rural communities that perceive this large carnivore as both a diabolic creature and a mythic and benign animal. Wolf-related cultural heritage is of great interest in terms of conservation strategies. This review emphasises the importance of local knowledge and provides useful information about several potential sources of phytochemicals and their claimed therapeutic effects, aiming at contributing to the conservation and appreciation of the Iberian biocultural heritage.

Plants from The Genus Daphne: A Review of its Traditional Uses, Phytochemistry, Biological and Pharmacological Activity

Plants have an important role in maintaining people’s health and improving the quality of human life. They are an important component of people’s diet, but they are also used in other spheres of human life as a therapeutic resources, ingredients of cosmetic products, paints and others. The Daphne genus belongs to family Thymeleaceae which includes 44 families with approximately 500 herbal species. The plant species of the genus Daphne are used in the traditional medicine in China and tropical part of Africa for the treatment of various conditions. Previous studies showed significant biological potential of these species as a source of pharmacologically active compounds. This indicates that this genus possess a broad spectrum of biological activity including antimicrobial, antioxidant, analgesic, anti-inflammatory, cytotoxic, anti-ulcerogenic, abortive, hypocholesterolemic and hemostatic effects. Additionally, Daphne plants are the source of valuable bioactive phytochemicals such as coumarins, flavonoids, lignans, steroids and different classes of terpenes. Different parts of the Daphne plants contain specific bioactive metabolites and can represent a source of new, natural, pharmacologically active compounds, which may potentially be used in pharmaceutical, cosmetic and food industries.

Fatty acid composition and antibacterial potential of Cassia tora (leaves and stem) collected from different geographic areas of India

The comparative analysis of the fatty acid composition of Cassia tora (leaves and stem) was determined using gas chromatography–mass spectrometry. Twenty-seven fatty acids were identified in C. tora (leaves and stem) which was collected from three different geographical areas of India: Lucknow (Uttar Pradesh), Nainital (Uttarakhand), and Bhavnagar (Gujarat), coded as CT-1, CT-2, and CT-3, respectively. The gas chromatography–mass spectrometry analysis showed the presence of various saturated and unsaturated fatty acids. The major fatty acids found were palmitic acid, linoleic acid, linolenic acid, margaric acid, melissic acid, and behenic acid. The highest amounts of saturated fatty acids were found in leaves of C. tora collected from Bhavnagar (Gujarat) (60.7% ± 0.5%). Thus, the study reveals that C. tora has a major amount of nutritionally important fatty acids, along with significant antimicrobial potential. Fatty acids play a significant role in the development of fat products with enhanced nutritional value and clinical application. Remarkable differences were found in the present study between fatty acid profiles of C. tora collected from different locations in India. To the best of our knowledge there is no previously reported comparative study of the fatty acids of C. tora.

Plants from Lamiaceae family as source of antifungal molecules in humane and veterinary medicine

This work aimed to review the main plants of Lamiaceae family with activity against pathogenic fungi of medical and veterinary interest. Published studies in the main international databases between January 2002 and June 2016 showed that 55 botanical species belonging to 27 genus presented antifungal activity in different forms of extractions, mainly essential oils. Pathogenic fungi of Aspergillus spp., Candida spp., Malassezia spp., Cryptococcus spp., Sporothrix spp., Microsporum spp., Trichophyton spp. and Epidermophyton spp. genus were in vitro sensitive to several plants of Lamiaceae family. Chemical molecules isolated were described as promising use as antifungals in mycoses, highlighting estragole, 1,8-cineole, terpineol-4, γ-terpinene, among others. However, it should be alert to need of universal standardization in the laboratories tests with natural products.

Antimicrobial activity of some plant materials used in Armenian traditional medicine

Background

Antibiotic resistance has become one of the major problems facing humanity. The need for new antimicrobials has been increased dramatically. Plants are considered as one of the most promising sources for new antimicrobials discovery. Despite relatively small area, Armenia has large diversity of flora with many endemic species. In Armenian folk medicine plant materials have been used to treat various microbial diseases since ancient times. The goal of our research was to evaluate antimicrobial efficiency of different parts of five wild plants species which are commonly used in Armenian traditional medicine.

Methods

Plant crude extracts were obtained with maceration technique using five solvents separately: distilled water, methanol, chloroform, acetone, and hexane. Agar well diffusion assay was used for initial evaluation of antimicrobial properties of plant materials against five bacterial and two yeast strains. Minimum inhibitory concentrations of the most active plant parts were determined by broth microdilution method.

Results

Crude extracts of all five tested plants expressed antimicrobial activity against at least four test strains at 500 μg ml⁻¹ concentration. Minimum inhibitory and bactericidal/fungicidal concentrations of selected plant parts were determined. Crude acetone and hexane extracts of Hypericum alpestre and acetone extract of Sanguisorba officinalis inhibited the growth of P. aeruginosa even at 64 μg ml⁻¹ concentration. Chloroform and acetone extracts of Sanguisorba officinalis exhibited cidal activity against P. aeruginosa till 256 μg ml⁻¹. Acetone was the most effective solvent for solubilizing antimicrobial compounds for almost all tested plant materials.

Conclusions

Thus, antimicrobial activity of some medicinal plants used in Armenian traditional medicine was evaluated. Some of the plants had rather low minimum bacteriostatic/bactericidal concentrations and therefore they have prospective for further more inclusive studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1573-y) contains supplementary material, which is available to authorized users.

Chemical Profile, Antioxidant and Antibacterial Activities of Achillea moschata Wulfen, an Endemic Species from the Alps

Aerial parts of Achillea moschata Wulfen (Asteraceae) growing wild in the Italian Rhaetian Alps were investigated to describe, for the first time, their phenolic content, as well as to characterize the essential oil. Inspection of the metabolic profile combining HPLC-DAD and ESI-MS/MS data showed that the methanol extract contained glycosylated flavonoids with luteolin and apigenin as the main aglycones. Among them, the major compound was 7-O-glucosyl apigenin. Caffeoyl derivates were other phenolics identified. The essential oil obtained by steam distillation and investigated by GC/FID and GC/MS showed camphor, 1,8-cineole, and bornylacetate as the main constituents. The antioxidant capacity of three different extracts with increasing polarity and of the essential oil was evaluated by employing ABTS·+ and DPPH· radical scavenging assays. The methanolic extract was the only significantly effective sample against both synthetic radicals. All samples were also tested against Gram-positive (Bacillus cereus, Enterococcus faecalis, Staphylococcus aureus) and Gram-negative (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa) bacterial species using the disk diffusion assay. The non-polar extracts (dichloromethane and petroleum ether) and the essential oil possessed a broad spectrum of antimicrobial activity expressed according to inhibition zone diameter (8–24 mm).

Anti-Inflammatory and Cytostatic Activities of a Parthenolide-Like Sesquiterpene Lactone from Cota palaestina subsp. syriaca

A sesquiterpene lactone 1-β,10-Epoxy-6-hydroxy-1,10H-inunolide (K100) was isolated through "bioassay-guided fractionation" from Cota palaestina subsp. syriaca, an Eastern Mediterranean endemic plant. K100 inhibited endotoxin- (ET-) induced proinflammatory markers: IL-6, MMP-9, and NO in normal mouse mammary SCp2 Cells. Molecular docking in silico suggested that K100, having highly analogous structure as parthenolide (PTL), an anticancer compound, could bind PTL target proteins at similar positions and with comparable binding affinities. Both compounds, K100 and PTL, inhibited the proliferation and prolonged the S-phase of the cell cycle of breast adenocarcinoma MDA-MB-231 cells grown in 2D cultures. Noncytotoxic concentrations of K100 and PTL decreased the proliferation rate of MDA-MB-231 and shifted their morphology from stellate to spherical colonies in 3D cultures. This was accompanied with a significant increase in the amount of small colonies and a decrease in the amount of large colonies. Moreover, K100 and PTL decreased cellular motility and invasiveness of MDA-MB-231 cells. In summary, these results suggest that K100 exhibits PTL-analogous anti-inflammatory, cytostatic, and antimetastatic effects.

Microbiological profiling and the demonstration of in vitro anti-bacterial traits of the major oral herbal medicines used in Dhaka Metropolis

Present study attempted to assess the level of microbiological contamination in oral herbal medicines, frequently used for medications, through conventional cultural and biochemical tests along with the antibiogram of the isolates. Moreover, the anti-bacterial potential of the herbal medicines was also aimed to be checked by the agar well diffusion method and minimum inhibitory concentration (MIC) assay. Out of 10 categories of liquid oral herbal medicine samples (n = 50) studied, all were found to be contaminated with bacteria (10(3)-10(5) cfu/mL), specifically with Staphylococcus spp. in 8 samples; while 2 samples harbored Klebsiella spp. Fungal presence was observed only in one sample. Study of antibiogram revealed Klebsiella spp. to be strongly resistant against penicillin G and erythromycin, whereas S. aureus possessed 80% sensitivity. The in vitro anti-bacterial activity was observed in 7 samples. Of them, one sample was found to exhibit the activity against almost all the test bacteria and another was found effective against 5 out of 8 test bacteria. Five samples showed the activity within a minor range while 3 samples were devoid of such trait. Samples 2 and 4 were found to stall the bacterial growth below 10 mg/mL of concentration in MIC test. Overall, the prevalence of specific pathogens was not so significant in the samples studied as well as only one drug-resistant isolate was identified. Besides, the anti-bacterial trait of 5 samples indicated that most of herbal medicines might be considered effective for medication.

Curcumin reverse methicillin resistance in Staphylococcus aureus

Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA) to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN) from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM). We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD₆₀₀) of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD) and sodium azide (NaN₃) were reduced to 94% and 55%, respectively. When peptidoglycan (PGN) from S. aureus was combined with curcumin, PGN (0–125 μg/mL) gradually blocked the antibacterial activity of curcumin (125 μg/mL); however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was investigated.

Influence of First-Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii De Wild. against Drug-Resistant Bacterial Isolates

Background. This study was aimed at evaluating the antibacterial activity of the acetone extract of A. mearnsii and its interactions with antibiotics against some resistant bacterial strains. Methods. The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract. Results. The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception of S. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibit Enterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are in μg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity. Conclusion. The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases.

Polarity of extracts and fractions of four Combretum (Combretaceae) species used to treat infections and gastrointestinal disorders in southern African traditional medicine has a major effect on different relevant in vitro activities

ETHNOPHARMACOLOGICAL IMPORTANCE

Gastrointestinal disorders and infections are the major pathoaetiologies of diarrhoea causing many problems in human health and animal production. Many Combretum species are used in traditional medicine to treat infectious diseases including diarrhoea and many other ailments by rural people in Africa and Asia. Much of the work done to date on this genus was on the non-polar or intermediate polarity components. Some parameters that may cause diarrhoea and the evaluation of more polar extracts have apparently not been investigated.

AIMS

The polar components were extracted and fractionated by solvent-solvent fractionation to yield fractions with different polarities. The activity of these fractions on different parameters that could be involved in factors associated with diarrhoea was investigated. The cytotoxic activities of the extracts were also determined to evaluate the potential of these extracts to combat diarrhoea in production animals.

MATERIALS AND METHODS

Phenolic-enriched leaf extracts of Combretum bracteosum (COB), Combretum padoides (COP), Combretum vendae (COV) and Combretum woodii (COW) were obtained by extracting with a mixture of 70% acetone acidified with 1% HCl and n-hexane. Acetone was removed from a portion of the 70% acetone extract and it was sequentially treated by solvent-solvent fractionation with dichloromethane, ethyl acetate, and butanol to yield fractions with a large variation in polarity. The phenolic constituents of the extracts and fractions were determined using standard procedures The antioxidant activities were determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH); 2,2'-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid (ABTS(+)) radical scavenging, ferric reducing antioxidant power (FRAP) methods and lipid peroxidation inhibitory capacity standard methods. The ferric reducing antioxidant activities of the fractions were also determined. The minimum inhibitory concentrations (MICs) of the crude extracts and fractions against four bacterial and three fungal strains were assessed with a microplate serial dilution method. Cyclooxygenase (COX) and lipoxygenase (LOX) enzyme inhibitory assays and cytotoxicity studies against Vero cells were also carried out.

RESULT

Some of the fractions had much higher antioxidant activity than the positive controls. The average EC50 values of the extracts for the DPPH and ABTS antioxidant assays were 0.21-12µg/ml (COP), 0.25-16µg/ml (COV), 0.33-9.41µg/ml (COW) and 4.97-85µg/ml (COB) respectively while the mean EC50 values for the positive controls ascorbic acid and trolox were 1.28-1.51 and 1.02-1.19µg/ml respectively. All the crude extracts inhibited lipid peroxidation of linoleic acid by more than 80% at a concentration of 64 µg/ml. COP had the highest antibacterial activity with MICs ranging between 19-2500µg/ml, followed by COV with MICs ranging between 39-625µg/ml; COW and COB had similar MICs ranging between 39-2500µg/ml. COP also had the highest antifungal activity with MICs between 19-625µg/ml. The MIC for COW and COV ranged from 19 to 1250 µg/ml. COB had the lowest antifungal activity (MIC values were between 39 and 625 µg/ml). In general non-polar fractions had a high antimicrobial activity and polar fractions had a high antioxidant activity. The extracts had no activity against COX 1 and 2 enzymes in the anti-inflammatory assay but had good lipoxygenase inhibition. The crude extracts had high concentration of hydrolysable tannin (gallotannin). A good correlation (R(2)= 0.99) was found between the antioxidant activity and total tannin content indicating that, gallotannins may be responsible for the antioxidant activity.

CONCLUSION

The results obtained in this study with more polar extracts indicate that the use of extracts of these plant species as antidiarrhoeal agents may have a scientific basis. The extractant used here extracted a much higher percentage of the phytochemicals than acetone. It was better for isolating antioxidant compounds (polar) but not good for isolating antimicrobial compounds (non-polar) from the same species compared to acetone, ethyl acetate, dichloromethane, and hexane.

Bioactivity of indigenous medicinal plants against the cotton whitefly, Bemisia tabaci

Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae), Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species.

Bioactivity of indigenous medicinal plants against the cotton whitefly, Bemisia tabaci

Forty-one methanol extracts of 28 indigenous medicinal plant species were tested for their insecticidal bioactivity against cotton whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), adults and second nymphal instars under controlled conditions. This study is within a bioprospection context, in the form of utilizing local plant species as an alternative in sustainable agriculture development. Eighteen and nine plant extracts caused a significant decrease in number of live adult and nymphal whiteflies, respectively, compared to the control. This is the first report for the potential effect on survival of insects for 22 out of 28 tested medicinal plant species. Whole plant extracts of Ranunculus myosuroudes Boiss. and Kotschy (Ranunculaceae), Achillea damascena L. (Asteraceae), and Anthemis hebronica Boiss. and Kotschy (Asteraceae) and leaf extracts of Verbascum leptostychum DC. (Scrophulariaceae) and Heliotropium rotundifolium Boiss. (Borangiaceae) caused both repellent and toxic effects against the adult and second nymphal instars, respectively. Extracts of leaves and stems of Anthemis scariosa Boiss. (Asteraceae) and Calendula palestina Pers. (Asteraceae) were found to be more bioactive against the adult and nymphal instars, respectively, than extracts of other plant parts, such as flowers. Thus, the bioactive extracts of these medicinal plants have the potential to lower whitefly populations in a comprehensive pest management program in local communities, pending cultivation of these medicinal plant species.