ORCID
https://orcid.org/0000-0003-3251-6477
Date of Award
2023
Document Type
Thesis
Degree Name
MS in Chemistry
Department
Chemistry
First Advisor
David P Brown
Second Advisor
Enju Wang
Third Advisor
Francisco Vazquez
Abstract
Chloroform, Ethanol and Methanol extracts of the leaves from DIGITARIA SANGUINALIS, DIGITARIA ISCHAEMUM and the bark from CARAPA GUIANENSIS found in Guyana were obtained via maceration and reflux extraction processes. Ethanol extracts obtained from the 25-minute reflux process produced the best percentage yield and the most thin layer chromatographic spots. All further analyses were conducted on the ethanol extracts of all plant materials. The ethanolic extracts showed positive phytochemical testing results for Terpenes, Flavonoids, Steroids, Tannins, Phenolic, Proteins, Cardiac Glycoside, Reducing Sugars, and Carbohydrates. Conversely, Saponins were absent in Smooth Crabgrass and Crabwood’s bark but present in Long Hairy Crabgrass. A mixture of elution solvents used in the column separation yielded 250, 128 and 188 fractions for Smooth Crabgrass, Long Hairy Crabgrass, and Crabwood’s bark respectively. These were analyzed with TLC and pooled into 27 fractions for Smooth Crabgrass, 26 for Long Hairy Crabgrass and 22 for Crabwood’s bark. GC – MS analyses of these fractions resulted in 682 NIST hits. Medicinal uses of the NIST compounds range from anti-inflammatory, insect repellent, skin moisturizer, antioxidant, antibacterial, anticancer, antidiabetic, anthelmintic, expectorant, antifungal, cholesterol lowering, treatment for acne. Some of these compounds are Eucalyptol, Isolongifolan-8-ol, Limonen-6-ol, pivalate, Estra-1,3,5(10)-trien-17β-ol, Ethyl iso-allocholate, Cryptomeridiol, γ-Sitostenone, Stigmasterol, Levodopa, Glycidyl palmitate, 2-Myristynoyl-glycinamide, Androst-5-en-4-one, Cholestan-3-one, Retinol, acetate, Linoleic acid ethyl ester, Neophytadiene, Vitamin E, Geranyl isovalerate, Melibiose, and d-Mannose. Antimicrobial Assay against; STAPHYLOCOCCUS AUREUS, STAPHYLOCOCCUS EPIDERMIS, ESCHERICHIA COLI, PSEUDOMONAS AERUGINOSA and CANDIDA ALBICANS were conducted via Disc Diffusion and Agar Well methods. Crabwood’s bark ethanol extract showed a positive indication of growth inhibition against STAPHYLOCOCCUS AUREUS and STAPHYLOCOCCUS EPIDERMIS in both antimicrobial testing methods, while Smooth crabgrass indicated inhibition for only STAPHYLOCOCCUS EPIDERMIS in the Disc diffusion assay.
Recommended Citation
Khelawan, Rajendra Kumar, "PHYTOCHEMICAL SCREENING, CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITIES OF ETHANOL, METHANOL AND CHLOROFORM EXTRACTS FROM THE LEAVES OF DIGITARIA SANGUINALIS, DIGITARIA ISCHAEMUM AND THE BARK OF CARAPA GUIANENSIS FOUND IN GUYANA, SOUTH AMERICA." (2023). Theses and Dissertations. 540.
https://scholar.stjohns.edu/theses_dissertations/540