Abdel Nasser Singab

Medicinal Plants with Potential Antidiabetic Activity and their Assessment

Objective: Diabetes mellitus is a clinical syndrome characterized by a deficiency in insulin production or resistance to insulin action. Consequently, it leads to inappropriate hyperglycemia. Prolonged hyperglycemia can cause severe complications that probably affect every system of the body and every drug taken by the patient. This study highlights the most popular medicinal plants with potential antidiabetic significance, their modes of action together with the method used for their assessment. nKey findings: Through antidiabetic evaluation conducted on different medicinal herbs since centuries revealed the presence of potent antidiabetic activity. Moreover, the candidates from natural source with diverse structures of secondary metabolites. This indicates various sites of action within the human body. Conclusions: Further investigations are required, and more attention should be drawn to explore the biological activity of hundreds of traditionally used medicinal plants both in vitro and in vivo to assess the claimed activity with the aim of finding potent antidiabetic candidates from the natural resources.

Acetylated flavonol triglycosides from Ammi majus L.

Two new acetylated flavonol triglycosides: kaempferol and isorhamnetin 3-O-[2-(4-acetylrhamnosyl)-6-glucosyl] glucosides, were isolated and identified from the aerial parts of Ammi majus L. In addition, three known flavonol glycosides namely; isorhamnetin-3-O-rutinoside, kaempferol-3-O-glucoside and isorhamnetin-3-O-glucoside were detected.

Genus Kalanchoe (Crassulaceae): a review of its ethnomedicinal, botanical, chemical and pharmacological properties.

Genus Kalanchoe comprises hundred species. Different extracts of these Kalanchoe species have been widely used in traditional medicine. Recently it has been reported that Kalanchoe extracts possess various biological activities viz. antiviral, sedative, antiulcer, immunomodulatory, antileishmanial, CNS depressant, anti-inflammatory, thyroid peroxidase inhibitor, cytotoxic, hepatoprotective, antioxidant, analgesic, anticonvulsant, antimicrobial, inhibition of B cell development, cardiovascular, antihyperglycemic, acetylcholinesterase inhibition, insecticidal and larvicidal activities. Earlier studies on different Kalanchoe species have reported the isolation of polysaccharides, flavonoids, sterols, ascorbic acid, trace elements, organic acids, hydrocarbons, triterpenoids, phenolic components and bufadenolides. This review presents the botany, chemistry, traditional uses and pharmacological data of genus Kalanchoe.

Discovery of Potent VEGFR-2 Inhibitors based on Furopyrimidine and Thienopyrimidne Scaffolds as Cancer Targeting Agents

Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a crucial role in cancer angiogenesis. In this study, a series of novel furo[2,3-d]pyrimidine and thieno[2,3-d]pyrimidine based-derivatives were designed and synthesized as VEGFR-2 inhibitors, in accordance to the structure activity relationship (SAR) studies of known type II VEGFR-2 inhibitors. The synthesized compounds were evaluated for their ability to in vitro inhibit VEGFR-2 kinase enzyme. Seven compounds (15b, 16c, 16e, 21a, 21b, 21c and 21e) demonstrated highly potent dose-related VEGFR-2 inhibition with IC50 values in nanomolar range, of which the thieno[2,3-d]pyrimidine based-derivatives (21b, 21c and 21e) exhibited IC50 values of 33.4, 47.0 and 21u2009nM respectively. Moreover, furo[2,3-d]pyrimidine-based derivative (15b) showed the strongest inhibition of human umbilical vein endothelial cells (HUVEC) proliferation with 99.5% inhibition at 10u2009μM concentration. Consistent with our in vitro findings, compounds (21b and 21e) orally administered at 5 and 10u2009mg/kg/day for 8 consecutive days demonstrated potent anticancer activity in Erhlich ascites carcinoma (EAC) solid tumor murine model. Such compounds blunted angiogenesis in EAC as evidenced by reduced percent microvessel via decreasing VEGFR-2 phosphorylation with subsequent induction of apoptotic machinery. Furthermore, Miles vascular permeability assay confirmed their antiangiogenic effects in vivo. Intriguingly, such compounds showed no obvious toxicity.

Pyrostegia venusta (Ker Gawl.) Miers: A Botanical, Pharmacological and Phytochemical Review

Objective: Pyrostegia venusta (Ker Gawl.) Miers (Bignoniaceae) has been commonly used in the traditional Brazilian medicine as a general tonic, treating skin infections (leukoderma, vitiligo), as well as a treatment for diarrhoea, cough and common respiratory diseases related to infections, such as bronchitis, flu and cold. This study highlights the botany, traditional uses, phytochemistry and pharmacology of Pyrostegia venusta. Information was obtained from Google Scholar, Scirus, PubMed and Science Direct. Key findings: Phytochemical studies on Pyrostegia venusta have shown the presence of triterpenes, sterols, flavonoids, fatty acids, n-alkanes, nitrogenous compounds as allantoin and carbohydrates. Crude extracts of Pyrostegia venusta possess a wide range of pharmacological activities, such as antioxidant, anti-inflammatory, analgesic, antinociceptive, wound healing, antimicrobial, and useful in the treatment of disorders that induced sickness behavior, such as flu and cold. Also used to reduce menopausal symptoms, and for enhancement of melanogenesis. Conclusions: Pyrostegia venusta is a natural source of antioxidants. and has been widely used in the traditional Brazilian medicine. Pyrostegia venusta could be exploited as a potential source for plant-based pharmaceutical products. The present review could form a sound basis for further investigation in the potential discovery of new natural bioactive compounds, and could provide preliminary information for future research.

Phytochemicals of Markhamia species (Bignoniaceae) and their therapeutic value: a review.

Aims: To present a compilation of data regarding the phytochemical content and pharmacological activities pertaining to genus Markhamia as one of 120 genera belonging to family Bignoniaceae. Study Design: Literature was collected from various published textbooks and scientific papers then the required data was summarized and presented in both tabulated form and concise text. Results: Phenyl propanoids, triterpenic acids and anthraquinones are the major phytochemicals reported in this genus. Traditional clinical practice demonstrated that the different species of Markhamia were used in curing anaemia and bloody diarrhoea in Africa as well as other ethnopharmacological uses. Many reports were published explaining the activity of the extracts of various species of Markhamia as potential anti-inflammatory, antiparasitic, anthelmintic, analgesic, anti-viral, antimicrobial and anti-fungal agents. Conclusion: This review presents an overview on the reported phytochemicals isolated from different Markhamia species and the biological activities associated with various Markhamia extracts and isolated compounds. Review Article Ali et al.; EJMP, 6(3): 124-142, 2015; Article no.EJMP.2015.049 125

Genus Terminalia: A phytochemical and Biological Review

Context: Terminalia is the second largest genus of family Combretaceae. The plants of this genus were used in traditional folk medicine worldwide. nObjectives: This review is a comprehensive literature survey of different Terminalia species regarding their biological activities and their isolated phytochemicals. The aim of this review is to attract the attention to unexplored potential of natural products obtained from Terminalia species, thereby contributing to the development of new therapeutic alternatives that may improve the health of people suffering from various health problems. nMaterials and methods: All the available information on genus Terminalia was compiled from electronic databases such as Medline, Google Scholar, PubMed, ScienceDirect, SCOPUS, Chemical Abstract Search and Springer Link. nResults: Phytochemical research has led to the isolation of different classes of compounds including, tannins, flavonoids, phenolic acids, triterpenes, triterpenoidal glycosides, lignan and lignan derivatives. Crude extracts and isolated components of different Terminalia species showed a wide spectrum of biological activities. nConclusion: phytochemical studies on genus Terminalia have revealed a variety of chemical constituents. Numerous biological activities have validated the use of this genus in treatment of various diseases in traditional medicine. Further studies are needed to explore the bioactive compounds responsible for the pharmacological effects and their mechanism of action.

Chemical composition and antimicrobial activity of flower essential oil of Jacaranda acutifolia Juss. against food-borne pathogens.

Aims: To investigate the chemical composition and antimicrobial activity of the hydrodistilled flower essential oil of Jacaranda acutifolia Juss. (Bignoniaceae) to validate some of its ethnopharmacologial uses such as treatment of wounds and dermatitis. Study Design: Volatile oil isolation, component identification and antimicrobial activity. Place and Duration of Study: Faculty of Pharmacy, Ain Shams University, the flowers were collected on 15 April 2012 and the study is completed within four months. Methodology: The essential oil of the flowers of Jacaranda acutifolia was extracted by hydrodistillation, analysed by capillary gas chromatography (GC/FID) and gas chromatography–mass spectrometry (GC/MS). Antimicrobial activity was studied in vitro, this included both antibacterial activity against food-borne pathogens and antifungal activity using agar diffusion method. Results: Fourty seven components, comprising almost 84.33% of the total peak area, were identified in the analysis. The main components were n-dodecanoic acid (17.48%), ntetradecanoic acid (15.59%), n-hexadecanoic acid (10.98%), hexahydrofarnesyl acetone (8.2%), n-decanoic acid (7.9%), and nonacosane (7.71%). The oil showed significantly high in-vitro antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans with minimum inhibitory concentration (MIC) values ranging from 0.09 up to 1.09 mg, and moderate antimicrobial activity against Salmonella typhimurium and Shigella flexneri. The % potency of the oil was calculated as compared to standard antibiotics (penicillin, gentamycin and nystatin) and ranged from 9.77 up to 126.47%. Conclusion: The essential oil of Jacaranda acutifolia exhibited promising antimicrobial activity, and this makes its local traditional uses rational.

Volatile constituents of Dietes bicolor (Iridaceae) and their antimicrobial activity

Abstract Volatile oils from the leaves, flowers and rhizomes of Dietes bicolor (Steud.) Sweet ex Klatt (Iridaceae) were analyzed using GLC/FID and GLC/MS. A total of 84 compounds were identified accounting for 94.65, 95.63 and 87.09% in the hydrodistilled oils from flowers, leaves and rhizomes, respectively. Spathulenol (48.44%) represented the major component in the leaf oil, followed by dihydro-edulan I (6.25%), cubenol (6.00%) and τ-cadinol (5.90%). For the flower and rhizome oils, fatty acids, their esters, aliphatic hydrocarbons and their derivatives predominate. The antimicrobial activity of both leaf and flower oils was investigated against four bacteria in addition to four fungi using the micro-broth dilution method. The leaf oil showed a more potent antimicrobial activity as compared to the flower oil against most of the assessed bacteria and fungi, with higher activities against Gram- positive organisms showing MIC values of 115 and 460 μg/ml for Bacillus subtilis and Streptococcus pneumonia, respectively. Gram-negative bacteria were generally less susceptible (MIC > 2 mg/ml for both oils against Escherichia coli) and being completely ineffective against Pseudomonas aeruginosa. A relevant antifungal potency of the leaf oil against Geotrichum candidum and Syncephalastrum racemosum was also observed with MIC values of 115 and 920 μg/ml, respectively.

Saponins from Genus Albizia: Phytochemical and Biological Review

Albizia is a large genus that belongs to family Fabaceae; most of Albizia species are rich in triterpenoidal saponins. These species were used in folk medicine for the treatment of rheumatism, stomach ache, cough, diarrhea, wounds, and as an anthelmintic. Many pharmacological activities were reported for the fractions or extracts containing saponins. Also, various pharmacological activities were reported for the pure isolated saponins. This review focuses on the distribution of saponins among the different species of genus Albizia and their pharmacological activities.