Antibacterial activities of the extracts, fractions and compounds from Dioscorea bulbifera

Phytoecdysteroids from Dioscorea dumetorum (Kunth) Pax. and their antioxidant and antidiabetic activities

Diabetes is a significant global health challenge, affecting circa 540 million adults worldwide. Dioscorea dumetorum, a Nigerian folkloric antidiabetic plant is severely understudied in terms of its bioactive phytochemical constituents. Antidiabetic guided isolation of the tubers and peels of D. dumetorum afforded three phytoecdysteroids bearing a cis-fused A/B ring junction including two new ones: 24-hydroxymuristerone A (1) and 24-hydroxykaladasterone (2), alongside the known muristerone A (3). Additionally, 2,2',7,7'-tetramethoxy-[1,1'-biphenanthrene]-4,4',6,6'-tetraol (4), batatasin I (5), and dihydroresveratrol (6) were isolated. Structural elucidation relied on spectroscopic, spectrometric methods, and comparison with existing literature. The ethyl acetate extracts of both the tubers and peels of D. dumetorum exhibited the highest phenolic content, correlating with potent antioxidant activity. Compounds 4 (IC50 = 0.10 mg/mL) and 6 (IC50 = 0.22 mg/mL) demonstrated superior inhibitory effects against α-glucosidase compared to acarbose (IC50 = 0.63 mg/mL). In contrast, compounds 3, 4, and 5 showed reduced α-amylase inhibition, with IC50 values of 2.58, 3.78, and 1.12 mg/mL, respectively, compared to acarbose (IC50 = 0.42 mg/mL). These observed bioactivities validate the traditional use of D. dumetorum and contribute valuable phytochemical data to the scientific literature of the species.

The genus Dioscorea L. (Dioscoreaceae), a review of traditional uses, phytochemistry, pharmacology, and toxicity

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Dioscorea, a member of the Dioscoreaceae family, comprises approximately 600 species and is widely distributed across temperate and tropical regions such as Asia, South Africa, and North America. The traditional medicinal uses of Dioscorea have been documented in Asian and African pharmacological systems. In Asia, this genus is traditionally used to treat respiratory illnesses, rheumatism, diabetes, diarrhea, dysentery, and other conditions. In Africa, this genus has been used to treat human immunodeficiency virus and ring worms. However, the traditional medicinal practices in North America rarely mention the use of this genus.

AIM OF THE STUDY

The aim of this review is to comprehensively review the genus Dioscorea, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. The research also aims to highlight the valuable bioactive compounds within Dioscorea and emphasize the need for further investigations into acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors to contribute to the discovery of novel pharmaceuticals.

MATERIALS AND METHODS

A search for available information on Dioscorea was conducted using scientific databases, including PubMed, ISI-WOS, Scopus, and Google Scholar, as well as recent academic publications from reputable publishers and other literature sources. The search was not limited by language and spanned the literature published between 1950 and 2022.

RESULTS

This article provides a comprehensive review of the Dioscorea genus, focusing on its traditional uses, phytochemical constituents, pharmacological activities, and potential toxicities. Extensive research has been conducted on this genus, resulting in the isolation and examination of over 1000 compounds, including steroids, terpenoids, and flavonoids, to determine their biological activities. These activities include anti-tumor, anti-inflammatory, immunomodulatory, neuroprotective, hypoglycemic, and hypolipidemic effects. However, some studies have indicated the potential toxicity of high doses of Dioscorea, highlighting the need for further investigations to assess the safety of this genus. Additionally, this review explores potential avenues for future research and discusses the challenges associated with a comprehensive understanding of the Dioscorea genus.

CONCLUSIONS

Based on the existing literature, it can be concluded that Dioscorea is a valuable source of bioactive compounds that have the potential to treat various disorders. Future research should prioritize the investigation of acute and chronic toxicity, activity mechanisms, molecular markers, and other relevant factors. This review provides a comprehensive analysis of the Dioscorea genus, emphasizing its potential to enable a deeper exploration of the biological activity mechanisms of these plants and contribute to the discovery of novel pharmaceuticals.

Anti-papillary thyroid carcinoma effects of dioscorea bulbifera L. through ferroptosis and the PI3K/AKT pathway based on network pharmacology and experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Papillary thyroid carcinoma (PTC) is the predominant form of thyroid cancer with a rising global incidence. Despite favorable prognoses, a significant recurrence rate persists. Dioscorea bulbifera L. (DBL), a traditional Chinese medicine, has been historically used for thyroid-related disorders. However, its therapeutic effects and mechanisms of action on PTC remain unclear.

AIM OF THE STUDY

To explore the potential therapeutic effects, principal active components, and molecular mechanisms of DBL in the treatment of PTC through network pharmacology and molecular docking, with experimental validation conducted to corroborate these findings.

MATERIALS AND METHODS

The Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) was utilized as a systematic tool for collecting and screening the phytochemical components of DBL, and for establishing associations between these components and molecular targets. Based on this, network data was visually processed using Cytoscape software (version 3.8.0). Concurrently, precise molecular docking studies of the principal active components of DBL and their corresponding targets were conducted using Autodock software. Additionally, PTC-related genes were selected through the GeneCards and GEO databases. We further employed the DAVID bioinformatics resources to conduct comprehensive Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses on the intersecting genes between DBL and PTC. These analyses aid in predicting the potential therapeutic actions of DBL on PTC and its mechanisms of action. To validate these findings, corresponding in vitro experimental studies were also conducted.

RESULTS

In this investigation, 14 bioactive compounds of DBL and 195 corresponding molecular targets were identified, with 127 common targets shared between DBL and PTC. Molecular docking revealed strong binding affinities between major bioactive compounds and target proteins. GO enrichment analysis unveiled key processes involved in DBL's action. KEGG analysis highlighted DBL's modulation of the PI3K/AKT signaling pathway. Experimental outcomes demonstrated DBL's potential in inhibiting PTC cell proliferation and migration, suppressing PI3K/AKT pathway activation, and promoting ferroptosis.

CONCLUSION

In conclusion, DBL offers a multifaceted therapeutic approach for PTC, targeting multiple molecular entities and influencing diverse biological pathways. Network pharmacology and molecular docking shed light on DBL's potential utility in PTC treatment, substantiated by experimental validation. This study contributes valuable insights into using DBL as a promising therapeutic agent for PTC management.

An Integrative Approach to Study the Inhibition of Providencia vermicola FabD Using C2-Quaternary Indolinones

Background

The present study investigates the potential bioactivity of twelve experimentally designed C-2 quaternary indolinones against Providencia spp., a bacterial group of the Enterobacteriaceae family known to cause urinary tract infections. The study aims to provide insights into the bioactive properties of the investigated compounds and their potential use in developing novel treatments against Providencia spp. The experimental design of indolinones, combined with their unique chemical structure, makes them attractive candidates for further investigation. The results of this research may contribute to the development of novel therapeutic agents to combat Providencia spp. infections.

Methods

The synthesized indolinones (moL1-moL12) are evaluated to identify any superior activity, particularly focusing on moL12, which possesses aza functionality. The antimicrobial activities of all twelve compounds are tested in triplicates against six different Gram-positive and Gram-negative organisms, including P. vermicola (P<0.05). Computational methods have been employed to assess the pharmacokinetic properties of the compounds.

Results

Among the synthesized indolinones, moL12 exhibits superior activity compared to the other compounds with similar skeleton but different functional moieties. All six strains tested, including P. vermicola, demonstrated sensitivity to moL12. Computational studies support the pharmacokinetic properties of moL12, indicating acceptable absorption, distribution, metabolism, excretion, and toxicity characteristics.

Conclusion

Utilizing the PPI approach, we have identified a promising target, FabD, in Gram-negative bacteria. Our analysis has shown that moL12 exhibits significant potential in binding with FabD, thereby, might inhibit cell wall formation, and display superior antimicrobial activity compared to other compounds. Consequently, moL12 may be a potential therapeutic agent that could be used to combat urinary tract infections caused by Providencia spp. The findings of this research hold significant promise for the development of new and effective treatments for bacterial infections.

Integrating network pharmacology and experimental studies for uncovering the molecular mechanisms of Dioscorea bulbifera L. in the treatment of thyroid cancer

Introduction

Thyroid cancer (TC), a common endocrine malignant tumor with a higher incidence in females than in males, is a serious threat to human life and health. Although current clinical treatments can alleviate this disease, the recurrence rate remains high. Tuber Dioscoreae Bulbiferae, also called Huang-Yao-Zi (HYZ), has remarkable curative properties, few side effects and is used for the treatment of sore throat, goiter, hemoptysis, and other diseases in traditional Chinese medicine (TCM). Existing clinical studies have found that HYZ can improve the clinical symptoms of TC patients and reduce tumor volume, while in vitro studies have found that HYZ can induce the death of thyroid cancer cells. However, the mechanism of HYZ in the treatment of TC is still unclear.

Methods

In this study, based on network pharmacology and bioinformatics, the target and molecular mechanism of HYZ in the treatment of TC were preliminarily explored. The results suggest that the antithyroid cancer effect of HYZ may be related to the PI3K-Akt and focal adhesion pathways. Then, a TC cell model was established to further explore the detail molecular mechanisms.

Results

Fortunately, HYZ induced apoptosis in KMH-2 cells and regulated the expression of apoptosis-related proteins and genes. At the same time, HYZ can also significantly inhibit the migration and invasion of TC cells. Further studies showed that the pharmacological activities of HYZ were related to the regulation of the PI3K-Akt and focal adhesion pathways.

Conclusion

Our study provides a reference for further animal or clinical studies investigating the effectiveness and molecular mechanisms of HYZ against thyroid cancer.

Phytochemicals as Antimicrobials: Prospecting Himalayan Medicinal Plants as Source of Alternate Medicine to Combat Antimicrobial Resistance

Among all available antimicrobials, antibiotics hold a prime position in the treatment of infectious diseases. However, the emergence of antimicrobial resistance (AMR) has posed a serious threat to the effectiveness of antibiotics, resulting in increased morbidity, mortality, and escalation in healthcare costs causing a global health crisis. The overuse and misuse of antibiotics in global healthcare setups have accelerated the development and spread of AMR, leading to the emergence of multidrug-resistant (MDR) pathogens, which further limits treatment options. This creates a critical need to explore alternative approaches to combat bacterial infections. Phytochemicals have gained attention as a potential source of alternative medicine to address the challenge of AMR. Phytochemicals are structurally and functionally diverse and have multitarget antimicrobial effects, disrupting essential cellular activities. Given the promising results of plant-based antimicrobials, coupled with the slow discovery of novel antibiotics, it has become highly imperative to explore the vast repository of phytocompounds to overcome the looming catastrophe of AMR. This review summarizes the emergence of AMR towards existing antibiotics and potent phytochemicals having antimicrobial activities, along with a comprehensive overview of 123 Himalayan medicinal plants reported to possess antimicrobial phytocompounds, thus compiling the existing information that will help researchers in the exploration of phytochemicals to combat AMR.

Antibacterial and Antifungal Terpenes from the Medicinal Angiosperms of Asia and the Pacific: Haystacks and Gold Needles

This review identifies terpenes isolated from the medicinal Angiosperms of Asia and the Pacific with antibacterial and/or antifungal activities and analyses their distribution, molecular mass, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and library searches from 1968 to 2022. About 300 antibacterial and/or antifungal terpenes were identified during this period. Terpenes with a MIC ≤ 2 µg/mL are mostly amphiphilic and active against Gram-positive bacteria, with a molecular mass ranging from about 150 to 550 g/mol, and a polar surface area around 20 Ų. Carvacrol, celastrol, cuminol, dysoxyhainic acid I, ent-1β,14β-diacetoxy-7α-hydroxykaur-16-en-15-one, ergosterol-5,8-endoperoxide, geranylgeraniol, gossypol, 16α-hydroxy-cleroda-3,13 (14)Z-diene-15,16-olide, 7-hydroxycadalene, 17-hydroxyjolkinolide B, (20R)-3β-hydroxy-24,25,26,27-tetranor-5α cycloartan-23,21-olide, mansonone F, (+)-6,6'-methoxygossypol, polygodial, pristimerin, terpinen-4-ol, and α-terpineol are chemical frameworks that could be candidates for the further development of lead antibacterial or antifungal drugs.

Janthinobacterium kumbetense sp. nov., a violacein-producing bacterium isolated from spring water in Turkey, and investigation of antimicrobial activity of violacein

Strain GKT was isolated from the Kumbet plateu of Giresun in Turkey. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GKT belonged to genus Janthinobacterium and 16S rRNA gene sequence similarities with all type strains of the genus Janthinobacterium were 98.89%-99.78%. The calculated pairwise average nucleotide identity (ANI) values between strain GKT and all type strains of Janthinobacterium species were in the range of 79.8%-93.2%. In addition, digital DNA-DNA hybridization (dDDH) values were in the range of 23.0%-51.7%. Major fatty acids are C10:03OH, C12:0, C16:1ω7c, C16:0, and C18:1ω7c, and polar lipids included phosphatidylethanolamine, phosphatidylglycerol, also one unidentified phospholipid and one unidentified aminophospholipid. The respiratory quinone of strain GKT was determinated to be Q-8. The genome sizes of strain GKT was 6 197 538 bp with 63.16% G + C ratio. Strain GKT is Gram-stain-negative, aerobic, rod-shaped, and motile. A violet pigment was produced by strain GKT. The crude violacein pigments were separated into three diferent bands on a TLC sheet. Then violacein and deoxyviolacein were purifed by vacuum liquid column chromatography and identifed by NMR spectroscopy. The antimicrobial activities of purifed violacein and deoxyviolacein were screened for seven microorganisms. Based on the results of the morphological, biochemical, physiological, phylogenetic, and genomic characteristics, we propose classifying the strain GKT as representative of a novel species of the genus Janthinobacterium, for which the name Janthinobacterium kumbetense sp. nov. is proposed (GKT = LMG 32662T = DSM 11423T).

Anti-Streptococcus mutans, anti-adherence and anti-acidogenic activity of Uvaria chamae P. Beauv

ETHNOPHARMACOLOGICAL RELEVANCE

Streptococcus mutans a key pathogen, produces biofilm, acids and extracellular polysaccharides in the oral cavity; which leads to the development of dental caries. Control of these pathogenic markers can prevent dental caries. Uvaria chamae P. Beauv. is a medicinal plant traditionally used for many ailments including oral infections. Root, leaves and bark extracts has proven antibacterial activity including activity against caries causing S. mutans. However, its effect on the virulence properties of S. mutans, responsible for the development of dental caries, has not been studied.

AIM OF THE STUDY

This study investigated the phytochemical constituents, anti-S. mutans, anti-adherence and anti-acidogenic activity of U. chamae root extract.

MATERIALS AND METHODS

Extracts were prepared and phytochemical analysis was performed. Minimum inhibitory concentrations (MIC) were determined, and MIC and sub-MIC concentrations of the best solvent were selected for their effect on the virulence factors of S. mutans. The results were analysed using one-way ANOVA and Wilcoxon Rank Sum Tests.

RESULTS

The dichloromethane extract, with proanthocyanidin as a major chemical constituent, produced an MIC of 0.02 mg/ml. At 6 h, exposure to 0.005, 0.01, and 0.02 mg/ml extract significantly reduced S. mutans adherence by 39, 59, and 77% respectively (p < 0.05). Uvaria chamae also significantly inhibited acid production in S. mutans at 10, 12, 14 and 16 h (p < 0.05). At ½ MIC, the plant extract caused remarkable downregulation of the virulence genes responsible for the adherence, biofilm formation, extracellular polysaccharide synthesis and acid production.

CONCLUSIONS

This suggests that U. chamae extract may potentially be used to inhibit the proliferation of S. mutans and silencing the expression of pathology-related genes, which will prevent the development of dental caries.

Isolation and Characterization of Werneria Chromene and Dihydroxyacidissimol from Burkillanthus malaccensis (Ridl.) Swingle

The secondary metabolites of endemic plants from the Rutaceae family, such as Burkillanthusmalaccensis (Ridl.) Swingle from the rainforest of Malaysia, has not been studied. Burkillanthusmalaccensis (Ridl.) Swingle may produce antibacterial and antibiotic-potentiating secondary metabolites. Hexane, chloroform, and methanol extracts of leaves, bark, wood, pericarps, and endocarps were tested against bacteria by broth microdilution assay and their antibiotic-potentiating activities. Chromatographic separations of hexane extracts of seeds were conducted to investigate effective phytochemicals and their antibacterial activities. Molecular docking studies of werneria chromene and dihydroxyacidissiminol against SARS-CoV-2 virus infection were conducted using AutoDock Vina. The methanol extract of bark inhibited the growth of Staphylococcusaureus, Escherichiacoli, and Pseudomonasaeruginosa with the minimum inhibitory concentration of 250, 500, and 250 µg/mL, respectively. The chloroform extract of endocarps potentiated the activity of imipenem against imipenem-resistant Acinetobacterbaumannii. The hexane extract of seeds increased the sensitivity of P. aeruginosa against ciprofloxacin and levofloxacin. The hexane extract of seeds and chloroform extract of endocarps were chromatographed, yielding werneria chromene and dihydroxyacidissiminol. Werneria chromene was bacteriostatic for P.aeruginosa and P.putida, with MIC/MBC values of 1000 > 1000 µg/mL. Dihydroxyacidissiminol showed the predicted binding energies of −8.1, −7.6, −7.0, and −7.5 kcal/mol with cathepsin L, nsp13 helicase, SARS-CoV-2 main protease, and SARS-CoV-2 spike protein receptor-binding domain S-RBD. Burkillanthusmalaccensis (Ridl.) Swingle can be a potential source of natural products with antibiotic-potentiating activity and that are anti-SARS-CoV-2.

Chemical Profile and In Vitro Evaluation of the Antibacterial Activity of Dioscorea communis Berry Juice

Within the large family of Dioscoreaceae, Dioscorea communis (L.) Caddick & Wilkin (syn. Tamus communis L.) is considered among the four most widespread representatives in Europe, and it is commonly known under the name black bryony or bryonia. To date, reports have revealed several chemical components from the leaves and tubers of this plant. Nevertheless, an extensive phytochemical investigation has not been performed on its berry juice. In the present study, metabolite profiling procedures, using LC-MS, GC-MS, and NMR approaches, were applied to investigate the chemical profile of the D. communis berries. This work reveals the presence of several metabolites belonging to different phytochemical groups, such as fatty acid esters, alkylamides, phenolic derivatives, and organic acids, with lactic acid being predominant. In parallel, based on orally transmitted traditional uses, the initial extract and selected fractions were tested in vitro for their antibacterial effects and exhibited good activity against two bacterial strains related to skin infections: methicillin-resistant Staphylococcus aureus and Cutibacterium acnes. The MIC and MBC values of the extract were determined at 1.56% w/v against both bacteria. The results of this study provide important information on the chemical characterization of the D. communis berry juice, unveiling the presence of 71 metabolites, which might contribute to and further explain its specific antibacterial activity and its occasional toxicity.

Ethnobotany and the Role of Plant Natural Products in Antibiotic Drug Discovery

The crisis of antibiotic resistance necessitates creative and innovative approaches, from chemical identification and analysis to the assessment of bioactivity. Plant natural products (NPs) represent a promising source of antibacterial lead compounds that could help fill the drug discovery pipeline in response to the growing antibiotic resistance crisis. The major strength of plant NPs lies in their rich and unique chemodiversity, their worldwide distribution and ease of access, their various antibacterial modes of action, and the proven clinical effectiveness of plant extracts from which they are isolated. While many studies have tried to summarize NPs with antibacterial activities, a comprehensive review with rigorous selection criteria has never been performed. In this work, the literature from 2012 to 2019 was systematically reviewed to highlight plant-derived compounds with antibacterial activity by focusing on their growth inhibitory activity. A total of 459 compounds are included in this Review, of which 50.8% are phenolic derivatives, 26.6% are terpenoids, 5.7% are alkaloids, and 17% are classified as other metabolites. A selection of 183 compounds is further discussed regarding their antibacterial activity, biosynthesis, structure-activity relationship, mechanism of action, and potential as antibiotics. Emerging trends in the field of antibacterial drug discovery from plants are also discussed. This Review brings to the forefront key findings on the antibacterial potential of plant NPs for consideration in future antibiotic discovery and development efforts.

Antibacterial activity of methanol extracts of the leaves of three medicinal plants against selected bacteria isolated from wounds of lymphoedema patients

Background

Patients with lymphoedema are at high risk of getting bacterial and fungal wound infections leading to acute inflammatory episodes associated with cellulitis and erysipelas. In Ethiopia, wound infections are traditionally treated with medicinal plants.

Methods

Agar well diffusion and colorimetric microdilution methods were used to determine the antibacterial activity of methanol extracts of the three medicinal plants against Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Shewanella alage, methicillin-resistant S. aureus ATCC®43300TM, Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, Klebsiella pneumoniae ATCC700603, and Pseudomonas aeruginosa ATCC37853.

Results

The methanol extract of L. inermis leaves showed high activity against all tested bacterial species, which was comparable to the standard drugs. Similarly, the extracts of A. indica showed activity against all tested species though at higher concentrations, and higher activity was recorded against Streptococcus pyogenes isolates at all concentrations. However, the extract of A. aspera showed the lowest activity against all tested species except Streptococcus pyogenes isolates. The lowest minimum inhibitory concentration (MIC) was recorded with the extract of L. inermis against E. coli isolate and S. aureus ATCC 25923.

Conclusion

Methanol extracts of L. inermis, A. indica, and A. aspera leaves exhibited antimicrobial activity against selected bacterial isolates involved in wound infections, of which the methanol extracts of L. inermis exhibited the highest activity. The results of the present study support the traditional use of plants against microbial infections, which could potentially be exploited for the treatment of wound infections associated with lymphoedema.

The Dioscorea Genus (Yam)-An Appraisal of Nutritional and Therapeutic Potentials

The quest for a food secure and safe world has led to continuous effort toward improvements of global food and health systems. While the developed countries seem to have these systems stabilized, some parts of the world still face enormous challenges. Yam (Dioscorea species) is an orphan crop, widely distributed globally; and has contributed enormously to food security especially in sub-Saharan Africa because of its role in providing nutritional benefits and income. Additionally, yam has non-nutritional components called bioactive compounds, which offer numerous health benefits ranging from prevention to treatment of degenerative diseases. Pharmaceutical application of diosgenin and dioscorin, among other compounds isolated from yam, has shown more prospects recently. Despite the benefits embedded in yam, reports on the nutritional and therapeutic potentials of yam have been fragmented and the diversity within the genus has led to much confusion. An overview of the nutritional and health importance of yam will harness the crop to meet its potential towards combating hunger and malnutrition, while improving global health. This review makes a conscious attempt to provide an overview regarding the nutritional, bioactive compositions and therapeutic potentials of yam diversity. Insights on how to increase its utilization for a greater impact are elucidated.

The search for plant activity against tuberculosis using breakpoints: A review

The present study proposes a discussion about the use of breakpoints when plant derivatives are used for investigating potential agents against Mycobacterium tuberculosis strains. A systematic review on these aspects was performed and supported that an arbitrary breakpoint may be considered inadequate in this kind of study. In addition, we propose that the adoption of this limiter should be done from the toxicity value found using the same plant derivative.

Dioscorea bulbifera induced apoptosis through inhibition of ERK 1/2 and activation of JNK signaling pathways in HCT116 human colorectal carcinoma cells

Dioscorea bulbifera, also known as air potato, has been cultivated as food crop mainly in tropical countries in Asia and Australia. The tubers are edible and have often been used in Traditional Chinese Medicine (TCM) and Ayurvedic medicine to treat cancer, diabetes, thyroid disease, and inflammation. This study aimed to investigate the effects of D. bulbifera on HCT116 human colorectal carcinoma cells and to unravel the plausible mechanisms underlying its apoptotic effects. The ethanol crude and fractions (hexane, ethyl acetate and water) of D. bulbifera were subjected to cell viability MTT assay against various cancer cell lines. The lowest IC50 of the extract and fractions on selected cancer cells were selected for further apoptosis assay and western blot analysis. HCT116 cancer cells were treated with D. bulbifera and stained with Annexin/PI or Hoechst 33342/PI for preliminary confirmation of apoptosis. The dissipation of mitochondria membrane potential (MMP) was determined by flow cytometry. The protein expressions of apoptosis-related proteins such as Bcl-2 family, caspases, Fas, PARP, ERK1/2 and JNK were detected by western blot analysis. Moreover, the HCT116 cells were treated with UO126 and SP600125 inhibitors to verify the involvement of ERK1/2 and JNK protein expressions in inducing apoptotic cell death. Based on the result, D. bulbifera ethyl acetate fraction (DBEAF) exhibited the most compelling cytotoxicity on HCT116 cells with an IC50 of 37.91 ± 1.30 µg/mL. The induction of apoptosis was confirmed by phosphatidylserine externalization and chromatin condensation. Depolarization of MMP further conferred the induction of apoptosis was through the regulation of Bcl-2 family proteins. Activation of caspase cascades (caspase-3, -9, -8 and -10) was elicited followed by the observation of cleaved PARP accumulation in DBEAF-treated cells. Furthermore, death receptor, Fas was activated upon exposure to DBEAF. Collective apoptotic evidences suggested the involvement of intrinsic and extrinsic pathways by DBEAF in HCT116 cells. Interestingly, the attenuation of ERK1/2 phosphorylation accompanied by the activation of JNK was detected in DBEAF-treated cells. In conclusion, the findings revealed that DBEAF induced apoptosis through intrinsic and extrinsic pathways involving ERK1/2 and JNK.

Multidrug resistant bacteria are sensitive to Euphorbia prostrata and six others Cameroonian medicinal plants extracts

Background

Multidrug resistant (MDR) bacteria are responsible for therapeutic failure and there is an urgent need for novels compounds efficient on them.

Methods

Eleven methanol extracts from seven Cameroonian medicinal plants were tested for their antibacterial activity using broth micro-dilution method against 36 MDR bacterial strains including Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus.

Results

Euphorbia prostrata extract was found active against all the 36 tested bacteria including Gram-negative phenotypes over-expressing efflux pumps such as P. aeruginosa PA124, E. aerogenes CM64 and E. coli AG102. E. prostrata had minimal inhibitory concentrations values between 128 and 256 µg/mL on 55.55% of the studied microorganisms. Other plants extract displayed selective antibacterial activity.

Conclusions

Results obtained in this study highlight the antibacterial potential of the tested plants and the possible use of E. prostrata to combat bacterial infections including MDR phenotypes.

Antispasmodic, bronchodilator, vasorelaxant and cardiosuppressant effects of Buxus papillosa

Background

The present research was carried out to investigate pharmacological properties of Buxus papillosa C.K. Schneid. (Buxaceae).

Methods

Buxus papillosa extracts of leaves (BpL), stem (BpS), roots (BpR) and BpL fractions: hexane (BpL-H), aqueous (BpL-A) also plant constituent, cyclomicrobuxine effect were studied in jejunum, atria, aorta and tracheal preparations from rabbit and guine-peg.

Results

Ca⁺⁺ antagonistic effect of BpS, BpR, BpL-H, BpL-A and cyclomicrobuxine were conclusively suggested, when spontaneous contractions of rabbit jejunal preparation was relaxed along with subsequent relaxation of potassium chloride (80 mM) induced contractions. Ca⁺⁺ antagonistic effect was further confirmed, when a prominent right shift like that of verapamil was observed in Ca⁺⁺ concentration-response curves, drawn in a tissue pretreated with BpL (0.3–1.0 mg/mL). In rabbit tracheal tissues BpL, BpS, BpR, BpL-H and BpL-A produced a prominent relaxation in contractions induced by potassium chloride (80 mM) and carbachol (1 μm). When tested in rabbit aortic rings, BpL, BpS, BpR, BpL-H and BpL-A showed concentration-dependent (0.1–3.0 mg/mL) vasorelaxant effect against phenylephrine (1 μM) and high K⁺-induced contractions. In isolated guinea-pig right atria, BpL, BpS, BpR, BpL-H and BpL-A suppressed atrial force of spontaneous contractions, with BpL-A being most potent.

Conclusions

Our results reveal that Buxus papillosa possesses gut, airways and cardiovascular inhibitory actions.

A single molecular marker to distinguish between species of Dioscorea

Yams are species of the genus Dioscorea (family Dioscoreaceae), which consists of approximately 630 species. The majority of the world production of yams occurs in Africa with 58.8 million t annually, but they are also produced in the Americas and Asia. The saponins in yams have been reported to possess various properties to improve health. The tuber and aerial parts of various species often share morphological similarities, which can cause problems in the proper identification of sample material. For example, the rootstocks and aerial parts of Dioscorea villosa L. share similarities with Dioscorea polystachia Turcz. Dioscorea bulbifera L. may be mistaken for Dioscorea alata L. owing to similar morphologies. Various molecular analyses have been published to help with the identification of species and varieties within the genus Dioscorea. The multi-loci or single-locus analysis has resulted in varying success, some with only a limited discrimination rate. In the present study, a single nuclear genomic region, biparentally inherited, was analyzed for its usefulness as a molecular marker for species identification and discrimination between D. bulbifera, D. villosa, D. nipponica, D. alata, D. caucasica, and D. deltoidea samples. The results of this study show that the LFY genomic region can be useful as a molecular marker to distinguish between samples.

Ethnobotanical Study of Medicinal Plants Used as Anti-Obesity Remedies in the Nomad and Hunter Communities of Burkina Faso

BACKGROUND

Obesity is a global epidemic that affects both developed and developing countries. According to World Health Organization (WHO), in 2014, over 1.9 billion adults were overweight. Burkina Faso, like other countries, faces the problem of obesity, with a prevalence of 7.3%. The main cause is excessive intake of caloric foods combined with low physical activity, although genetic, endocrine and environmental influences (pollution) can sometimes be predisposing factors. This metabolic imbalance often leads to multiple pathologies (heart failure, Type II diabetes, cancers, etc.). Drugs have been developed for the treatment of these diseases; but in addition to having many side effects, locally these products are not economically accessible to the majority of the population. Burkina Faso, like the other countries bordering the Sahara, has often been confronted in the past with periods of famine during which populations have generally used anorectic plants to regulate their food needs. This traditional ethnobotanical knowledge has not been previously investigated. An ethnobotanical survey was conducted in Burkina Faso in the provinces of Seno (North) and Nayala (Northwest) to list the plants used by local people as an anorectic and/or fort weight loss.

METHODS

The survey, conducted in the two provinces concerned traditional healers, herbalists, hunters, nomads and resourceful people with knowledge of plants. It was conducted over a period of two months and data were collected following a structured interview with the respondents. The approach was based on dialogue in the language of choice of the respondent and the use of a questionnaire. The data have been structured and then statistically analyzed.

RESULTS

The fifty-five (55) respondents of the survey were aged between 40 and 80 years. Sixty-one (61) plant species, belonging to thirty-one (31) families were listed as appetite suppressants and/or for their anti-obesity properties. The main families of plants are Mimosaceae, Rubiaceae, Asclepiadaceae and Cesalpiniaceae. Fruits are the most used part of the plant organs. Consumption in the raw state or as a decoction are the two main forms of preparation.

CONCLUSION

The great diversity of plants cited by informants demonstrates the existence of rich local knowledge to address obesity in Burkina Faso. Evaluation of the biochemical activity of the extracts of the most cited species could allow the development of a phytomedicine economically accessible to the majority of the population. This could allow for the preservation of biodiversity in this region which is weakened by climate change because some of the species cited are in fragile state or are threatened with extinction.

African flora has the potential to fight multidrug resistance of cancer

Background. Continuous efforts from scientists of diverse fields are necessary not only to better understand the mechanism by which multidrug-resistant (MDR) cancer cells occur, but also to boost the discovery of new cytotoxic compounds to fight MDR phenotypes. Objectives. The present review reports on the contribution of African flora in the discovery of potential cytotoxic phytochemicals against MDR cancer cells. Methodology. Scientific databases such as PubMed, ScienceDirect, Scopus, Google Scholar, and Web of Knowledge were used to retrieve publications related to African plants, isolated compounds, and drug resistant cancer cells. The data were analyzed to highlight cytotoxicity and the modes of actions of extracts and compounds of the most prominent African plants. Also, thresholds and cutoff points for the cytotoxicity and modes of action of phytochemicals have been provided. Results. Most published data related to the antiproliferative potential of African medicinal plants were from Cameroon, Egypt, Nigeria, or Madagascar. The cytotoxicity of phenolic compounds isolated in African plants was generally much better documented than that of terpenoids and alkaloids. Conclusion. African flora represents an enormous resource for novel cytotoxic compounds. To unravel the full potential, efforts should be strengthened throughout the continent, to meet the challenge of a successful fight against MDR cancers.

Comparative micromorphological study of wild and micropropagated Dioscorea bulbifera Linn

OBJECTIVE

To study the leaf epidermis of wild and micropropagated Dioscorea bulbifera Linn. (D. bulbifera) in order to document useful diagnostic features that may be employed for correct crude drug identification and to clear any taxonomic uncertainties in the micropropagated medicinal plant.

METHODS

Growth responses of micropropagated D. bulbifera were observed on Murashige Skoog medium supplemented with 6-benzylamino purine (1.0 mg/L)+α-naphthaleneacetic acid (0.2 mg/L)+cysteine (20 mg/L) using nodal segments as explants. Leaves of the wild and micropropagated plants were studied microscopically.

RESULTS

More than 80% shoot regeneration and formation of 10%-30% whitish-brown callus were observed within 3 weeks. The highest root proliferation was obtained from Murashige Skoog medium of 6-benzylamino purine (0.05 mg/L) and α-naphthaleneacetic acid (0.01 mg/L) with mean root length of (27.00±1.25) mm and elongated single shoot of mean length (38.00±11.09) mm. Leaf epidermal features that revealed similarities between the wild and micropropagated plants included amphistomatic condition, presence of mucilage, glandular unicellular trichome with multicellular head, polygonal cells with smooth walls, stomata type and shape. Slight variations included thick cuticular wall with closed stomata in wild plant compared to thin walled opened stomata in the in vitro plant. Opening of stomata accounted for larger average stomata sizes of (7.68±0.38) µm and (6.14±0.46) µm on the adaxial and abaxial surfaces, respectively of the micropropagated plant compared to the wild.

CONCLUSIONS

The diagnostic features obtained in the study could serve as a basis for proper identification for quality control for standardization of the medicinal plant.

Plants used for treatment of dysentery and diarrhoea by the Bhoxa community of district Dehradun, Uttarakhand, India

ETHNOPHARMACOLOGICAL RELEVANCE

Dysentery and diarrhoea are major causes of morbidity and mortality in rural communities of developing world. The Bhoxa community is an important primitive indigenous community of Uttarakhand, India. In this paper we have tried to scientifically enumerate ethnomedicinal plants and herbal preparations used by Bhoxa community to treat dysentery and diarrhoea, and discuss their antidiarrhoeal properties in the light of previous ethnomedicinal, pharmacological, microbiological and phytochemical studies. To record plants and herbal preparations used by Bhoxa community of district Dehradun, Uttarakhand, India in treatment of dysentery and diarrhoea, and to discuss antidiarrhoeal and antimicrobial properties of the recorded plants.

MATERIALS AND METHODS

Ethnomedicinal survey was conducted in different villages of Bhoxa community located in district Dehradun, Uttarakhand, India. Thirty Bhoxa traditional healers were interviewed to collect information on plants used by them for treating dysentery and diarrhoea. For each of the recorded plant species the use value (UV) and fidelity level (FL) was calculated. Detailed literature survey was conducted to summarize ethnomedicinal, pharmacological, microbiological and phytochemical information on the medicinal plants listed in the present study.

RESULTS

Fifty medicinal plants (45 genera and 30 families) were used by Bhoxa community to treat dysentery and diarrhoea, among which 27 species were used for dysentery, 41 for diarrhoea and 18 for both dysentery and diarrhoea. Three plants viz., Dioscorea bulbifera L., Euphorbia thymifolia L. and Prunus persica (L.) Stokes, recorded in the present survey have been reported for the first time in treatment of dysentery and diarrhoea by any indigenous communities in India. FL and UV values revealed that most preferred species for the treatment of dysentery and diarrhoea by Bhoxa community are Euphorbia hirta L. followed by Holarrhena pubescens Wall., Helicteres isora L. and Cassia fistula L. Earlier pharmacological studies confirmed that 27 of the recorded plants have some proven antidiarrhoeal properties and remaining 23 plants have to be pharmacologically evaluated for their antidiarrhoeal properties. Except 6 plants all the other recorded plants have shown antimicrobial properties in previous microbiological studies. Previous studies have corroborated the ethnomedicinal claims made by the traditional healers of the Bhoxa community.

CONCLUSIONS

Present study has provided new information on many medicinal plants and their uses. All the three newly reported plants for treatment of dysentery and diarrhoea have not been pharmacologically evaluated yet for their possible antidiarrhoeal properties. Twenty-three and six plants have not been evaluated pharmacologically and microbiologically, respectively. The present information may serve as a baseline data to initiate further research for discovery of new compounds and biological activities of these potential plants. Further research on these plants may provide some important clues for development of new drugs for dysentery and diarrhoea or other related diseases.

Cytotoxicity of Elaoephorbia drupifera and other Cameroonian medicinal plants against drug sensitive and multidrug resistant cancer cells

Background

Multidrug resistance (MDR) is a major hurdle for cancer treatment worldwide and accounts for chemotherapy failure in over 90% of patients with metastatic cancer. Evidence of the cytotoxicity of Cameroonian plants against cancer cell lines including MDR phenotypes is been intensively and progressively provided. The present work was therefore designed to evaluate the cytotoxicity of the methanol extracts of twenty-two Cameroonian medicinal plants against sensitive and MDR cancer cell lines.

Methods

The methanol maceration was used to obtain the crude plant extracts whilst the cytotoxicity of the studied extracts was determined using a resazurin reduction assay.

Results

A preliminary assay on leukemia CCRF-CEM cells at 40 μg/mL shows that six of the twenty plant extract were able to enhance less than 50% of the growth proliferation of CCRF-CEM cells. These include Crinum zeylanicum (32.22%), Entada abyssinica (34.67%), Elaoephorbia drupifera (35.05%), Dioscorea bulbifera (45.88%), Eremomastax speciosa (46.07%) and Polistigma thonningii (45.11%). Among these six plants, E. drupifera showed the best activity with IC₅₀ values below or around 30 μg/mL against the nine tested cancer cell lines. The lowest IC₅₀ value of 8.40 μg/mL was recorded with the extract of E. drupifera against MDA-MB231 breast cancer cell line. The IC₅₀ values below 10 μg/mL were recorded with the extracts of E. drupifera against MDA-MB231 breast cancer cells, C. zeylanicum against HCT116 p53⁺/⁺ and HCT116p53^-/^- colon cancer cells and E. abyssinica against HCT116 p53⁺/⁺ cells.

Conclusion

The results of the present study provide evidence of the cytotoxic potential of some Cameroonian medicinal plants and a baseline information for the potential use of Elaoephorbia drupifera in the treatment of sensitive and drug-resistant cancer cell lines.