- Title
- Bioprospectin of medicinal cannabis from Eastern Cape, South Africa
- Creator
- Odieka, Anwuli, Endurance
- Subject
- Organic chemistry
- Date Issued
- 2024-02
- Date
- 2024-02
- Type
- Doctoral theses
- Type
- text
- Identifier
- http://hdl.handle.net/11260/9427
- Identifier
- vital:73532
- Description
- Cannabis sativa L. (Family Cannabaceae) has continued to attract much interest among natural product scientists in recent time because of its known medicinal values and remarkable chemical diversity. This study reports the investigation of C. sativa cultivated in the Eastern Cape Province of South Africa, with a view to obtaining its chemical fingerprint and isolating compounds from its stem bark for possible biological applications. Fresh and dried leaves, flowers, stem barks and roots of two Cannabis cultivars were obtained under permit NO. PIA-HP-EC-2022-0023. The fresh and dried plant materials were extracted for their essential oils (EOs), using hydro-distillation method on a Clevenger apparatus set at optimum extraction condition. The EOs were characterized by a gas chromatography coupled to a mass spectrometer (GC-MS). The chemical components of the EOs were elucidated based on their retention indices, as well as with reference to literature report. Other portions of the dried leaf, inflorescence and stem bark of each cultivar were extracted with methanol. The methanol extract was profiled for its cannabinoid content using liquid chromatography mass spectrometry (LCMS) based metabolomics approach, with reference to standard cannabinoids (∆9-THC, ∆9-THCA, and CBD). Lastly, the dried stem bark of Cultivar II was investigated for its compounds. The stem bark powder was subjected to sequential extraction at room temperature with n-hexane, dichloromethane, ethyl acetate and methanol. Based on the TLC analysis, the afforded n-hexane and ethyl acetate extracts were further individually fractionated on a repeated column chromatography, using silica gel and Sephadex LH20 as stationary phases. The column fractionation process led to the isolation of seven compounds, E1-E4, A20, A21, and A23. The isolated compounds were characterized by spectroscopic and spectrometric methods on nuclear magnetic resonance (NMR) spectrometer and ultra high-performance liquid chromatography hyphenated to a mass spectrometer, respectively. The results from the study showed that the EOs of the C. sativa cultivars contain majorly sesquiterpenes in their oxygenated and non-oxygenated forms. Caryophyllene (0.6421.4%), caryophyllene oxide (1.27-20.34%), -pinene (0.35-13.21%), D-limonene (0.51-10.99%), humulene (0.37-10.56%), humulene-1,2-epoxide (0.45-5.98%), pinene (0.16-5.22%), nerolidol (0.32-4.99%), -myrcene (0.31-4.23%), -selinene (0.92-2.51%), and trans--bergamotene (0.50-2.70%), were the main terpene constituents of the EOs in both cultivars. Neutral cannabinoids were also detected in both cultivars with cannabidiol found in significant amount up to 85.03% in the fresh stem oil (LSO) of Cultivar I (Lifter). LC-MS fingerprints revealed that Cultivar I had the highest accumulation of cannabinoids with CBDA having the highest amount (88.65%) in the stembark and CBD at about 23% in the leaves. The inflorescence (flower) contained 51.55% of CBDA. Cultivar II had the least number of cannabinoids but contains the highest amount of ∆9-THCA (94.8%) in the leaf sample. Cultivar II showed ∆9-THCA and ∆9-THC dominant profiles with less than 2% of ∆8-THC. ∆9-THC, ∆8- THC were the only neutral cannabinoids detected in Cultivar II while CBD, ∆9-THC, and ∆8- THC were found in significant amounts in Cultivar I. The compounds isolated from the stem bark of Cultivar II were elucidated as five triterpenoids: Sativalenic acid ethyl ester (E1), Phyllanthone (E2), Friedelin (E3), Sativalonone (A20) and Sativaol (A23); an alkaloid, Sativacherine (E4); and a fatty acid ester, Ethyl stearate (A21). Four of these compounds are newly described, while all the compounds are reported for the first time from the Eastern Cape Cultivar (Cherrywine) of C. sativa stem.
- Description
- Thesis (PHD) -- Faculty of Natural Sciences, 2024
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (250 leaves)
- Format
- Publisher
- Walter Sisulu University
- Publisher
- Faculty of Natural Sciences
- Language
- English
- Rights
- Walter Sisulu University
- Rights
- All Rights Reserved
- Rights
- Open Access
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | ODIEKA_ THESIS Final.pdf | 6 MB | Adobe Acrobat PDF | View Details Download |