Spectroscopic monitoring of cannabinoids in glandular trichomes of selected Cannabis sativa strains and their biological activities

Title : Spectroscopic monitoring of cannabinoids in glandular trichomes of selected Cannabis sativa strains and their biological activities

Abstract:

This study presents a comprehensive chemical composition and biological properties using the in-vitro and the molecular docking approach of three South African-cultivated strains of C. sativa (Cheese 1, Cheese 2, and JB1) with a view to developing medicinal relevant strains. Biological evaluations demonstrated robust antioxidant activity across extracts, with notable total phenolic content (TPC) and total flavonoid content (TFC). The CH1 ethyl acetate extract recorded the highest TPC (93.51 ± 1.8 mg QAE/g), followed by JB1 ethanol (40.06 ± 0.3 mg QAE/g), while CH2 ethanol displayed the highest TFC (45.95 ± 1.8 mg QE/g). DPPH (2,2-Diphenyl-1-picrylhydrazyl) and FRAP (Ferric Reducing Antioxidant Power) assays showed that antioxidant activity was both strain- and solvent-dependent. DPPH scavenging activity exhibited concentration-dependent reductions in absorbance, with CH1 ethyl acetate extract exhibiting the most potent radical scavenging capacity (IC50 = 0.01 mg/mL), while CH2 methanol extract showed the strongest reducing capacity (IC50 = 51.47 µg/mL) for the FRAP analysis. These results support the role of polyphenols and cannabinoid–terpene interactions in redox modulation. Antidiabetic evaluation of the extracts using the α-amylase, α-glucosidase, pancreatic lipase inhibitory, and glucose uptake assays further revealed significant antidiabetic inhibitory properties of the extracts. Extracts across all strains exhibited varying degrees of enzyme inhibition, with some surpassing the reference drug. Antimicrobial assays demonstrated concentration-dependent inhibitory effects, with zones of inhibition ranging from 12.5 mm to 28.5 mm at 100mg/mL, against selected Gram-positive (B. cereus and S. aureus) and Gram-negative bacteria (E. coli and S. Typhi). Cytotoxicity assessment using the MTT assay further demonstrated the selective anticancer potential of the extracts. MCF-7 breast cancer cells showed greater sensitivity (ranging from 22.32 - 79.6%; 25 -250 µg/mL) compared to RAW 264.7 (1.35 - 76.9%; 25 -250 µg/mL) macrophages, indicating preferential cytotoxicity toward malignant cells. Polar extracts exhibited stronger, dose-dependent inhibition, whereas hexane extracts displayed the weakest activity. Non-monotonic dose-response patterns suggest complex interactions involving both cytotoxic and cytoprotective phytochemicals, reflecting the intrinsic synergy within crude extracts. 
Keywords: Cannabis sativa, Endocannabinoid system, Cannabinoids, taxonomy, Extraction, TLC, FTIR, GC-MS, Antioxidant activity, Antidiabetic activity, Antimicrobial activity, Phytochemical profiling 

Biography:

Moses Fanyana Mtunzi holds a PhD in Chemistry from North-West University and an Advanced Diploma in Higher Education from the University of the Free State. He is a committed academic with extensive experience in both teaching and research. He joined Vaal University of Technology in 2008 after serving for four years as a lecturer at North-West University, Mafikeng Campus, South Africa. He has published 153 peer-reviewed journal articles and has successfully supervised six PhD graduates, co-supervised four PhD candidates, and hosted four postdoctoral fellows. In addition, he has supervised more than ten master’s students and over 80 B.Tech students. He is currently supervising four PhD and four master’s candidates. He is presently serving as the Acting Manager of the Institute of Chemical and Biotechnology (ICBT) at the Vaal University of Technology. Over the years, he has contributed to academic leadership as Research Coordinator in the Department of Chemistry for five years, member of the Faculty Research Committee, member of the Senate Library Committee, and Coordinator of Organic Chemistry within the department. He has also served as an external examiner for Master’s and PhD theses at several South African universities, including UNISA, UJ, WSU, UL, Sefako Makgatho Health Sciences University, and the University of Zululand. His research focuses on phytochemistry and drug discovery. He has presented at more than 12 international and 20 national conferences. His research excellence has been recognized through several awards, including second and third positions in the VUT Faculty and University Research Awards (2016) and first position in the Faculty Research Awards (2020). From 2019 to 2021, he secured R1.23 million (R410,000 annually) in research funding from SASOL for a project on the removal of water contaminants using biomass. In 2018, he received R20,000 travel funding from the National Research Foundation (NRF) to present his research at a conference in Mauritius.