Open Access Original Research Article

Antimicrobial Potential of the Crude Extracts and Peptide Fractions of Two Marine Molluscs: Tympanatonus fuscatus Var Radula (Linneaus) and Pachymelania aurita (Muller)

Eghianruwa Queensley, Omolaja Osoniyi, Adeyemo Stella, Maina Naomi, Imbuga Mabel

South Asian Research Journal of Natural Products, Page 1-10

Aims: This study was aimed at evaluating the antimicrobial potential of the alcohol and aqueous extracts as well as peptide fractions of T. fuscatus and P. aurita.

Place and Duration of Study: Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria.

Methodology: The antimicrobial activity of the whole body aqueous and acetone-methanol extracts of T.fuscatus Var Radula and P.aurita, collected from the Niger-Delta region of Nigeria, were evaluated based on inhibition zone diameter using the agar well diffusion method against ten bacterial isolates and C. albicans. These organisms were further used in the TLC bioautography experiment. The peptide fraction from the organic extracts of both organisms was obtained by Molecular sieve chromatography on Sephadex LH20. Peaks obtained were pooled and further analysed on TLC. A simple contact TLC bioautographic procedure was used to detect the number of antibacterial and antifungal peptides present in the extracts of both T. fuscatus and P. aurita.

Results: The aqueous extract of both T. fuscatus and P. aurita had no antimicrobial effect against the test microorganisms whereas the acetone-methanol extract showed broad-spectrum antibacterial activity against five bacterial isolates at the highest concentration (100 mg/ml). It also showed inhibition against C. albicans at this concentration (100 mg/ml).

All the peptides exhibited bactericidal activity against the five test bacterial isolates and bacteriostatic activity against C. albicans. This activity was denoted by inhibition of growth in the region in which the peptides on the TLC plate made contact with the agar containing the isolates.

Conclusion:  Further studies to effectively separate these peptide fractions into individual peptides and further investigate the antimicrobial activity of the individual peptides is required.

Open Access Original Research Article

Fagaramide and Pellitorine from the Stem Bark of Zanthoxylum zanthoxyloides and Their Antimicrobial Activities

P. J. Nna, T. A. Tor-Anyiin, J. O. Igoli

South Asian Research Journal of Natural Products, Page 1-8

Aim: Zanthoxylum zanthoxyloides is a plant of the family Rutaceae used for treating different ailments such as malaria, sickle cell anaemia, tuberculosis, paralysis and intestinal disorder due to the presence of some bioactive constituents. The present study was aimed at identifying and characterizing some of the active principles from the stem bark of the plant.

Places and Duration of Study: The isolation and characterization of the compounds was carried out at the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), University of Strathclyde, Glasgow, United Kingdom between October, 2018 to February, 2019 while the bioassay analysis was done at Ahmadu Bello University, Zaria, Nigeria.

Methodology: The stem bark powder was subjected to Soxhlet extraction with hexane to obtain the crude extract, which was fractionated on column using hexane, and ethyl acetate in increasing ratios. The isolated components were tested for their antimicrobial activities against some plants and animal pathogens at Ahmadu Bello University, Zaria, Nigeria.

Results: White crystals were obtained which on spectra analysis (IR, 1H-NMR, 13C-NMR, 2D-NMR) were identified as Fagaramide and Pellitorine The isolated compounds exhibited appreciable antimicrobial activities against some microbes, thus confirming the many ethnomedical uses of the plant.

Conclusion: The compounds isolated were identified as fagaramide and pellitorine. They showed moderate sensitivity towards the pathogens tested in the study.

Open Access Original Research Article

Antimicrobial, Antioxidant Activities and Phytochemical Screening of Extracts and Essential Oil of Cymbopogon schoenanthus Flowers

Loai Abd Elgadir Babiker, Muzamil Mahdi Abdel Hamid, Ahmed Hassan Arbab

South Asian Research Journal of Natural Products, Page 1-8

Introduction: Antibiotic resistance represents one of the major worldwide health problems.  Though many medicinal plants are traditionally used to treat microbial infections. The antimicrobial potential of Cymbopogon schoenanthus flowers has not been investigated yet. Furthermore, exploring novel antioxidants has been a major goal for the management of various human health problems.

Objectives: To evaluate in vitro antimicrobial and antioxidant activities as well as a phytochemical screening of Cymbopogon schoenanthus flowers extracts and essential oil.

Materials and Methods: The methanol, aqueous extracts and essential oil of Cymbopogon schoenanthus were tested for antimicrobial activity against standard gram positives bacteria (Staphylococcus aureus and Bacillus subtilis), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and fungus of Candida albicans.  Antioxidant activity was determined by using DPPH radical scavenging assay, and then extracts were subjected to qualitative phytochemical screening for the major secondary metabolites.

Results: Extracts and volatile oils showed promising activities against standard microorganisms with inhibition zone values 20-14 mm/20µL and minimum inhibitory concertation values 3.12 to 12.5 mg/ml. The highest activity was associated with methanol extract and volatile oil. Antioxidant activity found in order; methanol extract > aqueous extract > essential oil with DPPH radical scavenging activity (%) 77.0 ± 0.06, 64.0 ± 0.03, 40.0 ± 0.04 respectively. Phytochemical screening indicates the presence of, alkaloids, tannins, flavonoids, saponins, steroids, and triterpenes.

Conclusion: Cymbopogon schoenanthus flowers extract and volatile oils showed promising antimicrobial and antioxidant activities.  However, a detailed phytochemical study of these extracts and the essential oil is essential to standardize the extract and isolate the active principle(s) responsible for their activities.

Open Access Original Research Article

Method Development and Validation for the Estimation of Valerenic Acid Content in Valerian Tablets Using RP-HPLC Method

M. Sahiti, B. M. Gurupadayya

South Asian Research Journal of Natural Products, Page 1-9

Valerian (Valeriana officinalis) has been used from so long as a traditional medicine since it has therapeutic effects such as enhances sleep, acts as an anxiolytic for nervous unrest etc. For determining the dose of herbal formulations and to estimate the quality of dosage form, we need to develop an effective reproducible validated method for the determination of the bioactive molecules essential for the sedative activity of the valerian tablets. So, the primary objective of the present work was to develop an efficient and sensitive method for the determination of valerenic acid content in valerian tablets using reverse-phase high-performance liquid chromatography technique. Since it is RP-HPLC method the column used was Phenomenex C18 Luna® 5 µm (250 x 4.6mm) column. The LC system used was Shimadzu UFLC, Nexera series utilizing a Photo-diode Array detector (SPD-M20A) detector and the software used was LC Solutions. The mobile phase used is acetonitrile: Ortho-phosphoric -acid in the ratio of 97:3 v/v. Ortho-phosphoric acid (gradient mode) employed was of 5% solution with a pH of 3.5. The chromatographic conditions employed are 1ml/min flow rate and absorbances were observed at 220 nm. The selected chromatographic conditions were found to give effective separation of Valerenic acid at 4.4±0.2 min. Validation was carried out for linearity, system suitability, accuracy, precision (intra-day and inter-day), and robustness, the limit of detection and limit of quantification which were found to be within acceptable limits according to ICH Guidelines. Thus, the method proposed was found to be accurate, precise, reproducible and analyte-specific. In this work, based on the observations made from the literature review a relatively best suitable method was developed for the estimation of valerenic acid in valerian tablets with shortened retention time along with better resolution thus, reducing the wastage of solvents and the time of analysis.

Open Access Original Research Article

Poly-3-hydroxybutyrate Biosynthesis by Bacillus megaterium Utilizing a Pleustophytic Ecological Plague in the Legendary Source of River Nile as the Sole Carbon Source

Timothy Omara, Immaculate Mbabazi, Lucy Nyambura Karanja, Decrah Moraa Nyangena, Papias Nteziyaremye, Abigael Jepchirchir

South Asian Research Journal of Natural Products, Page 1-8

Environmental isolates, genetically manipulated organisms, plants, animals and their products and economical methods are being expertly explored to biosynthesize poly-3-hydroxybutyrate plastics of comparable properties to petroplastics. This study assessed a hypothesized feasibility of utilizing water hyacinth (Eichhornia crassipes (Mart.) Solms-Laubach) from Lake Victoria (Uganda) as a potential carbon source for poly-3-hydroxybutyrate biosynthesis. The poly-3-hydroxybutyrate biosynthesizing bacteria (Bacillus megaterium) was isolated from municipal sewage sludge and harnessed for batch fermentation of acid-catalysed water hyacinth biomass. Poly-3-hydroxybutyrate formed in the cytoplasm of the bacterial cells was extracted by chloroform extraction method, and thereof confirmed and quantified by UV spectroscopy. Batch fermentation was carried out in 100 ml of the culture media for different times (48, 96, 144 and 192 h) to determine the best incubation time for maximum yield. A maximum yield of 61.3% was realized after 96 h of fermentation beyond which the bioplastic yield started decreasing. Utilization of this ecological plague for poly-3-hydroxybutyrate biosynthesis is a promising strategy for regulating the weed population along the length of River Nile and the Victorian basin.