Date of Award


Document Type


Degree Name

MS in Chemistry



First Advisor

David P Brown

Second Advisor

Enju Wang

Third Advisor

Francisco Vazquez


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.

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